'use strict';

/*eslint-disable max-len,no-use-before-define*/

var common = require('./common'); var YAMLException = require('./exception'); var Mark = require('./mark'); var DEFAULT_SAFE_SCHEMA = require('./schema/default_safe'); var DEFAULT_FULL_SCHEMA = require('./schema/default_full');

var _hasOwnProperty = Object.prototype.hasOwnProperty;

var CONTEXT_FLOW_IN = 1; var CONTEXT_FLOW_OUT = 2; var CONTEXT_BLOCK_IN = 3; var CONTEXT_BLOCK_OUT = 4;

var CHOMPING_CLIP = 1; var CHOMPING_STRIP = 2; var CHOMPING_KEEP = 3;

var PATTERN_NON_PRINTABLE = /[x00-x08x0Bx0Cx0E-x1Fx7F-x84x86-x9FuFFFEuFFFF]|(?![uDC00-uDFFF])|(?:|^)[uDC00-uDFFF]/; var PATTERN_NON_ASCII_LINE_BREAKS = /[x85u2028u2029]/; var PATTERN_FLOW_INDICATORS = /[,[]{}]/; var PATTERN_TAG_HANDLE = /^(?:!|!!|![a-z-]+!)$/i; var PATTERN_TAG_URI = /^(?:!|[^,[]{}])(?:%[0-9a-f]{2}|[0-9a-z-#;/?:@&=+$,_.!~*‘()])*$/i;

function _class(obj) { return Object.prototype.toString.call(obj); }

function is_EOL© {

return (c === 0x0A/* LF */) || (c === 0x0D/* CR */);

}

function is_WHITE_SPACE© {

return (c === 0x09/* Tab */) || (c === 0x20/* Space */);

}

function is_WS_OR_EOL© {

return (c === 0x09/* Tab */) ||
       (c === 0x20/* Space */) ||
       (c === 0x0A/* LF */) ||
       (c === 0x0D/* CR */);

}

function is_FLOW_INDICATOR© {

return c === 0x2C/* , */ ||
       c === 0x5B/* [ */ ||
       c === 0x5D/* ] */ ||
       c === 0x7B/* { */ ||
       c === 0x7D/* } */;

}

function fromHexCode© {

var lc;

if ((0x30/* 0 */ <= c) && (c <= 0x39/* 9 */)) {
  return c - 0x30;
}

/*eslint-disable no-bitwise*/
lc = c | 0x20;

if ((0x61/* a */ <= lc) && (lc <= 0x66/* f */)) {
  return lc - 0x61 + 10;
}

return -1;

}

function escapedHexLen© {

if (c === 0x78/* x */) { return 2; }
if (c === 0x75/* u */) { return 4; }
if (c === 0x55/* U */) { return 8; }
return 0;

}

function fromDecimalCode© {

if ((0x30/* 0 */ <= c) && (c <= 0x39/* 9 */)) {
  return c - 0x30;
}

return -1;

}

function simpleEscapeSequence© {

/* eslint-disable indent */
return (c === 0x30/* 0 */) ? '\x00' :
      (c === 0x61/* a */) ? '\x07' :
      (c === 0x62/* b */) ? '\x08' :
      (c === 0x74/* t */) ? '\x09' :
      (c === 0x09/* Tab */) ? '\x09' :
      (c === 0x6E/* n */) ? '\x0A' :
      (c === 0x76/* v */) ? '\x0B' :
      (c === 0x66/* f */) ? '\x0C' :
      (c === 0x72/* r */) ? '\x0D' :
      (c === 0x65/* e */) ? '\x1B' :
      (c === 0x20/* Space */) ? ' ' :
      (c === 0x22/* " */) ? '\x22' :
      (c === 0x2F/* / */) ? '/' :
      (c === 0x5C/* \ */) ? '\x5C' :
      (c === 0x4E/* N */) ? '\x85' :
      (c === 0x5F/* _ */) ? '\xA0' :
      (c === 0x4C/* L */) ? '\u2028' :
      (c === 0x50/* P */) ? '\u2029' : '';

}

function charFromCodepoint© {

if (c <= 0xFFFF) {
  return String.fromCharCode(c);
}
// Encode UTF-16 surrogate pair
// https://en.wikipedia.org/wiki/UTF-16#Code_points_U.2B010000_to_U.2B10FFFF
return String.fromCharCode(
  ((c - 0x010000) >> 10) + 0xD800,
  ((c - 0x010000) & 0x03FF) + 0xDC00
);

}

var simpleEscapeCheck = new Array(256); // integer, for fast access var simpleEscapeMap = new Array(256); for (var i = 0; i < 256; i++) {

simpleEscapeCheck[i] = simpleEscapeSequence(i) ? 1 : 0;
simpleEscapeMap[i] = simpleEscapeSequence(i);

}

function State(input, options) {

this.input = input;

this.filename  = options['filename']  || null;
this.schema    = options['schema']    || DEFAULT_FULL_SCHEMA;
this.onWarning = options['onWarning'] || null;
this.legacy    = options['legacy']    || false;
this.json      = options['json']      || false;
this.listener  = options['listener']  || null;

this.implicitTypes = this.schema.compiledImplicit;
this.typeMap       = this.schema.compiledTypeMap;

this.length     = input.length;
this.position   = 0;
this.line       = 0;
this.lineStart  = 0;
this.lineIndent = 0;

this.documents = [];

/*
this.version;
this.checkLineBreaks;
this.tagMap;
this.anchorMap;
this.tag;
this.anchor;
this.kind;
this.result;*/

}

function generateError(state, message) {

return new YAMLException(
  message,
  new Mark(state.filename, state.input, state.position, state.line, (state.position - state.lineStart)));

