/* XzIn.c - Xz input

2014-12-30 : Igor Pavlov : Public domain */

#include "Precomp.h"

#include <string.h>

#include "7zCrc.h"

#include "CpuArch.h"

#include "Xz.h"

SRes Xz_ReadHeader(CXzStreamFlags *p, ISeqInStream *inStream)

{

Byte sig[XZ_STREAM_HEADER_SIZE];

RINOK(SeqInStream_Read2(inStream, sig, XZ_STREAM_HEADER_SIZE, SZ_ERROR_NO_ARCHIVE));

if (memcmp(sig, XZ_SIG, XZ_SIG_SIZE) != 0)

return SZ_ERROR_NO_ARCHIVE;

return Xz_ParseHeader(p, sig);

}

#define READ_VARINT_AND_CHECK(buf, pos, size, res) \

{ unsigned s = Xz_ReadVarInt(buf + pos, size - pos, res); \

if (s == 0) return SZ_ERROR_ARCHIVE; pos += s; }

SRes XzBlock_ReadHeader(CXzBlock *p, ISeqInStream *inStream, Bool *isIndex, UInt32 *headerSizeRes)

{

Byte header[XZ_BLOCK_HEADER_SIZE_MAX];

unsigned headerSize;

*headerSizeRes = 0;

RINOK(SeqInStream_ReadByte(inStream, &header[0]));

headerSize = ((unsigned)header[0] << 2) + 4;

if (headerSize == 0)

{

*headerSizeRes = 1;

*isIndex = True;

return SZ_OK;

}

*isIndex = False;

*headerSizeRes = headerSize;

RINOK(SeqInStream_Read(inStream, header + 1, headerSize - 1));

return XzBlock_Parse(p, header);

}

#define ADD_SIZE_CHECH(size, val) \

{ UInt64 newSize = size + (val); if (newSize < size) return XZ_SIZE_OVERFLOW; size = newSize; }

UInt64 Xz_GetUnpackSize(const CXzStream *p)

{

UInt64 size = 0;

size_t i;

for (i = 0; i < p->numBlocks; i++)

ADD_SIZE_CHECH(size, p->blocks[i].unpackSize);

return size;

}

UInt64 Xz_GetPackSize(const CXzStream *p)

{

UInt64 size = 0;

size_t i;

for (i = 0; i < p->numBlocks; i++)

ADD_SIZE_CHECH(size, (p->blocks[i].totalSize + 3) & ~(UInt64)3);

return size;

}

/*

SRes XzBlock_ReadFooter(CXzBlock *p, CXzStreamFlags f, ISeqInStream *inStream)

{

return SeqInStream_Read(inStream, p->check, XzFlags_GetCheckSize(f));

}

*/

static SRes Xz_ReadIndex2(CXzStream *p, const Byte *buf, size_t size, ISzAlloc *alloc)

{

size_t i, numBlocks, pos = 1;

UInt32 crc;

if (size < 5 || buf[0] != 0)

return SZ_ERROR_ARCHIVE;

size -= 4;

crc = CrcCalc(buf, size);

if (crc != GetUi32(buf + size))

return SZ_ERROR_ARCHIVE;

{

UInt64 numBlocks64;

READ_VARINT_AND_CHECK(buf, pos, size, &numBlocks64);

numBlocks = (size_t)numBlocks64;

if (numBlocks != numBlocks64 || numBlocks * 2 > size)

return SZ_ERROR_ARCHIVE;

}

Xz_Free(p, alloc);

if (numBlocks != 0)

{

p->numBlocks = numBlocks;

p->numBlocksAllocated = numBlocks;

p->blocks = alloc->Alloc(alloc, sizeof(CXzBlockSizes) * numBlocks);

if (p->blocks == 0)

return SZ_ERROR_MEM;

for (i = 0; i < numBlocks; i++)

{

CXzBlockSizes *block = &p->blocks[i];

READ_VARINT_AND_CHECK(buf, pos, size, &block->totalSize);

