/*
  NrrdIO: stand-alone code for basic nrrd functionality
  Copyright (C) 2008, 2007, 2006, 2005  Gordon Kindlmann
  Copyright (C) 2004, 2003, 2002, 2001, 2000, 1999, 1998  University of Utah
 
  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:
 
  1. 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.
 
  2. Altered source versions must be plainly marked as such, and must
     not be misrepresented as being the original software.
 
  3. This notice may not be removed or altered from any source distribution.
*/

#include "NrrdIO.h"
#include "privateAir.h"

/*
******** airSanity()
**
** Does run-time checks to see if the compile-time constants are correct.
** Returns a value from the airInsane* enum; airInsane_not means all
** the checks came back without detecting any problems.
*/
int
airSanity(void) {
  double nanValue, pinf, ninf;
  float nanF, pinfF, ninfF;
  unsigned int sign, expvalue, mant;
  int tmpI, size;
  char endian;
  unsigned char uc0, uc1;
  static int _airSanity=0;
  
  if (_airSanity) {
    return airInsane_not;
  }

  /* run-time endian check */
  tmpI = 1;
  endian = !(*((char*)(&tmpI)));
  if (endian) {
    /* big endian */
    if (4321 != AIR_ENDIAN) {
      return airInsane_endian;
    }
  }
  else {
    if (1234 != AIR_ENDIAN) {
      return airInsane_endian;
    }
  }    

  /* checks on sizes of uchar, float, int, double, airLLong */  
  uc0 = 255;
  uc1 = uc0 + 1;  /* to avoid compiler warnings */
  if (!( 255 == uc0 && 0 == uc1 )) {
    return airInsane_UCSize;
  }
  /* these justify the AIR_EXISTS_F and AIR_EXISTS_D macros */
  if (!( (sizeof(float) == sizeof(int)) && (4 == sizeof(int)) )) {
    return airInsane_FISize;
  }
  if (!( (sizeof(double) == sizeof(airLLong)) && (8 == sizeof(airLLong)) )) {
    return airInsane_DLSize;
  }

  /* run-time NaN checks */
  pinf = DBL_MAX;
  pinf = _airSanityHelper(pinf);
  pinf = _airSanityHelper(pinf);
  pinf = _airSanityHelper(pinf);
  if (AIR_EXISTS(pinf)) {
    return airInsane_pInfExists;
  }
  ninf = -pinf;
  if (AIR_EXISTS(ninf)) {
    return airInsane_nInfExists;
  }
  nanValue = pinf / pinf;
  if (AIR_EXISTS(nanValue)) {
    return airInsane_NaNExists;
  }
  nanF = (float)nanValue;
  pinfF = (float)pinf;
  ninfF = (float)ninf;
  airFPValToParts_f(&sign, &expvalue, &mant, nanF);
  mant >>= 22;
  if (AIR_QNANHIBIT != (int)mant) {
    return airInsane_QNaNHiBit;
  }

  if (!( airFP_QNAN == airFPClass_f(AIR_NAN)
         && airFP_QNAN == airFPClass_f(AIR_QNAN)
/*
  Exclude the following platforms from the airFP_SNAN test.

 1) APPLE builds due to a cross-compilation problem, and
 2) Visual Studio builds for version newer than 2005 (not included)
 when building in 32bits. */

#if defined(__APPLE__) || ( defined(_MSC_VER) && _MSC_VER >= 1400 ) 
         /* don't compare airFP_SNAN */
#else
         && airFP_SNAN == airFPClass_f(AIR_SNAN) 
#endif
         && airFP_QNAN == airFPClass_d(AIR_NAN)
         && airFP_QNAN == airFPClass_d(AIR_QNAN) )) {
    /* we don't bother checking for 
       airFP_SNAN == airFPClass_d(AIR_SNAN) because
       on some platforms the signal-ness of the NaN
       is not preserved in double-float conversion */

    return airInsane_AIR_NAN;
  }
  if (!(airFP_QNAN == airFPClass_f(nanF)
        && airFP_POS_INF == airFPClass_f(pinfF)
        && airFP_NEG_INF == airFPClass_f(ninfF))) {
    /* really, this is verifying that assigning from a double to a 
       float maintains the FPClass for non-existant values */
    return airInsane_FltDblFPClass;
  }
  
  /* just make sure AIR_DIO is reasonably set 
     (actually, this should be done by include/teem/need/dio.h) */
  switch (AIR_DIO) {
  case 0: break;
  case 1: break;
  default:
    return airInsane_dio;
  }

  /* run-time 32/64-bit check */
  size = 0;
  switch (AIR_32BIT) {
  case 1: size = 4; break;
  case 0: size = 8; break;
  default: break;
  }
  if (size != sizeof(size_t)) {
    return airInsane_32Bit;
  }

  _airSanity = 1;
  return airInsane_not;
}

const char
_airInsaneErr[AIR_INSANE_MAX+1][AIR_STRLEN_MED] = {
  "sanity checked PASSED!",
  "TEEM_ENDIAN is wrong",
  "AIR_EXISTS(+inf) was true",
  "AIR_EXISTS(-inf) was true",
  "AIR_EXISTS(NaN) was true",
  "air_FPClass_f() wrong after double->float assignment",
  "TEEM_QNANHIBIT is wrong",
  "airFPClass(AIR_QNAN,AIR_SNAN) wrong",
  "TEEM_DIO has invalid value",
  "TEEM_32BIT is wrong",
  "unsigned char isn't 8 bits",
  "sizeof(float), sizeof(int) not both == 4",
  "sizeof(double), sizeof(airLLong) not both == 8",
};

char _airBadInsane[] = "(invalid insane value)";

const char *
airInsaneErr(int insane) {
  
  if (AIR_IN_CL(0, insane, AIR_INSANE_MAX)) {
    return _airInsaneErr[insane];
  }
  else {
    return _airBadInsane;
  }
}