}

function throwError(state, message) {

throw generateError(state, message);

}

function throwWarning(state, message) {

if (state.onWarning) {
  state.onWarning.call(null, generateError(state, message));
}

}

var directiveHandlers = {

YAML: function handleYamlDirective(state, name, args) {

  var match, major, minor;

  if (state.version !== null) {
    throwError(state, 'duplication of %YAML directive');
  }

  if (args.length !== 1) {
    throwError(state, 'YAML directive accepts exactly one argument');
  }

  match = /^([0-9]+)\.([0-9]+)$/.exec(args[0]);

  if (match === null) {
    throwError(state, 'ill-formed argument of the YAML directive');
  }

  major = parseInt(match[1], 10);
  minor = parseInt(match[2], 10);

  if (major !== 1) {
    throwError(state, 'unacceptable YAML version of the document');
  }

  state.version = args[0];
  state.checkLineBreaks = (minor < 2);

  if (minor !== 1 && minor !== 2) {
    throwWarning(state, 'unsupported YAML version of the document');
  }
},

TAG: function handleTagDirective(state, name, args) {

  var handle, prefix;

  if (args.length !== 2) {
    throwError(state, 'TAG directive accepts exactly two arguments');
  }

  handle = args[0];
  prefix = args[1];

  if (!PATTERN_TAG_HANDLE.test(handle)) {
    throwError(state, 'ill-formed tag handle (first argument) of the TAG directive');
  }

  if (_hasOwnProperty.call(state.tagMap, handle)) {
    throwError(state, 'there is a previously declared suffix for "' + handle + '" tag handle');
  }

  if (!PATTERN_TAG_URI.test(prefix)) {
    throwError(state, 'ill-formed tag prefix (second argument) of the TAG directive');
  }

  state.tagMap[handle] = prefix;
}

};

function captureSegment(state, start, end, checkJson) {

var _position, _length, _character, _result;

if (start < end) {
  _result = state.input.slice(start, end);

  if (checkJson) {
    for (_position = 0, _length = _result.length; _position < _length; _position += 1) {
      _character = _result.charCodeAt(_position);
      if (!(_character === 0x09 ||
            (0x20 <= _character && _character <= 0x10FFFF))) {
        throwError(state, 'expected valid JSON character');
      }
    }
  } else if (PATTERN_NON_PRINTABLE.test(_result)) {
    throwError(state, 'the stream contains non-printable characters');
  }

  state.result += _result;
}

}

function mergeMappings(state, destination, source, overridableKeys) {

var sourceKeys, key, index, quantity;

if (!common.isObject(source)) {
  throwError(state, 'cannot merge mappings; the provided source object is unacceptable');
}

sourceKeys = Object.keys(source);

for (index = 0, quantity = sourceKeys.length; index < quantity; index += 1) {
  key = sourceKeys[index];

  if (!_hasOwnProperty.call(destination, key)) {
    destination[key] = source[key];
    overridableKeys[key] = true;
  }
}

}

function storeMappingPair(state, _result, overridableKeys, keyTag, keyNode, valueNode, startLine, startPos) {

var index, quantity;

// The output is a plain object here, so keys can only be strings.
// We need to convert keyNode to a string, but doing so can hang the process
// (deeply nested arrays that explode exponentially using aliases).
if (Array.isArray(keyNode)) {
  keyNode = Array.prototype.slice.call(keyNode);

  for (index = 0, quantity = keyNode.length; index < quantity; index += 1) {
    if (Array.isArray(keyNode[index])) {
      throwError(state, 'nested arrays are not supported inside keys');
    }

    if (typeof keyNode === 'object' && _class(keyNode[index]) === '[object Object]') {
      keyNode[index] = '[object Object]';
    }
  }
}

// Avoid code execution in load() via toString property
// (still use its own toString for arrays, timestamps,
// and whatever user schema extensions happen to have @@toStringTag)
if (typeof keyNode === 'object' && _class(keyNode) === '[object Object]') {
  keyNode = '[object Object]';
}

keyNode = String(keyNode);

if (_result === null) {
  _result = {};
}

if (keyTag === 'tag:yaml.org,2002:merge') {
  if (Array.isArray(valueNode)) {
    for (index = 0, quantity = valueNode.length; index < quantity; index += 1) {
      mergeMappings(state, _result, valueNode[index], overridableKeys);
    }
  } else {
    mergeMappings(state, _result, valueNode, overridableKeys);
  }
} else {
  if (!state.json &&
      !_hasOwnProperty.call(overridableKeys, keyNode) &&
      _hasOwnProperty.call(_result, keyNode)) {
    state.line = startLine || state.line;
    state.position = startPos || state.position;
    throwError(state, 'duplicated mapping key');
  }
  _result[keyNode] = valueNode;
  delete overridableKeys[keyNode];
}

return _result;

}

function readLineBreak(state) {

var ch;

ch = state.input.charCodeAt(state.position);

if (ch === 0x0A/* LF */) {
  state.position++;
} else if (ch === 0x0D/* CR */) {
  state.position++;
  if (state.input.charCodeAt(state.position) === 0x0A/* LF */) {
    state.position++;
  }
} else {
  throwError(state, 'a line break is expected');
}

state.line += 1;
state.lineStart = state.position;

