mirror of
https://github.com/ZDoom/gzdoom.git
synced 2024-12-25 12:00:55 +00:00
36 lines
718 B
C
36 lines
718 B
C
|
/* 7zCrc.c -- CRC32 calculation
|
||
|
|
2008-08-05
|
||
|
|
Igor Pavlov
|
||
|
|
Public domain */
|
||
|
|
|
||
|
|
#include "7zCrc.h"
|
||
|
|
|
||
|
|
#define kCrcPoly 0xEDB88320
|
||
|
|
UInt32 g_CrcTable[256];
|
||
|
|
|
||
|
|
void MY_FAST_CALL CrcGenerateTable(void)
|
||
|
|
{
|
||
|
|
UInt32 i;
|
||
|
|
for (i = 0; i < 256; i++)
|
||
|
|
{
|
||
|
|
UInt32 r = i;
|
||
|
|
int j;
|
||
|
|
for (j = 0; j < 8; j++)
|
||
|
|
r = (r >> 1) ^ (kCrcPoly & ~((r & 1) - 1));
|
||
|
|
g_CrcTable[i] = r;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
UInt32 MY_FAST_CALL CrcUpdate(UInt32 v, const void *data, size_t size)
|
||
|
|
{
|
||
|
|
const Byte *p = (const Byte *)data;
|
||
|
|
for (; size > 0 ; size--, p++)
|
||
|
|
v = CRC_UPDATE_BYTE(v, *p);
|
||
|
|
return v;
|
||
|
|
}
|
||
|
|
|
||
|
|
UInt32 MY_FAST_CALL CrcCalc(const void *data, size_t size)
|
||
|
|
{
|
||
|
|
return CrcUpdate(CRC_INIT_VAL, data, size) ^ 0xFFFFFFFF;
|
||
|
|
}
|