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Diffstat (limited to 'thirdparty/zstd/common/bitstream.h')
-rw-r--r--thirdparty/zstd/common/bitstream.h81
1 files changed, 40 insertions, 41 deletions
diff --git a/thirdparty/zstd/common/bitstream.h b/thirdparty/zstd/common/bitstream.h
index 07b85026c9..06121f21c5 100644
--- a/thirdparty/zstd/common/bitstream.h
+++ b/thirdparty/zstd/common/bitstream.h
@@ -80,9 +80,9 @@ extern "C" {
* bitStream encoding API (write forward)
********************************************/
/* bitStream can mix input from multiple sources.
-* A critical property of these streams is that they encode and decode in **reverse** direction.
-* So the first bit sequence you add will be the last to be read, like a LIFO stack.
-*/
+ * A critical property of these streams is that they encode and decode in **reverse** direction.
+ * So the first bit sequence you add will be the last to be read, like a LIFO stack.
+ */
typedef struct
{
size_t bitContainer;
@@ -203,7 +203,7 @@ static const unsigned BIT_mask[] = { 0, 1, 3, 7, 0xF, 0x1F, 0x3F, 0x7F,
/*! BIT_initCStream() :
* `dstCapacity` must be > sizeof(size_t)
* @return : 0 if success,
- otherwise an error code (can be tested using ERR_isError() ) */
+ * otherwise an error code (can be tested using ERR_isError()) */
MEM_STATIC size_t BIT_initCStream(BIT_CStream_t* bitC,
void* startPtr, size_t dstCapacity)
{
@@ -217,8 +217,8 @@ MEM_STATIC size_t BIT_initCStream(BIT_CStream_t* bitC,
}
/*! BIT_addBits() :
- can add up to 26 bits into `bitC`.
- Does not check for register overflow ! */
+ * can add up to 26 bits into `bitC`.
+ * Note : does not check for register overflow ! */
MEM_STATIC void BIT_addBits(BIT_CStream_t* bitC,
size_t value, unsigned nbBits)
{
@@ -268,7 +268,7 @@ MEM_STATIC void BIT_flushBits(BIT_CStream_t* bitC)
/*! BIT_closeCStream() :
* @return : size of CStream, in bytes,
- or 0 if it could not fit into dstBuffer */
+ * or 0 if it could not fit into dstBuffer */
MEM_STATIC size_t BIT_closeCStream(BIT_CStream_t* bitC)
{
BIT_addBitsFast(bitC, 1, 1); /* endMark */
@@ -279,14 +279,14 @@ MEM_STATIC size_t BIT_closeCStream(BIT_CStream_t* bitC)
/*-********************************************************
-* bitStream decoding
+* bitStream decoding
**********************************************************/
/*! BIT_initDStream() :
-* Initialize a BIT_DStream_t.
-* `bitD` : a pointer to an already allocated BIT_DStream_t structure.
-* `srcSize` must be the *exact* size of the bitStream, in bytes.
-* @return : size of stream (== srcSize) or an errorCode if a problem is detected
-*/
+ * Initialize a BIT_DStream_t.
+ * `bitD` : a pointer to an already allocated BIT_DStream_t structure.
+ * `srcSize` must be the *exact* size of the bitStream, in bytes.
