nel/3rdparty/seven_zip/Xz.c

   1 /* Xz.c - Xz
   2 2017-05-12 : 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[(size_t)i - 1] &= 0x7F;
  24   return i;
  25 }
  26
  27 void Xz_Construct(CXzStream *p)
  28 {
  29   p->numBlocks = 0;
  30   p->blocks = NULL;
  31   p->flags = 0;
  32 }
  33
  34 void Xz_Free(CXzStream *p, ISzAllocPtr alloc)
  35 {
  36   ISzAlloc_Free(alloc, p->blocks);
  37   p->numBlocks = 0;
  38   p->blocks = NULL;
  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 }