READ_VARINT_AND_CHECK(buf, pos, size, &block->unpackSize);

if (block->totalSize == 0)

return SZ_ERROR_ARCHIVE;

}

}

while ((pos & 3) != 0)

if (buf[pos++] != 0)

return SZ_ERROR_ARCHIVE;

return (pos == size) ? SZ_OK : SZ_ERROR_ARCHIVE;

}

static SRes Xz_ReadIndex(CXzStream *p, ILookInStream *stream, UInt64 indexSize, ISzAlloc *alloc)

{

SRes res;

size_t size;

Byte *buf;

if (indexSize > ((UInt32)1 << 31))

return SZ_ERROR_UNSUPPORTED;

size = (size_t)indexSize;

if (size != indexSize)

return SZ_ERROR_UNSUPPORTED;

buf = alloc->Alloc(alloc, size);

if (buf == 0)

return SZ_ERROR_MEM;

res = LookInStream_Read2(stream, buf, size, SZ_ERROR_UNSUPPORTED);

if (res == SZ_OK)

res = Xz_ReadIndex2(p, buf, size, alloc);

alloc->Free(alloc, buf);

return res;

}

static SRes SeekFromCur(ILookInStream *inStream, Int64 *res)

{

return inStream->Seek(inStream, res, SZ_SEEK_CUR);

}

static SRes Xz_ReadBackward(CXzStream *p, ILookInStream *stream, Int64 *startOffset, ISzAlloc *alloc)

{

UInt64 indexSize;

Byte buf[XZ_STREAM_FOOTER_SIZE];

if ((*startOffset & 3) != 0 || *startOffset < XZ_STREAM_FOOTER_SIZE)

return SZ_ERROR_NO_ARCHIVE;

*startOffset = -XZ_STREAM_FOOTER_SIZE;

RINOK(SeekFromCur(stream, startOffset));

RINOK(LookInStream_Read2(stream, buf, XZ_STREAM_FOOTER_SIZE, SZ_ERROR_NO_ARCHIVE));

if (memcmp(buf + 10, XZ_FOOTER_SIG, XZ_FOOTER_SIG_SIZE) != 0)

{

UInt32 total = 0;

*startOffset += XZ_STREAM_FOOTER_SIZE;

for (;;)

{

size_t i;

#define TEMP_BUF_SIZE (1 << 10)

Byte tempBuf[TEMP_BUF_SIZE];

if (*startOffset < XZ_STREAM_FOOTER_SIZE || total > (1 << 16))

return SZ_ERROR_NO_ARCHIVE;

i = (*startOffset > TEMP_BUF_SIZE) ? TEMP_BUF_SIZE : (size_t)*startOffset;

total += (UInt32)i;

*startOffset = -(Int64)i;

RINOK(SeekFromCur(stream, startOffset));

RINOK(LookInStream_Read2(stream, tempBuf, i, SZ_ERROR_NO_ARCHIVE));

for (; i != 0; i--)

if (tempBuf[i - 1] != 0)

break;

if (i != 0)

{

if ((i & 3) != 0)

return SZ_ERROR_NO_ARCHIVE;

*startOffset += i;

break;

}

}

if (*startOffset < XZ_STREAM_FOOTER_SIZE)

return SZ_ERROR_NO_ARCHIVE;

*startOffset -= XZ_STREAM_FOOTER_SIZE;

RINOK(stream->Seek(stream, startOffset, SZ_SEEK_SET));

RINOK(LookInStream_Read2(stream, buf, XZ_STREAM_FOOTER_SIZE, SZ_ERROR_NO_ARCHIVE));

if (memcmp(buf + 10, XZ_FOOTER_SIG, XZ_FOOTER_SIG_SIZE) != 0)

return SZ_ERROR_NO_ARCHIVE;

