/* Xz.c - Xz
2015-05-01 : 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[i - 1] &= 0x7F;
    return i;
}

void Xz_Construct(CXzStream* p)
{
    p->numBlocks = p->numBlocksAllocated = 0;
    p->blocks = 0;
    p->flags = 0;
}

void Xz_Free(CXzStream* p, ISzAlloc* alloc)
{
    alloc->Free(alloc, p->blocks);
    p->numBlocks = p->numBlocksAllocated = 0;
    p->blocks = 0;
}

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;
}
