ref: 949671fbac526e9c6ed31b12cbc19ca24c8e3887
dir: /src/modloaders/pt2_xpk_unpack.c/
/* Taken from the OpenMPT project and converted to C.
** OpenMPT shares the same license as the PT2 clone (BSD 3-clause),
** so the licensing is compatible.
**
** This is probably not 100% safe code, but it works.
*/
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <stdbool.h>
#include "../pt2_helpers.h"
typedef struct XPKFILEHEADER
{
char XPKF[4];
uint32_t SrcLen;
char SQSH[4];
uint32_t DstLen;
char Name[16];
uint32_t Reserved;
} XPKFILEHEADER;
typedef struct XPK_BufferBounds
{
const uint8_t *pSrcBeg;
size_t SrcSize;
} XPK_BufferBounds;
static const uint8_t xpk_table[56] =
{
2,3,4,5,6,7,8,0,3,2,4,5,6,7,8,0,4,3,5,
2,6,7,8,0,5,4,6,2,3,7,8,0,6,5,7,2,3,4,
8,0,7,6,8,2,3,4,5,0,8,7,6,2,3,4,5,0
};
static inline uint8_t SrcRead(size_t index, XPK_BufferBounds *bufs)
{
assert(index < bufs->SrcSize);
if (index >= bufs->SrcSize)
return 0; // this is actually not how to do it, ugh...
return bufs->pSrcBeg[index];
}
static inline int32_t bfextu(size_t p, int32_t bo, int32_t bc, XPK_BufferBounds *bufs)
{
p += (uint32_t)bo >> 3;
uint32_t r = SrcRead(p, bufs); p++;
r <<= 8;
r |= SrcRead(p, bufs); p++;
r <<= 8;
r |= SrcRead(p, bufs);
r <<= bo & 7;
r &= 0x00FFFFFF;
r >>= 24 - bc;
return r;
}
static inline int32_t bfexts(size_t p, int32_t bo, int32_t bc, XPK_BufferBounds *bufs)
{
p += (uint32_t)bo >> 3;
uint32_t r = SrcRead(p, bufs); p++;
r <<= 8;
r |= SrcRead(p, bufs); p++;
r <<= 8;
r |= SrcRead(p, bufs);
r <<= (bo & 7) + 8;
r = (int32_t)r >> (32-bc);
return r;
}
static inline uint8_t XPK_ReadTable(int32_t index)
{
if (index < 0 || index >= (int32_t)sizeof (xpk_table))
return 0; // this is actually not how to do it, ugh...
return xpk_table[index];
}
static bool XPK_DoUnpack(const uint8_t *src_, uint32_t srcLen, int32_t len, uint8_t **out)
{
*out = NULL;
if (len <= 0)
return false;
int32_t d0, d1, d2, d3, d4, d5, d6, a2, a5, cup1;
const uint32_t unpackedLen = MIN((uint32_t)len, MIN(srcLen, UINT32_MAX / 20) * 20);
uint8_t *unpackedData = (uint8_t *)malloc(unpackedLen);
if (unpackedData == NULL)
return false;
uint8_t *PtrEnd = unpackedData + unpackedLen;
uint8_t *PtrOut = unpackedData;
XPK_BufferBounds bufs;
bufs.pSrcBeg = src_;
bufs.SrcSize = srcLen;
size_t src = 0;
size_t c = src;
while (len > 0)
{
int32_t type = SrcRead(c+0, &bufs);
int32_t cp = (SrcRead(c+4, &bufs)<<8) | (SrcRead(c+5, &bufs)); // packed
cup1 = (SrcRead(c+6, &bufs)<<8) | (SrcRead(c+7, &bufs)); // unpacked
c += 8;
src = c + 2;
if (type == 0) // RAW chunk
{
if (cp < 0 || cp > len)
{
free(unpackedData);
return false;
}
for (int32_t i = 0; i < cp; i++)
*PtrOut++ = SrcRead(c + i, &bufs);
c += cp;
len -= cp;
continue;
}
if (type != 1)
break;
if (cup1 > len)
cup1 = len;
len -= cup1;
cp = (cp + 3) & 0xFFFC;
c += cp;
d0 = d1 = d2 = a2 = 0;
d3 = SrcRead(src, &bufs); src++;
*PtrOut++ = (uint8_t)d3;
cup1--;
while (cup1 > 0)
{
if (d1 >= 8) goto l6dc;
if (bfextu(src, d0, 1, &bufs)) goto l75a;
d0++;
d5 = 0;
d6 = 8;
goto l734;
l6dc:
if (bfextu(src, d0, 1, &bufs)) goto l726;
d0++;
if (!bfextu(src, d0, 1, &bufs)) goto l75a;
d0++;
if (bfextu(src, d0, 1, &bufs)) goto l6f6;
d6 = 2;
goto l708;
l6f6:
d0++;
if (!bfextu(src, d0, 1, &bufs)) goto l706;
d6 = bfextu(src, d0, 3, &bufs);
d0 += 3;
goto l70a;
l706:
d6 = 3;
