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[libzstd] Fix decompression dictionary bugs and clean up initialization

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Bugs:

* `ZSTD_DCtx_refPrefix()` didn't clear the dictionary after the first
  use. Fix and add a test case.
* `ZSTD_DCtx_reset()` always cleared the dictionary. Fix and add a test
  case.
* After calling `ZSTD_resetDStream()` you could no longer load a
  dictionary, since the stage was set to `zdss_loadHeader`. Fix and add
  a test case.

Cleanup:

* Make `ZSTD_initDStream*()` and `ZSTD_resetDStream()` wrap the new
 advanced API, and add test cases.
* Document the equivalent of these functions in the advanced API and
  document the unstable functions as deprecated.
This commit is contained in:
Nick Terrell
2019-04-10 12:59:02 -07:00
parent f86d4bd1d5
commit 50b9c41196
5 changed files with 274 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/decompress/zstd_decompress.c
+53 -26
View File
@@ -106,6 +106,7 @@ static void ZSTD_initDCtx_internal(ZSTD_DCtx* dctx)
dctx->ddictLocal = NULL;
dctx->dictEnd = NULL;
dctx->ddictIsCold = 0;
dctx->dictUsesRemaining = 0;
dctx->inBuff = NULL;
dctx->inBuffSize = 0;
dctx->outBuffSize = 0;
@@ -147,13 +148,20 @@ ZSTD_DCtx* ZSTD_createDCtx(void)
return ZSTD_createDCtx_advanced(ZSTD_defaultCMem);
}
static void ZSTD_clearDict(ZSTD_DCtx* dctx)
{
ZSTD_freeDDict(dctx->ddictLocal);
dctx->ddictLocal = NULL;
dctx->ddict = NULL;
dctx->dictUsesRemaining = 0;
}
size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx)
{
if (dctx==NULL) return 0; /* support free on NULL */
RETURN_ERROR_IF(dctx->staticSize, memory_allocation, "not compatible with static DCtx");
{ ZSTD_customMem const cMem = dctx->customMem;
ZSTD_freeDDict(dctx->ddictLocal);
dctx->ddictLocal = NULL;
ZSTD_clearDict(dctx);
ZSTD_free(dctx->inBuff, cMem);
dctx->inBuff = NULL;
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1)
@@ -786,9 +794,22 @@ size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx,
}
static ZSTD_DDict const* ZSTD_getDDict(ZSTD_DCtx* dctx)
{
if (dctx->dictUsesRemaining == 0) {
ZSTD_clearDict(dctx);
return NULL;
}
if (dctx->dictUsesRemaining < 0) {
return dctx->ddict;
}
--dctx->dictUsesRemaining;
return dctx->ddict;
}
size_t ZSTD_decompressDCtx(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize)
{
return ZSTD_decompress_usingDDict(dctx, dst, dstCapacity, src, srcSize, dctx->ddict);
return ZSTD_decompress_usingDDict(dctx, dst, dstCapacity, src, srcSize, ZSTD_getDDict(dctx));
}
@@ -1235,14 +1256,13 @@ size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx,
ZSTD_dictContentType_e dictContentType)
{
RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong);
ZSTD_freeDDict(dctx->ddictLocal);
ZSTD_clearDict(dctx);
if (dict && dictSize >= 8) {
dctx->ddictLocal = ZSTD_createDDict_advanced(dict, dictSize, dictLoadMethod, dictContentType, dctx->customMem);
RETURN_ERROR_IF(dctx->ddictLocal == NULL, memory_allocation);
} else {
dctx->ddictLocal = NULL;
dctx->ddict = dctx->ddictLocal;
dctx->dictUsesRemaining = -1;
}
dctx->ddict = dctx->ddictLocal;
return 0;
}
@@ -1258,7 +1278,9 @@ size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSi
size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType)
{
return ZSTD_DCtx_loadDictionary_advanced(dctx, prefix, prefixSize, ZSTD_dlm_byRef, dictContentType);
FORWARD_IF_ERROR(ZSTD_DCtx_loadDictionary_advanced(dctx, prefix, prefixSize, ZSTD_dlm_byRef, dictContentType));
dctx->dictUsesRemaining = 1;
return 0;
}
size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize)
@@ -1273,8 +1295,7 @@ size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSiz
size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize)
{
DEBUGLOG(4, "ZSTD_initDStream_usingDict");
zds->streamStage = zdss_init;
zds->noForwardProgress = 0;
FORWARD_IF_ERROR( ZSTD_DCtx_reset(zds, ZSTD_reset_session_only) );
FORWARD_IF_ERROR( ZSTD_DCtx_loadDictionary(zds, dict, dictSize) );
return ZSTD_FRAMEHEADERSIZE_PREFIX;
}
@@ -1283,7 +1304,7 @@ size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t di
size_t ZSTD_initDStream(ZSTD_DStream* zds)
{
DEBUGLOG(4, "ZSTD_initDStream");
return ZSTD_initDStream_usingDict(zds, NULL, 0);
return ZSTD_initDStream_usingDDict(zds, NULL);
}
/* ZSTD_initDStream_usingDDict() :
@@ -1291,9 +1312,9 @@ size_t ZSTD_initDStream(ZSTD_DStream* zds)
* this function cannot fail */
