module Rbzlib
rbrzlib – pure ruby version of 'zlib' general purpose compression library version 1.2.3, July 18th, 2005
Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler
This software is provided 'as-is', without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions:
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The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
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Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
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This notice may not be removed or altered from any source distribution.
Jean-loup Gailly Mark Adler jloup@gzip.org madler@alumni.caltech.edu
The data format used by the zlib library is described by RFCs (Request for Comments) 1950 to 1952 in the files www.ietf.org/rfc/rfc1950.txt (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
Ruby translation Copyright (C) 2009 by Park Heesob phasis@gmail.com
Constants
- ASCII_FLAG
- BASE
- BL_CODES
- BUSY_STATE
- Buf_size
- COMMENT_
- COMMENT_STATE
- Code
- Config
- Ct_data
- DEF_MEM_LEVEL
- DEF_WBITS
- DISTS
- DIST_CODE_LEN
- DYN_TREES
- D_CODES
- Deflate_state
- END_BLOCK
- ENOUGH
- EQUAL
- EXTRA_FIELD
- EXTRA_STATE
- FINISH_STATE
- Gz_header
- Gz_stream
- HCRC_STATE
- HEAD_CRC
- HEAP_SIZE
- INIT_STATE
- Inflate_copyright
- Inflate_state
- LENGTH_CODES
- LITERALS
- L_CODES
- MAXBITS
- MAXD
- MAX_BITS
- MAX_BL_BITS
- MAX_MATCH
- MAX_MEM_LEVEL
- MAX_WBITS
- MIN_LOOKAHEAD
- MIN_MATCH
- NAME_STATE
- NMAX
- ORIG_NAME
- OS_CODE
- PRESET_DICT
- REPZ_11_138
- REPZ_3_10
- REP_3_6
- RESERVED
- SEEK_CUR
- SEEK_END
- SEEK_SET
- SMALLEST
- STATIC_TREES
- STORED_BLOCK
- SYNC
- Static_tree_desc
- TOO_FAR
- Tree_desc
- ZLIB_VERSION
- ZNIL
- Z_ASCII
- Z_BEST_COMPRESSION
- Z_BEST_SPEED
- Z_BINARY
- Z_BLOCK
- Z_BUFSIZE
- Z_BUF_ERROR
- Z_DATA_ERROR
- Z_DEFAULT_COMPRESSION
- Z_DEFAULT_STRATEGY
- Z_DEFLATED
- Z_EOF
- Z_ERRNO
- Z_FILTERED
- Z_FINISH
- Z_FIXED
- Z_FULL_FLUSH
- Z_HUFFMAN_ONLY
- Z_MEM_ERROR
- Z_NEED_DICT
- Z_NO_COMPRESSION
- Z_NO_FLUSH
- Z_OK
- Z_PARTIAL_FLUSH
- Z_RLE
- Z_STREAM_END
- Z_STREAM_ERROR
- Z_SYNC_FLUSH
- Z_TEXT
- Z_UNKNOWN
- Z_VERSION_ERROR
- Z_errbase
- Z_stream
Public Instance Methods
Return the low n bits of the bit accumulator (n < 16)
# File lib/pr/rbzlib.rb, line 4187 def BITS(n) (@@hold & ((1 << (n)) - 1)) end
Remove zero to seven bits as needed to go to a byte boundary
# File lib/pr/rbzlib.rb, line 4198 def BYTEBITS() @@hold >>= @@bits & 7 @@bits -= @@bits & 7 end
compute crc
# File lib/pr/rbzlib.rb, line 4124 def CRC2(check, word) hbuf = 0.chr * 2 hbuf[0] = (word & 0xff).chr hbuf[1] = ((word >> 8) & 0xff).chr check = crc32(check, hbuf) end
compute crc
# File lib/pr/rbzlib.rb, line 4132 def CRC4(check, word) hbuf = 0.chr * 4 hbuf[0] = (word & 0xff).chr hbuf[1] = ((word >> 8) & 0xff).chr hbuf[2] = ((word >> 16) & 0xff).chr hbuf[3] = ((word >> 24) & 0xff).chr check = crc32(check, hbuf) end
Remove n bits from the bit accumulator
# File lib/pr/rbzlib.rb, line 4192 def DROPBITS(n) @@hold >>= (n) @@bits -= (n) end
Flush the current block, with given end-of-file flag. IN assertion: strstart is set to the end of the current match.
# File lib/pr/rbzlib.rb, line 2233 def FLUSH_BLOCK_ONLY(s,eof) if (s.block_start >= (0)) _tr_flush_block(s, s.window[(s.block_start)..-1], ((s.strstart) - s.block_start), eof) else _tr_flush_block(s, nil, ((s.strstart) - s.block_start), eof) end s.block_start = s.strstart flush_pending(s.strm) end
Clear the input bit accumulator
# File lib/pr/rbzlib.rb, line 4162 def INITBITS() @@hold = 0 @@bits = 0 end
Insert string str in the dictionary and set match_head to the previous head of the hash chain (the most recent string with same hash key). Return the previous length of the hash chain. If this file is compiled with -DFASTEST, the compression level is forced to 1, and no hash chains are maintained. IN assertion: all calls to to INSERT_STRING
are made with consecutive
input characters and the first MIN_MATCH bytes of str are valid (except for the last MIN_MATCH-1 bytes of the input file).
# File lib/pr/rbzlib.rb, line 1309 def INSERT_STRING(s,str,match_head) s.ins_h = ((s.ins_h << s.hash_shift) ^ (s.window[str + 2].ord)) & s.hash_mask match_head = s.head[s.ins_h] s.prev[(str) & s.w_mask] = match_head s.head[s.ins_h] = str return match_head end
Load registers with state in inflate() for speed
# File lib/pr/rbzlib.rb, line 4142 def LOAD(strm,state) @@put = strm.next_out @@left = strm.avail_out @@next = strm.next_in @@have = strm.avail_in @@hold = state.hold @@bits = state.bits end
Assure that there are at least n bits in the bit accumulator. If there is not enough available input to do that, then return from inflate().
# File lib/pr/rbzlib.rb, line 4180 def NEEDBITS(n) while (@@bits < (n)) PULLBYTE() end end
Get a byte of input into the bit accumulator, or return from inflate() if there is no input available.
# File lib/pr/rbzlib.rb, line 4169 def PULLBYTE() throw :inf_leave if @@have == 0 @@have -= 1 @@next.get @@hold += (@@next.get) << @@bits @@next += 1 @@bits += 8 end
Restore state from registers in inflate()
# File lib/pr/rbzlib.rb, line 4152 def RESTORE(strm,state) strm.next_out = @@put strm.avail_out = @@left strm.next_in = @@next strm.avail_in = @@have state.hold = @@hold state.bits = @@bits end
Reverse the bytes in a 32-bit value
# File lib/pr/rbzlib.rb, line 4204 def REVERSE(q) ((((q) >> 24) & 0xff) + (((q) >> 8) & 0xff00) + (((q) & 0xff00) << 8) + (((q) & 0xff) << 24)) end
check function to use adler32() for zlib or crc32() for gzip
# File lib/pr/rbzlib.rb, line 4119 def UPDATE(state, check, buf) state.flags != 0 ? crc32(check, buf) : adler32(check, buf) end
Send one empty static block to give enough lookahead for inflate. This takes 10 bits, of which 7 may remain in the bit buffer. The current inflate code requires 9 bits of lookahead. If the last two codes for the previous block (real code plus EOB) were coded on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode the last real code. In this case we send two empty static blocks instead of one. (There are no problems if the previous block is stored or fixed.) To simplify the code, we assume the worst case of last real code encoded on one bit only.
# File lib/pr/rbzlib.rb, line 3193 def _tr_align(s) send_bits(s, STATIC_TREES << 1, 3) send_bits(s, @@static_ltree[END_BLOCK].fc, @@static_ltree[END_BLOCK].dl) bi_flush(s) if (1 + s.last_eob_len + 10 - s.bi_valid < 9) send_bits(s, STATIC_TREES << 1, 3) send_bits(s, @@static_ltree[END_BLOCK].fc, @@static_ltree[END_BLOCK].dl) bi_flush(s) end s.last_eob_len = 7 end
Determine the best encoding for the current block: dynamic trees, static
trees or store, and output the encoded block to the zip file.
# File lib/pr/rbzlib.rb, line 3259 def _tr_flush_block(s,buf,stored_len,eof) max_blindex = 0 if (s.level > 0) if (stored_len>0 && s.strm.data_type == Z_UNKNOWN) set_data_type(s) end build_tree(s, s.l_desc) build_tree(s, s.d_desc) max_blindex = build_bl_tree(s) opt_lenb = (s.opt_len+3+7) >> 3 static_lenb = (s.static_len+3+7) >> 3 if (static_lenb <= opt_lenb) opt_lenb = static_lenb end else static_lenb = stored_len + 5 opt_lenb = static_lenb end if (stored_len+4 <= opt_lenb) && buf _tr_stored_block(s, buf, stored_len, eof) elsif (s.strategy == Z_FIXED || static_lenb == opt_lenb) send_bits(s, (STATIC_TREES << 1)+(eof ? 1 : 0), 3) compress_block(s, @@static_ltree, @@static_dtree) else send_bits(s, (DYN_TREES << 1)+(eof ? 1 : 0), 3) send_all_trees(s, s.l_desc.max_code+1, s.d_desc.max_code+1, max_blindex+1) compress_block(s, s.dyn_ltree, s.dyn_dtree) end init_block(s) bi_windup(s) if eof end
Initialize the tree data structures for a new zlib stream.
# File lib/pr/rbzlib.rb, line 2780 def _tr_init(s) s.l_desc = Tree_desc.new s.l_desc.dyn_tree = s.dyn_ltree s.l_desc.stat_desc = @@static_l_desc s.d_desc = Tree_desc.new s.d_desc.dyn_tree = s.dyn_dtree s.d_desc.stat_desc = @@static_d_desc s.bl_desc = Tree_desc.new s.bl_desc.dyn_tree = s.bl_tree s.bl_desc.stat_desc = @@static_bl_desc s.bi_buf = 0 s.bi_valid = 0 s.last_eob_len = 8 init_block(s) end
Send a stored block
# File lib/pr/rbzlib.rb, line 3159 def _tr_stored_block(s,buf,stored_len,eof) send_bits(s, (STORED_BLOCK << 1) + (eof ? 1 : 0), 3) copy_block(s, buf, stored_len, true) end
Save the match info and tally the frequency counts. Return true if
the current block must be flushed.
# File lib/pr/rbzlib.rb, line 3299 def _tr_tally(s,dist,lc) s.d_buf[s.last_lit] = dist s.l_buf[s.last_lit] = lc s.last_lit+=1 if dist == 0 s.dyn_ltree[lc].fc+=1 else s.matches+=1 dist-=1 code = (dist < 256) ? @@_dist_code[dist] : @@_dist_code[256+(dist >> 7)] s.dyn_ltree[@@_length_code[lc]+LITERALS+1].fc += 1 s.dyn_dtree[code].fc += 1 end (s.last_lit == s.lit_bufsize-1) end
Compute the Adler-32 checksum of a data stream
# File lib/pr/rbzlib.rb, line 262 def adler32(adler, buf, len=0) return 1 if buf.nil? len = buf.length if len == 0 sum2 = (adler >> 16) & 0xFFFF adler &= 0xffff if len == 1 adler += buf[0].ord if adler >= BASE adler -= BASE end sum2 += adler if sum2 >= BASE sum2 -= BASE end return adler | (sum2 << 16) end if len < 16 i = 0 while len > 0 len -= 1 adler += buf[i].ord i += 1 sum2 += adler end if adler >= BASE adler -= BASE end sum2 %= BASE return adler | (sum2 << 16) end i = 0 while len >= NMAX len -= NMAX n = NMAX / 16 loop do for j in 0 .. 15 adler += buf[i+j].ord sum2 += adler end i += 16 n -= 1 break if n == 0 end adler %= BASE sum2 %= BASE end if len != 0 while (len >= 16) len -= 16 for j in 0 .. 15 adler += buf[i+j].ord sum2 += adler end i += 16 end while len != 0 len -= 1 adler += buf[i].ord i += 1 sum2 += adler end adler %= BASE sum2 %= BASE end return adler | (sum2 << 16) end
Flush the bit buffer, keeping at most 7 bits in it.
# File lib/pr/rbzlib.rb, line 3166 def bi_flush(s) if (s.bi_valid == 16) s.pending_buf[s.pending] = (s.bi_buf & 0xff) s.pending += 1 s.pending_buf[s.pending] = (s.bi_buf >> 8) s.pending += 1 s.bi_buf = 0 s.bi_valid = 0 elsif (s.bi_valid >= 8) s.pending_buf[s.pending] = s.bi_buf s.pending += 1 s.bi_buf >>= 8 s.bi_valid -= 8 end end
Reverse the first len bits of a code, using straightforward code (a faster method would use a table) IN assertion: 1 <= len <= 15
# File lib/pr/rbzlib.rb, line 2725 def bi_reverse(code,len) res = 0 loop do res |= (code & 1) code >>= 1 res <<= 1 len -= 1 break if len<=0 end res >> 1 end
Flush the bit buffer and align the output on a byte boundary
# File lib/pr/rbzlib.rb, line 3119 def bi_windup(s) if (s.bi_valid > 8) s.pending_buf[s.pending] = s.bi_buf & 0xff s.pending+=1 s.pending_buf[s.pending] = s.bi_buf >> 8 s.pending+=1 elsif (s.bi_valid > 0) s.pending_buf[s.pending] = s.bi_buf s.pending+=1 end s.bi_buf = 0 s.bi_valid = 0 end
Construct the Huffman tree for the bit lengths and return the index in bl_order of the last bit length code to send.
# File lib/pr/rbzlib.rb, line 3086 def build_bl_tree(s) scan_tree(s, s.dyn_ltree, s.l_desc.max_code) scan_tree(s, s.dyn_dtree, s.d_desc.max_code) build_tree(s, s.bl_desc) max_blindex = 0 (BL_CODES-1).downto(3) do |i| max_blindex = i break if s.bl_tree[@@bl_order[i]].dl != 0 end s.opt_len += 3*(max_blindex+1) + 5+5+4 max_blindex end
Construct one Huffman tree and assigns the code bit strings and lengths. Update the total bit length for the current block. IN assertion: the field freq is set for all tree elements. OUT assertions: the fields len and code are set to the optimal bit length
and corresponding code. The length opt_len is updated; static_len is also updated if stree is not null. The field max_code is set.
# File lib/pr/rbzlib.rb, line 2903 def build_tree(s,desc) tree = desc.dyn_tree stree = desc.stat_desc.static_tree elems = desc.stat_desc.elems max_code = -1 s.heap_len = 0 s.heap_max = HEAP_SIZE for n in 0 ... elems if tree[n].fc != 0 max_code = n s.heap_len+=1 s.heap[s.heap_len] = n s.depth[n] = 0 else tree[n].dl = 0 end end while (s.heap_len < 2) s.heap_len+=1 if (max_code < 2) max_code+=1 s.heap[s.heap_len] = max_code node = max_code else s.heap[s.heap_len] = 0 node = 0 end tree[node].fc = 1 s.depth[node] = 0 s.opt_len-=1 if stree s.static_len -= stree[node].dl end end desc.max_code = max_code (s.heap_len / 2).downto(1) do |nheap| pqdownheap(s, tree, nheap) end node = elems loop do n = s.heap[SMALLEST] s.heap[SMALLEST] = s.heap[s.heap_len] s.heap_len-=1 pqdownheap(s, tree, SMALLEST) m = s.heap[SMALLEST] s.heap_max-=1 s.heap[s.heap_max] = n s.heap_max-=1 s.heap[s.heap_max] = m tree[node].fc = tree[n].fc + tree[m].fc if (s.depth[n] >= s.depth[m]) s.depth[node] = s.depth[n] + 1 else s.depth[node] = s.depth[m] + 1 end tree[m].dl = node tree[n].dl = node s.heap[SMALLEST] = node node+=1 pqdownheap(s, tree, SMALLEST) break if (s.heap_len < 2) end s.heap_max-=1 s.heap[s.heap_max] = s.heap[SMALLEST] gen_bitlen(s, desc) gen_codes(tree, max_code, s.bl_count) end
Check the gzip header of a gz_stream opened for reading. Set the stream mode to transparent if the gzip magic header is not present; set s->err to Z_DATA_ERROR
if the magic header is present but the rest of the header is incorrect.