}

function skipSeparationSpace(state, allowComments, checkIndent) {

var lineBreaks = 0,
    ch = state.input.charCodeAt(state.position);

while (ch !== 0) {
  while (is_WHITE_SPACE(ch)) {
    ch = state.input.charCodeAt(++state.position);
  }

  if (allowComments && ch === 0x23/* # */) {
    do {
      ch = state.input.charCodeAt(++state.position);
    } while (ch !== 0x0A/* LF */ && ch !== 0x0D/* CR */ && ch !== 0);
  }

  if (is_EOL(ch)) {
    readLineBreak(state);

    ch = state.input.charCodeAt(state.position);
    lineBreaks++;
    state.lineIndent = 0;

    while (ch === 0x20/* Space */) {
      state.lineIndent++;
      ch = state.input.charCodeAt(++state.position);
    }
  } else {
    break;
  }
}

if (checkIndent !== -1 && lineBreaks !== 0 && state.lineIndent < checkIndent) {
  throwWarning(state, 'deficient indentation');
}

return lineBreaks;

}

function testDocumentSeparator(state) {

var _position = state.position,
    ch;

ch = state.input.charCodeAt(_position);

// Condition state.position === state.lineStart is tested
// in parent on each call, for efficiency. No needs to test here again.
if ((ch === 0x2D/* - */ || ch === 0x2E/* . */) &&
    ch === state.input.charCodeAt(_position + 1) &&
    ch === state.input.charCodeAt(_position + 2)) {

  _position += 3;

  ch = state.input.charCodeAt(_position);

  if (ch === 0 || is_WS_OR_EOL(ch)) {
    return true;
  }
}

return false;

}

function writeFoldedLines(state, count) {

if (count === 1) {
  state.result += ' ';
} else if (count > 1) {
  state.result += common.repeat('\n', count - 1);
}

}

function readPlainScalar(state, nodeIndent, withinFlowCollection) {

var preceding,
    following,
    captureStart,
    captureEnd,
    hasPendingContent,
    _line,
    _lineStart,
    _lineIndent,
    _kind = state.kind,
    _result = state.result,
    ch;

ch = state.input.charCodeAt(state.position);

if (is_WS_OR_EOL(ch)      ||
    is_FLOW_INDICATOR(ch) ||
    ch === 0x23/* # */    ||
    ch === 0x26/* & */    ||
    ch === 0x2A/* * */    ||
    ch === 0x21/* ! */    ||
    ch === 0x7C/* | */    ||
    ch === 0x3E/* > */    ||
    ch === 0x27/* ' */    ||
    ch === 0x22/* " */    ||
    ch === 0x25/* % */    ||
    ch === 0x40/* @ */    ||
    ch === 0x60/* ` */) {
  return false;
}

if (ch === 0x3F/* ? */ || ch === 0x2D/* - */) {
  following = state.input.charCodeAt(state.position + 1);

  if (is_WS_OR_EOL(following) ||
      withinFlowCollection && is_FLOW_INDICATOR(following)) {
    return false;
  }
}

state.kind = 'scalar';
state.result = '';
captureStart = captureEnd = state.position;
hasPendingContent = false;

while (ch !== 0) {
  if (ch === 0x3A/* : */) {
    following = state.input.charCodeAt(state.position + 1);

    if (is_WS_OR_EOL(following) ||
        withinFlowCollection && is_FLOW_INDICATOR(following)) {
      break;
    }

  } else if (ch === 0x23/* # */) {
    preceding = state.input.charCodeAt(state.position - 1);

    if (is_WS_OR_EOL(preceding)) {
      break;
    }

  } else if ((state.position === state.lineStart && testDocumentSeparator(state)) ||
             withinFlowCollection && is_FLOW_INDICATOR(ch)) {
    break;

  } else if (is_EOL(ch)) {
    _line = state.line;
    _lineStart = state.lineStart;
    _lineIndent = state.lineIndent;
    skipSeparationSpace(state, false, -1);

    if (state.lineIndent >= nodeIndent) {
      hasPendingContent = true;
      ch = state.input.charCodeAt(state.position);
      continue;
    } else {
      state.position = captureEnd;
      state.line = _line;
      state.lineStart = _lineStart;
      state.lineIndent = _lineIndent;
      break;
    }
  }

  if (hasPendingContent) {
    captureSegment(state, captureStart, captureEnd, false);
    writeFoldedLines(state, state.line - _line);
    captureStart = captureEnd = state.position;
    hasPendingContent = false;
  }

  if (!is_WHITE_SPACE(ch)) {
    captureEnd = state.position + 1;
  }

  ch = state.input.charCodeAt(++state.position);
}

captureSegment(state, captureStart, captureEnd, false);

if (state.result) {
  return true;
}

state.kind = _kind;
state.result = _result;
return false;

}

function readSingleQuotedScalar(state, nodeIndent) {

var ch,
    captureStart, captureEnd;

ch = state.input.charCodeAt(state.position);

if (ch !== 0x27/* ' */) {
  return false;
}

state.kind = 'scalar';
state.result = '';
state.position++;
captureStart = captureEnd = state.position;

while ((ch = state.input.charCodeAt(state.position)) !== 0) {
  if (ch === 0x27/* ' */) {
    captureSegment(state, captureStart, state.position, true);
    ch = state.input.charCodeAt(++state.position);

    if (ch === 0x27/* ' */) {
      captureStart = state.position;
      state.position++;
      captureEnd = state.position;
    } else {
      return true;
    }

  } else if (is_EOL(ch)) {
    captureSegment(state, captureStart, captureEnd, true);
    writeFoldedLines(state, skipSeparationSpace(state, false, nodeIndent));
    captureStart = captureEnd = state.position;

  } else if (state.position === state.lineStart && testDocumentSeparator(state)) {
    throwError(state, 'unexpected end of the document within a single quoted scalar');

  } else {
    state.position++;
    captureEnd = state.position;
  }
}

throwError(state, 'unexpected end of the stream within a single quoted scalar');

