[FFmpeg-devel] [PATCH 3/4] lavc/bitstream: templatize for BE/LE
Anton Khirnov
anton at khirnov.net
Thu Jun 23 15:26:35 EEST 2022
Allows using both BE and LE bitstream readers in the same file.
---
libavcodec/bitstream.h | 379 ++----------------------------
libavcodec/bitstream_template.h | 392 ++++++++++++++++++++++++++++++++
tests/ref/fate/source | 1 +
3 files changed, 415 insertions(+), 357 deletions(-)
create mode 100644 libavcodec/bitstream_template.h
diff --git a/libavcodec/bitstream.h b/libavcodec/bitstream.h
index 8a710bcecc..3fa63695d3 100644
--- a/libavcodec/bitstream.h
+++ b/libavcodec/bitstream.h
@@ -49,88 +49,6 @@ typedef struct BitstreamContext {
unsigned size_in_bits;
} BitstreamContext;
-static inline void refill_64(BitstreamContext *bc)
-{
-#if !UNCHECKED_BITSTREAM_READER
- if (bc->ptr >= bc->buffer_end)
- return;
-#endif
-
-#ifdef BITSTREAM_READER_LE
- bc->bits = AV_RL64(bc->ptr);
-#else
- bc->bits = AV_RB64(bc->ptr);
-#endif
- bc->ptr += 8;
- bc->bits_left = 64;
-}
-
-static inline void refill_32(BitstreamContext *bc)
-{
-#if !UNCHECKED_BITSTREAM_READER
- if (bc->ptr >= bc->buffer_end)
- return;
-#endif
-
-#ifdef BITSTREAM_READER_LE
- bc->bits = (uint64_t)AV_RL32(bc->ptr) << bc->bits_left | bc->bits;
-#else
- bc->bits = bc->bits | (uint64_t)AV_RB32(bc->ptr) << (32 - bc->bits_left);
-#endif
- bc->ptr += 4;
- bc->bits_left += 32;
-}
-
-/**
- * Initialize BitstreamContext.
- * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
- * larger than the actual read bits because some optimized bitstream
- * readers read 32 or 64 bits at once and could read over the end
- * @param bit_size the size of the buffer in bits
- * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
- */
-static inline int bitstream_init(BitstreamContext *bc, const uint8_t *buffer,
- unsigned int bit_size)
-{
- unsigned int buffer_size;
-
- if (bit_size > INT_MAX - 7 || !buffer) {
- bc->buffer = NULL;
- bc->ptr = NULL;
- bc->bits_left = 0;
- return AVERROR_INVALIDDATA;
- }
-
- buffer_size = (bit_size + 7) >> 3;
-
- bc->buffer = buffer;
- bc->buffer_end = buffer + buffer_size;
- bc->ptr = bc->buffer;
- bc->size_in_bits = bit_size;
- bc->bits_left = 0;
- bc->bits = 0;
-
- refill_64(bc);
-
- return 0;
-}
-
-/**
- * Initialize BitstreamContext.
- * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
- * larger than the actual read bits because some optimized bitstream
- * readers read 32 or 64 bits at once and could read over the end
- * @param byte_size the size of the buffer in bytes
- * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow
- */
-static inline int bitstream_init8(BitstreamContext *bc, const uint8_t *buffer,
- unsigned int byte_size)
-{
- if (byte_size > INT_MAX / 8)
- return AVERROR_INVALIDDATA;
- return bitstream_init(bc, buffer, byte_size * 8);
-}
-
/**
* Return number of bits already read.
*/
@@ -155,235 +73,6 @@ static inline int bitstream_bits_left(const BitstreamContext *bc)
return (bc->buffer - bc->ptr) * 8 + bc->size_in_bits + bc->bits_left;
}
-static inline uint64_t get_val(BitstreamContext *bc, unsigned int n)
-{
- uint64_t ret;
-
-#ifdef BITSTREAM_READER_LE
- ret = bc->bits & ((UINT64_C(1) << n) - 1);
- bc->bits >>= n;
-#else
- ret = bc->bits >> (64 - n);
- bc->bits <<= n;
-#endif
- bc->bits_left -= n;
-
- return ret;
-}
-
-/**
- * Return one bit from the buffer.
