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New streaming API behavior, to solve issue 19 (https://github.com/Cyan4973/zstd/issues/19)

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This commit is contained in:
Yann Collet
2015-02-16 18:06:26 +01:00
parent f66d2babf8
commit c5d46b5c90
4 changed files with 61 additions and 54 deletions
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lib/zstd.c
+44 -40
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@@ -141,7 +141,7 @@ static const U32 ZSTD_magicNumber = 0xFD2FB51C; /* Initial (limited) frame for
#define KB *(1 <<10)
#define MB *(1 <<20)
#define GB *(1U<<20)
#define GB *(1U<<30)
#define BLOCKSIZE (128 KB) /* define, for static allocation */
static const U32 g_maxDistance = 512 KB;
@@ -1708,24 +1708,24 @@ size_t ZSTD_decompress(void* dst, size_t maxDstSize, const void* src, size_t src
}
/******************************
/*******************************
* Streaming Decompression API
******************************/
*******************************/
typedef struct
{
U32 ctx[FSE_DTABLE_SIZE_U32(LLFSELog) + FSE_DTABLE_SIZE_U32(OffFSELog) + FSE_DTABLE_SIZE_U32(MLFSELog)];
size_t expected;
blockType_t bType;
U32 started;
U32 phase;
} dctx_t;
ZSTD_dctx_t ZSTD_createDCtx(void)
{
dctx_t* dctx = (dctx_t*)malloc(sizeof(dctx_t));
dctx->expected = 4 + ZSTD_blockHeaderSize; // Frame Header + Block Header
dctx->started = 0;
dctx->expected = ZSTD_frameHeaderSize;
dctx->phase = 0;
return (ZSTD_dctx_t)dctx;
}
@@ -1736,7 +1736,7 @@ size_t ZSTD_freeDCtx(ZSTD_dctx_t dctx)
}
size_t ZSTD_getNextcBlockSize(ZSTD_dctx_t dctx)
size_t ZSTD_nextSrcSizeToDecompress(ZSTD_dctx_t dctx)
{
return ((dctx_t*)dctx)->expected;
}
@@ -1744,63 +1744,67 @@ size_t ZSTD_getNextcBlockSize(ZSTD_dctx_t dctx)
size_t ZSTD_decompressContinue(ZSTD_dctx_t dctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
{
dctx_t* ctx = (dctx_t*)dctx;
size_t cSize = srcSize - ZSTD_blockHeaderSize;
size_t rSize;
// Sanity check
/* Sanity check */
if (srcSize != ctx->expected) return (size_t)-ZSTD_ERROR_wrongSrcSize;
// Decompress
if (!ctx->started)
/* Decompress : frame header */
if (ctx->phase == 0)
{
// Just check correct magic header
/* Check frame magic header */
U32 magicNumber = ZSTD_readBE32(src);
if (magicNumber != ZSTD_magicNumber) return (size_t)-ZSTD_ERROR_wrongMagicNumber;
rSize = 0;
ctx->phase = 1;
ctx->expected = ZSTD_blockHeaderSize;
return 0;
}
else
/* Decompress : block header */
if (ctx->phase == 1)
{
blockProperties_t bp;
size_t blockSize = ZSTD_getcBlockSize(src, ZSTD_blockHeaderSize, &bp);
if (ZSTD_isError(blockSize)) return blockSize;
if (bp.blockType == bt_end)
{
ctx->expected = 0;
ctx->phase = 0;
}
else
{
ctx->expected = blockSize;
ctx->bType = bp.blockType;
ctx->phase = 2;
}
return 0;
}
/* Decompress : block content */
{
size_t rSize;
switch(ctx->bType)
{
case bt_compressed:
rSize = ZSTD_decompressBlock(ctx, dst, maxDstSize, src, cSize);
rSize = ZSTD_decompressBlock(ctx, dst, maxDstSize, src, srcSize);
break;
case bt_raw :
rSize = ZSTD_copyUncompressedBlock(dst, maxDstSize, src, cSize);
rSize = ZSTD_copyUncompressedBlock(dst, maxDstSize, src, srcSize);
break;
case bt_rle :
return (size_t)-ZSTD_ERROR_GENERIC; /* not yet handled */
break;
case bt_end :
case bt_end : /* should never happen (filtered at phase 1) */
rSize = 0;
break;
default:
return (size_t)-ZSTD_ERROR_GENERIC;
}
ctx->phase = 1;
ctx->expected = ZSTD_blockHeaderSize;
return rSize;
}
// Prepare next block
{
const BYTE* header = (const BYTE*)src;
blockProperties_t bp;
size_t blockSize;
header += cSize;
blockSize = ZSTD_getcBlockSize(header, ZSTD_blockHeaderSize, &bp);
if (ZSTD_isError(blockSize)) return blockSize;
if (bp.blockType == bt_end)
{
ctx->expected = 0;
ctx->started = 0;
}
else
{
ctx->expected = blockSize + ZSTD_blockHeaderSize;
ctx->bType = bp.blockType;
ctx->started = 1;
}
}
return rSize;
}