}

function readDoubleQuotedScalar(state, nodeIndent) {

var captureStart,
    captureEnd,
    hexLength,
    hexResult,
    tmp,
    ch;

ch = state.input.charCodeAt(state.position);

if (ch !== 0x22/* " */) {
  return false;
}

state.kind = 'scalar';
state.result = '';
state.position++;
captureStart = captureEnd = state.position;

while ((ch = state.input.charCodeAt(state.position)) !== 0) {
  if (ch === 0x22/* " */) {
    captureSegment(state, captureStart, state.position, true);
    state.position++;
    return true;

  } else if (ch === 0x5C/* \ */) {
    captureSegment(state, captureStart, state.position, true);
    ch = state.input.charCodeAt(++state.position);

    if (is_EOL(ch)) {
      skipSeparationSpace(state, false, nodeIndent);

      // TODO: rework to inline fn with no type cast?
    } else if (ch < 256 && simpleEscapeCheck[ch]) {
      state.result += simpleEscapeMap[ch];
      state.position++;

    } else if ((tmp = escapedHexLen(ch)) > 0) {
      hexLength = tmp;
      hexResult = 0;

      for (; hexLength > 0; hexLength--) {
        ch = state.input.charCodeAt(++state.position);

        if ((tmp = fromHexCode(ch)) >= 0) {
          hexResult = (hexResult << 4) + tmp;

        } else {
          throwError(state, 'expected hexadecimal character');
        }
      }

      state.result += charFromCodepoint(hexResult);

      state.position++;

    } else {
      throwError(state, 'unknown escape sequence');
    }

    captureStart = captureEnd = state.position;

  } else if (is_EOL(ch)) {
    captureSegment(state, captureStart, captureEnd, true);
    writeFoldedLines(state, skipSeparationSpace(state, false, nodeIndent));
    captureStart = captureEnd = state.position;

  } else if (state.position === state.lineStart && testDocumentSeparator(state)) {
    throwError(state, 'unexpected end of the document within a double quoted scalar');

  } else {
    state.position++;
    captureEnd = state.position;
  }
}

throwError(state, 'unexpected end of the stream within a double quoted scalar');

}

function readFlowCollection(state, nodeIndent) {

var readNext = true,
    _line,
    _tag     = state.tag,
    _result,
    _anchor  = state.anchor,
    following,
    terminator,
    isPair,
    isExplicitPair,
    isMapping,
    overridableKeys = {},
    keyNode,
    keyTag,
    valueNode,
    ch;

ch = state.input.charCodeAt(state.position);

if (ch === 0x5B/* [ */) {
  terminator = 0x5D;/* ] */
  isMapping = false;
  _result = [];
} else if (ch === 0x7B/* { */) {
  terminator = 0x7D;/* } */
  isMapping = true;
  _result = {};
} else {
  return false;
}

if (state.anchor !== null) {
  state.anchorMap[state.anchor] = _result;
}

ch = state.input.charCodeAt(++state.position);

while (ch !== 0) {
  skipSeparationSpace(state, true, nodeIndent);

  ch = state.input.charCodeAt(state.position);

  if (ch === terminator) {
    state.position++;
    state.tag = _tag;
    state.anchor = _anchor;
    state.kind = isMapping ? 'mapping' : 'sequence';
    state.result = _result;
    return true;
  } else if (!readNext) {
    throwError(state, 'missed comma between flow collection entries');
  }

  keyTag = keyNode = valueNode = null;
  isPair = isExplicitPair = false;

  if (ch === 0x3F/* ? */) {
    following = state.input.charCodeAt(state.position + 1);

    if (is_WS_OR_EOL(following)) {
      isPair = isExplicitPair = true;
      state.position++;
      skipSeparationSpace(state, true, nodeIndent);
    }
  }

  _line = state.line;
  composeNode(state, nodeIndent, CONTEXT_FLOW_IN, false, true);
  keyTag = state.tag;
  keyNode = state.result;
  skipSeparationSpace(state, true, nodeIndent);

  ch = state.input.charCodeAt(state.position);

  if ((isExplicitPair || state.line === _line) && ch === 0x3A/* : */) {
    isPair = true;
    ch = state.input.charCodeAt(++state.position);
    skipSeparationSpace(state, true, nodeIndent);
    composeNode(state, nodeIndent, CONTEXT_FLOW_IN, false, true);
    valueNode = state.result;
  }

  if (isMapping) {
    storeMappingPair(state, _result, overridableKeys, keyTag, keyNode, valueNode);
  } else if (isPair) {
    _result.push(storeMappingPair(state, null, overridableKeys, keyTag, keyNode, valueNode));
  } else {
    _result.push(keyNode);
  }

  skipSeparationSpace(state, true, nodeIndent);

  ch = state.input.charCodeAt(state.position);

  if (ch === 0x2C/* , */) {
    readNext = true;
    ch = state.input.charCodeAt(++state.position);
  } else {
    readNext = false;
  }
}

throwError(state, 'unexpected end of the stream within a flow collection');

}

function readBlockScalar(state, nodeIndent) {

var captureStart,
    folding,
    chomping       = CHOMPING_CLIP,
    didReadContent = false,
    detectedIndent = false,
    textIndent     = nodeIndent,
    emptyLines     = 0,
    atMoreIndented = false,
    tmp,
    ch;

ch = state.input.charCodeAt(state.position);

if (ch === 0x7C/* | */) {
  folding = false;
} else if (ch === 0x3E/* > */) {
  folding = true;
} else {
  return false;
}

state.kind = 'scalar';
state.result = '';

while (ch !== 0) {
  ch = state.input.charCodeAt(++state.position);

  if (ch === 0x2B/* + */ || ch === 0x2D/* - */) {
    if (CHOMPING_CLIP === chomping) {
      chomping = (ch === 0x2B/* + */) ? CHOMPING_KEEP : CHOMPING_STRIP;
    } else {
      throwError(state, 'repeat of a chomping mode identifier');
    }