- */
-static inline unsigned int bitstream_read_bit(BitstreamContext *bc)
-{
- if (!bc->bits_left)
- refill_64(bc);
-
- return get_val(bc, 1);
-}
-
-/**
- * Return n bits from the buffer, n has to be in the 0-63 range.
- */
-static inline uint64_t bitstream_read_63(BitstreamContext *bc, unsigned int n)
-{
- uint64_t ret = 0;
-#ifdef BITSTREAM_READER_LE
- uint64_t left = 0;
-#endif
-
- if (!n)
- return 0;
-
- if (n > bc->bits_left) {
- n -= bc->bits_left;
-#ifdef BITSTREAM_READER_LE
- left = bc->bits_left;
-#endif
- ret = get_val(bc, bc->bits_left);
- refill_64(bc);
- }
-
-#ifdef BITSTREAM_READER_LE
- ret = get_val(bc, n) << left | ret;
-#else
- ret = get_val(bc, n) | ret << n;
-#endif
-
- return ret;
-}
-
-/**
- * Return n bits from the buffer, n has to be in the 0-32 range.
- */
-static inline uint32_t bitstream_read(BitstreamContext *bc, unsigned int n)
-{
- if (!n)
- return 0;
-
- if (n > bc->bits_left) {
- refill_32(bc);
- if (bc->bits_left < 32)
- bc->bits_left = n;
- }
-
- return get_val(bc, n);
-}
-
-/**
- * Return n bits from the buffer as a signed integer.
- * n has to be in the 0-32 range.
- */
-static inline int32_t bitstream_read_signed(BitstreamContext *bc, unsigned int n)
-{
- return sign_extend(bitstream_read(bc, n), n);
-}
-
-static inline unsigned int show_val(BitstreamContext *bc, unsigned int n)
-{
-#ifdef BITSTREAM_READER_LE
- return bc->bits & ((UINT64_C(1) << n) - 1);
-#else
- return bc->bits >> (64 - n);
-#endif
-}
-
-/**
- * Return n bits from the buffer but do not change the buffer state.
- * n has to be in the 0-32 range.
- */
-static inline unsigned int bitstream_peek(BitstreamContext *bc, unsigned int n)
-{
- if (n > bc->bits_left)
- refill_32(bc);
-
- return show_val(bc, n);
-}
-
-/**
- * Return n bits from the buffer as a signed integer,
- * do not change the buffer state.
- * n has to be in the 0-32 range.
- */
-static inline int bitstream_peek_signed(BitstreamContext *bc, unsigned int n)
-{
- return sign_extend(bitstream_peek(bc, n), n);
-}
-
-static inline void skip_remaining(BitstreamContext *bc, unsigned int n)
-{
-#ifdef BITSTREAM_READER_LE
- bc->bits >>= n;
-#else
- bc->bits <<= n;
-#endif
- bc->bits_left -= n;
-}
-
-/**
- * Skip n bits in the buffer.
- */
-static inline void bitstream_skip(BitstreamContext *bc, unsigned int n)
-{
- if (n < bc->bits_left)
- skip_remaining(bc, n);
- else {
- n -= bc->bits_left;
- bc->bits = 0;
- bc->bits_left = 0;
-
- if (n >= 64) {
- unsigned int skip = n / 8;
-
- n -= skip * 8;
- bc->ptr += skip;
- }
- refill_64(bc);
- if (n)
- skip_remaining(bc, n);
- }
-}
-
-/**
- * Seek to the given bit position.