IN assertion: the stream s has already been created sucessfully;
s->stream.avail_in is zero for the first time, but may be non-zero for concatenated .gz files.
# File lib/pr/rbzlib.rb, line 679 def check_header(s) len = s.stream.avail_in if len < 2 if len != 0 s.inbuf[0] = s.stream.next_in[0] end begin buf = s.file.read(Z_BUFSIZE >> len) if buf s.inbuf[len,buf.length] = buf len = buf.length else len = 0 end rescue len = 0 s.z_err = Z_ERRNO end s.stream.avail_in += len s.stream.next_in = Bytef.new(s.inbuf) if s.stream.avail_in < 2 s.transparent = !s.stream.avail_in == 0 return end end if s.stream.next_in[0] != @@gz_magic[0].ord || s.stream.next_in[1] != @@gz_magic[1].ord then s.transparent = true return end s.stream.avail_in -= 2 s.stream.next_in += 2 method = get_byte(s) flags = get_byte(s) if (method != Z_DEFLATED) || (flags & RESERVED) != 0 s.z_err = Z_DATA_ERROR return end for len in 0 .. 5 get_byte(s) end if (flags & EXTRA_FIELD) != 0 len = (get_byte(s)) len += ((get_byte(s)) << 8) while len != 0 || (get_byte(s) != Z_EOF) len -= 1 end end if (flags & ORIG_NAME) != 0 loop do c = get_byte(s) break if c == 0 || (c == Z_EOF) end end if (flags & COMMENT_) != 0 loop do c = get_byte(s) break if c == 0 || (c == Z_EOF) end end if (flags & HEAD_CRC) != 0 get_byte(s) get_byte(s) end s.z_err = s.z_eof ? Z_DATA_ERROR : Z_OK end
Check that the match at match_start is indeed a match.
# File lib/pr/rbzlib.rb, line 2161 def check_match(s,start, match,length) end
# File lib/pr/rbzlib.rb, line 3357 def compress(dest,destLen,source,sourceLen) return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION) end
Compresses the source buffer into the destination buffer. The level
parameter has the same meaning as in deflateInit. sourceLen is the byte length of the source buffer. Upon entry, destLen is the total size of the destination buffer, which must be at least 0.1% larger than sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
memory, Z_BUF_ERROR
if there was not enough room in the output buffer, Z_STREAM_ERROR
if the level parameter is invalid.
# File lib/pr/rbzlib.rb, line 3326 def compress2(dest,destLen,source,sourceLen,level) stream = Z_stream.new stream.next_in = Bytef.new(source) stream.avail_in = sourceLen stream.next_out = Bytef.new(dest) stream.avail_out = destLen if (stream.avail_out != destLen) return [Z_BUF_ERROR,destLen] end err = deflateInit(stream, level) if (err != Z_OK) return [err,destLen] end err = deflate(stream, Z_FINISH) if (err != Z_STREAM_END) deflateEnd(stream) if err == Z_OK return [Z_BUF_ERROR,destLen] else return [err,destLen] end end destLen = stream.total_out err = deflateEnd(stream) return [err,destLen] end
Send the block data compressed using the given Huffman trees
# File lib/pr/rbzlib.rb, line 3223 def compress_block(s,ltree,dtree) lx = 0 if s.last_lit != 0 loop do dist = s.d_buf[lx] lc = s.l_buf[lx] lx+=1 if dist == 0 send_bits(s, ltree[lc].fc, ltree[lc].dl) else code = @@_length_code[lc] send_bits(s, ltree[code+LITERALS+1].fc, ltree[code+LITERALS+1].dl) extra = @@extra_lbits[code] if extra != 0 lc -= @@base_length[code] send_bits(s, lc, extra) end dist-=1 code = (dist < 256) ? @@_dist_code[dist] : @@_dist_code[256+(dist >> 7)] send_bits(s, dtree[code].fc, dtree[code].dl) extra = @@extra_dbits[code] if extra != 0 dist-= @@base_dist[code] send_bits(s, dist, extra) end end break if (lx >= s.last_lit) end end send_bits(s, ltree[END_BLOCK].fc, ltree[END_BLOCK].dl) s.last_eob_len = ltree[END_BLOCK].dl end
Copy a stored block, storing first the length and its one's complement if requested.
# File lib/pr/rbzlib.rb, line 3135 def copy_block(s,buf,len,header) bi_windup(s) s.last_eob_len = 8 if header s.pending_buf[s.pending] = len & 0xff s.pending+=1 s.pending_buf[s.pending] = len >> 8 s.pending+=1 s.pending_buf[s.pending] = ((~len) & 0xff) s.pending+=1 s.pending_buf[s.pending] = ((~len) >> 8) & 0xff s.pending+=1 end i = 0 while len != 0 len-=1 s.pending_buf[s.pending] = buf[i].ord i+=1 s.pending+=1 end end
Compute the CRC-32 of a data stream.
# File lib/pr/rbzlib.rb, line 408 def crc32(crc, buf, len=0) return 0 if buf.nil? len = buf.length if len == 0 crc = crc ^ 0xffffffff i = 0 while len >= 8 while i < 8 crc = @@crc_table[(crc ^ buf[i].ord) & 0xff] ^ (crc >> 8) i += 1 end len -= 8 end if len != 0 loop do crc = @@crc_table[(crc ^ buf[i].ord) & 0xff] ^ (crc >> 8) i += 1 len -= 1 break if len == 0 end end crc ^ 0xffffffff end
# File lib/pr/rbzlib.rb, line 1604 def deflate(strm,flush) if strm.state.nil? || (flush > Z_FINISH) || (flush < 0) return Z_STREAM_ERROR end s = strm.state if strm.next_out.nil? || (strm.next_in.nil? && strm.avail_in != 0) || ((s.status == FINISH_STATE) && (flush != Z_FINISH)) strm.msg = @@z_errmsg[Z_errbase - Z_STREAM_ERROR] return Z_STREAM_ERROR end if strm.avail_out == 0 strm.msg = @@z_errmsg[Z_errbase - Z_BUF_ERROR] return Z_BUF_ERROR end s.strm = strm old_flush = s.last_flush s.last_flush = flush if (s.status == INIT_STATE) if (s.wrap == 2) strm.adler = crc32(0,nil) s.pending_buf[s.pending] = 31 s.pending+=1 s.pending_buf[s.pending] = 139 s.pending+=1 s.pending_buf[s.pending] = 8 s.pending+=1 if s.gzhead.nil? s.pending_buf[s.pending] = 0 s.pending+=1 s.pending_buf[s.pending] = 0 s.pending+=1 s.pending_buf[s.pending] = 0 s.pending+=1 s.pending_buf[s.pending] = 0 s.pending+=1 s.pending_buf[s.pending] = 0 s.pending+=1 s.pending_buf[s.pending] = (s.level==9) ? 2 : (s.strategy >= Z_HUFFMAN_ONLY || s.level < 2 ? 4 : 0) s.pending+=1 else c = (s.gzhead.text ? 1 : 0) + (s.gzhead.hcrc ? 2 : 0) + (s.gzhead.extra.nil? ? 0 : 4) + (s.gzhead.name.nil? ? 0 : 8) + (s.gzhead.comment.nil? ? 0 : 16) s.pending_buf[s.pending] = c s.pending+=1 c = s.gzhead.time & 0xff s.pending_buf[s.pending] = c s.pending+=1 c = (s.gzhead.time >> 8) & 0xff s.pending_buf[s.pending] = c s.pending+=1 c = (s.gzhead.time >> 16) & 0xff s.pending_buf[s.pending] = c s.pending+=1 c = (s.gzhead.time >> 24) & 0xff s.pending_buf[s.pending] = c s.pending+=1 c = s.level == 9 ? 2 : (s.strategy >= Z_HUFFMAN_ONLY || s.level < 2 ? 4 : 0) s.pending_buf[s.pending] = c s.pending+=1 c = s.gzhead.os & 0xff s.pending_buf[s.pending] = c s.pending+=1 if s.gzhead.extra c = s.gzhead.extra_len & 0xff s.pending_buf[s.pending] = c s.pending+=1 c = (s.gzhead.extra_len >> 8) & 0xff s.pending_buf[s.pending] = c s.pending+=1 end if (s.gzhead.hcrc) strm.adler = crc32(strm.adler, s.pending_buf.buffer, s.pending) s.gzindex = 0 s.status = EXTRA_STATE end end else header = (Z_DEFLATED + ((s.w_bits-8) << 4)) << 8 if (s.strategy >= Z_HUFFMAN_ONLY || s.level < 2) level_flags = 0 elsif (s.level < 6) level_flags = 1 elsif (s.level == 6) level_flags = 2 else level_flags = 3 end header |= (level_flags << 6) if s.strstart != 0 header |= PRESET_DICT end header += 31 - (header % 31) s.status = BUSY_STATE putShortMSB(s, header) if s.strstart != 0 putShortMSB(s, (strm.adler >> 16)) putShortMSB(s, (strm.adler & 0xffff)) end strm.adler = adler32(0,nil) end end if (s.status == EXTRA_STATE) if s.gzhead.extra beg = s.pending while (s.gzindex < (s.gzhead.extra_len & 0xffff)) if (s.pending == s.pending_buf_size) if (s.gzhead.hcrc && s.pending > beg) strm.adler = crc32(strm.adler, s.pending_buf.buffer[beg,s.pending - beg]) end flush_pending(strm) beg = s.pending break if (s.pending == s.pending_buf_size) end s.pending_buf[s.pending] = s.gzhead.extra[s.gzindex] s.pending+=1 s.gzindex+=1 end if (s.gzhead.hcrc && s.pending > beg) strm.adler = crc32(strm.adler, s.pending_buf[beg,s.pending - beg]) end if (s.gzindex == s.gzhead.extra_len) s.gzindex = 0 s.status = NAME_STATE end else s.status = NAME_STATE end end if (s.status == NAME_STATE) if s.gzhead.name beg = s.pending loop do if (s.pending == s.pending_buf_size) if (s.gzhead.hcrc && s.pending > beg) strm.adler = crc32(strm.adler, s.pending_buf.buffer[beg,s.pending - beg]) end flush_pending(strm) beg = s.pending if (s.pending == s.pending_buf_size) val = 1 break end end val = s.gzhead.name[s.gzindex] s.gzindex+=1 s.pending_buf[s.pending] = val s.pending+=1 break if val == 0 end if (s.gzhead.hcrc && s.pending > beg) strm.adler = crc32(strm.adler, s.pending_buf.buffer[beg,s.pending - beg]) end if val == 0 s.gzindex = 0 s.status = COMMENT_STATE end else s.status = COMMENT_STATE end end if (s.status == COMMENT_STATE) if s.gzhead.comment beg = s.pending loop do if (s.pending == s.pending_buf_size) if (s.gzhead.hcrc && s.pending > beg) strm.adler = crc32(strm.adler, s.pending_buf.buffer[beg,s.pending - beg]) end flush_pending(strm) beg = s.pending if (s.pending == s.pending_buf_size) val = 1 break end end val = s.gzhead.comment[s.gzindex] s.gzindex+=1 s.pending_buf[s.pending] = val s.pending+=1 break if val == 0 end if (s.gzhead.hcrc && s.pending > beg) strm.adler = crc32(strm.adler, s.pending_buf.buffer[beg,s.pending - beg]) end if val == 0 s.status = HCRC_STATE end else s.status = HCRC_STATE end end if (s.status == HCRC_STATE) if (s.gzhead.hcrc) if (s.pending + 2 > s.pending_buf_size) flush_pending(strm) end if (s.pending + 2 <= s.pending_buf_size) s.pending_buf[s.pending] = strm.adler & 0xff s.pending+=1 s.pending_buf[s.pending] = (strm.adler >> 8) & 0xff s.pending+=1 strm.adler = crc32(0, nil) s.status = BUSY_STATE end else s.status = BUSY_STATE end end if s.pending != 0 flush_pending(strm) if strm.avail_out == 0 s.last_flush = -1 return Z_OK end elsif strm.avail_in == 0 && (flush <= old_flush) && (flush != Z_FINISH) strm.msg = @@z_errmsg[Z_errbase - Z_BUF_ERROR] return Z_BUF_ERROR end if (s.status == FINISH_STATE) && strm.avail_in != 0 strm.msg = @@z_errmsg[Z_errbase - Z_BUF_ERROR] return Z_BUF_ERROR end if strm.avail_in != 0 || s.lookahead != 0 || ((flush != Z_NO_FLUSH) && (s.status != FINISH_STATE)) bstate = send(@@configuration_table[s.level].func, s, flush) if (bstate == :finish_started) || (bstate == :finish_done) s.status = FINISH_STATE end if (bstate == :need_more) || (bstate == :finish_started) if strm.avail_out == 0 s.last_flush = -1 end return Z_OK end if (bstate == :block_done) if (flush == Z_PARTIAL_FLUSH) _tr_align(s) else _tr_stored_block(s, nil, (0), false) if (flush == Z_FULL_FLUSH) s.head = Array.new(s.hash_size,0) s.head[s.hash_size-1] = ZNIL end end flush_pending(strm) if strm.avail_out == 0 s.last_flush = -1 return Z_OK end end end if (flush != Z_FINISH) return Z_OK end if (s.wrap <= 0) return Z_STREAM_END end if (s.wrap == 2) s.pending_buf[s.pending] = strm.adler & 0xff s.pending+=1 s.pending_buf[s.pending] = (strm.adler >> 8) & 0xff s.pending+=1 s.pending_buf[s.pending] = (strm.adler >> 16) & 0xff s.pending+=1 s.pending_buf[s.pending] = (strm.adler >> 24) & 0xff s.pending+=1 s.pending_buf[s.pending] = strm.total_in & 0xff s.pending+=1 s.pending_buf[s.pending] = (strm.total_in >> 8) & 0xff s.pending+=1 s.pending_buf[s.pending] = (strm.total_in >> 16) & 0xff s.pending+=1 s.pending_buf[s.pending] = (strm.total_in >> 24) & 0xff s.pending+=1 else putShortMSB(s, (strm.adler >> 16)) putShortMSB(s, (strm.adler & 0xffff)) end flush_pending(strm) s.wrap = -s.wrap if (s.wrap > 0) return s.pending != 0 ? Z_OK : Z_STREAM_END end
For the default windowBits of 15 and memLevel of 8, this function returns a close to exact, as well as small, upper bound on the compressed size. They are coded as constants here for a reason–if the define's are changed, then this function needs to be changed as well. The return value for 15 and 8 only works for those exact settings.
For any setting other than those defaults for windowBits and memLevel, the value returned is a conservative worst case for the maximum expansion resulting from using fixed blocks instead of stored blocks, which deflate can emit on compressed data for some combinations of the parameters.