  } else if ((tmp = fromDecimalCode(ch)) >= 0) {
    if (tmp === 0) {
      throwError(state, 'bad explicit indentation width of a block scalar; it cannot be less than one');
    } else if (!detectedIndent) {
      textIndent = nodeIndent + tmp - 1;
      detectedIndent = true;
    } else {
      throwError(state, 'repeat of an indentation width identifier');
    }

  } else {
    break;
  }
}

if (is_WHITE_SPACE(ch)) {
  do { ch = state.input.charCodeAt(++state.position); }
  while (is_WHITE_SPACE(ch));

  if (ch === 0x23/* # */) {
    do { ch = state.input.charCodeAt(++state.position); }
    while (!is_EOL(ch) && (ch !== 0));
  }
}

while (ch !== 0) {
  readLineBreak(state);
  state.lineIndent = 0;

  ch = state.input.charCodeAt(state.position);

  while ((!detectedIndent || state.lineIndent < textIndent) &&
         (ch === 0x20/* Space */)) {
    state.lineIndent++;
    ch = state.input.charCodeAt(++state.position);
  }

  if (!detectedIndent && state.lineIndent > textIndent) {
    textIndent = state.lineIndent;
  }

  if (is_EOL(ch)) {
    emptyLines++;
    continue;
  }

  // End of the scalar.
  if (state.lineIndent < textIndent) {

    // Perform the chomping.
    if (chomping === CHOMPING_KEEP) {
      state.result += common.repeat('\n', didReadContent ? 1 + emptyLines : emptyLines);
    } else if (chomping === CHOMPING_CLIP) {
      if (didReadContent) { // i.e. only if the scalar is not empty.
        state.result += '\n';
      }
    }

    // Break this `while` cycle and go to the funciton's epilogue.
    break;
  }

  // Folded style: use fancy rules to handle line breaks.
  if (folding) {

    // Lines starting with white space characters (more-indented lines) are not folded.
    if (is_WHITE_SPACE(ch)) {
      atMoreIndented = true;
      // except for the first content line (cf. Example 8.1)
      state.result += common.repeat('\n', didReadContent ? 1 + emptyLines : emptyLines);

    // End of more-indented block.
    } else if (atMoreIndented) {
      atMoreIndented = false;
      state.result += common.repeat('\n', emptyLines + 1);

    // Just one line break - perceive as the same line.
    } else if (emptyLines === 0) {
      if (didReadContent) { // i.e. only if we have already read some scalar content.
        state.result += ' ';
      }

    // Several line breaks - perceive as different lines.
    } else {
      state.result += common.repeat('\n', emptyLines);
    }

  // Literal style: just add exact number of line breaks between content lines.
  } else {
    // Keep all line breaks except the header line break.
    state.result += common.repeat('\n', didReadContent ? 1 + emptyLines : emptyLines);
  }

  didReadContent = true;
  detectedIndent = true;
  emptyLines = 0;
  captureStart = state.position;

  while (!is_EOL(ch) && (ch !== 0)) {
    ch = state.input.charCodeAt(++state.position);
  }

  captureSegment(state, captureStart, state.position, false);
}

return true;

}

function readBlockSequence(state, nodeIndent) {

var _line,
    _tag      = state.tag,
    _anchor   = state.anchor,
    _result   = [],
    following,
    detected  = false,
    ch;

if (state.anchor !== null) {
  state.anchorMap[state.anchor] = _result;
}

ch = state.input.charCodeAt(state.position);

while (ch !== 0) {

  if (ch !== 0x2D/* - */) {
    break;
  }

  following = state.input.charCodeAt(state.position + 1);

  if (!is_WS_OR_EOL(following)) {
    break;
  }

  detected = true;
  state.position++;

  if (skipSeparationSpace(state, true, -1)) {
    if (state.lineIndent <= nodeIndent) {
      _result.push(null);
      ch = state.input.charCodeAt(state.position);
      continue;
    }
  }

  _line = state.line;
  composeNode(state, nodeIndent, CONTEXT_BLOCK_IN, false, true);
  _result.push(state.result);
  skipSeparationSpace(state, true, -1);

  ch = state.input.charCodeAt(state.position);

  if ((state.line === _line || state.lineIndent > nodeIndent) && (ch !== 0)) {
    throwError(state, 'bad indentation of a sequence entry');
  } else if (state.lineIndent < nodeIndent) {
    break;
  }
}

if (detected) {
  state.tag = _tag;
  state.anchor = _anchor;
  state.kind = 'sequence';
  state.result = _result;
  return true;
}
return false;

}

function readBlockMapping(state, nodeIndent, flowIndent) {

var following,
    allowCompact,
    _line,
    _pos,
    _tag          = state.tag,
    _anchor       = state.anchor,
    _result       = {},
    overridableKeys = {},
    keyTag        = null,
    keyNode       = null,
    valueNode     = null,
    atExplicitKey = false,
    detected      = false,
    ch;

if (state.anchor !== null) {
  state.anchorMap[state.anchor] = _result;
}

ch = state.input.charCodeAt(state.position);

while (ch !== 0) {
  following = state.input.charCodeAt(state.position + 1);
  _line = state.line; // Save the current line.
  _pos = state.position;

  //
  // Explicit notation case. There are two separate blocks:
  // first for the key (denoted by "?") and second for the value (denoted by ":")
  //
  if ((ch === 0x3F/* ? */ || ch === 0x3A/* : */) && is_WS_OR_EOL(following)) {

    if (ch === 0x3F/* ? */) {
      if (atExplicitKey) {
        storeMappingPair(state, _result, overridableKeys, keyTag, keyNode, null);
        keyTag = keyNode = valueNode = null;
      }

      detected = true;
      atExplicitKey = true;
      allowCompact = true;