- */
-static inline void bitstream_seek(BitstreamContext *bc, unsigned pos)
-{
- bc->ptr = bc->buffer;
- bc->bits = 0;
- bc->bits_left = 0;
-
- bitstream_skip(bc, pos);
-}
-
-/**
- * Skip bits to a byte boundary.
- */
-static inline const uint8_t *bitstream_align(BitstreamContext *bc)
-{
- unsigned int n = -bitstream_tell(bc) & 7;
- if (n)
- bitstream_skip(bc, n);
- return bc->buffer + (bitstream_tell(bc) >> 3);
-}
-
-/**
- * Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB).
- * If MSB not set it is negative.
- * @param n length in bits
- */
-static inline int bitstream_read_xbits(BitstreamContext *bc, unsigned int n)
-{
- int32_t cache = bitstream_peek(bc, 32);
- int sign = ~cache >> 31;
- skip_remaining(bc, n);
-
- return ((((uint32_t)(sign ^ cache)) >> (32 - n)) ^ sign) - sign;
-}
-
-/**
- * Return decoded truncated unary code for the values 0, 1, 2.
- */
-static inline int bitstream_decode012(BitstreamContext *bc)
-{
- if (!bitstream_read_bit(bc))
- return 0;
- else
- return bitstream_read_bit(bc) + 1;
-}
-
-/**
- * Return decoded truncated unary code for the values 2, 1, 0.
- */
-static inline int bitstream_decode210(BitstreamContext *bc)
-{
- if (bitstream_read_bit(bc))
- return 0;
- else
- return 2 - bitstream_read_bit(bc);
-}
-
-/* Read sign bit and flip the sign of the provided value accordingly. */
-static inline int bitstream_apply_sign(BitstreamContext *bc, int val)
-{
- int sign = bitstream_read_signed(bc, 1);
- return (val ^ sign) - sign;
-}
-
-static inline int bitstream_skip_1stop_8data(BitstreamContext *s)
-{
- if (bitstream_bits_left(s) <= 0)
- return AVERROR_INVALIDDATA;
-
- while (bitstream_read(s, 1)) {
- bitstream_skip(s, 8);
- if (bitstream_bits_left(s) <= 0)
- return AVERROR_INVALIDDATA;
- }
-
- return 0;
-}
-
/* Unwind the cache so a refill_32 can fill it again. */
static inline void bitstream_unwind(BitstreamContext *bc)
{
@@ -412,52 +101,28 @@ static inline void bitstream_unget(BitstreamContext *bc, uint64_t value,
bc->bits_left += amount;
}
-/**
- * Return the LUT element for the given bitstream configuration.
- */
-static inline int set_idx(BitstreamContext *bc, int code, int *n, int *nb_bits,
- const VLCElem *table)
-{
- unsigned idx;
-
- *nb_bits = -*n;
- idx = bitstream_peek(bc, *nb_bits) + code;
- *n = table[idx].len;
-
- return table[idx].sym;
-}
-
-/**
- * Parse a vlc code.
- * @param bits is the number of bits which will be read at once, must be
- * identical to nb_bits in init_vlc()
- * @param max_depth is the number of times bits bits must be read to completely
- * read the longest vlc code
- * = (max_vlc_length + bits - 1) / bits
- * If the vlc code is invalid and max_depth=1, then no bits will be removed.
- * If the vlc code is invalid and max_depth>1, then the number of bits removed
- * is undefined.