This function could be more sophisticated to provide closer upper bounds for every combination of windowBits and memLevel, as well as wrap. But even the conservative upper bound of about 14% expansion does not seem onerous for output buffer allocation.
# File lib/pr/rbzlib.rb, line 1555 def deflateBound(strm, sourceLen) destLen = sourceLen + ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11 if (strm.nil? || strm.state.nil?) return destLen end s = strm.state if (s.w_bits != 15 || s.hash_bits != 8 + 7) return destLen end return compressBound(sourceLen) end
Copy the source state to the destination state. To simplify the source, this is not supported for 16-bit MSDOS (which doesn't have enough memory anyway to duplicate compression states).
# File lib/pr/rbzlib.rb, line 1938 def deflateCopy(dest,source) if source.nil? || dest.nil? || source.state.nil? return Z_STREAM_ERROR end ss = (source.state) dest = source.dup ds = Deflate_state.new dest.state = ds ds = ss.dup ds.strm = dest ds.window = ss.window.dup ds.prev = ss.prev.dup ds.head = ss.head.dup ds.pending_buf = ss.pending_buf.dup ds.pending_buf.buffer = ss.pending_buf.buffer.dup ds.pending_out = Bytef.new(ds.pending_buf,ss.pending_out.offset) ds.d_buf = Posf.new(ds.pending_buf,ds.lit_bufsize) ds.l_buf = Bytef.new(ds.pending_buf,(1+2) * ds.lit_bufsize) ds.l_desc.dyn_tree = ds.dyn_ltree ds.d_desc.dyn_tree = ds.dyn_dtree ds.bl_desc.dyn_tree = ds.bl_tree return Z_OK end
# File lib/pr/rbzlib.rb, line 1910 def deflateEnd(strm) if (strm.nil? || strm.state.nil?) return Z_STREAM_ERROR end s = strm.state status = s.status if (status != INIT_STATE && status != EXTRA_STATE && status != NAME_STATE && status != COMMENT_STATE && status != HCRC_STATE && status != BUSY_STATE && status != FINISH_STATE) return Z_STREAM_ERROR end strm.state = nil if status == BUSY_STATE return Z_DATA_ERROR else return Z_OK end end
# File lib/pr/rbzlib.rb, line 1406 def deflateInit(strm,level) deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY, ZLIB_VERSION,strm.size) end
# File lib/pr/rbzlib.rb, line 1392 def deflateInit2(strm,level,method,windowBits,memLevel,strategy) deflateInit2_(strm, level, method, windowBits, memLevel, strategy, ZLIB_VERSION,strm.size) end
Initialize the hash table (avoiding 64K overflow for 16 bit systems). prev[] will be initialized on the fly.
# File lib/pr/rbzlib.rb, line 1320 def deflateInit2_(strm,level,method,windowBits,memLevel,strategy,version,stream_size) wrap = 1 my_version = ZLIB_VERSION if (version == '') || (version[1] != my_version[1]) || (stream_size!=Z_stream.new.size) return Z_VERSION_ERROR end strm.msg = '' if (level == Z_DEFAULT_COMPRESSION) level = 6 end if (windowBits < 0) wrap = 0 windowBits = -windowBits elsif (windowBits > 15) wrap = 2 windowBits -= 16 end if (memLevel < 1) || (memLevel > MAX_MEM_LEVEL) || (method != Z_DEFLATED) || (windowBits < 8) || (windowBits > 15) || (level < 0) || (level > 9) || (strategy < 0) || (strategy > Z_FIXED) return Z_STREAM_ERROR end windowBits = 9 if(windowBits==8) s = Deflate_state.new s.dyn_ltree = Array.new(HEAP_SIZE).map{|i|Ct_data.new()} s.dyn_dtree = Array.new(2*D_CODES+1).map{|i|Ct_data.new()} s.bl_tree = Array.new(2*BL_CODES+1).map{|i|Ct_data.new()} s.bl_count = Array.new(MAX_BITS+1,0) s.heap = Array.new(2*L_CODES+1,0) s.depth = Array.new(2*L_CODES+1,0) strm.state = s s.strm = strm s.wrap = wrap s.gzhead = nil s.w_bits = windowBits s.w_size = 1 << s.w_bits s.w_mask = s.w_size - 1 s.hash_bits = memLevel + 7 s.hash_size = 1 << s.hash_bits s.hash_mask = s.hash_size - 1 s.hash_shift = ((s.hash_bits+MIN_MATCH-1) / MIN_MATCH) s.window = 0.chr * (s.w_size * 2) s.prev = Array.new(s.w_size,0) s.head = Array.new(s.hash_size,0) s.lit_bufsize = 1 << (memLevel + 6) overlay = 0.chr * (s.lit_bufsize * (2+2)) s.pending_buf = Bytef.new(overlay) s.pending_buf_size = (s.lit_bufsize) * (2+2) if s.window.nil? || s.prev.nil? || s.head.nil? || s.pending_buf.nil? s.status = FINISH_STATE strm.msg = @@z_errmsg[Z_errbase-Z_MEM_ERROR] deflateEnd(strm) return Z_MEM_ERROR end s.d_buf = Posf.new(overlay,s.lit_bufsize) s.l_buf = Bytef.new(overlay,(1+2) * s.lit_bufsize) s.level = level s.strategy = strategy s.method = method deflateReset(strm) end
# File lib/pr/rbzlib.rb, line 1397 def deflateInit_(strm,level,version,stream_size) if strm.nil? return Z_STREAM_ERROR else return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY, version, stream_size) end end
# File lib/pr/rbzlib.rb, line 1497 def deflateParams(strm,level,strategy) err = Z_OK if strm.state.nil? return Z_STREAM_ERROR end s = strm.state if (level == Z_DEFAULT_COMPRESSION) level = 6 end if (level < 0) || (level > 9) || (strategy < 0) || (strategy > Z_HUFFMAN_ONLY) return Z_STREAM_ERROR end func = @@configuration_table[s.level].func if (func != @@configuration_table[level].func) && strm.total_in != 0 err = deflate(strm, Z_PARTIAL_FLUSH) end if (s.level != level) s.level = level s.max_lazy_match = @@configuration_table[level].max_lazy s.good_match = @@configuration_table[level].good_length s.nice_match = @@configuration_table[level].nice_length s.max_chain_length = @@configuration_table[level].max_chain end s.strategy = strategy return err end
# File lib/pr/rbzlib.rb, line 1487 def deflatePrime(strm,bits,value) if (strm.nil? || strm.state.nil?) return Z_STREAM_ERROR end strm.state.bi_valid = bits strm.state.bi_buf = (value & ((1<<bits)-1)) return Z_OK end
# File lib/pr/rbzlib.rb, line 1449 def deflateReset(strm) if (strm.nil? || strm.state.nil?) return Z_STREAM_ERROR end strm.total_out = 0 strm.total_in = 0 strm.msg = '' strm.data_type = Z_UNKNOWN s = strm.state s.pending = 0 s.pending_out = Bytef.new(s.pending_buf) if (s.wrap < 0) s.wrap = -s.wrap end s.status = s.wrap != 0 ? INIT_STATE : BUSY_STATE strm.adler = (s.wrap==2) ? crc32(0,nil) : adler32(0,nil) s.last_flush = Z_NO_FLUSH _tr_init(s) lm_init(s) return Z_OK end
# File lib/pr/rbzlib.rb, line 1412 def deflateSetDictionary(strm,dictionary,dictLength) length = dictLength offset = 0 hash_head = 0 if (strm.nil? || strm.state.nil? || dictionary.nil? || strm.state.wrap==2 || (strm.state.wrap==1 && strm.state.status != INIT_STATE)) return Z_STREAM_ERROR end s = strm.state strm.adler = adler32(strm.adler, dictionary,dictLength) if s.wrap != 0 if (length < MIN_MATCH) return Z_OK end _MAX_DIST = (s.w_size - MIN_LOOKAHEAD) if (length > _MAX_DIST) length = _MAX_DIST offset += dictLength - length end s.window[0,length] = dictionary[offset,length] s.strstart = length s.block_start = length s.ins_h = s.window[0].ord s.ins_h = ((s.ins_h << s.hash_shift) ^ (s.window[1].ord)) & s.hash_mask for n in 0 .. (length - MIN_MATCH) hash_head = INSERT_STRING(s, n, hash_head) end return Z_OK end
# File lib/pr/rbzlib.rb, line 1477 def deflateSetHeader(strm,head) if (strm.nil? || strm.state.nil?) return Z_STREAM_ERROR end return Z_STREAM_ERROR if(strm.state.wrap != 2) strm.state.gzhead = head return Z_OK end
# File lib/pr/rbzlib.rb, line 1528 def deflateTune(strm, good_length, max_lazy, nice_length, max_chain) if (strm.nil? || strm.state.nil?) return Z_STREAM_ERROR end s = strm.state s.good_match = good_length s.max_lazy_match = max_lazy s.nice_match = nice_length s.max_chain_length = max_chain return Z_OK end
Compress as much as possible from the input stream, return the current block state. This function does not perform lazy evaluation of matches and inserts new strings in the dictionary only for unmatched strings or for short matches. It is used only for the fast compression options.
# File lib/pr/rbzlib.rb, line 2311 def deflate_fast(s,flush) hash_head = ZNIL loop do if (s.lookahead < MIN_LOOKAHEAD) fill_window(s) if (s.lookahead < MIN_LOOKAHEAD) && (flush == Z_NO_FLUSH) return :need_more end break if s.lookahead == 0 end if (s.lookahead >= MIN_MATCH) hash_head = INSERT_STRING(s, s.strstart, hash_head) end if (hash_head != ZNIL) && (s.strstart - hash_head <= (s.w_size-MIN_LOOKAHEAD)) if (s.strategy != Z_HUFFMAN_ONLY && s.strategy != Z_RLE) s.match_length = longest_match(s, hash_head) elsif(s.strategy == Z_RLE && s.srstart - hash_end == 1) s.match_length = longest_match_fast(s, hash_head) end end if (s.match_length >= MIN_MATCH) bflush = _tr_tally(s, s.strstart - s.match_start, s.match_length - MIN_MATCH) s.lookahead -= s.match_length if (s.match_length <= s.max_lazy_match) && (s.lookahead >= MIN_MATCH) s.match_length -= 1 loop do s.strstart += 1 hash_head = INSERT_STRING(s, s.strstart, hash_head) s.match_length -= 1 break if s.match_length == 0 end s.strstart += 1 else s.strstart += s.match_length s.match_length = 0 s.ins_h = s.window[s.strstart].ord s.ins_h = (( s.ins_h << s.hash_shift) ^ s.window[s.strstart+1].ord) & s.hash_mask end else bflush = _tr_tally(s, 0, s.window[s.strstart].ord) s.lookahead-=1 s.strstart+=1 end if bflush FLUSH_BLOCK_ONLY(s, false) if s.strm.avail_out == 0 return :need_more end end end FLUSH_BLOCK_ONLY(s, flush == Z_FINISH) if s.strm.avail_out == 0 if flush == Z_FINISH return :finish_started else return :need_more end end if flush == Z_FINISH return :finish_done else return :block_done end end
Same as above, but achieves better compression. We use a lazy evaluation for matches: a match is finally adopted only if there is no better match at the next window position.
# File lib/pr/rbzlib.rb, line 2389 def deflate_slow(s,flush) hash_head = ZNIL loop do if (s.lookahead < MIN_LOOKAHEAD) fill_window(s) if (s.lookahead < MIN_LOOKAHEAD) && (flush == Z_NO_FLUSH) return :need_more end break if s.lookahead == 0 end if (s.lookahead >= MIN_MATCH) hash_head = INSERT_STRING(s, s.strstart, hash_head) end s.prev_length = s.match_length s.prev_match = s.match_start s.match_length = MIN_MATCH-1 if (hash_head != ZNIL) && (s.prev_length < s.max_lazy_match) && (s.strstart - hash_head <= (s.w_size-MIN_LOOKAHEAD)) if (s.strategy != Z_HUFFMAN_ONLY && s.strategy != Z_RLE) s.match_length = longest_match(s, hash_head) elsif(s.strategy == Z_RLE && s.strstart - hash_head == 1) s.match_length = longest_match_fast(s, hash_head) end if (s.match_length <= 5) && ((s.strategy == Z_FILTERED) || ((s.match_length == MIN_MATCH) && (s.strstart - s.match_start > TOO_FAR))) s.match_length = MIN_MATCH-1 end end if (s.prev_length >= MIN_MATCH) && (s.match_length <= s.prev_length) max_insert = s.strstart + s.lookahead - MIN_MATCH bflush = _tr_tally(s, s.strstart - 1 - s.prev_match, s.prev_length - MIN_MATCH) s.lookahead -= s.prev_length-1 s.prev_length -= 2 loop do s.strstart+=1 if (s.strstart <= max_insert) hash_head = INSERT_STRING(s, s.strstart, hash_head) end s.prev_length-=1 break if s.prev_length == 0 end s.match_available = false s.match_length = MIN_MATCH-1 s.strstart+=1 if (bflush) FLUSH_BLOCK_ONLY(s, false) if s.strm.avail_out == 0 return :need_more end end elsif (s.match_available) bflush = _tr_tally(s, 0, s.window[s.strstart-1].ord) if bflush FLUSH_BLOCK_ONLY(s, false) end s.strstart+=1 s.lookahead-=1 if s.strm.avail_out == 0 return :need_more end else s.match_available = true s.strstart+=1 s.lookahead-=1 end end if (s.match_available) _tr_tally(s, 0, s.window[s.strstart-1].ord) s.match_available = false end FLUSH_BLOCK_ONLY(s, flush == Z_FINISH) if s.strm.avail_out == 0 if flush == Z_FINISH return :finish_started else return :need_more end end if flush == Z_FINISH return :finish_done else return :block_done end end
Copy without compression as much as possible from the input stream, return the current block state. This function does not insert new strings in the dictionary since uncompressible data is probably not useful. This function is used only for the level=0 compression option. NOTE: this function should be optimized to avoid extra copying from window to pending_buf.
# File lib/pr/rbzlib.rb, line 2253 def deflate_stored(s,flush) max_block_size = 0xffff if (max_block_size > s.pending_buf_size - 5) max_block_size = s.pending_buf_size - 5 end loop do if (s.lookahead <= 1) fill_window(s) if s.lookahead == 0 && (flush == Z_NO_FLUSH) return :need_more end break if s.lookahead == 0 end s.strstart += s.lookahead s.lookahead = 0 max_start = s.block_start + max_block_size if s.strstart == 0 || ((s.strstart) >= max_start) s.lookahead = (s.strstart - max_start) s.strstart = (max_start) FLUSH_BLOCK_ONLY(s, false) if s.strm.avail_out == 0 return :need_more end end if (s.strstart - (s.block_start) >= s.w_size-MIN_LOOKAHEAD) FLUSH_BLOCK_ONLY(s, false) if s.strm.avail_out == 0 return :need_more end end end FLUSH_BLOCK_ONLY(s, flush == Z_FINISH) if s.strm.avail_out == 0 if flush == Z_FINISH return :finish_started else return :need_more end end if flush == Z_FINISH return :finish_done else return :block_done end end
Cleanup then free the given gz_stream. Return a zlib error code.
# File lib/pr/rbzlib.rb, line 762 def destroy(s) err = Z_OK return Z_STREAM_ERROR if s.nil? if s.stream.state if s.mode == 'w' err = deflateEnd(s.stream) elsif s.mode == 'r' err = inflateEnd(s.stream) end end begin s.file.close if s.file s.file = nil rescue err = Z_ERRNO end if s.z_err < 0 err = s.z_err end return err end
Flushes all pending output into the compressed file. The parameter
flush is as in the deflate() function.