    } else if (atExplicitKey) {
      // i.e. 0x3A/* : */ === character after the explicit key.
      atExplicitKey = false;
      allowCompact = true;

    } else {
      throwError(state, 'incomplete explicit mapping pair; a key node is missed; or followed by a non-tabulated empty line');
    }

    state.position += 1;
    ch = following;

  //
  // Implicit notation case. Flow-style node as the key first, then ":", and the value.
  //
  } else if (composeNode(state, flowIndent, CONTEXT_FLOW_OUT, false, true)) {

    if (state.line === _line) {
      ch = state.input.charCodeAt(state.position);

      while (is_WHITE_SPACE(ch)) {
        ch = state.input.charCodeAt(++state.position);
      }

      if (ch === 0x3A/* : */) {
        ch = state.input.charCodeAt(++state.position);

        if (!is_WS_OR_EOL(ch)) {
          throwError(state, 'a whitespace character is expected after the key-value separator within a block mapping');
        }

        if (atExplicitKey) {
          storeMappingPair(state, _result, overridableKeys, keyTag, keyNode, null);
          keyTag = keyNode = valueNode = null;
        }

        detected = true;
        atExplicitKey = false;
        allowCompact = false;
        keyTag = state.tag;
        keyNode = state.result;

      } else if (detected) {
        throwError(state, 'can not read an implicit mapping pair; a colon is missed');

      } else {
        state.tag = _tag;
        state.anchor = _anchor;
        return true; // Keep the result of `composeNode`.
      }

    } else if (detected) {
      throwError(state, 'can not read a block mapping entry; a multiline key may not be an implicit key');

    } else {
      state.tag = _tag;
      state.anchor = _anchor;
      return true; // Keep the result of `composeNode`.
    }

  } else {
    break; // Reading is done. Go to the epilogue.
  }

  //
  // Common reading code for both explicit and implicit notations.
  //
  if (state.line === _line || state.lineIndent > nodeIndent) {
    if (composeNode(state, nodeIndent, CONTEXT_BLOCK_OUT, true, allowCompact)) {
      if (atExplicitKey) {
        keyNode = state.result;
      } else {
        valueNode = state.result;
      }
    }

    if (!atExplicitKey) {
      storeMappingPair(state, _result, overridableKeys, keyTag, keyNode, valueNode, _line, _pos);
      keyTag = keyNode = valueNode = null;
    }

    skipSeparationSpace(state, true, -1);
    ch = state.input.charCodeAt(state.position);
  }

  if (state.lineIndent > nodeIndent && (ch !== 0)) {
    throwError(state, 'bad indentation of a mapping entry');
  } else if (state.lineIndent < nodeIndent) {
    break;
  }
}

//
// Epilogue.
//

// Special case: last mapping's node contains only the key in explicit notation.
if (atExplicitKey) {
  storeMappingPair(state, _result, overridableKeys, keyTag, keyNode, null);
}

// Expose the resulting mapping.
if (detected) {
  state.tag = _tag;
  state.anchor = _anchor;
  state.kind = 'mapping';
  state.result = _result;
}

return detected;

}

function readTagProperty(state) {

var _position,
    isVerbatim = false,
    isNamed    = false,
    tagHandle,
    tagName,
    ch;

ch = state.input.charCodeAt(state.position);

if (ch !== 0x21/* ! */) return false;

if (state.tag !== null) {
  throwError(state, 'duplication of a tag property');
}

ch = state.input.charCodeAt(++state.position);

if (ch === 0x3C/* < */) {
  isVerbatim = true;
  ch = state.input.charCodeAt(++state.position);

} else if (ch === 0x21/* ! */) {
  isNamed = true;
  tagHandle = '!!';
  ch = state.input.charCodeAt(++state.position);

} else {
  tagHandle = '!';
}

_position = state.position;

if (isVerbatim) {
  do { ch = state.input.charCodeAt(++state.position); }
  while (ch !== 0 && ch !== 0x3E/* > */);

  if (state.position < state.length) {
    tagName = state.input.slice(_position, state.position);
    ch = state.input.charCodeAt(++state.position);
  } else {
    throwError(state, 'unexpected end of the stream within a verbatim tag');
  }
} else {
  while (ch !== 0 && !is_WS_OR_EOL(ch)) {

    if (ch === 0x21/* ! */) {
      if (!isNamed) {
        tagHandle = state.input.slice(_position - 1, state.position + 1);

        if (!PATTERN_TAG_HANDLE.test(tagHandle)) {
          throwError(state, 'named tag handle cannot contain such characters');
        }

        isNamed = true;
        _position = state.position + 1;
      } else {
        throwError(state, 'tag suffix cannot contain exclamation marks');
      }
    }

    ch = state.input.charCodeAt(++state.position);
  }

  tagName = state.input.slice(_position, state.position);

  if (PATTERN_FLOW_INDICATORS.test(tagName)) {
    throwError(state, 'tag suffix cannot contain flow indicator characters');
  }
}

if (tagName && !PATTERN_TAG_URI.test(tagName)) {
  throwError(state, 'tag name cannot contain such characters: ' + tagName);
}

if (isVerbatim) {
  state.tag = tagName;

} else if (_hasOwnProperty.call(state.tagMap, tagHandle)) {
  state.tag = state.tagMap[tagHandle] + tagName;

} else if (tagHandle === '!') {
  state.tag = '!' + tagName;

} else if (tagHandle === '!!') {
  state.tag = 'tag:yaml.org,2002:' + tagName;

} else {
  throwError(state, 'undeclared tag handle "' + tagHandle + '"');
}

return true;