}

p->flags = (CXzStreamFlags)GetBe16(buf + 8);

if (!XzFlags_IsSupported(p->flags))

return SZ_ERROR_UNSUPPORTED;

if (GetUi32(buf) != CrcCalc(buf + 4, 6))

return SZ_ERROR_ARCHIVE;

indexSize = ((UInt64)GetUi32(buf + 4) + 1) << 2;

*startOffset = -(Int64)(indexSize + XZ_STREAM_FOOTER_SIZE);

RINOK(SeekFromCur(stream, startOffset));

RINOK(Xz_ReadIndex(p, stream, indexSize, alloc));

{

UInt64 totalSize = Xz_GetPackSize(p);

UInt64 sum = XZ_STREAM_HEADER_SIZE + totalSize + indexSize;

if (totalSize == XZ_SIZE_OVERFLOW ||

sum >= ((UInt64)1 << 63) ||

totalSize >= ((UInt64)1 << 63))

return SZ_ERROR_ARCHIVE;

*startOffset = -(Int64)sum;

RINOK(SeekFromCur(stream, startOffset));

}

{

CXzStreamFlags headerFlags;

CSecToRead secToRead;

SecToRead_CreateVTable(&secToRead);

secToRead.realStream = stream;

RINOK(Xz_ReadHeader(&headerFlags, &secToRead.s));

return (p->flags == headerFlags) ? SZ_OK : SZ_ERROR_ARCHIVE;

}

}

/* ---------- Xz Streams ---------- */

void Xzs_Construct(CXzs *p)

{

p->num = p->numAllocated = 0;

p->streams = 0;

}

void Xzs_Free(CXzs *p, ISzAlloc *alloc)

{

size_t i;

for (i = 0; i < p->num; i++)

Xz_Free(&p->streams[i], alloc);

alloc->Free(alloc, p->streams);

p->num = p->numAllocated = 0;

p->streams = 0;

}

UInt64 Xzs_GetNumBlocks(const CXzs *p)

{

UInt64 num = 0;

size_t i;

for (i = 0; i < p->num; i++)

num += p->streams[i].numBlocks;

return num;

}

UInt64 Xzs_GetUnpackSize(const CXzs *p)

{

UInt64 size = 0;

size_t i;

for (i = 0; i < p->num; i++)

ADD_SIZE_CHECH(size, Xz_GetUnpackSize(&p->streams[i]));

return size;

}

/*

UInt64 Xzs_GetPackSize(const CXzs *p)

{

UInt64 size = 0;

size_t i;

for (i = 0; i < p->num; i++)

ADD_SIZE_CHECH(size, Xz_GetTotalSize(&p->streams[i]));

return size;

}

*/

SRes Xzs_ReadBackward(CXzs *p, ILookInStream *stream, Int64 *startOffset, ICompressProgress *progress, ISzAlloc *alloc)

{

Int64 endOffset = 0;

RINOK(stream->Seek(stream, &endOffset, SZ_SEEK_END));

*startOffset = endOffset;

for (;;)

{

CXzStream st;

SRes res;

Xz_Construct(&st);

res = Xz_ReadBackward(&st, stream, startOffset, alloc);

st.startOffset = *startOffset;

RINOK(res);

if (p->num == p->numAllocated)

{

size_t newNum = p->num + p->num / 4 + 1;

Byte *data = (Byte *)alloc->Alloc(alloc, newNum * sizeof(CXzStream));

if (data == 0)

return SZ_ERROR_MEM;

p->numAllocated = newNum;

if (p->num != 0)

memcpy(data, p->streams, p->num * sizeof(CXzStream));

alloc->Free(alloc, p->streams);

p->streams = (CXzStream *)data;

}

p->streams[p->num++] = st;

if (*startOffset == 0)

break;

RINOK(stream->Seek(stream, startOffset, SZ_SEEK_SET));

if (progress && progress->Progress(progress, endOffset - *startOffset, (UInt64)(Int64)-1) != SZ_OK)

return SZ_ERROR_PROGRESS;

}

return SZ_OK;

}