l708:
d0++;
l70a:
d6 = XPK_ReadTable((a2*8) + d6 - 17);
if (d6 != 8) goto l730;
l718:
if (d2 >= 20)
{
d5 = 1;
goto l732;
}
d5 = 0;
goto l734;
l726:
d0++;
d6 = 8;
if (d6 == a2) goto l718;
d6 = a2;
l730:
d5 = 4;
l732:
d2 += 8;
l734:
while (d5 >= 0 && cup1 > 0)
{
d4 = bfexts(src, d0, d6, &bufs);
d0 += d6;
d3 -= d4;
*PtrOut++ = (uint8_t)d3;
cup1--;
d5--;
}
if (d1 != 31)
d1++;
a2 = d6;
l74c:
d6 = d2;
d6 >>= 3;
d2 -= d6;
}
}
if (PtrOut > PtrEnd)
{
free(unpackedData);
return false;
}
*out = unpackedData;
return true;
l75a:
d0++;
if (bfextu(src, d0, 1, &bufs)) goto l766;
d4 = 2;
goto l79e;
l766:
d0++;
if (bfextu(src, d0, 1, &bufs)) goto l772;
d4 = 4;
goto l79e;
l772:
d0++;
if (bfextu(src, d0, 1, &bufs)) goto l77e;
d4 = 6;
goto l79e;
l77e:
d0++;
if (bfextu(src, d0, 1, &bufs)) goto l792;
d0++;
d6 = bfextu(src, d0, 3, &bufs);
d0 += 3;
d6 += 8;
goto l7a8;
l792:
d0++;
d6 = bfextu(src, d0, 5, &bufs);
d0 += 5;
d4 = 16;
goto l7a6;
l79e:
d0++;
d6 = bfextu(src, d0, 1, &bufs);
d0++;
l7a6:
d6 += d4;
l7a8:
if (bfextu(src, d0, 1, &bufs))
{
d5 = 12;
a5 = -0x100;
}
else
{
d0++;
if (bfextu(src, d0, 1, &bufs))
{
d5 = 14;
a5 = -0x1100;
}
else
{
d5 = 8;
a5 = 0;
}
}
d0++;
d4 = bfextu(src, d0, d5, &bufs);
d0 += d5;
d6 -= 3;
if (d6 >= 0)
{
if (d6 > 0)
d1--;
d1--;
if (d1 < 0)
d1 = 0;
}
d6 += 2;
size_t phist = (size_t)(PtrOut-unpackedData) + a5 - d4 - 1;
if (phist >= (size_t)(PtrOut-unpackedData))
{
free(unpackedData);
return false;
}
while (d6 >= 0 && cup1 > 0)
{
d3 = unpackedData[phist];
phist++;
*PtrOut++ = (uint8_t)d3;
cup1--;
d6--;
}
goto l74c;
}
static bool ValidateHeader(XPKFILEHEADER *header)
{
if (memcmp(header->XPKF, "XPKF", 4) != 0)
return false;
if (memcmp(header->SQSH, "SQSH", 4) != 0)
return false;
if (header->SrcLen == 0 || header->DstLen == 0)
return false;
if (header->SrcLen < sizeof (XPKFILEHEADER)-8)
return false;
return true;
}
bool ReadHeader(FILE *f, XPKFILEHEADER *header)
{
if (f == NULL || fread(header, sizeof (XPKFILEHEADER), 1, f) != 1)
return false;
header->SrcLen = SWAP32(header->SrcLen);
header->DstLen = SWAP32(header->DstLen);
return true;
}
bool detectXPK(FILE *f)
{
XPKFILEHEADER header;
uint32_t OldPos = ftell(f);
rewind(f);
bool result = ReadHeader(f, &header);
fseek(f, OldPos, SEEK_SET);
if (result == false)
return false;
return ValidateHeader(&header);
}
bool unpackXPK(FILE *f, uint32_t *filesize, uint8_t **out)
{
XPKFILEHEADER header;
*filesize = 0;
*out = NULL;
if (f == NULL)
return false;
uint32_t oldPos = ftell(f);
rewind(f);
if (!ReadHeader(f, &header))
{
fseek(f, oldPos, SEEK_SET);
return false;
}
if (!ValidateHeader(&header))
{
fseek(f, oldPos, SEEK_SET);
return false;
}
fseek(f, 0, SEEK_END);
uint32_t inputfilesize = ftell(f) - sizeof (XPKFILEHEADER);
fseek(f, sizeof (XPKFILEHEADER), SEEK_SET);
uint8_t *packedData = (uint8_t *)malloc(inputfilesize);
if (packedData == NULL)
{
fseek(f, oldPos, SEEK_SET);
return false;
}
if (fread(packedData, 1, inputfilesize, f) != inputfilesize)
{
free(packedData);
fseek(f, oldPos, SEEK_SET);
return false;
}
uint8_t *unpackedData = NULL;
bool result = XPK_DoUnpack(packedData, header.SrcLen - (sizeof (XPKFILEHEADER) - 8), header.DstLen, &unpackedData);
free(packedData);
if (result == true)
{
*filesize = header.DstLen;
*out = unpackedData;
return true;
}
else
{
return false;
}
}