/* Xz.c - Xz

2017-05-12 : Igor Pavlov : Public domain */

#include "Precomp.h"

#include "7zCrc.h"

#include "CpuArch.h"

#include "Xz.h"

#include "XzCrc64.h"

const Byte XZ_SIG[XZ_SIG_SIZE] = { 0xFD, '7', 'z', 'X', 'Z', 0 };

/* const Byte XZ_FOOTER_SIG[XZ_FOOTER_SIG_SIZE] = { 'Y', 'Z' }; */

unsigned Xz_WriteVarInt(Byte *buf, UInt64 v)

{

  unsigned i = 0;

  do

  {

    buf[i++] = (Byte)((v & 0x7F) | 0x80);

    v >>= 7;

  }

  while (v != 0);

  buf[(size_t)i - 1] &= 0x7F;

  return i;

}

void Xz_Construct(CXzStream *p)

{

  p->numBlocks = 0;

  p->blocks = NULL;

  p->flags = 0;

}

void Xz_Free(CXzStream *p, ISzAllocPtr alloc)

{

  ISzAlloc_Free(alloc, p->blocks);

  p->numBlocks = 0;

  p->blocks = NULL;

}

unsigned XzFlags_GetCheckSize(CXzStreamFlags f)

{

  unsigned t = XzFlags_GetCheckType(f);

  return (t == 0) ? 0 : (4 << ((t - 1) / 3));

}

void XzCheck_Init(CXzCheck *p, unsigned mode)

{

  p->mode = mode;

  switch (mode)

  {

    case XZ_CHECK_CRC32: p->crc = CRC_INIT_VAL; break;

    case XZ_CHECK_CRC64: p->crc64 = CRC64_INIT_VAL; break;

    case XZ_CHECK_SHA256: Sha256_Init(&p->sha); break;

  }

}

void XzCheck_Update(CXzCheck *p, const void *data, size_t size)

{

  switch (p->mode)

  {

    case XZ_CHECK_CRC32: p->crc = CrcUpdate(p->crc, data, size); break;

    case XZ_CHECK_CRC64: p->crc64 = Crc64Update(p->crc64, data, size); break;

    case XZ_CHECK_SHA256: Sha256_Update(&p->sha, (const Byte *)data, size); break;

  }

}

int XzCheck_Final(CXzCheck *p, Byte *digest)

{

  switch (p->mode)

  {

    case XZ_CHECK_CRC32:

      SetUi32(digest, CRC_GET_DIGEST(p->crc));

      break;

    case XZ_CHECK_CRC64:

    {

      int i;

      UInt64 v = CRC64_GET_DIGEST(p->crc64);

      for (i = 0; i < 8; i++, v >>= 8)

        digest[i] = (Byte)(v & 0xFF);

      break;

    }

    case XZ_CHECK_SHA256:

      Sha256_Final(&p->sha, digest);

      break;

    default:

      return 0;

  }

  return 1;

}