Home | History | Annotate | Download | only in C 
      1 /* Xz.c - Xz
      2 2015-05-01 : Igor Pavlov : Public domain */
      3 
      4 #include "Precomp.h"
      5 
      6 #include "7zCrc.h"
      7 #include "CpuArch.h"
      8 #include "Xz.h"
      9 #include "XzCrc64.h"
     10 
     11 const Byte XZ_SIG[XZ_SIG_SIZE] = { 0xFD, '7', 'z', 'X', 'Z', 0 };
     12 const Byte XZ_FOOTER_SIG[XZ_FOOTER_SIG_SIZE] = { 'Y', 'Z' };
     13 
     14 unsigned Xz_WriteVarInt(Byte *buf, UInt64 v)
     15 {
     16   unsigned i = 0;
     17   do
     18   {
     19     buf[i++] = (Byte)((v & 0x7F) | 0x80);
     20     v >>= 7;
     21   }
     22   while (v != 0);
     23   buf[i - 1] &= 0x7F;
     24   return i;
     25 }
     26 
     27 void Xz_Construct(CXzStream *p)
     28 {
     29   p->numBlocks = p->numBlocksAllocated = 0;
     30   p->blocks = 0;
     31   p->flags = 0;
     32 }
     33 
     34 void Xz_Free(CXzStream *p, ISzAlloc *alloc)
     35 {
     36   alloc->Free(alloc, p->blocks);
     37   p->numBlocks = p->numBlocksAllocated = 0;
     38   p->blocks = 0;
     39 }
     40 
     41 unsigned XzFlags_GetCheckSize(CXzStreamFlags f)
     42 {
     43   unsigned t = XzFlags_GetCheckType(f);
     44   return (t == 0) ? 0 : (4 << ((t - 1) / 3));
     45 }
     46 
     47 void XzCheck_Init(CXzCheck *p, unsigned mode)
     48 {
     49   p->mode = mode;
     50   switch (mode)
     51   {
     52     case XZ_CHECK_CRC32: p->crc = CRC_INIT_VAL; break;
     53     case XZ_CHECK_CRC64: p->crc64 = CRC64_INIT_VAL; break;
     54     case XZ_CHECK_SHA256: Sha256_Init(&p->sha); break;
     55   }
     56 }
     57 
     58 void XzCheck_Update(CXzCheck *p, const void *data, size_t size)
     59 {
     60   switch (p->mode)
     61   {
     62     case XZ_CHECK_CRC32: p->crc = CrcUpdate(p->crc, data, size); break;
     63     case XZ_CHECK_CRC64: p->crc64 = Crc64Update(p->crc64, data, size); break;
     64     case XZ_CHECK_SHA256: Sha256_Update(&p->sha, (const Byte *)data, size); break;
     65   }
     66 }
     67 
     68 int XzCheck_Final(CXzCheck *p, Byte *digest)
     69 {
     70   switch (p->mode)
     71   {
     72     case XZ_CHECK_CRC32:
     73       SetUi32(digest, CRC_GET_DIGEST(p->crc));
     74       break;
     75     case XZ_CHECK_CRC64:
     76     {
     77       int i;
     78       UInt64 v = CRC64_GET_DIGEST(p->crc64);
     79       for (i = 0; i < 8; i++, v >>= 8)
     80         digest[i] = (Byte)(v & 0xFF);
     81       break;
     82     }
     83     case XZ_CHECK_SHA256:
     84       Sha256_Final(&p->sha, digest);
     85       break;
     86     default:
     87       return 0;
     88   }
     89   return 1;
     90 }
     91