}

function readAnchorProperty(state) {

var _position,
    ch;

ch = state.input.charCodeAt(state.position);

if (ch !== 0x26/* & */) return false;

if (state.anchor !== null) {
  throwError(state, 'duplication of an anchor property');
}

ch = state.input.charCodeAt(++state.position);
_position = state.position;

while (ch !== 0 && !is_WS_OR_EOL(ch) && !is_FLOW_INDICATOR(ch)) {
  ch = state.input.charCodeAt(++state.position);
}

if (state.position === _position) {
  throwError(state, 'name of an anchor node must contain at least one character');
}

state.anchor = state.input.slice(_position, state.position);
return true;

}

function readAlias(state) {

var _position, alias,
    ch;

ch = state.input.charCodeAt(state.position);

if (ch !== 0x2A/* * */) return false;

ch = state.input.charCodeAt(++state.position);
_position = state.position;

while (ch !== 0 && !is_WS_OR_EOL(ch) && !is_FLOW_INDICATOR(ch)) {
  ch = state.input.charCodeAt(++state.position);
}

if (state.position === _position) {
  throwError(state, 'name of an alias node must contain at least one character');
}

alias = state.input.slice(_position, state.position);

if (!state.anchorMap.hasOwnProperty(alias)) {
  throwError(state, 'unidentified alias "' + alias + '"');
}

state.result = state.anchorMap[alias];
skipSeparationSpace(state, true, -1);
return true;

}

function composeNode(state, parentIndent, nodeContext, allowToSeek, allowCompact) {

var allowBlockStyles,
    allowBlockScalars,
    allowBlockCollections,
    indentStatus = 1, // 1: this>parent, 0: this=parent, -1: this<parent
    atNewLine  = false,
    hasContent = false,
    typeIndex,
    typeQuantity,
    type,
    flowIndent,
    blockIndent;

if (state.listener !== null) {
  state.listener('open', state);
}

state.tag    = null;
state.anchor = null;
state.kind   = null;
state.result = null;

allowBlockStyles = allowBlockScalars = allowBlockCollections =
  CONTEXT_BLOCK_OUT === nodeContext ||
  CONTEXT_BLOCK_IN  === nodeContext;

if (allowToSeek) {
  if (skipSeparationSpace(state, true, -1)) {
    atNewLine = true;

    if (state.lineIndent > parentIndent) {
      indentStatus = 1;
    } else if (state.lineIndent === parentIndent) {
      indentStatus = 0;
    } else if (state.lineIndent < parentIndent) {
      indentStatus = -1;
    }
  }
}

if (indentStatus === 1) {
  while (readTagProperty(state) || readAnchorProperty(state)) {
    if (skipSeparationSpace(state, true, -1)) {
      atNewLine = true;
      allowBlockCollections = allowBlockStyles;

      if (state.lineIndent > parentIndent) {
        indentStatus = 1;
      } else if (state.lineIndent === parentIndent) {
        indentStatus = 0;
      } else if (state.lineIndent < parentIndent) {
        indentStatus = -1;
      }
    } else {
      allowBlockCollections = false;
    }
  }
}

if (allowBlockCollections) {
  allowBlockCollections = atNewLine || allowCompact;
}

if (indentStatus === 1 || CONTEXT_BLOCK_OUT === nodeContext) {
  if (CONTEXT_FLOW_IN === nodeContext || CONTEXT_FLOW_OUT === nodeContext) {
    flowIndent = parentIndent;
  } else {
    flowIndent = parentIndent + 1;
  }

  blockIndent = state.position - state.lineStart;

  if (indentStatus === 1) {
    if (allowBlockCollections &&
        (readBlockSequence(state, blockIndent) ||
         readBlockMapping(state, blockIndent, flowIndent)) ||
        readFlowCollection(state, flowIndent)) {
      hasContent = true;
    } else {
      if ((allowBlockScalars && readBlockScalar(state, flowIndent)) ||
          readSingleQuotedScalar(state, flowIndent) ||
          readDoubleQuotedScalar(state, flowIndent)) {
        hasContent = true;

      } else if (readAlias(state)) {
        hasContent = true;

        if (state.tag !== null || state.anchor !== null) {
          throwError(state, 'alias node should not have any properties');
        }

      } else if (readPlainScalar(state, flowIndent, CONTEXT_FLOW_IN === nodeContext)) {
        hasContent = true;

        if (state.tag === null) {
          state.tag = '?';
        }
      }

      if (state.anchor !== null) {
        state.anchorMap[state.anchor] = state.result;
      }
    }
  } else if (indentStatus === 0) {
    // Special case: block sequences are allowed to have same indentation level as the parent.
    // http://www.yaml.org/spec/1.2/spec.html#id2799784
    hasContent = allowBlockCollections && readBlockSequence(state, blockIndent);
  }
}

if (state.tag !== null && state.tag !== '!') {
  if (state.tag === '?') {
    for (typeIndex = 0, typeQuantity = state.implicitTypes.length; typeIndex < typeQuantity; typeIndex += 1) {
      type = state.implicitTypes[typeIndex];

      // Implicit resolving is not allowed for non-scalar types, and '?'
      // non-specific tag is only assigned to plain scalars. So, it isn't
      // needed to check for 'kind' conformity.