# File lib/pr/rbzlib.rb, line 1015 def do_flush(file,flush) done = false s = file if (s.nil?) || (s.mode != 'w') return Z_STREAM_ERROR end s.stream.avail_in = 0 loop do len = Z_BUFSIZE - s.stream.avail_out if len != 0 written = s.file.write(s.outbuf[0,len]) if (written != len) s.z_err = Z_ERRNO return Z_ERRNO end s.stream.next_out = Bytef.new(s.outbuf) s.stream.avail_out = Z_BUFSIZE end break if (done) s.out += s.stream.avail_out s.z_err = deflate(s.stream, flush) s.out -= s.stream.avail_out if len == 0 && (s.z_err == Z_BUF_ERROR) s.z_err = Z_OK end done = s.stream.avail_out != 0 || (s.z_err == Z_STREAM_END) break if (s.z_err != Z_OK) && (s.z_err != Z_STREAM_END) end if (s.z_err = Z_STREAM_END) return Z_OK else return s.z_err end end
Fill the window when the lookahead becomes insufficient. Updates strstart and lookahead.
IN assertion: lookahead < MIN_LOOKAHEAD
OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
At least one byte has been read, or avail_in == 0; reads are performed for at least two bytes (required for the zip translate_eol option -- not supported here).
# File lib/pr/rbzlib.rb, line 2172 def fill_window(s) wsize = s.w_size loop do more = s.window_size - s.lookahead - s.strstart if more == 0 && s.strstart == 0 && s.lookahead == 0 more = wsize elsif (more == (-1)) more -= 1 end if (s.strstart >= wsize+ (wsize-MIN_LOOKAHEAD)) s.window[0,wsize] = s.window[wsize,wsize] s.match_start -= wsize s.strstart -= wsize s.block_start -= wsize n = s.hash_size ap = n loop do ap -= 1 m = s.head[ap] if (m >= wsize) s.head[ap] = m-wsize else s.head[ap] = ZNIL end n -= 1 break if n == 0 end n = wsize ap = n loop do ap-=1 m = s.prev[ap] if (m >= wsize) s.prev[ap] = (m-wsize) else s.prev[ap] = ZNIL end n-=1 break if n == 0 end more += wsize end return if s.strm.avail_in == 0 n = read_buf(s.strm, s.window,(s.strstart + s.lookahead),more) s.lookahead += n if (s.lookahead >= MIN_MATCH) s.ins_h = s.window[s.strstart].ord s.ins_h = ((s.ins_h << s.hash_shift) ^ s.window[s.strstart+1].ord) & s.hash_mask end break if (s.lookahead >= MIN_LOOKAHEAD) || s.strm.avail_in == 0 end end
Return state with length and distance decoding tables and index sizes set to fixed code decoding. Normally this returns fixed tables from inffixed.h. If BUILDFIXED is defined, then instead this routine builds the tables the first time it's called, and returns those tables the first time and thereafter. This reduces the size of the code by about 2K bytes, in exchange for a little execution time. However, BUILDFIXED should not be used for threaded applications, since the rewriting of the tables and virgin may not be thread-safe.
# File lib/pr/rbzlib.rb, line 3975 def fixedtables(state) lenfix = [ [96,7,0],[0,8,80],[0,8,16],[20,8,115],[18,7,31],[0,8,112],[0,8,48], [0,9,192],[16,7,10],[0,8,96],[0,8,32],[0,9,160],[0,8,0],[0,8,128], [0,8,64],[0,9,224],[16,7,6],[0,8,88],[0,8,24],[0,9,144],[19,7,59], [0,8,120],[0,8,56],[0,9,208],[17,7,17],[0,8,104],[0,8,40],[0,9,176], [0,8,8],[0,8,136],[0,8,72],[0,9,240],[16,7,4],[0,8,84],[0,8,20], [21,8,227],[19,7,43],[0,8,116],[0,8,52],[0,9,200],[17,7,13],[0,8,100], [0,8,36],[0,9,168],[0,8,4],[0,8,132],[0,8,68],[0,9,232],[16,7,8], [0,8,92],[0,8,28],[0,9,152],[20,7,83],[0,8,124],[0,8,60],[0,9,216], [18,7,23],[0,8,108],[0,8,44],[0,9,184],[0,8,12],[0,8,140],[0,8,76], [0,9,248],[16,7,3],[0,8,82],[0,8,18],[21,8,163],[19,7,35],[0,8,114], [0,8,50],[0,9,196],[17,7,11],[0,8,98],[0,8,34],[0,9,164],[0,8,2], [0,8,130],[0,8,66],[0,9,228],[16,7,7],[0,8,90],[0,8,26],[0,9,148], [20,7,67],[0,8,122],[0,8,58],[0,9,212],[18,7,19],[0,8,106],[0,8,42], [0,9,180],[0,8,10],[0,8,138],[0,8,74],[0,9,244],[16,7,5],[0,8,86], [0,8,22],[64,8,0],[19,7,51],[0,8,118],[0,8,54],[0,9,204],[17,7,15], [0,8,102],[0,8,38],[0,9,172],[0,8,6],[0,8,134],[0,8,70],[0,9,236], [16,7,9],[0,8,94],[0,8,30],[0,9,156],[20,7,99],[0,8,126],[0,8,62], [0,9,220],[18,7,27],[0,8,110],[0,8,46],[0,9,188],[0,8,14],[0,8,142], [0,8,78],[0,9,252],[96,7,0],[0,8,81],[0,8,17],[21,8,131],[18,7,31], [0,8,113],[0,8,49],[0,9,194],[16,7,10],[0,8,97],[0,8,33],[0,9,162], [0,8,1],[0,8,129],[0,8,65],[0,9,226],[16,7,6],[0,8,89],[0,8,25], [0,9,146],[19,7,59],[0,8,121],[0,8,57],[0,9,210],[17,7,17],[0,8,105], [0,8,41],[0,9,178],[0,8,9],[0,8,137],[0,8,73],[0,9,242],[16,7,4], [0,8,85],[0,8,21],[16,8,258],[19,7,43],[0,8,117],[0,8,53],[0,9,202], [17,7,13],[0,8,101],[0,8,37],[0,9,170],[0,8,5],[0,8,133],[0,8,69], [0,9,234],[16,7,8],[0,8,93],[0,8,29],[0,9,154],[20,7,83],[0,8,125], [0,8,61],[0,9,218],[18,7,23],[0,8,109],[0,8,45],[0,9,186],[0,8,13], [0,8,141],[0,8,77],[0,9,250],[16,7,3],[0,8,83],[0,8,19],[21,8,195], [19,7,35],[0,8,115],[0,8,51],[0,9,198],[17,7,11],[0,8,99],[0,8,35], [0,9,166],[0,8,3],[0,8,131],[0,8,67],[0,9,230],[16,7,7],[0,8,91], [0,8,27],[0,9,150],[20,7,67],[0,8,123],[0,8,59],[0,9,214],[18,7,19], [0,8,107],[0,8,43],[0,9,182],[0,8,11],[0,8,139],[0,8,75],[0,9,246], [16,7,5],[0,8,87],[0,8,23],[64,8,0],[19,7,51],[0,8,119],[0,8,55], [0,9,206],[17,7,15],[0,8,103],[0,8,39],[0,9,174],[0,8,7],[0,8,135], [0,8,71],[0,9,238],[16,7,9],[0,8,95],[0,8,31],[0,9,158],[20,7,99], [0,8,127],[0,8,63],[0,9,222],[18,7,27],[0,8,111],[0,8,47],[0,9,190], [0,8,15],[0,8,143],[0,8,79],[0,9,254],[96,7,0],[0,8,80],[0,8,16], [20,8,115],[18,7,31],[0,8,112],[0,8,48],[0,9,193],[16,7,10],[0,8,96], [0,8,32],[0,9,161],[0,8,0],[0,8,128],[0,8,64],[0,9,225],[16,7,6], [0,8,88],[0,8,24],[0,9,145],[19,7,59],[0,8,120],[0,8,56],[0,9,209], [17,7,17],[0,8,104],[0,8,40],[0,9,177],[0,8,8],[0,8,136],[0,8,72], [0,9,241],[16,7,4],[0,8,84],[0,8,20],[21,8,227],[19,7,43],[0,8,116], [0,8,52],[0,9,201],[17,7,13],[0,8,100],[0,8,36],[0,9,169],[0,8,4], [0,8,132],[0,8,68],[0,9,233],[16,7,8],[0,8,92],[0,8,28],[0,9,153], [20,7,83],[0,8,124],[0,8,60],[0,9,217],[18,7,23],[0,8,108],[0,8,44], [0,9,185],[0,8,12],[0,8,140],[0,8,76],[0,9,249],[16,7,3],[0,8,82], [0,8,18],[21,8,163],[19,7,35],[0,8,114],[0,8,50],[0,9,197],[17,7,11], [0,8,98],[0,8,34],[0,9,165],[0,8,2],[0,8,130],[0,8,66],[0,9,229], [16,7,7],[0,8,90],[0,8,26],[0,9,149],[20,7,67],[0,8,122],[0,8,58], [0,9,213],[18,7,19],[0,8,106],[0,8,42],[0,9,181],[0,8,10],[0,8,138], [0,8,74],[0,9,245],[16,7,5],[0,8,86],[0,8,22],[64,8,0],[19,7,51], [0,8,118],[0,8,54],[0,9,205],[17,7,15],[0,8,102],[0,8,38],[0,9,173], [0,8,6],[0,8,134],[0,8,70],[0,9,237],[16,7,9],[0,8,94],[0,8,30], [0,9,157],[20,7,99],[0,8,126],[0,8,62],[0,9,221],[18,7,27],[0,8,110], [0,8,46],[0,9,189],[0,8,14],[0,8,142],[0,8,78],[0,9,253],[96,7,0], [0,8,81],[0,8,17],[21,8,131],[18,7,31],[0,8,113],[0,8,49],[0,9,195], [16,7,10],[0,8,97],[0,8,33],[0,9,163],[0,8,1],[0,8,129],[0,8,65], [0,9,227],[16,7,6],[0,8,89],[0,8,25],[0,9,147],[19,7,59],[0,8,121], [0,8,57],[0,9,211],[17,7,17],[0,8,105],[0,8,41],[0,9,179],[0,8,9], [0,8,137],[0,8,73],[0,9,243],[16,7,4],[0,8,85],[0,8,21],[16,8,258], [19,7,43],[0,8,117],[0,8,53],[0,9,203],[17,7,13],[0,8,101],[0,8,37], [0,9,171],[0,8,5],[0,8,133],[0,8,69],[0,9,235],[16,7,8],[0,8,93], [0,8,29],[0,9,155],[20,7,83],[0,8,125],[0,8,61],[0,9,219],[18,7,23], [0,8,109],[0,8,45],[0,9,187],[0,8,13],[0,8,141],[0,8,77],[0,9,251], [16,7,3],[0,8,83],[0,8,19],[21,8,195],[19,7,35],[0,8,115],[0,8,51], [0,9,199],[17,7,11],[0,8,99],[0,8,35],[0,9,167],[0,8,3],[0,8,131], [0,8,67],[0,9,231],[16,7,7],[0,8,91],[0,8,27],[0,9,151],[20,7,67], [0,8,123],[0,8,59],[0,9,215],[18,7,19],[0,8,107],[0,8,43],[0,9,183], [0,8,11],[0,8,139],[0,8,75],[0,9,247],[16,7,5],[0,8,87],[0,8,23], [64,8,0],[19,7,51],[0,8,119],[0,8,55],[0,9,207],[17,7,15],[0,8,103], [0,8,39],[0,9,175],[0,8,7],[0,8,135],[0,8,71],[0,9,239],[16,7,9], [0,8,95],[0,8,31],[0,9,159],[20,7,99],[0,8,127],[0,8,63],[0,9,223], [18,7,27],[0,8,111],[0,8,47],[0,9,191],[0,8,15],[0,8,143],[0,8,79], [0,9,255]].map{|i|Code.new(*i)} distfix = [ [16,5,1],[23,5,257],[19,5,17],[27,5,4097],[17,5,5],[25,5,1025], [21,5,65],[29,5,16385],[16,5,3],[24,5,513],[20,5,33],[28,5,8193], [18,5,9],[26,5,2049],[22,5,129],[64,5,0],[16,5,2],[23,5,385], [19,5,25],[27,5,6145],[17,5,7],[25,5,1537],[21,5,97],[29,5,24577], [16,5,4],[24,5,769],[20,5,49],[28,5,12289],[18,5,13],[26,5,3073], [22,5,193],[64,5,0]].map{|i|Code.new(*i)} state.lencode = Bytef.new(lenfix) state.lenbits = 9 state.distcode = Bytef.new(distfix) state.distbits = 5 end
Flush as much pending output as possible. All deflate() output goes through this function so some applications may wish to modify it to avoid allocating a large strm->next_out buffer and copying into it. (See also read_buf
()).
# File lib/pr/rbzlib.rb, line 1585 def flush_pending(strm) s = strm.state len = s.pending if (len > strm.avail_out) len = strm.avail_out end return if len == 0 strm.next_out.buffer[strm.next_out.offset,len] = s.pending_out.current[0,len] strm.next_out += len s.pending_out += len strm.total_out += len strm.avail_out -= len s.pending -= len if s.pending == 0 s.pending_out = Bytef.new(strm.state.pending_buf) end end
Compute the optimal bit lengths for a tree and update the total bit length for the current block. IN assertion: the fields freq and dad are set, heap and
above are the tree nodes sorted by increasing frequency.
OUT assertions: the field len is set to the optimal bit length, the
array bl_count contains the frequencies for each bit length. The length opt_len is updated; static_len is also updated if stree is not null.
# File lib/pr/rbzlib.rb, line 2832 def gen_bitlen(s,desc) tree = desc.dyn_tree max_code = desc.max_code stree = desc.stat_desc.static_tree extra = desc.stat_desc.extra_bits base = desc.stat_desc.extra_base max_length = desc.stat_desc.max_length overflow = 0 for bits in 0 .. MAX_BITS s.bl_count[bits] = 0 end tree[s.heap[s.heap_max]].dl = 0 for h in s.heap_max+1 ... HEAP_SIZE n = s.heap[h] bits = tree[tree[n].dl].dl + 1 if (bits > max_length) bits = max_length overflow+=1 end tree[n].dl = bits next if (n > max_code) s.bl_count[bits]+=1 xbits = 0 xbits = extra[n-base] if (n >= base) f = tree[n].fc s.opt_len += (f) * (bits + xbits) if stree s.static_len += (f) * (stree[n].dl + xbits) end end return if overflow == 0 loop do bits = max_length-1 bits -= 1 while s.bl_count[bits] == 0 s.bl_count[bits] -= 1 s.bl_count[bits+1] += 2 s.bl_count[max_length] -= 1 overflow -= 2 break if (overflow <= 0) end h = HEAP_SIZE max_length.downto(1) do |nbits| n = s.bl_count[nbits] while n != 0 h -= 1 m = s.heap[h] next if (m > max_code) if (tree[m].dl != nbits) s.opt_len += (nbits - tree[m].dl) * tree[m].fc tree[m].dl = nbits end n-=1 end end end
Generate the codes for a given tree and bit counts (which need not be optimal). IN assertion: the array bl_count contains the bit length statistics for the given tree and the field len is set for all tree elements. OUT assertion: the field code is set for all tree elements of non
zero code length.
