/* ******************************************************************
- bitstream
- Part of FSE library
- Copyright (C) 2013-present, Yann Collet.
-
- BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
-
- Redistribution and use in source and binary forms, with or without
- modification, are permitted provided that the following conditions are
- met:
-
- * Redistributions of source code must retain the above copyright
- notice, this list of conditions and the following disclaimer.
- * Redistributions in binary form must reproduce the above
- copyright notice, this list of conditions and the following disclaimer
- in the documentation and/or other materials provided with the
- distribution.
-
- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
- You can contact the author at :
- - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
+ * bitstream
+ * Part of FSE library
+ * Copyright (c) 2013-2020, Yann Collet, Facebook, Inc.
+ *
+ * You can contact the author at :
+ * - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
****************************************************************** */
#ifndef BITSTREAM_H_MODULE
#define BITSTREAM_H_MODULE
* Dependencies
******************************************/
#include "mem.h" /* unaligned access routines */
+#include "compiler.h" /* UNLIKELY() */
#include "debug.h" /* assert(), DEBUGLOG(), RAWLOG() */
#include "error_private.h" /* error codes and messages */
=========================================*/
#if defined(__BMI__) && defined(__GNUC__)
# include <immintrin.h> /* support for bextr (experimental) */
+#elif defined(__ICCARM__)
+# include <intrinsics.h>
#endif
#define STREAM_ACCUMULATOR_MIN_32 25
{
# if defined(_MSC_VER) /* Visual */
unsigned long r=0;
- _BitScanReverse ( &r, val );
- return (unsigned) r;
+ return _BitScanReverse ( &r, val ) ? (unsigned)r : 0;
# elif defined(__GNUC__) && (__GNUC__ >= 3) /* Use GCC Intrinsic */
- return 31 - __builtin_clz (val);
+ return __builtin_clz (val) ^ 31;
+# elif defined(__ICCARM__) /* IAR Intrinsic */
+ return 31 - __CLZ(val);
# else /* Software version */
static const unsigned DeBruijnClz[32] = { 0, 9, 1, 10, 13, 21, 2, 29,
11, 14, 16, 18, 22, 25, 3, 30,
{
size_t const nbBytes = bitC->bitPos >> 3;
assert(bitC->bitPos < sizeof(bitC->bitContainer) * 8);
+ assert(bitC->ptr <= bitC->endPtr);
MEM_writeLEST(bitC->ptr, bitC->bitContainer);
bitC->ptr += nbBytes;
- assert(bitC->ptr <= bitC->endPtr);
bitC->bitPos &= 7;
bitC->bitContainer >>= nbBytes*8;
}
{
size_t const nbBytes = bitC->bitPos >> 3;
assert(bitC->bitPos < sizeof(bitC->bitContainer) * 8);
+ assert(bitC->ptr <= bitC->endPtr);
MEM_writeLEST(bitC->ptr, bitC->bitContainer);
bitC->ptr += nbBytes;
if (bitC->ptr > bitC->endPtr) bitC->ptr = bitC->endPtr;
* 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. */
-MEM_STATIC size_t BIT_readBits(BIT_DStream_t* bitD, U32 nbBits)
+MEM_STATIC size_t BIT_readBits(BIT_DStream_t* bitD, unsigned nbBits)
{
size_t const value = BIT_lookBits(bitD, nbBits);
BIT_skipBits(bitD, nbBits);
/*! BIT_readBitsFast() :
* unsafe version; only works only if nbBits >= 1 */
-MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, U32 nbBits)
+MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, unsigned nbBits)
{
size_t const value = BIT_lookBitsFast(bitD, nbBits);
assert(nbBits >= 1);
return value;
}
+/*! BIT_reloadDStreamFast() :
+ * Similar to BIT_reloadDStream(), but with two differences:
+ * 1. bitsConsumed <= sizeof(bitD->bitContainer)*8 must hold!
+ * 2. Returns BIT_DStream_overflow when bitD->ptr < bitD->limitPtr, at this
+ * point you must use BIT_reloadDStream() to reload.
+ */
+MEM_STATIC BIT_DStream_status BIT_reloadDStreamFast(BIT_DStream_t* bitD)
+{
+ if (UNLIKELY(bitD->ptr < bitD->limitPtr))
+ return BIT_DStream_overflow;
+ assert(bitD->bitsConsumed <= sizeof(bitD->bitContainer)*8);
+ bitD->ptr -= bitD->bitsConsumed >> 3;
+ bitD->bitsConsumed &= 7;
+ bitD->bitContainer = MEM_readLEST(bitD->ptr);
+ return BIT_DStream_unfinished;
+}
+
/*! 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 BIT_DStream_overflow;
if (bitD->ptr >= bitD->limitPtr) {
- bitD->ptr -= bitD->bitsConsumed >> 3;
- bitD->bitsConsumed &= 7;
- bitD->bitContainer = MEM_readLEST(bitD->ptr);
- return BIT_DStream_unfinished;
+ return BIT_reloadDStreamFast(bitD);
}
if (bitD->ptr == bitD->start) {
if (bitD->bitsConsumed < sizeof(bitD->bitContainer)*8) return BIT_DStream_endOfBuffer;
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