SDL_test_crc32.c File Reference

#include "SDL_config.h"
#include "SDL_test.h"

Include dependency graph for SDL_test_crc32.c:

Go to the source code of this file.

Functions
int	SDLTest_Crc32Init (SDLTest_Crc32Context *crcContext)
	Initialize the CRC context.
int	SDLTest_Crc32Calc (SDLTest_Crc32Context *crcContext, CrcUint8 *inBuf, CrcUint32 inLen, CrcUint32 *crc32)
	calculate a crc32 from a data block
int	SDLTest_Crc32CalcStart (SDLTest_Crc32Context *crcContext, CrcUint32 *crc32)
int	SDLTest_Crc32CalcEnd (SDLTest_Crc32Context *crcContext, CrcUint32 *crc32)
int	SDLTest_Crc32CalcBuffer (SDLTest_Crc32Context *crcContext, CrcUint8 *inBuf, CrcUint32 inLen, CrcUint32 *crc32)
int	SDLTest_Crc32Done (SDLTest_Crc32Context *crcContext)
	clean up CRC context

Function Documentation

int SDLTest_Crc32Calc	(	SDLTest_Crc32Context *	crcContext,
		CrcUint8 *	inBuf,
		CrcUint32	inLen,
		CrcUint32 *	crc32
	)

calculate a crc32 from a data block

Parameters

crcContext	pointer to context variable
inBuf	input buffer to checksum
inLen	length of input buffer
crc32	pointer to Uint32 to store the final CRC into

Returns

0 for OK, -1 on error

Definition at line 72 of file SDL_test_crc32.c.

References SDLTest_Crc32CalcBuffer(), SDLTest_Crc32CalcEnd(), and SDLTest_Crc32CalcStart().

Referenced by get_allocation_bucket().

{
  if (SDLTest_Crc32CalcStart(crcContext,crc32)) {
   return -1;
  }

  if (SDLTest_Crc32CalcBuffer(crcContext, inBuf, inLen, crc32)) {
   return -1;
  }

  if (SDLTest_Crc32CalcEnd(crcContext, crc32)) {
   return -1;
  }

  return 0;
}

int SDLTest_Crc32CalcBuffer	(	SDLTest_Crc32Context *	crcContext,
		CrcUint8 *	inBuf,
		CrcUint32	inLen,
		CrcUint32 *	crc32
	)

Definition at line 127 of file SDL_test_crc32.c.

References SDLTest_Crc32Context::crc32_table, CrcUint32, CrcUint8, and NULL.

Referenced by SDLTest_Crc32Calc().

{
  CrcUint8    *p;
  register CrcUint32    crc;

  if (crcContext==NULL) {
   *crc32=0;
   return -1;
  }

  if (inBuf==NULL) {
   return -1;
  }

  /*
   * Calculate CRC from data
   */
  crc = *crc32;
  for (p = inBuf; inLen > 0; ++p, --inLen) {
#ifdef ORIGINAL_METHOD
    crc = (crc << 8) ^ crcContext->crc32_table[(crc >> 24) ^ *p];
#else
    crc = ((crc >> 8) & 0x00FFFFFF) ^ crcContext->crc32_table[ (crc ^ *p) & 0xFF ];
#endif
  }
  *crc32 = crc;

  return 0;
}

int SDLTest_Crc32CalcEnd	(	SDLTest_Crc32Context *	crcContext,
		CrcUint32 *	crc32
	)

Definition at line 109 of file SDL_test_crc32.c.

References NULL.

Referenced by SDLTest_Crc32Calc().

{
  /* Sanity check pointers */
  if (crcContext==NULL) {
   *crc32=0;
   return -1;
  }

  /*
   * Return complement, per CRC-32 spec
   */
  *crc32 = (~(*crc32));

  return 0;
}

int SDLTest_Crc32CalcStart	(	SDLTest_Crc32Context *	crcContext,
		CrcUint32 *	crc32
	)

Definition at line 91 of file SDL_test_crc32.c.

References NULL.

Referenced by SDLTest_Crc32Calc().

{
  /* Sanity check pointers */
  if (crcContext==NULL) {
   *crc32=0;
   return -1;
  }

  /*
   * Preload shift register, per CRC-32 spec
   */
  *crc32 = 0xffffffff;

  return 0;
}

int SDLTest_Crc32Done

(

SDLTest_Crc32Context *

crcContext

)

clean up CRC context

Parameters

crcContext

pointer to context variable

Returns

0 for OK, -1 on error

Definition at line 157 of file SDL_test_crc32.c.

References NULL.

{
  if (crcContext==NULL) {
     return -1;
  }

  return 0;
}

int SDLTest_Crc32Init

(

SDLTest_Crc32Context *

crcContext

)

Initialize the CRC context.

Note: The function initializes the crc table required for all crc calculations.

Parameters

crcContext

pointer to context variable

Returns

0 for OK, -1 on error

Definition at line 34 of file SDL_test_crc32.c.

References CRC32_POLY, SDLTest_Crc32Context::crc32_table, CrcUint32, i, j, and NULL.

Referenced by SDLTest_TrackAllocations().

{
  int i,j;
  CrcUint32 c;

  /* Sanity check context pointer */
  if (crcContext==NULL) {
   return -1;
  }

  /*
   * Build auxiliary table for parallel byte-at-a-time CRC-32
   */
#ifdef ORIGINAL_METHOD
  for (i = 0; i < 256; ++i) {
    for (c = i << 24, j = 8; j > 0; --j) {
      c = c & 0x80000000 ? (c << 1) ^ CRC32_POLY : (c << 1);
    }
    crcContext->crc32_table[i] = c;
  }
#else
  for (i=0; i<256; i++) {
   c = i;
   for (j=8; j>0; j--) {
    if (c & 1) {
     c = (c >> 1) ^ CRC32_POLY;
    } else {
     c >>= 1;
    }
   }
   crcContext->crc32_table[i] = c;
  }
#endif

  return 0;
}