      if (type.resolve(state.result)) { // `state.result` updated in resolver if matched
        state.result = type.construct(state.result);
        state.tag = type.tag;
        if (state.anchor !== null) {
          state.anchorMap[state.anchor] = state.result;
        }
        break;
      }
    }
  } else if (_hasOwnProperty.call(state.typeMap[state.kind || 'fallback'], state.tag)) {
    type = state.typeMap[state.kind || 'fallback'][state.tag];

    if (state.result !== null && type.kind !== state.kind) {
      throwError(state, 'unacceptable node kind for !<' + state.tag + '> tag; it should be "' + type.kind + '", not "' + state.kind + '"');
    }

    if (!type.resolve(state.result)) { // `state.result` updated in resolver if matched
      throwError(state, 'cannot resolve a node with !<' + state.tag + '> explicit tag');
    } else {
      state.result = type.construct(state.result);
      if (state.anchor !== null) {
        state.anchorMap[state.anchor] = state.result;
      }
    }
  } else {
    throwError(state, 'unknown tag !<' + state.tag + '>');
  }
}

if (state.listener !== null) {
  state.listener('close', state);
}
return state.tag !== null ||  state.anchor !== null || hasContent;

}

function readDocument(state) {

var documentStart = state.position,
    _position,
    directiveName,
    directiveArgs,
    hasDirectives = false,
    ch;

state.version = null;
state.checkLineBreaks = state.legacy;
state.tagMap = {};
state.anchorMap = {};

while ((ch = state.input.charCodeAt(state.position)) !== 0) {
  skipSeparationSpace(state, true, -1);

  ch = state.input.charCodeAt(state.position);

  if (state.lineIndent > 0 || ch !== 0x25/* % */) {
    break;
  }

  hasDirectives = true;
  ch = state.input.charCodeAt(++state.position);
  _position = state.position;

  while (ch !== 0 && !is_WS_OR_EOL(ch)) {
    ch = state.input.charCodeAt(++state.position);
  }

  directiveName = state.input.slice(_position, state.position);
  directiveArgs = [];

  if (directiveName.length < 1) {
    throwError(state, 'directive name must not be less than one character in length');
  }

  while (ch !== 0) {
    while (is_WHITE_SPACE(ch)) {
      ch = state.input.charCodeAt(++state.position);
    }

    if (ch === 0x23/* # */) {
      do { ch = state.input.charCodeAt(++state.position); }
      while (ch !== 0 && !is_EOL(ch));
      break;
    }

    if (is_EOL(ch)) break;

    _position = state.position;

    while (ch !== 0 && !is_WS_OR_EOL(ch)) {
      ch = state.input.charCodeAt(++state.position);
    }

    directiveArgs.push(state.input.slice(_position, state.position));
  }

  if (ch !== 0) readLineBreak(state);

  if (_hasOwnProperty.call(directiveHandlers, directiveName)) {
    directiveHandlers[directiveName](state, directiveName, directiveArgs);
  } else {
    throwWarning(state, 'unknown document directive "' + directiveName + '"');
  }
}

skipSeparationSpace(state, true, -1);

if (state.lineIndent === 0 &&
    state.input.charCodeAt(state.position)     === 0x2D/* - */ &&
    state.input.charCodeAt(state.position + 1) === 0x2D/* - */ &&
    state.input.charCodeAt(state.position + 2) === 0x2D/* - */) {
  state.position += 3;
  skipSeparationSpace(state, true, -1);

} else if (hasDirectives) {
  throwError(state, 'directives end mark is expected');
}

composeNode(state, state.lineIndent - 1, CONTEXT_BLOCK_OUT, false, true);
skipSeparationSpace(state, true, -1);

if (state.checkLineBreaks &&
    PATTERN_NON_ASCII_LINE_BREAKS.test(state.input.slice(documentStart, state.position))) {
  throwWarning(state, 'non-ASCII line breaks are interpreted as content');
}

state.documents.push(state.result);

if (state.position === state.lineStart && testDocumentSeparator(state)) {

  if (state.input.charCodeAt(state.position) === 0x2E/* . */) {
    state.position += 3;
    skipSeparationSpace(state, true, -1);
  }
  return;
}

if (state.position < (state.length - 1)) {
  throwError(state, 'end of the stream or a document separator is expected');
} else {
  return;
}

}

function loadDocuments(input, options) {

input = String(input);
options = options || {};

if (input.length !== 0) {

  // Add tailing `\n` if not exists
  if (input.charCodeAt(input.length - 1) !== 0x0A/* LF */ &&
      input.charCodeAt(input.length - 1) !== 0x0D/* CR */) {
    input += '\n';
  }

  // Strip BOM
  if (input.charCodeAt(0) === 0xFEFF) {
    input = input.slice(1);
  }
}

var state = new State(input, options);

// Use 0 as string terminator. That significantly simplifies bounds check.
state.input += '\0';

while (state.input.charCodeAt(state.position) === 0x20/* Space */) {
  state.lineIndent += 1;
  state.position += 1;
}

while (state.position < (state.length - 1)) {
  readDocument(state);
}

return state.documents;

}

function loadAll(input, iterator, options) {

var documents = loadDocuments(input, options), index, length;

if (typeof iterator !== 'function') {
  return documents;
}

for (index = 0, length = documents.length; index < length; index += 1) {
  iterator(documents[index]);
}

}

function load(input, options) {

var documents = loadDocuments(input, options);

if (documents.length === 0) {
  /*eslint-disable no-undefined*/
  return undefined;
} else if (documents.length === 1) {
  return documents[0];
}
throw new YAMLException('expected a single document in the stream, but found more');

}

function safeLoadAll(input, output, options) {

if (typeof output === 'function') {
  loadAll(input, output, common.extend({ schema: DEFAULT_SAFE_SCHEMA }, options));
} else {
  return loadAll(input, common.extend({ schema: DEFAULT_SAFE_SCHEMA }, options));
}

}

function safeLoad(input, options) {

return load(input, common.extend({ schema: DEFAULT_SAFE_SCHEMA }, options));

}

module.exports.loadAll = loadAll; module.exports.load = load; module.exports.safeLoadAll = safeLoadAll; module.exports.safeLoad = safeLoad;