size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* dctx, const ZSTD_DDict* ddict)
{
size_t const initResult = ZSTD_initDStream(dctx);
dctx->ddict = ddict;
return initResult;
FORWARD_IF_ERROR( ZSTD_DCtx_reset(dctx, ZSTD_reset_session_only) );
FORWARD_IF_ERROR( ZSTD_DCtx_refDDict(dctx, ddict) );
return ZSTD_FRAMEHEADERSIZE_PREFIX;
}
/* ZSTD_resetDStream() :
@@ -1301,11 +1322,7 @@ size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* dctx, const ZSTD_DDict* ddict)
* this function cannot fail */
size_t ZSTD_resetDStream(ZSTD_DStream* dctx)
{
DEBUGLOG(4, "ZSTD_resetDStream");
dctx->streamStage = zdss_loadHeader;
dctx->lhSize = dctx->inPos = dctx->outStart = dctx->outEnd = 0;
dctx->legacyVersion = 0;
dctx->hostageByte = 0;
FORWARD_IF_ERROR(ZSTD_DCtx_reset(dctx, ZSTD_reset_session_only));
return ZSTD_FRAMEHEADERSIZE_PREFIX;
}
@@ -1313,7 +1330,11 @@ size_t ZSTD_resetDStream(ZSTD_DStream* dctx)
size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict)
{
RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong);
dctx->ddict = ddict;
ZSTD_clearDict(dctx);
if (ddict) {
dctx->ddict = ddict;
dctx->dictUsesRemaining = -1;
}
return 0;
}
@@ -1394,11 +1415,13 @@ size_t ZSTD_DCtx_reset(ZSTD_DCtx* dctx, ZSTD_ResetDirective reset)
{
if ( (reset == ZSTD_reset_session_only)
|| (reset == ZSTD_reset_session_and_parameters) ) {
(void)ZSTD_initDStream(dctx);
dctx->streamStage = zdss_init;
dctx->noForwardProgress = 0;
}
if ( (reset == ZSTD_reset_parameters)
|| (reset == ZSTD_reset_session_and_parameters) ) {
RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong);
ZSTD_clearDict(dctx);
dctx->format = ZSTD_f_zstd1;
dctx->maxWindowSize = ZSTD_MAXWINDOWSIZE_DEFAULT;
}
@@ -1481,7 +1504,10 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
{
case zdss_init :
DEBUGLOG(5, "stage zdss_init => transparent reset ");
ZSTD_resetDStream(zds); /* transparent reset on starting decoding a new frame */
zds->streamStage = zdss_loadHeader;
zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0;
zds->legacyVersion = 0;
zds->hostageByte = 0;
/* fall-through */
case zdss_loadHeader :
@@ -1501,8 +1527,9 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
U32 const legacyVersion = ZSTD_isLegacy(istart, iend-istart);
if (legacyVersion) {
const void* const dict = zds->ddict ? ZSTD_DDict_dictContent(zds->ddict) : NULL;
size_t const dictSize = zds->ddict ? ZSTD_DDict_dictSize(zds->ddict) : 0;
ZSTD_DDict const* const ddict = ZSTD_getDDict(zds);
const void* const dict = ddict ? ZSTD_DDict_dictContent(ddict) : NULL;
size_t const dictSize = ddict ? ZSTD_DDict_dictSize(ddict) : 0;
DEBUGLOG(5, "ZSTD_decompressStream: detected legacy version v0.%u", legacyVersion);
RETURN_ERROR_IF(zds->staticSize, memory_allocation,
"legacy support is incompatible with static dctx");
@@ -1540,7 +1567,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
size_t const cSize = ZSTD_findFrameCompressedSize(istart, iend-istart);
if (cSize <= (size_t)(iend-istart)) {
/* shortcut : using single-pass mode */
size_t const decompressedSize = ZSTD_decompress_usingDDict(zds, op, oend-op, istart, cSize, zds->ddict);
size_t const decompressedSize = ZSTD_decompress_usingDDict(zds, op, oend-op, istart, cSize, ZSTD_getDDict(zds));
if (ZSTD_isError(decompressedSize)) return decompressedSize;
DEBUGLOG(4, "shortcut to single-pass ZSTD_decompress_usingDDict()")
ip = istart + cSize;
@@ -1553,7 +1580,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
/* Consume header (see ZSTDds_decodeFrameHeader) */
DEBUGLOG(4, "Consume header");
FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDDict(zds, zds->ddict));
FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDDict(zds, ZSTD_getDDict(zds)));
if ((MEM_readLE32(zds->headerBuffer) & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) { /* skippable frame */
zds->expected = MEM_readLE32(zds->headerBuffer + ZSTD_FRAMEIDSIZE);
lib/decompress/zstd_decompress_internal.h
+3
View File
@@ -123,6 +123,9 @@ struct ZSTD_DCtx_s
const ZSTD_DDict* ddict; /* set by ZSTD_initDStream_usingDDict(), or ZSTD_DCtx_refDDict() */
U32 dictID;
int ddictIsCold; /* if == 1 : dictionary is "new" for working context, and presumed "cold" (not in cpu cache) */
int dictUsesRemaining; /* if == 1 : dictionary should be used once.
* if == 0 : dictionary should be forgotten now.
* if < 0 : dictionary should be used indefinitely. */
/* streaming */
ZSTD_dStreamStage streamStage;