mirror of
https://github.com/DarkflameUniverse/DarkflameServer.git
synced 2024-12-04 20:53:40 +00:00
123 lines
2.9 KiB
C++
123 lines
2.9 KiB
C++
#include "SuperFastHash.h"
|
|
#include "RakNetTypes.h"
|
|
#include <assert.h>
|
|
#include <stdlib.h>
|
|
|
|
#if !defined(_WIN32)
|
|
#include <stdint.h>
|
|
#endif
|
|
|
|
#undef get16bits
|
|
#if (defined(__GNUC__) && defined(__i386__)) || defined(__WATCOMC__) \
|
|
|| defined(_MSC_VER) || defined (__BORLANDC__) || defined (__TURBOC__)
|
|
#define get16bits(d) (*((const uint16_t *) (d)))
|
|
#endif
|
|
|
|
#if !defined (get16bits)
|
|
#define get16bits(d) ((((uint32_t)(((const uint8_t *)(d))[1])) << 8)\
|
|
+(uint32_t)(((const uint8_t *)(d))[0]) )
|
|
#endif
|
|
|
|
static const int INCREMENTAL_READ_BLOCK=65536;
|
|
|
|
unsigned int SuperFastHash (const char * data, int length)
|
|
{
|
|
// All this is necessary or the hash does not match SuperFastHashIncremental
|
|
int bytesRemaining=length;
|
|
unsigned int lastHash = length;
|
|
int offset=0;
|
|
while (bytesRemaining>=INCREMENTAL_READ_BLOCK)
|
|
{
|
|
lastHash=SuperFastHashIncremental (data+offset, INCREMENTAL_READ_BLOCK, lastHash );
|
|
bytesRemaining-=INCREMENTAL_READ_BLOCK;
|
|
offset+=INCREMENTAL_READ_BLOCK;
|
|
}
|
|
if (bytesRemaining>0)
|
|
{
|
|
lastHash=SuperFastHashIncremental (data+offset, bytesRemaining, lastHash );
|
|
}
|
|
return lastHash;
|
|
|
|
// return SuperFastHashIncremental(data,len,len);
|
|
}
|
|
unsigned int SuperFastHashIncremental (const char * data, int len, unsigned int lastHash )
|
|
{
|
|
uint32_t hash = (uint32_t) lastHash;
|
|
uint32_t tmp;
|
|
int rem;
|
|
|
|
if (len <= 0 || data == NULL) return 0;
|
|
|
|
rem = len & 3;
|
|
len >>= 2;
|
|
|
|
/* Main loop */
|
|
for (;len > 0; len--) {
|
|
hash += get16bits (data);
|
|
tmp = (get16bits (data+2) << 11) ^ hash;
|
|
hash = (hash << 16) ^ tmp;
|
|
data += 2*sizeof (uint16_t);
|
|
hash += hash >> 11;
|
|
}
|
|
|
|
/* Handle end cases */
|
|
switch (rem) {
|
|
case 3: hash += get16bits (data);
|
|
hash ^= hash << 16;
|
|
hash ^= data[sizeof (uint16_t)] << 18;
|
|
hash += hash >> 11;
|
|
break;
|
|
case 2: hash += get16bits (data);
|
|
hash ^= hash << 11;
|
|
hash += hash >> 17;
|
|
break;
|
|
case 1: hash += *data;
|
|
hash ^= hash << 10;
|
|
hash += hash >> 1;
|
|
}
|
|
|
|
/* Force "avalanching" of final 127 bits */
|
|
hash ^= hash << 3;
|
|
hash += hash >> 5;
|
|
hash ^= hash << 4;
|
|
hash += hash >> 17;
|
|
hash ^= hash << 25;
|
|
hash += hash >> 6;
|
|
|
|
return (unsigned int) hash;
|
|
|
|
}
|
|
|
|
unsigned int SuperFastHashFile (const char * filename)
|
|
{
|
|
FILE *fp = fopen(filename, "rb");
|
|
assert(fp);
|
|
if (fp==0)
|
|
return 0;
|
|
unsigned int hash = SuperFastHashFilePtr(fp);
|
|
fclose(fp);
|
|
return hash;
|
|
}
|
|
|
|
unsigned int SuperFastHashFilePtr (FILE *fp)
|
|
{
|
|
fseek(fp, 0, SEEK_END);
|
|
int length = ftell(fp);
|
|
fseek(fp, 0, SEEK_SET);
|
|
int bytesRemaining=length;
|
|
unsigned int lastHash = length;
|
|
char readBlock[INCREMENTAL_READ_BLOCK];
|
|
while (bytesRemaining>=(int) sizeof(readBlock))
|
|
{
|
|
fread(readBlock, sizeof(readBlock), 1, fp);
|
|
lastHash=SuperFastHashIncremental (readBlock, (int) sizeof(readBlock), lastHash );
|
|
bytesRemaining-=(int) sizeof(readBlock);
|
|
}
|
|
if (bytesRemaining>0)
|
|
{
|
|
fread(readBlock, bytesRemaining, 1, fp);
|
|
lastHash=SuperFastHashIncremental (readBlock, bytesRemaining, lastHash );
|
|
}
|
|
return lastHash;
|
|
}
|