# File lib/pr/rbzlib.rb, line 2743 def gen_codes(tree,max_code,bl_count) next_code = Array.new(MAX_BITS+1,0) code = 0 for bits in 1 .. MAX_BITS code = ((code + bl_count[bits-1]) << 1) next_code[bits] = code end for n in 0..max_code len = tree[n].dl next if len == 0 tree[n].fc = bi_reverse(next_code[len], len) next_code[len] += 1 end end
Reads a long in LSB order from the given gz_stream. Sets z_err in case of error.
# File lib/pr/rbzlib.rb, line 657 def getLong(s) x = 0.chr * 4 x[0] = (get_byte(s)).chr x[1] = (get_byte(s)).chr x[2] = (get_byte(s)).chr c = get_byte(s) x[3] = (c).chr s.z_err = Z_DATA_ERROR if (c == Z_EOF) return (x.unpack('v').first) end
Read a byte from a gz_stream; update next_in and avail_in. Return EOF for end of file. IN assertion: the stream s has been sucessfully opened for reading.
# File lib/pr/rbzlib.rb, line 629 def get_byte(s) return Z_EOF if s.z_eof if s.stream.avail_in == 0 begin s.inbuf = s.file.read(Z_BUFSIZE) s.stream.avail_in = s.inbuf.length if s.inbuf rescue s.inbuf = nil s.z_err = Z_ERRNO end if s.inbuf.nil? s.z_eof = true return Z_EOF end s.stream.next_in = Bytef.new(s.inbuf) end s.stream.avail_in-=1 _get_byte = s.stream.next_in.get s.stream.next_in+=1 return _get_byte end
Tables of CRC-32s of all single-byte values, made by make_crc_table().
# File lib/pr/rbzlib.rb, line 402 def get_crc_table @@crc_table end
Opens a gzip (.gz) file for reading or writing. The mode parameter is as in fopen (“rb” or “wb”). The file is given either by file descriptor or path name (if fd == -1).
gz_open
returns NULL if the file could not be opened or if there was insufficient memory to allocate the (de)compression state; errno can be checked to distinguish the two cases (if errno is zero, the zlib error is Z_MEM_ERROR
).
# File lib/pr/rbzlib.rb, line 479 def gz_open(path, mode, fd) return nil if path.nil? || mode.nil? s = Gz_stream.new s.stream = Z_stream.new level = Z_DEFAULT_COMPRESSION strategy = Z_DEFAULT_STRATEGY s.stream.next_in = nil s.stream.next_out = nil s.stream.avail_in = 0 s.stream.avail_out = 0 s.stream.msg = '' s.file = nil s.z_err = Z_OK s.z_eof = false s.inbuf = nil s.outbuf = nil s.in = 0 s.out = 0 s.back = Z_EOF s.crc = crc32(0, nil) s.msg = '' s.transparent = false s.path = path.dup s.mode = nil fmode = '' mode.each_byte do |c| s.mode = 'r' if c == ?r.ord s.mode = 'w' if c == ?w.ord || c == ?a.ord if c >= ?0.ord && c <= ?9.ord level = c - ?0.ord elsif c == ?f.ord strategy = Z_FILTERED elsif c == ?h.ord strategy = Z_HUFFMAN_ONLY elsif c == ?R.ord strategy = Z_RLE else fmode += c.chr end end if s.mode.nil? destroy(s) return nil end if s.mode == 'w' err = deflateInit2( s.stream, level, Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL, strategy ) s.outbuf = 0.chr * Z_BUFSIZE s.stream.next_out = Bytef.new(s.outbuf) if err != Z_OK || s.outbuf.nil? destroy(s) return nil end else s.inbuf = 0.chr * Z_BUFSIZE s.stream.next_in = Bytef.new(s.inbuf) err = inflateInit2_(s.stream, -MAX_WBITS, ZLIB_VERSION, s.stream.size) if err != Z_OK || s.inbuf.nil? destroy(s) return nil end end s.stream.avail_out = Z_BUFSIZE s.file = fd < 0 ? File.new(path, fmode) : IO.new(fd, fmode) if s.mode == 'w' gzheader = 0.chr * 10 gzheader[0] = @@gz_magic[0] gzheader[1] = @@gz_magic[1] gzheader[2] = Z_DEFLATED.chr gzheader[3] = 0.chr gzheader[4] = 0.chr gzheader[5] = 0.chr gzheader[6] = 0.chr gzheader[7] = 0.chr gzheader[8] = 0.chr gzheader[9] = OS_CODE.chr s.file.write(gzheader) s.start = 10 else check_header(s) s.start = s.file.pos - s.stream.avail_in end return s end
Clear the error and end-of-file flags, and do the same for the real file.
# File lib/pr/rbzlib.rb, line 1273 def gzclearerr(file) s = file return if s.nil? s.z_err = Z_OK if(s.z_err != Z_STREAM_END) s.z_eof = false end
Flushes all pending output if necessary, closes the compressed file and deallocates all the (de)compression state.
# File lib/pr/rbzlib.rb, line 1225 def gzclose(file) s = file if s.nil? return Z_STREAM_ERROR end if s.mode == 'w' err = do_flush(file, Z_FINISH) if err != Z_OK return destroy(f) end putLong(s.file, s.crc) putLong(s.file, s.in & 0xffffffff) end return destroy(file) end
Returns 1 if reading and doing so transparently, otherwise zero.
# File lib/pr/rbzlib.rb, line 1206 def gzdirect(file) s = file return false if (s.nil? || s.mode != 'r') return s.transparent end
Associate a gzFile with the file descriptor fd. fd is not dup'ed here to mimic the behavio(u)r of fdopen.
# File lib/pr/rbzlib.rb, line 596 def gzdopen(fd,mode) return nil if fd < 0 name = "<fd:#{fd}" return gz_open(name, mode, fd) end
Returns 1 when EOF has previously been detected reading the given
input stream, otherwise zero.
# File lib/pr/rbzlib.rb, line 1197 def gzeof(file) s = file return false if s.nil? || (s.mode!='r') return s.z_eof if s.z_eof return s.z_err == Z_STREAM_END end
Returns the error message for the last error which occurred on the
given compressed file. errnum is set to zlib error number. If an error occurred in the file system and not in the compression library, errnum is set to Z_ERRNO
and the application may consult errno
# File lib/pr/rbzlib.rb, line 1249 def gzerror(file,errnum) s = file if s.nil? errnum = Z_STREAM_ERROR return zError(Z_STREAM_ERROR) end errnum = s.z_err if (errnum == Z_OK) return zError(Z_OK) end m = s.stream.msg if (errnum == Z_ERRNO) m = '' end if (m == '') m = zError(s.z_err) end s.msg = s.path + ': ' + m return s.msg end
Flush output file.
# File lib/pr/rbzlib.rb, line 1060 def gzflush(file,flush) s = file err = do_flush(file, flush) if err != 0 return err end if (s.z_err == Z_STREAM_END) return Z_OK else return s.z_err end end
Reads one byte from the compressed file. gzgetc returns this byte or -1 in case of end of file or error.
# File lib/pr/rbzlib.rb, line 912 def gzgetc(file) c = 0.chr if (gzread(file,c,1) == 1) return c else return -1 end end
Reads bytes from the compressed file until len-1 characters are read, or a newline character is read and transferred to buf, or an end-of-file condition is encountered. The string is then terminated with a null character.
Returns buf, or Z_NULL in case of error.
# File lib/pr/rbzlib.rb, line 941 def gzgets(file,buf,len) return nil if buf.nil? || (len <= 0) i = 0 gzchar = 0.chr loop do len-=1 bytes = gzread(file, gzchar, 1) buf[i] = gzchar[0] i += 1 break if len == 0 || (bytes != 1) || (gzchar == (13).chr) end buf[i..-1] = '' buf.chomp!(0.chr) if i == 0 && (len > 0) return nil else return buf end end
Opens a gzip (.gz) file for reading or writing.
# File lib/pr/rbzlib.rb, line 589 def gzopen(path,mode) return gz_open(path, mode, -1) end
Writes c, converted to an unsigned char, into the compressed file.
gzputc returns the value that was written, or -1 in case of error.
# File lib/pr/rbzlib.rb, line 998 def gzputc(file,c) if (gzwrite(file,c,1) == 1) return c else return -1 end end
Writes the given null-terminated string to the compressed file, excluding
the terminating null character.
gzputs returns the number of characters written, or -1 in case of error.
# File lib/pr/rbzlib.rb, line 1009 def gzputs(file,s) return gzwrite(file,s,s.length) end
Reads the given number of uncompressed bytes from the compressed file. gzread returns the number of bytes actually read (0 for end of file).
# File lib/pr/rbzlib.rb, line 790 def gzread(file,buf,len) s = file start = Bytef.new(buf) if s.nil? || s.mode != 'r' return Z_STREAM_ERROR end return -1 if (s.z_err == Z_DATA_ERROR) || (s.z_err == Z_ERRNO) return 0 if (s.z_err == Z_STREAM_END) next_out = Bytef.new(buf) s.stream.next_out = Bytef.new(buf) s.stream.avail_out = len if s.stream.avail_out != 0 && s.back != Z_EOF next_out.set(s.back) next_out += 1 s.stream.next_out += 1 s.stream.avail_out -= 1 s.back = Z_EOF s.out += 1 start += 1 if s.last s.z_err = Z_STREAM_END return 1 end end while s.stream.avail_out != 0 if s.transparent n = s.stream.avail_in if n > s.stream.avail_out n = s.stream.avail_out end if n > 0 s.stream.next_out.buffer[s.stream.next_out.offset,n] = s.stream.next_in.current[0,n] next_out += n s.stream.next_out.offset = next_out.offset s.stream.next_in += n s.stream.avail_out -= n s.stream.avail_in -= n end if s.stream.avail_out > 0 buff = s.file.read(s.stream.avail_out) if buff next_out.buffer[next_out.offset,buff.length] = buff s.stream.avail_out -= buff.length end end len -= s.stream.avail_out s.in += len s.out += len if len == 0 s.z_eof = true end return len end if s.stream.avail_in == 0 && !s.z_eof begin buf = s.file.read(Z_BUFSIZE) if buf s.inbuf[0,buf.length] = buf s.stream.avail_in = buf.length else s.stream.avail_in = 0 end rescue s.z_err = Z_ERRNO end if s.stream.avail_in == 0 s.z_eof = true break if(s.z_err == Z_ERRNO) end s.stream.next_in = Bytef.new(s.inbuf) end s.in += s.stream.avail_in s.out += s.stream.avail_out s.z_err = inflate(s.stream, Z_NO_FLUSH) s.in -= s.stream.avail_in s.out -= s.stream.avail_out if s.z_err == Z_STREAM_END s.crc = crc32(s.crc, start.current,s.stream.next_out.offset - start.offset) start = s.stream.next_out.dup if getLong(s) != s.crc s.z_err = Z_DATA_ERROR else getLong(s) check_header(s) if s.z_err == Z_OK inflateReset(s.stream) s.crc = crc32(0, nil) end end end break if s.z_err != Z_OK || s.z_eof end s.crc = crc32(s.crc, start.current,s.stream.next_out.offset - start.offset) if len == s.stream.avail_out && (s.z_err == Z_DATA_ERROR || s.z_err = Z_ERRNO) return -1 end return len - s.stream.avail_out end
Rewinds input file.
# File lib/pr/rbzlib.rb, line 1076 def gzrewind(file) s = file if s.nil? || (s.mode != 'r') return -1 end s.z_err = Z_OK s.z_eof = false s.stream.avail_in = 0 s.stream.next_in = Bytef.new(s.inbuf) s.crc = crc32(0,nil) if !s.transparent inflateReset(s.stream) end s.in = 0 s.out = 0 return s.file.seek(s.start, SEEK_SET) end
Sets the starting position for the next gzread or gzwrite on the given
compressed file. The offset represents a number of bytes in the
gzseek returns the resulting offset location as measured in bytes from
the beginning of the uncompressed stream, or -1 in case of error.
SEEK_END is not implemented, returns error. In this version of the library, gzseek can be extremely slow.
# File lib/pr/rbzlib.rb, line 1102 def gzseek(file,offset,whence) s = file if s.nil? || (whence == SEEK_END) || (s.z_err == Z_ERRNO) || (s.z_err == Z_DATA_ERROR) return(-1) end if (s.mode == 'w') if (whence == SEEK_SET) offset -= s.in end if (offset < 0) return(-1) end if (s.inbuf.nil?) s.inbuf = 0.chr*Z_BUFSIZE end while (offset > 0) size = Z_BUFSIZE if (offset < Z_BUFSIZE) size = (offset) end size = gzwrite(file, s.inbuf, size) if size == 0 return(-1) end offset -= size end return(s.in) end if (whence == SEEK_CUR) offset += s.out end if (offset < 0) return(-1) end if s.transparent s.back = Z_EOF s.stream.avail_in = 0 s.stream.next_in = Bytef.new(s.inbuf) s.file.seek(offset, SEEK_SET) s.in = offset s.out = offset return offset end if (offset >= s.out) offset -= s.out elsif (gzrewind(file) < 0) return(-1) end if offset != 0 && s.outbuf.nil? s.outbuf = 0.chr * Z_BUFSIZE end if(offset != 0 && s.back != Z_EOF) s.back = Z_EOF s.out += 1 offset -= 1 s.z_err = Z_STREAM_END if s.last end while (offset > 0) size = Z_BUFSIZE if (offset < Z_BUFSIZE) size = (offset) end size = gzread(file, s.outbuf, size) if (size <= 0) return(-1) end offset -= size end return(s.out) end
Update the compression level and strategy
# File lib/pr/rbzlib.rb, line 604 def gzsetparams(file,level,strategy) s = file if s.nil? || s.mode != 'w' return Z_STREAM_ERROR end if s.stream.avail_out == 0 s.stream.next_out = Bytef.new(s.outbuf) written = s.file.write(s.outbuf) if written != Z_BUFSIZE s.z_err = Z_ERRNO end s.stream.avail_out = Z_BUFSIZE end return deflateParams(s.stream, level, strategy) end
Returns the starting position for the next gzread or gzwrite on the
given compressed file. This position represents a number of bytes in the uncompressed data stream.
# File lib/pr/rbzlib.rb, line 1191 def gztell(file) return gzseek(file, 0, SEEK_CUR) end
Push one byte back onto the stream.
# File lib/pr/rbzlib.rb, line 923 def gzungetc(c, file) s = file return Z_EOF if s.nil? || s.mode != 'r' || c == Z_EOF || s.back != Z_EOF s.back = c s.out -= 1 s.last = (s.z_err == Z_STREAM_END) s.z_err = Z_OK if s.last s.z_eof = false return c end
Writes the given number of uncompressed bytes into the compressed file.
gzwrite returns the number of bytes actually written (0 in case of error).