+ * @return : size of stream (== srcSize), or an errorCode if a problem is detected
+ */
MEM_STATIC size_t BIT_initDStream(BIT_DStream_t* bitD, const void* srcBuffer, size_t srcSize)
{
if (srcSize < 1) { memset(bitD, 0, sizeof(*bitD)); return ERROR(srcSize_wrong); }
@@ -305,29 +305,30 @@ MEM_STATIC size_t BIT_initDStream(BIT_DStream_t* bitD, const void* srcBuffer, si
bitD->bitContainer = *(const BYTE*)(bitD->start);
switch(srcSize)
{
- case 7: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[6]) << (sizeof(bitD->bitContainer)*8 - 16);
- /* fall-through */
+ case 7: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[6]) << (sizeof(bitD->bitContainer)*8 - 16);
+ /* fall-through */
- case 6: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[5]) << (sizeof(bitD->bitContainer)*8 - 24);
- /* fall-through */
+ case 6: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[5]) << (sizeof(bitD->bitContainer)*8 - 24);
+ /* fall-through */
- case 5: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[4]) << (sizeof(bitD->bitContainer)*8 - 32);
- /* fall-through */
+ case 5: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[4]) << (sizeof(bitD->bitContainer)*8 - 32);
+ /* fall-through */
- case 4: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[3]) << 24;
- /* fall-through */
+ case 4: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[3]) << 24;
+ /* fall-through */
- case 3: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[2]) << 16;
- /* fall-through */
+ case 3: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[2]) << 16;
+ /* fall-through */
- case 2: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[1]) << 8;
- /* fall-through */
+ case 2: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[1]) << 8;
+ /* fall-through */
- default: break;
+ default: break;
+ }
+ { BYTE const lastByte = ((const BYTE*)srcBuffer)[srcSize-1];
+ bitD->bitsConsumed = lastByte ? 8 - BIT_highbit32(lastByte) : 0;
+ if (lastByte == 0) return ERROR(corruption_detected); /* endMark not present */
}
- { BYTE const lastByte = ((const BYTE*)srcBuffer)[srcSize-1];
- bitD->bitsConsumed = lastByte ? 8 - BIT_highbit32(lastByte) : 0;
- if (lastByte == 0) return ERROR(GENERIC); /* endMark not present */ }
bitD->bitsConsumed += (U32)(sizeof(bitD->bitContainer) - srcSize)*8;
}
@@ -363,9 +364,8 @@ MEM_STATIC size_t BIT_getLowerBits(size_t bitContainer, U32 const nbBits)
* local register is not modified.
* On 32-bits, maxNbBits==24.
* On 64-bits, maxNbBits==56.
- * @return : value extracted
- */
- MEM_STATIC size_t BIT_lookBits(const BIT_DStream_t* bitD, U32 nbBits)
+ * @return : value extracted */
+MEM_STATIC size_t BIT_lookBits(const BIT_DStream_t* bitD, U32 nbBits)
{
#if defined(__BMI__) && defined(__GNUC__) /* experimental; fails if bitD->bitsConsumed + nbBits > sizeof(bitD->bitContainer)*8 */
return BIT_getMiddleBits(bitD->bitContainer, (sizeof(bitD->bitContainer)*8) - bitD->bitsConsumed - nbBits, nbBits);
@@ -392,8 +392,7 @@ MEM_STATIC void BIT_skipBits(BIT_DStream_t* bitD, U32 nbBits)
/*! BIT_readBits() :
* Read (consume) next n bits from local register and update.
* Pay attention to not read more than nbBits contained into local register.
- * @return : extracted value.
- */
+ * @return : extracted value. */
MEM_STATIC size_t BIT_readBits(BIT_DStream_t* bitD, U32 nbBits)
{
size_t const value = BIT_lookBits(bitD, nbBits);
@@ -402,7 +401,7 @@ MEM_STATIC size_t BIT_readBits(BIT_DStream_t* bitD, U32 nbBits)
}
/*! BIT_readBitsFast() :
-* unsafe version; only works only if nbBits >= 1 */
+ * unsafe version; only works only if nbBits >= 1 */
MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, U32 nbBits)
{
size_t const value = BIT_lookBitsFast(bitD, nbBits);
@@ -412,10 +411,10 @@ MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, U32 nbBits)
}
/*! BIT_reloadDStream() :
-* Refill `bitD` from buffer previously set in BIT_initDStream() .
-* This function is safe, it guarantees it will not read beyond src buffer.
-* @return : status of `BIT_DStream_t` internal register.
- if status == BIT_DStream_unfinished, internal register is filled with >= (sizeof(bitD->bitContainer)*8 - 7) bits */
+ * Refill `bitD` from buffer previously set in BIT_initDStream() .
+ * This function is safe, it guarantees it will not read beyond src buffer.
+ * @return : status of `BIT_DStream_t` internal register.
+ * when status == BIT_DStream_unfinished, internal register is filled with at least 25 or 57 bits */
MEM_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t* bitD)
{
if (bitD->bitsConsumed > (sizeof(bitD->bitContainer)*8)) /* overflow detected, like end of stream */
@@ -446,8 +445,8 @@ MEM_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t* bitD)
}
/*! BIT_endOfDStream() :
-* @return Tells if DStream has exactly reached its end (all bits consumed).
-*/
+ * @return : 1 if DStream has _exactly_ reached its end (all bits consumed).
+ */
MEM_STATIC unsigned BIT_endOfDStream(const BIT_DStream_t* DStream)
{
return ((DStream->ptr == DStream->start) && (DStream->bitsConsumed == sizeof(DStream->bitContainer)*8));
generated by cgit v1.2.3 (git 2.25.1) at 2025-04-01 08:04:36 +0000