# File lib/pr/rbzlib.rb, line 967 def gzwrite(file,buf,len) s = file if s.nil? || (s.mode != 'w') return Z_STREAM_ERROR end s.stream.next_in = Bytef.new(buf) s.stream.avail_in = len while s.stream.avail_in != 0 if s.stream.avail_out == 0 s.stream.next_out = Bytef.new(s.outbuf) written = s.file.write(s.outbuf) if (written != Z_BUFSIZE) s.z_err = Z_ERRNO break end s.stream.avail_out = Z_BUFSIZE end s.in += s.stream.avail_in s.out += s.stream.avail_out s.z_err = deflate(s.stream, Z_NO_FLUSH) s.in -= s.stream.avail_in s.out -= s.stream.avail_out break if (s.z_err != Z_OK) end s.crc = crc32(s.crc, buf, len) return (len - s.stream.avail_in) end
inflate() uses a state machine to process as much input data and generate as much output data as possible before returning. The state machine is structured roughly as follows:
for (;;) switch (state) { ... case STATEn: if (not enough input data or output space to make progress) return; ... make progress ... state = STATEm; break; ... }
so when inflate() is called again, the same case is attempted again, and if the appropriate resources are provided, the machine proceeds to the next state. The NEEDBITS() macro is usually the way the state evaluates whether it can proceed or should return. NEEDBITS() does the return if the requested bits are not available. The typical use of the BITS
macros is:
NEEDBITS(n); ... do something with BITS(n) ... DROPBITS(n);
where NEEDBITS(n) either returns from inflate() if there isn't enough input left to load n bits into the accumulator, or it continues. BITS(n) gives the low n bits in the accumulator. When done, DROPBITS(n) drops the low n bits off the accumulator. INITBITS() clears the accumulator and sets the number of available bits to zero. BYTEBITS() discards just enough bits to put the accumulator on a byte boundary. After BYTEBITS() and a NEEDBITS(8), then BITS(8) would return the next byte in the stream.
NEEDBITS(n) uses PULLBYTE() to get an available byte of input, or to return if there is no input available. The decoding of variable length codes uses PULLBYTE() directly in order to pull just enough bytes to decode the next code, and no more.
Some states loop until they get enough input, making sure that enough state information is maintained to continue the loop where it left off if NEEDBITS() returns in the loop. For example, want, need, and keep would all have to actually be part of the saved state in case NEEDBITS() returns:
case STATEw: while (want < need) { NEEDBITS(n); keep[want++] = BITS(n); DROPBITS(n); } state = STATEx; case STATEx:
As shown above, if the next state is also the next case, then the break is omitted.
A state may also return if there is not enough output space available to complete that state. Those states are copying stored data, writing a literal byte, and copying a matching string.
When returning, a “goto inf_leave” is used to update the total counters, update the check value, and determine whether any progress has been made during that inflate() call in order to return the proper return code. Progress is defined as a change in either strm->avail_in or strm->avail_out. When there is a window, goto inf_leave will update the window with the last output written. If a goto inf_leave occurs in the middle of decompression and there is no window currently, goto inf_leave will create one and copy output to the window for the next call of inflate().
In this implementation, the flush parameter of inflate() only affects the return code (per zlib.h). inflate() always writes as much as possible to strm->next_out, given the space available and the provided input–the effect documented in zlib.h of Z_SYNC_FLUSH
. Furthermore, inflate() always defers the allocation of and copying into a sliding window until necessary, which provides the effect documented in zlib.h for Z_FINISH
when the entire input stream available. So the only thing the flush parameter actually does is: when flush is set to Z_FINISH
, inflate() cannot return Z_OK
. Instead it will return Z_BUF_ERROR
if it has not reached the end of the stream.
# File lib/pr/rbzlib.rb, line 4288 def inflate(strm, flush) order = [ 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15] if strm.nil? || strm.state.nil? || strm.next_out.nil? || (strm.next_in.nil? && strm.avail_in != 0) return Z_STREAM_ERROR end state = strm.state state.mode = TYPEDO if (state.mode == TYPE) LOAD(strm,state) _in = @@have out = @@left ret = Z_OK catch :inf_leave do loop do if(state.mode==HEAD) if state.wrap == 0 state.mode = TYPEDO next end NEEDBITS(16) if ((state.wrap & 2) != 0 && @@hold == 0x8b1f) state.check = crc32(0, nil) state.check = CRC2(state.check, @@hold) INITBITS() state.mode = FLAGS next end state.flags = 0 if state.head state.head.done = -1 end if ((state.wrap & 1) == 0 || ((BITS(8) << 8) + (@@hold >> 8)) % 31) != 0 strm.msg = "incorrect header check" state.mode = BAD next end if (BITS(4) != Z_DEFLATED) strm.msg = "unknown compression method" state.mode = BAD next end DROPBITS(4) len = BITS(4) + 8 if (len > state.wbits) strm.msg = "invalid window size" state.mode = BAD next end state.dmax = 1 << len strm.adler = state.check = adler32(0, nil) state.mode = (@@hold & 0x200) != 0 ? DICTID : TYPE INITBITS() end if(state.mode==FLAGS) NEEDBITS(16) state.flags = (@@hold) if ((state.flags & 0xff) != Z_DEFLATED) strm.msg = "unknown compression method" state.mode = BAD next end if (state.flags & 0xe000) != 0 strm.msg = "unknown header flags set" state.mode = BAD next end if state.head state.head.text = ((@@hold >> 8) & 1) end state.check = CRC2(state.check, @@hold) if (state.flags & 0x0200) != 0 INITBITS() state.mode = TIME end if(state.mode==TIME) NEEDBITS(32) if state.head state.head.time = @@hold end state.check = CRC4(state.check, @@hold) if (state.flags & 0x0200) != 0 INITBITS() state.mode = OS end if(state.mode==OS) NEEDBITS(16) if state.head state.head.xflags = (@@hold & 0xff) state.head.os = (@@hold >> 8) end state.check = CRC2(state.check, @@hold) if (state.flags & 0x0200) != 0 INITBITS() state.mode = EXLEN end if(state.mode==EXLEN) if (state.flags & 0x0400) != 0 NEEDBITS(16) state.length = @@hold if state.head state.head.extra_len = @@hold end state.check = CRC2(state.check, @@hold) if (state.flags & 0x0200) != 0 INITBITS() elsif state.head state.head.extra = nil end state.mode = EXTRA end if(state.mode==EXTRA) if (state.flags & 0x0400) != 0 copy = state.length copy = @@have if (copy > @@have) if copy != 0 if state.head && state.head.extra len = state.head.extra_len - state.length l = len + copy > state.head.extra_max ? state.head.extra_max - len : copy state.head.extra[len,l] = @@next.current[0,l] end if (state.flags & 0x0200) != 0 state.check = crc32(state.check, @@next.current,copy) end @@have -= copy @@next += copy state.length -= copy end throw :inf_leave if state.length != 0 end state.length = 0 state.mode = NAME end if(state.mode==NAME) if (state.flags & 0x0800) != 0 throw :inf_leave if @@have == 0 copy = 0 loop do len = (@@next[copy]) copy+=1 if (state.head && state.head.name && state.length < state.head.name_max) state.head.name[state.length] = len state.length+=1 end break unless (len != 0 && copy < @@have) end if (state.flags & 0x0200) != 0 state.check = crc32(state.check, @@next.current,copy) end @@have -= copy @@next += copy throw :inf_leave if len != 0 elsif state.head state.head.name = nil end state.length = 0 state.mode = COMMENT end if(state.mode==COMMENT) if (state.flags & 0x1000) != 0 throw :inf_leave if @@have == 0 copy = 0 loop do len = (@@next[copy]) copy += 1 if (state.head && state.head.comment && state.length < state.head.comm_max) state.head.comment[state.length] = len state.length+=1 end break unless (len != 0 && copy < have) end if (state.flags & 0x0200) != 0 state.check = crc32(state.check, @@next.current, copy) end @@have -= copy @@next += copy throw :inf_leave if len != 0 elsif state.head state.head.comment = nil end state.mode = HCRC end if(state.mode==HCRC) if (state.flags & 0x0200) != 0 NEEDBITS(16) if (@@hold != (state.check & 0xffff)) strm.msg = "header crc mismatch" state.mode = BAD next end INITBITS() end if state.head state.head.hcrc = ((state.flags >> 9) & 1) state.head.done = 1 end strm.adler = state.check = crc32(0, nil) state.mode = TYPE end if(state.mode==DICTID) NEEDBITS(32) strm.adler = state.check = REVERSE(@@hold) INITBITS() state.mode = DICT end if(state.mode==DICT) if state.havedict == 0 RESTORE(strm,state) return Z_NEED_DICT end strm.adler = state.check = adler32(0, nil) state.mode = TYPE end if(state.mode==TYPE) throw :inf_leave if (flush == Z_BLOCK) end if([TYPE,TYPEDO].include?(state.mode)) if state.last != 0 BYTEBITS() state.mode = CHECK next end NEEDBITS(3) state.last = BITS(1) DROPBITS(1) case (BITS(2)) when 0 state.mode = STORED when 1 fixedtables(state) state.mode = LEN when 2 state.mode = TABLE when 3 strm.msg = "invalid block type" state.mode = BAD end DROPBITS(2) end if(state.mode==STORED) BYTEBITS() NEEDBITS(32) if ((@@hold & 0xffff) != ((@@hold >> 16) ^ 0xffff)) strm.msg = "invalid stored block lengths" state.mode = BAD next end state.length = @@hold & 0xffff INITBITS() state.mode = COPY end if(state.mode==COPY) copy = state.length if copy != 0 copy = @@have if (copy > @@have) copy = @@left if (copy > @@left) throw :inf_leave if copy == 0 @@put.buffer[@@put.offset,copy] = @@next.current[0,copy] @@have -= copy @@next += copy @@left -= copy @@put += copy state.length -= copy next end state.mode = TYPE end if(state.mode==TABLE) NEEDBITS(14) state.nlen = BITS(5) + 257 DROPBITS(5) state.ndist = BITS(5) + 1 DROPBITS(5) state.ncode = BITS(4) + 4 DROPBITS(4) if (state.nlen > 286 || state.ndist > 30) strm.msg = "too many length or distance symbols" state.mode = BAD next end state.have = 0 state.mode = LENLENS end if(state.mode==LENLENS) while (state.have < state.ncode) NEEDBITS(3) state.lens[order[state.have]] = BITS(3) state.have += 1 DROPBITS(3) end while (state.have < 19) state.lens[order[state.have]] = 0 state.have += 1 end state.next = Bytef.new(state.codes) state.lencode = Bytef.new(state.codes) state.lenbits = 7 ret,state.lenbits,state.next.offset = inflate_table(CODES, state.lens, 19, state.codes, state.next.offset,state.lenbits, state.work) if ret != 0 strm.msg = "invalid code lengths set" state.mode = BAD next end state.have = 0 state.mode = CODELENS end if(state.mode==CODELENS) while (state.have < state.nlen + state.ndist) this = nil loop do this = state.lencode[BITS(state.lenbits)] break if ((this.bits) <= @@bits) PULLBYTE() end if (this.val < 16) NEEDBITS(this.bits) DROPBITS(this.bits) state.lens[state.have] = this.val state.have += 1 else if (this.val == 16) NEEDBITS(this.bits + 2) DROPBITS(this.bits) if state.have == 0 strm.msg = "invalid bit length repeat" state.mode = BAD break end len = state.lens[state.have - 1] copy = 3 + BITS(2) DROPBITS(2) elsif (this.val == 17) NEEDBITS(this.bits + 3) DROPBITS(this.bits) len = 0 copy = 3 + BITS(3) DROPBITS(3) else NEEDBITS(this.bits + 7) DROPBITS(this.bits) len = 0 copy = 11 + BITS(7) DROPBITS(7) end if (state.have + copy > state.nlen + state.ndist) strm.msg = "invalid bit length repeat" state.mode = BAD break end while copy != 0 copy -= 1 state.lens[state.have] = len state.have+=1 end end end next if (state.mode == BAD) state.next = Bytef.new(state.codes) state.lencode = Bytef.new(state.codes) state.lenbits = 9 ret,state.lenbits,state.next.offset = inflate_table(LENS, state.lens, state.nlen, state.codes,state.next.offset,state.lenbits, state.work) if ret != 0 strm.msg = "invalid literal/lengths set" state.mode = BAD next end state.distcode = Bytef.new(state.codes,state.next.offset) state.distbits = 6 ret,state.distbits,state.next.offset = inflate_table(DISTS, state.lens+state.nlen, state.ndist, state.codes,state.next.offset, state.distbits, state.work) if ret != 0 strm.msg = "invalid distances set" state.mode = BAD next end state.mode = LEN end if(state.mode==LEN) if (@@have >= 6 && @@left >= 258) RESTORE(strm,state) inflate_fast(strm, out) LOAD(strm,state) next end this = nil loop do this = state.lencode[BITS(state.lenbits)] break if ((this.bits) <= @@bits) PULLBYTE() end if (this.op != 0 && (this.op & 0xf0) == 0) last = this loop do this = state.lencode[last.val + (BITS(last.bits + last.op) >> last.bits)] break if ((last.bits + this.bits) <= @@bits) PULLBYTE() end DROPBITS(last.bits) end DROPBITS(this.bits) state.length = this.val if this.op == 0 state.mode = LIT next end if (this.op & 32) != 0 state.mode = TYPE next end if (this.op & 64) != 0 strm.msg = "invalid literal/length code" state.mode = BAD next end state.extra = (this.op) & 15 state.mode = LENEXT end if(state.mode==LENEXT) if state.extra != 0 NEEDBITS(state.extra) state.length += BITS(state.extra) DROPBITS(state.extra) end state.mode = DIST end if(state.mode==DIST) loop do this = state.distcode[BITS(state.distbits)] break if ((this.bits) <= @@bits) PULLBYTE() end if (this.op & 0xf0) == 0 last = this loop do this = state.distcode[last.val + (BITS(last.bits + last.op) >> last.bits)] break if ((last.bits + this.bits) <= @@bits) PULLBYTE() end DROPBITS(last.bits) end DROPBITS(this.bits) if (this.op & 64) != 0 strm.msg = "invalid distance code" state.mode = BAD next end state.offset = this.val state.extra = (this.op) & 15 state.mode = DISTEXT end if(state.mode==DISTEXT) if state.extra != 0 NEEDBITS(state.extra) state.offset += BITS(state.extra) DROPBITS(state.extra) end if (state.offset > state.whave + out - @@left) strm.msg = "invalid distance too far back" state.mode = BAD next end state.mode = MATCH end if(state.mode==MATCH) throw :inf_leave if @@left == 0 copy = out - @@left if (state.offset > copy) copy = state.offset - copy if (copy > state.write) copy -= state.write from = Bytef.new(state.window,state.wsize - copy) else from = Bytef.new(state.window,state.write - copy) end copy = state.length if (copy > state.length) else from = Bytef.new(@@put,@@put.offset - state.offset) copy = state.length end copy = @@left if (copy > @@left) @@left -= copy state.length -= copy loop do @@put.set(from.get) @@put += 1 from += 1 copy-=1 break if copy == 0 end state.mode = LEN if state.length == 0 end if(state.mode==LIT) throw :inf_leave if @@left == 0 @@put.set(state.length) @@put += 1 @@left-=1 state.mode = LEN end if(state.mode==CHECK) if state.wrap != 0 NEEDBITS(32) out -= @@left strm.total_out += out state.total += out if out != 0 strm.adler = state.check = UPDATE(state, state.check, @@put.buffer[@@put.offset - out, out]) end out = @@left if ((state.flags != 0 ? @@hold : REVERSE(@@hold)) != state.check) strm.msg = "incorrect data check" state.mode = BAD next end INITBITS() end state.mode = LENGTH end if(state.mode==LENGTH) if (state.wrap != 0 && state.flags != 0) NEEDBITS(32) if (@@hold != (state.total & 0xffffffff)) strm.msg = "incorrect length check" state.mode = BAD next end INITBITS() end state.mode = DONE end if(state.mode==DONE) ret = Z_STREAM_END throw :inf_leave end if(state.mode==BAD) ret = Z_DATA_ERROR throw :inf_leave elsif(state.mode==MEM) return Z_MEM_ERROR elsif(state.mode==SYNC) return Z_STREAM_ERROR end end end RESTORE(strm,state) if (state.wsize != 0 || (state.mode < CHECK && out != strm.avail_out)) if (updatewindow(strm, out)) state.mode = MEM return Z_MEM_ERROR end end _in -= strm.avail_in out -= strm.avail_out strm.total_in += _in strm.total_out += out state.total += out if (state.wrap != 0 && out != 0) strm.adler = state.check = UPDATE(state, state.check, strm.next_out.buffer[strm.next_out.offset - out, out]) end strm.data_type = state.bits + (state.last != 0 ? 64 : 0) + (state.mode == TYPE ? 128 : 0) if (((_in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK) ret = Z_BUF_ERROR end return ret end
# File lib/pr/rbzlib.rb, line 5000 def inflateCopy(dest, source) if (dest.nil? || source.nil? || source.state.nil?) return Z_STREAM_ERROR end state = source.state copy = Inflate_state.new() return Z_MEM_ERROR if copy.nil? window = nil if state.window window = 0.chr * (1 << state.wbits) if window.nil? copy = nil return Z_MEM_ERROR end end dest = source.dup copy = state.dup if (state.lencode.offset >= 0 && state.lencode.offset <= 0 + ENOUGH - 1) copy.lencode.offset = 0 + (state.lencode.offset - 0) copy.distcode.offset = 0 + (state.distcode.offset - 0) end copy.next.offset = 0 + (state.next.offset - 0) if window wsize = 1 << state.wbits window[0,wsize] = state.window[0,wsize] end copy.window = window dest.state = copy return Z_OK end
# File lib/pr/rbzlib.rb, line 4871 def inflateEnd(strm) if (strm.nil? || strm.state.nil?) return Z_STREAM_ERROR end state = strm.state state.window = nil strm.state = nil return Z_OK end
# File lib/pr/rbzlib.rb, line 4915 def inflateGetHeader(strm, head) return Z_STREAM_ERROR if (strm.nil? || strm.state.nil?) state = strm.state return Z_STREAM_ERROR if (state.wrap & 2) == 0 state.head = head head.done = 0 return Z_OK end
# File lib/pr/rbzlib.rb, line 3885 def inflateInit(strm) return inflateInit_(strm,ZLIB_VERSION, strm.size) end
# File lib/pr/rbzlib.rb, line 3890 def inflateInit2(strm, windowBits) return inflateInit2_(strm,windowBits, ZLIB_VERSION, strm.size) end
# File lib/pr/rbzlib.rb, line 3932 def inflateInit2_(strm, windowBits, version, stream_size) if (version.nil? || version[0] != ZLIB_VERSION[0] || stream_size != strm.size) return Z_VERSION_ERROR end return Z_STREAM_ERROR if strm.nil? strm.msg = '' state = Inflate_state.new state.lens = Array.new(320,0) state.work = Array.new(288,0) state.codes = Array.new(ENOUGH,0) return Z_MEM_ERROR if state.nil? strm.state = state if (windowBits < 0) state.wrap = 0 windowBits = -windowBits else state.wrap = (windowBits >> 4) + 1 windowBits &= 15 if (windowBits < 48) end if (windowBits < 8 || windowBits > 15) ZFREE(strm, state) strm.state = nil return Z_STREAM_ERROR end state.wbits = windowBits state.window = nil return inflateReset(strm) end
# File lib/pr/rbzlib.rb, line 3963 def inflateInit_(strm, version, stream_size) return inflateInit2_(strm, DEF_WBITS, version, stream_size) end
# File lib/pr/rbzlib.rb, line 3921 def inflatePrime(strm, bits, value) return Z_STREAM_ERROR if (strm.nil? || strm.state.nil?) state = strm.state return Z_STREAM_ERROR if (bits > 16 || state.bits + bits > 32) value &= (1 << bits) - 1 state.hold += value << state.bits state.bits += bits return Z_OK end
# File lib/pr/rbzlib.rb, line 3895 def inflateReset(strm) return Z_STREAM_ERROR if (strm.nil? || strm.state.nil?) state = strm.state strm.total_in = strm.total_out = state.total = 0 strm.msg = '' strm.adler = 1 state.mode = HEAD state.last = 0 state.havedict = 0 state.dmax = 32768 state.head = nil state.wsize = 0 state.whave = 0 state.write = 0 state.hold = 0 state.bits = 0 state.lens = Bytef.new(Array.new(320,0)) state.work = Array.new(288,0) state.codes = Array.new(ENOUGH,0) state.next = Bytef.new(state.codes) state.distcode = Bytef.new(state.codes) state.lencode = Bytef.new(state.codes) return Z_OK end
# File lib/pr/rbzlib.rb, line 4882 def inflateSetDictionary(strm, dictionary, dictLength) return Z_STREAM_ERROR if (strm.nil? || strm.state.nil?) state = strm.state if (state.wrap != 0 && state.mode != DICT) return Z_STREAM_ERROR end if (state.mode == DICT) id = adler32(0, nil) id = adler32(id, dictionary, dictLength) if (id != state.check) return Z_DATA_ERROR end end if (updatewindow(strm, strm.avail_out)) state.mode = MEM return Z_MEM_ERROR end if (dictLength > state.wsize) state.window[0,state.wsize] = dictionary[dictLength - state.wsize,state.wsize] state.whave = state.wsize else state.window[state.wsize - dictLength,dictLength] = dictionary[0,dictLength] state.whave = dictLength end state.havedict = 1 return Z_OK end
# File lib/pr/rbzlib.rb, line 4952 def inflateSync(strm) return Z_STREAM_ERROR if (strm.nil? || strm.state.nil?) state = strm.state return Z_BUF_ERROR if (strm.avail_in == 0 && state.bits < 8) buf = 0.chr * 4 if (state.mode != SYNC) state.mode = SYNC state.hold <<= state.bits & 7 state.bits -= state.bits & 7 len = 0 while (state.bits >= 8) buf[len] = (state.hold).chr len+=1 state.hold >>= 8 state.bits -= 8 end state.have = 0 _,state.have = syncsearch((state.have), buf, len) end len,state.have = syncsearch((state.have), strm.next_in, strm.avail_in) strm.avail_in -= len strm.next_in += len strm.total_in += len return Z_DATA_ERROR if (state.have != 4) _in = strm.total_in out = strm.total_out inflateReset(strm) strm.total_in = _in strm.total_out = out state.mode = TYPE return Z_OK end
Returns true if inflate is currently at the end of a block generated by Z_SYNC_FLUSH
or Z_FULL_FLUSH
. This function is used by one PPP implementation to provide an additional safety check. PPP uses Z_SYNC_FLUSH
but removes the length bytes of the resulting empty stored block. When decompressing, PPP checks that at the end of input packet, inflate is waiting for these length bytes.
# File lib/pr/rbzlib.rb, line 4993 def inflateSyncPoint(strm) return Z_STREAM_ERROR if (strm.nil? || strm.state.nil?) state = strm.state return state.mode == STORED && state.bits == 0 end
Decode literal, length, and distance codes and write out the resulting literal and match bytes until either not enough input or output is available, an end-of-block is encountered, or a data error is encountered. When large enough input and output buffers are supplied to inflate(), for example, a 16K input buffer and a 64K output buffer, more than 95% of the inflate execution time is spent in this routine.
Entry assumptions:
state->mode == LEN strm->avail_in >= 6 strm->avail_out >= 258 start >= strm->avail_out state->bits < 8
On return, state->mode is one of:
LEN -- ran out of enough output space or enough available input TYPE -- reached end of block code, inflate() to interpret next block BAD -- error in block data
Notes:
- The maximum input bits used by a length/distance pair is 15 bits for the length code, 5 bits for the length extra, 15 bits for the distance code, and 13 bits for the distance extra. This totals 48 bits, or six bytes. Therefore if strm->avail_in >= 6, then there is enough input to avoid checking for available input while decoding. - The maximum bytes that a single length/distance pair can output is 258 bytes, which is the maximum length that can be coded. inflate_fast() requires strm->avail_out >= 258 for each loop to avoid checking for output space.
# File lib/pr/rbzlib.rb, line 3611 def inflate_fast(strm, start) state = strm.state _in = Bytef.new(strm.next_in,strm.next_in.offset - 1) last = Bytef.new(_in,_in.offset + (strm.avail_in - 5)) out = Bytef.new(strm.next_out, strm.next_out.offset - 1) beg = Bytef.new(out, out.offset - (start - strm.avail_out)) _end = Bytef.new(out, out.offset + (strm.avail_out - 257)) wsize = state.wsize whave = state.whave write = state.write window = state.window hold = state.hold bits = state.bits lcode = state.lencode dcode = state.distcode lmask = (1 << state.lenbits) - 1 dmask = (1 << state.distbits) - 1 status = nil this = nil op = -1 len = -1 loop do if status.nil? if (bits < 15) _in += 1 hold += _in.get << bits bits += 8 _in += 1 hold += _in.get << bits bits += 8 end this = lcode[hold & lmask] status = :dolen if status.nil? end if(status==:dolen) op = (this.bits) hold >>= op bits -= op op = (this.op) end if op == 0 out += 1 out.set(this.val) elsif (op & 16) != 0 || status == :dodist if(status != :dodist && (op & 16) != 0) len = (this.val) op &= 15 if op != 0 if (bits < op) _in += 1 hold += _in.get << bits bits += 8 end len += hold & ((1 << op) - 1) hold >>= op bits -= op end if (bits < 15) _in += 1 hold += _in.get << bits bits += 8 _in += 1 hold += _in.get << bits bits += 8 end this = dcode[hold & dmask] end op = (this.bits) hold >>= op bits -= op op = this.op if (op & 16) != 0 dist = this.val op &= 15 if (bits < op) _in += 1 hold += _in.get << bits bits += 8 if (bits < op) _in += 1 hold += _in.get << bits bits += 8 end end dist += hold & ((1 << op) - 1) hold >>= op bits -= op op = (out.offset - beg.offset) if (dist > op) op = dist - op if (op > whave) strm.msg = "invalid distance too far back" state.mode = BAD break end from = Bytef.new(window,-1) if write == 0 from += wsize - op if (op < len) len -= op loop do out += 1 from += 1 out.set(from.get) op -= 1 break if op == 0 end from = Bytef.new(out,out.offset - dist) end elsif (write < op) from += wsize + write - op op -= write if (op < len) len -= op loop do out += 1 from += 1 out.set(from.get) op -= 1 break if op == 0 end from = Bytef.new(window,-1) if (write < len) op = write len -= op loop do out += 1 from += 1 out.set(from.get) op -= 1 break if op == 0 end from = Bytef.new(out,out.offset - dist) end end else from += write - op if (op < len) len -= op loop do out += 1 from += 1 out.set(from.get) op -= 1 break if op == 0 end from = Bytef.new(out,out.offset - dist) end end while (len > 2) out += 1 from += 1 out.set(from.get) out += 1 from += 1 out.set(from.get) out += 1 from += 1 out.set(from.get) len -= 3 end if len != 0 out += 1 from += 1 out.set(from.get) if (len > 1) out += 1 from += 1 out.set(from.get) end end else from = Bytef.new(out,out.offset - dist) loop do out += 1 from += 1 out.set(from.get) out += 1 from += 1 out.set(from.get) out += 1 from += 1 out.set(from.get) len -= 3 break if (len <= 2) end if len != 0 out += 1 from += 1 out.set(from.get) if (len > 1) out += 1 from += 1 out.set(from.get) end end end elsif (op & 64) == 0 this = dcode[this.val + (hold & ((1 << op) - 1))] status = :dodist redo else strm.msg = "invalid distance code" state.mode = BAD break end elsif (op & 64) == 0 this = lcode[this.val + (hold & ((1 << op) - 1))] status = :dolen redo elsif (op & 32) != 0 state.mode = TYPE break else strm.msg = "invalid literal/length code" state.mode = BAD break end status = nil break unless (_in.offset < last.offset && out.offset < _end.offset) end len = bits >> 3 _in -= len bits -= len << 3 hold &= (1 << bits) - 1 strm.next_in.offset = _in.offset + 1 strm.next_out.offset = out.offset + 1 strm.avail_in = (_in.offset < last.offset ? 5 + (last.offset - _in.offset) : 5 - (_in.offset - last.offset)) strm.avail_out = (out.offset < _end.offset ? 257 + (_end.offset - out.offset) : 257 - (out.offset - _end.offset)) state.hold = hold state.bits = bits return end
Build a set of tables to decode the provided canonical Huffman code. The code lengths are lens. The result starts at *table, whose indices are 0..2^bits-1. work is a writable array of at least lens shorts, which is used as a work area. type is the type of code to be generated, CODES, LENS, or DISTS
. On return, zero is success, -1 is an invalid code, and +1 means that ENOUGH
isn't enough. table on return points to the next available entry's address. bits is the requested root table index bits, and on return it is the actual root table index bits. It will differ if the request is greater than the longest code or if it is less than the shortest code.
# File lib/pr/rbzlib.rb, line 3383 def inflate_table(type, lens, codes, table, offset, bits, work) lbase = [ 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0] lext = [ 16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 16, 201, 196] dbase = [ 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577, 0, 0] dext = [ 16, 16, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22, 23, 23, 24, 24, 25, 25, 26, 26, 27, 27, 28, 28, 29, 29, 64, 64] this = Code.new count = Array.new(MAXBITS+1,0) offs = Array.new(MAXBITS+1,0) for sym in 0 ... codes count[lens[sym]]+=1 end root = bits max = 0 MAXBITS.downto(1) do |i| max = i break if count[max] != 0 end root = max if (root > max) if max == 0 this.op = 64 this.bits = 1 this.val = 0 table[offset] = this.dup offset += 1 table[offset] = this.dup offset += 1 bits = 1 return [0,bits,offset] end for min in 1 .. MAXBITS break if count[min] != 0 end root = min if (root < min) left = 1 for len in 1 .. MAXBITS left <<= 1 left -= count[len] return [-1,bits,offset] if (left < 0) end if (left > 0 && (type == CODES || max != 1)) return [-1,bits,offset] end offs[1] = 0 for len in 1 ... MAXBITS offs[len + 1] = offs[len] + count[len] end for sym in 0 ... codes if lens[sym] != 0 work[offs[lens[sym]]] = sym offs[lens[sym]]+=1 end end case (type) when CODES extra = Bytef.new(work) base = Bytef.new(work) _end = 19 when LENS base = Bytef.new(lbase) base -= 257 extra = Bytef.new(lext) extra -= 257 _end = 256 else base = Bytef.new(dbase) extra = Bytef.new(dext) _end = -1 end huff = 0 sym = 0 len = min _next = Bytef.new(table,offset) curr = root drop = 0 low = (-1) used = 1 << root mask = used - 1 if (type == LENS && used >= ENOUGH - MAXD) return [1,bits,offset] end loop do this.bits = (len - drop) if ((work[sym]) < _end) this.op = 0 this.val = work[sym] elsif ((work[sym]) > _end) this.op = (extra[work[sym]]) this.val = base[work[sym]] else this.op = (32 + 64) this.val = 0 end incr = 1 << (len - drop) fill = 1 << curr min = fill loop do fill -= incr _next[((huff >> drop) + fill)] = this.dup break if fill == 0 end incr = 1 << (len - 1) while (huff & incr) != 0 incr >>= 1 end if incr != 0 huff &= incr - 1 huff += incr else huff = 0 end sym+=1 count[len]-=1 if count[len] == 0 break if (len == max) len = lens[work[sym]] end if (len > root && (huff & mask) != low) if drop == 0 drop = root end _next += min curr = len - drop left = (1 << curr) while (curr + drop < max) left -= count[curr + drop] break if (left <= 0) curr+=1 left <<= 1 end used += 1 << curr if (type == LENS && used >= ENOUGH - MAXD) return [1,bits,offset] end low = huff & mask table[offset+low] = Code.new table[offset+low].op = curr table[offset+low].bits = root table[offset+low].val = (_next.offset - offset) end end this.op = 64 this.bits = (len - drop) this.val = 0 while huff != 0 if (drop != 0 && (huff & mask) != low) drop = 0 len = root _next.offset = offset this.bits = len end _next[(huff >> drop)] = this.dup incr = 1 << (len - 1) while (huff & incr) != 0 incr >>= 1 end if incr != 0 huff &= incr - 1 huff += incr else huff = 0 end end offset += used bits = root return [0,bits,offset] end
Initialize a new block.
# File lib/pr/rbzlib.rb, line 2760 def init_block(s) for n in 0 ... L_CODES s.dyn_ltree[n].fc = 0 end for n in 0 ... D_CODES s.dyn_dtree[n].fc = 0 end for n in 0 ... BL_CODES s.bl_tree[n].fc = 0 end s.dyn_ltree[END_BLOCK].fc = 1 s.static_len = 0 s.opt_len = 0 s.matches = 0 s.last_lit = 0 end
Initialize the “longest match” routines for a new zlib stream
# File lib/pr/rbzlib.rb, line 1998 def lm_init(s) s.window_size = (2*s.w_size) s.head = Array.new(s.hash_size,0) s.head[s.hash_size-1] = ZNIL s.max_lazy_match = @@configuration_table[s.level].max_lazy s.good_match = @@configuration_table[s.level].good_length s.nice_match = @@configuration_table[s.level].nice_length s.max_chain_length = @@configuration_table[s.level].max_chain s.strstart = 0 s.block_start = (0) s.lookahead = 0 s.prev_length = MIN_MATCH-1 s.match_length = MIN_MATCH-1 s.match_available = false s.ins_h = 0 end
Set match_start to the longest match starting at the given string and return its length. Matches shorter or equal to prev_length are discarded, in which case the result is equal to prev_length and match_start is garbage. IN assertions: cur_match is the head of the hash chain for the current
string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
OUT assertion: the match length is not greater than s->lookahead.
# File lib/pr/rbzlib.rb, line 2025 def longest_match(s,cur_match) chain_length = s.max_chain_length scan = s.strstart best_len = s.prev_length nice_match = s.nice_match _MAX_DIST = s.w_size - MIN_LOOKAHEAD if s.strstart > (_MAX_DIST) limit = s.strstart - (_MAX_DIST) else limit = ZNIL end prev = s.prev wmask = s.w_mask strend = s.strstart + MAX_MATCH scan_end1 = s.window[scan + best_len-1] scan_end = s.window[scan + best_len] if s.prev_length >= s.good_match chain_length >>= 2 end if nice_match > s.lookahead nice_match = s.lookahead end begin match = cur_match if (s.window[match + best_len] != scan_end) || (s.window[match + best_len-1] != scan_end1) || (s.window[match] != s.window[scan]) then cur_match = prev[cur_match & wmask] chain_length -= 1 next end match += 1 if s.window[match] != s.window[scan+1] cur_match = prev[cur_match & wmask] chain_length -= 1 next end scan += 2 match += 1 # Seems redundant, but mimics the C code loop do break if s.window[scan+=1] != s.window[match+=1] break if s.window[scan+=1] != s.window[match+=1] break if s.window[scan+=1] != s.window[match+=1] break if s.window[scan+=1] != s.window[match+=1] break if s.window[scan+=1] != s.window[match+=1] break if s.window[scan+=1] != s.window[match+=1] break if s.window[scan+=1] != s.window[match+=1] break if s.window[scan+=1] != s.window[match+=1] break if scan >= strend end len = MAX_MATCH - (strend - scan) scan = strend scan -= MAX_MATCH if len > best_len s.match_start = cur_match best_len = len break if (len >= nice_match) scan_end1 = s.window[scan+best_len-1] scan_end = s.window[scan+best_len] end cur_match = prev[cur_match & wmask] chain_length -= 1 end until (cur_match <= limit) || chain_length == 0 if best_len <= s.lookahead return best_len else return s.lookahead end end
Optimized version for level == 1 or strategy == Z_RLE
only
# File lib/pr/rbzlib.rb, line 2114 def longest_match_fast(s, cur_match) scan = Bytef.new(s.window,s.strstart) strend = Bytef.new(s.window,s.strstart + MAX_MATCH) match = Bytef.new(s.window,cur_match) return (MIN_MATCH-1) if (match[0] != scan[0] || match[1] != scan[1]) scan += 2 match += 2 loop do scan += 1 match += 1 break if scan.get == match.get scan += 1 match += 1 break if scan.get == match.get scan += 1 match += 1 break if scan.get == match.get scan += 1 match += 1 break if scan.get == match.get scan += 1 match += 1 break if scan.get == match.get scan += 1 match += 1 break if scan.get == match.get scan += 1 match += 1 break if scan.get == match.get scan += 1 match += 1 break if scan.get == match.get break if (scan.offset >= strend.offset) end len = MAX_MATCH - (strend.offset - scan.offset) return (MIN_MATCH - 1) if (len < MIN_MATCH) s.match_start = cur_match return len <= s.lookahead ? len : s.lookahead end
Restore the heap property by moving down the tree starting at node k, exchanging a node with the smallest of its two sons if necessary, stopping when the heap property is re-established (each father smaller than its two sons).
# File lib/pr/rbzlib.rb, line 2802 def pqdownheap(s,tree,k) v = s.heap[k] j = k << 1 while (j <= s.heap_len) if (j < s.heap_len) && ( (tree[s.heap[j+1]].fc < tree[s.heap[j]].fc) || ((tree[s.heap[j+1]].fc == tree[s.heap[j]].fc) && (s.depth[s.heap[j+1]] <= s.depth[s.heap[j]])) ) j+=1 end break if ( (tree[v].fc < tree[s.heap[j]].fc) || ((tree[v].fc == tree[s.heap[j]].fc) && (s.depth[v] <= s.depth[s.heap[j]])) ) s.heap[k] = s.heap[j] k = j j <<= 1 end s.heap[k] = v end
Outputs a long in LSB order to the given file
# File lib/pr/rbzlib.rb, line 1214 def putLong(s,x) 4.times{ c = x & 0xFF s.putc(c) x = x >> 8 } end
Put a short in the pending buffer. The 16-bit value is put in MSB order. IN assertion: the stream state is correct and there is enough room in pending_buf.
# File lib/pr/rbzlib.rb, line 1574 def putShortMSB(s,b) s.pending_buf[s.pending] = (b >> 8) s.pending+=1 s.pending_buf[s.pending] = (b & 0xff) s.pending+=1 end
Read a new buffer from the current input stream, update the adler32 and total number of bytes read. All deflate() input goes through this function so some applications may wish to modify it to avoid allocating a large strm->next_in buffer and copying from it. (See also flush_pending
()).
# File lib/pr/rbzlib.rb, line 1972 def read_buf(strm,buf,offset,size) len = strm.avail_in if (len > size) len = size end if len == 0 return 0 end strm.avail_in -= len if strm.state.wrap == 1 strm.adler = adler32(strm.adler, strm.next_in.current,len) elsif (strm.state.wrap == 2) strm.adler = crc32(strm.adler,strm.next_in.current,len) end buf[offset,len] = strm.next_in.current[0,len] strm.next_in += len strm.total_in += len return len end
Scan a literal or distance tree to determine the frequencies of the codes in the bit length tree.
# File lib/pr/rbzlib.rb, line 2984 def scan_tree(s,tree,max_code) prevlen = -1 nextlen = tree[0].dl count = 0 max_count = 7 min_count = 4 if nextlen == 0 max_count = 138 min_count = 3 end tree[max_code+1].dl = 0xffff for n in 0 .. max_code curlen = nextlen nextlen = tree[n+1].dl count+=1 if (count < max_count) && (curlen == nextlen) next elsif (count < min_count) s.bl_tree[curlen].fc += count elsif curlen != 0 if (curlen != prevlen) s.bl_tree[curlen].fc+=1 end s.bl_tree[REP_3_6].fc+=1 elsif (count <= 10) s.bl_tree[REPZ_3_10].fc+=1 else s.bl_tree[REPZ_11_138].fc+=1 end count = 0 prevlen = curlen if nextlen == 0 max_count = 138 min_count = 3 elsif (curlen == nextlen) max_count = 6 min_count = 3 else max_count = 7 min_count = 4 end end end
Send the header for a block using dynamic Huffman trees: the counts, the lengths of the bit length codes, the literal tree and the distance tree. IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
# File lib/pr/rbzlib.rb, line 3105 def send_all_trees(s,lcodes,dcodes,blcodes) send_bits(s, lcodes-257, 5) send_bits(s, dcodes-1, 5) send_bits(s, blcodes-4, 4) for rank in 0 ... blcodes send_bits(s, s.bl_tree[@@bl_order[rank]].dl, 3) end send_tree(s, s.dyn_ltree, lcodes-1) send_tree(s, s.dyn_dtree, dcodes-1) end
Send a value on a given number of bits. IN assertion: length <= 16 and value fits in length bits.
# File lib/pr/rbzlib.rb, line 2706 def send_bits(s,value,length) if (s.bi_valid > Buf_size - length) s.bi_buf |= (value << s.bi_valid) s.bi_buf &= 0xffff s.pending_buf[s.pending] = s.bi_buf & 0xff s.pending += 1 s.pending_buf[s.pending] = s.bi_buf >> 8 s.pending += 1 s.bi_buf = value >> (Buf_size - s.bi_valid) s.bi_valid += length - Buf_size else s.bi_buf |= (value << s.bi_valid) s.bi_valid += length end end
Send a literal or distance tree in compressed form, using the codes in bl_tree.
# File lib/pr/rbzlib.rb, line 3032 def send_tree(s,tree,max_code) prevlen = -1 nextlen = tree[0].dl count = 0 max_count = 7 min_count = 4 if nextlen == 0 max_count = 138 min_count = 3 end for n in 0 .. max_code curlen = nextlen nextlen = tree[n+1].dl count+=1 if (count < max_count) && (curlen == nextlen) next elsif (count < min_count) loop do send_bits(s, s.bl_tree[curlen].fc, s.bl_tree[curlen].dl) count-=1 break if count == 0 end elsif curlen != 0 if (curlen != prevlen) send_bits(s, s.bl_tree[curlen].fc, s.bl_tree[curlen].dl) count-=1 end send_bits(s, s.bl_tree[REP_3_6].fc, s.bl_tree[REP_3_6].dl) send_bits(s, count-3, 2) elsif (count <= 10) send_bits(s, s.bl_tree[REPZ_3_10].fc, s.bl_tree[REPZ_3_10].dl) send_bits(s, count-3, 3) else send_bits(s, s.bl_tree[REPZ_11_138].fc, s.bl_tree[REPZ_11_138].dl) send_bits(s, count-11, 7) end count = 0 prevlen = curlen if nextlen == 0 max_count = 138 min_count = 3 elsif (curlen == nextlen) max_count = 6 min_count = 3 else max_count = 7 min_count = 4 end end end
Set the data type to BINARY or TEXT, using a crude approximation: set it to Z_TEXT
if all symbols are either printable characters (33 to 255) or white spaces (9 to 13, or 32); or set it to Z_BINARY
otherwise. IN assertion: the fields Freq of dyn_ltree are set.
# File lib/pr/rbzlib.rb, line 3210 def set_data_type(s) for n in 0 ... 9 break if s.dyn_ltree[n].fc != 0 end if n == 9 for n in 14 ... 32 break if s.dyn_ltree[n].fc != 0 end end s.strm.data_type = (n == 32) ? Z_TEXT : Z_BINARY end
Search buf for the pattern: 0, 0, 0xff, 0xff. Return when found or when out of input. When called, *have is the number of pattern bytes found in order so far, in 0..3. On return *have is updated to the new state. If on return *have equals four, then the pattern was found and the return value is how many bytes were read including the last byte of the pattern. If *have is less than four, then the pattern has not been found yet and the return value is len. In the latter case, syncsearch() can be called again with more data and the *have state. *have is initialized to zero for the first call.
# File lib/pr/rbzlib.rb, line 4934 def syncsearch(have, buf, len) got = have _next = 0 while (_next < len && got < 4) if ((buf[_next]) == (got < 2 ? 0 : 0xff)) got+=1 elsif buf[_next] != 0 got = 0 else got = 4 - got end _next+=1 end have = got return [_next,have] end
Decompresses the source buffer into the destination buffer. sourceLen is
the byte length of the source buffer. Upon entry, destLen is the total size of the destination buffer, which must be large enough to hold the entire uncompressed data. (The size of the uncompressed data must have been saved previously by the compressor and transmitted to the decompressor by some mechanism outside the scope of this compression library.) Upon exit, destLen is the actual size of the compressed buffer.
This function can be used to decompress a whole file at once if the
input file is mmap'ed.
uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
enough memory, Z_BUF_ERROR
if there was not enough room in the output buffer, or Z_DATA_ERROR
if the input data was corrupted.
# File lib/pr/rbzlib.rb, line 5047 def uncompress(dest,destLen,source,sourceLen) stream = Z_stream.new stream.next_in = Bytef.new(source) stream.avail_in = sourceLen return [Z_BUF_ERROR,destLen] if (stream.avail_in != sourceLen) stream.next_out = Bytef.new(dest) stream.avail_out = destLen return [Z_BUF_ERROR,destLen] if (stream.avail_out != destLen) err = inflateInit(stream) return [err,destLen] if (err != Z_OK) err = inflate(stream, Z_FINISH) if (err != Z_STREAM_END) inflateEnd(stream) if (err == Z_NEED_DICT || (err == Z_BUF_ERROR && stream.avail_in == 0)) return [Z_DATA_ERROR,destLen] end return [err,destLen] end destLen = stream.total_out err = inflateEnd(stream) return [err,destLen] end
Update the window with the last wsize (normally 32K) bytes written before returning. If window does not exist yet, create it. This is only called when a window is already in use, or when output has been written during this inflate call, but the end of the deflate stream has not been reached yet. It is also called to create a window for dictionary data when a dictionary is loaded.
Providing output buffers larger than 32K to inflate() should provide a speed advantage, since only the last 32K of output is copied to the sliding window upon return from inflate(), and since all distances after the first 32K of output will fall in the output data, making match copies simpler and faster. The advantage may be dependent on the size of the processor's data caches.
# File lib/pr/rbzlib.rb, line 4078 def updatewindow(strm, out) state = strm.state if state.window.nil? state.window = 0.chr * (1 << state.wbits) return true if state.window.nil? end if state.wsize == 0 state.wsize = 1 << state.wbits state.write = 0 state.whave = 0 end copy = out - strm.avail_out if (copy >= state.wsize) state.window[0,state.wsize] = strm.next_out.buffer[strm.next_out.offset-state.wsize,state.wsize] state.write = 0 state.whave = state.wsize else dist = state.wsize - state.write dist = copy if (dist > copy) state.window[state.write,dist] = strm.next_out.buffer[strm.next_out.offset-copy,dist] copy -= dist if copy != 0 state.window[0,copy] = strm.next_out.buffer[strm.next_out.offset-copy,copy] state.write = copy state.whave = state.wsize else state.write += dist state.write = 0 if (state.write == state.wsize) state.whave += dist if (state.whave < state.wsize) end end return false end
# File lib/pr/rbzlib.rb, line 133 def zError(err) @@z_errmsg[Z_NEED_DICT - err] end
# File lib/pr/rbzlib.rb, line 141 def z_error(m) raise RuntimeError, m end
# File lib/pr/rbzlib.rb, line 137 def zlibVersion ZLIB_VERSION end