- */
-static inline int bitstream_read_vlc(BitstreamContext *bc, const VLCElem *table,
- int bits, int max_depth)
-{
- int nb_bits;
- unsigned idx = bitstream_peek(bc, bits);
- int code = table[idx].sym;
- int n = table[idx].len;
-
- if (max_depth > 1 && n < 0) {
- skip_remaining(bc, bits);
- code = set_idx(bc, code, &n, &nb_bits, table);
- if (max_depth > 2 && n < 0) {
- skip_remaining(bc, nb_bits);
- code = set_idx(bc, code, &n, &nb_bits, table);
- }
- }
- skip_remaining(bc, n);
-
- return code;
-}
+#define BITSTREAM_LE
+#include "bitstream_template.h"
+
+#undef BITSTREAM_LE
+#include "bitstream_template.h"
+
+#define bitstream_init bitstream_init_be
+#define bitstream_init8 bitstream_init8_be
+#define bitstream_read_bit bitstream_read_bit_be
+#define bitstream_read_63 bitstream_read_63_be
+#define bitstream_read bitstream_read_be
+#define bitstream_read_signed bitstream_read_signed_be
+#define bitstream_peek bitstream_peek_be
+#define bitstream_peek_signed bitstream_peek_signed_be
+#define bitstream_skip bitstream_skip_be
+#define bitstream_seek bitstream_seek_be
+#define bitstream_align bitstream_align_be
+#define bitstream_read_xbits bitstream_read_xbits_be
+#define bitstream_decode012 bitstream_decode012_be
+#define bitstream_decode210 bitstream_decode210_be
+#define bitstream_apply_sign bitstream_apply_sign_be
+#define bitstream_read_vlc bitstream_read_vlc_be
#define BITSTREAM_RL_VLC(level, run, bc, table, bits, max_depth) \
do { \
diff --git a/libavcodec/bitstream_template.h b/libavcodec/bitstream_template.h
new file mode 100644
index 0000000000..6b31bc53a2
--- /dev/null
+++ b/libavcodec/bitstream_template.h
@@ -0,0 +1,392 @@
+/*
+ * Copyright (c) 2016 Alexandra Hájková
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifdef BITSTREAM_LE
+# define BS_SUFFIX le
+#else
+# define BS_SUFFIX be
+#endif
+
+#define BS_JOIN(x, y) x ## _ ## y
+#define BS_FUNC2(x, y) BS_JOIN(x, y)
+#define BS_FUNC(x) BS_FUNC2(x, BS_SUFFIX)
+
+static inline void BS_FUNC(refill_64)(BitstreamContext *bc)
+{
+#if !UNCHECKED_BITSTREAM_READER
+ if (bc->ptr >= bc->buffer_end)
+ return;
+#endif
+
+#ifdef BITSTREAM_LE
+ bc->bits = AV_RL64(bc->ptr);
+#else
+ bc->bits = AV_RB64(bc->ptr);
+#endif
+ bc->ptr += 8;
+ bc->bits_left = 64;
+}
+
+static inline void BS_FUNC(refill_32)(BitstreamContext *bc)
+{
+#if !UNCHECKED_BITSTREAM_READER
+ if (bc->ptr >= bc->buffer_end)
+ return;
+#endif
+
+#ifdef BITSTREAM_LE
+ bc->bits = (uint64_t)AV_RL32(bc->ptr) << bc->bits_left | bc->bits;
+#else
+ bc->bits = bc->bits | (uint64_t)AV_RB32(bc->ptr) << (32 - bc->bits_left);
+#endif
+ bc->ptr += 4;
+ bc->bits_left += 32;
+}
+
+/**
+ * Initialize BitstreamContext.
+ * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
+ * larger than the actual read bits because some optimized bitstream
+ * readers read 32 or 64 bits at once and could read over the end
+ * @param bit_size the size of the buffer in bits
+ * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
+ */
+static inline int BS_FUNC(bitstream_init)(BitstreamContext *bc, const uint8_t *buffer,
+ unsigned int bit_size)
+{
+ unsigned int buffer_size;
+
+ if (bit_size > INT_MAX - 7 || !buffer) {
+ bc->buffer = NULL;
+ bc->ptr = NULL;
+ bc->bits_left = 0;
+ return AVERROR_INVALIDDATA;
+ }
+
+ buffer_size = (bit_size + 7) >> 3;
+
+ bc->buffer = buffer;
+ bc->buffer_end = buffer + buffer_size;
+ bc->ptr = bc->buffer;
+ bc->size_in_bits = bit_size;
+ bc->bits_left = 0;
+ bc->bits = 0;
+
+ BS_FUNC(refill_64)(bc);
+
+ return 0;
+}
+
+/**
+ * Initialize BitstreamContext.
+ * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
+ * larger than the actual read bits because some optimized bitstream
+ * readers read 32 or 64 bits at once and could read over the end
+ * @param byte_size the size of the buffer in bytes
+ * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow
+ */
+static inline int BS_FUNC(bitstream_init8)(BitstreamContext *bc, const uint8_t *buffer,
+ unsigned int byte_size)
+{
+ if (byte_size > INT_MAX / 8)
+ return AVERROR_INVALIDDATA;
+ return BS_FUNC(bitstream_init)(bc, buffer, byte_size * 8);
+}
+
+static inline uint64_t BS_FUNC(get_val)(BitstreamContext *bc, unsigned int n)
+{
+ uint64_t ret;
+
+#ifdef BITSTREAM_LE
+ ret = bc->bits & ((UINT64_C(1) << n) - 1);
+ bc->bits >>= n;
+#else
+ ret = bc->bits >> (64 - n);
+ bc->bits <<= n;
+#endif
+ bc->bits_left -= n;
+
+ return ret;
+}
+
+/**
+ * Return one bit from the buffer.
+ */
+static inline unsigned int BS_FUNC(bitstream_read_bit)(BitstreamContext *bc)
+{
+ if (!bc->bits_left)
+ BS_FUNC(refill_64)(bc);
+
+ return BS_FUNC(get_val)(bc, 1);
+}
+
+/**
+ * Return n bits from the buffer, n has to be in the 0-63 range.
+ */
+static inline uint64_t BS_FUNC(bitstream_read_63)(BitstreamContext *bc, unsigned int n)
+{
+ uint64_t ret = 0;
+#ifdef BITSTREAM_LE
+ uint64_t left = 0;
+#endif
+
+ if (!n)
+ return 0;
+
+ if (n > bc->bits_left) {
+ n -= bc->bits_left;
+#ifdef BITSTREAM_LE
+ left = bc->bits_left;
+#endif
+ ret = BS_FUNC(get_val)(bc, bc->bits_left);
+ BS_FUNC(refill_64)(bc);
+ }
+
+#ifdef BITSTREAM_LE
+ ret = get_val_le(bc, n) << left | ret;
+#else
+ ret = get_val_be(bc, n) | ret << n;
+#endif
+
+ return ret;
+}
+
+/**
+ * Return n bits from the buffer, n has to be in the 0-32 range.
+ */
+static inline uint32_t BS_FUNC(bitstream_read)(BitstreamContext *bc, unsigned int n)
+{
+ if (!n)
+ return 0;
+
+ if (n > bc->bits_left) {
+ BS_FUNC(refill_32)(bc);
+ if (bc->bits_left < 32)
+ bc->bits_left = n;
+ }
+
+ return BS_FUNC(get_val)(bc, n);
+}
+
+/**
+ * Return n bits from the buffer as a signed integer.
+ * n has to be in the 0-32 range.
+ */
+static inline int32_t BS_FUNC(bitstream_read_signed)(BitstreamContext *bc, unsigned int n)
+{
+ return sign_extend(BS_FUNC(bitstream_read)(bc, n), n);
+}
+
+static inline unsigned int BS_FUNC(show_val)(BitstreamContext *bc, unsigned int n)
+{
+#ifdef BITSTREAM_LE
+ return bc->bits & ((UINT64_C(1) << n) - 1);
+#else
+ return bc->bits >> (64 - n);
+#endif
+}
+
+/**
+ * Return n bits from the buffer but do not change the buffer state.
+ * n has to be in the 0-32 range.
+ */
+static inline unsigned int BS_FUNC(bitstream_peek)(BitstreamContext *bc, unsigned int n)
+{
+ if (n > bc->bits_left)
+ BS_FUNC(refill_32)(bc);
+
+ return BS_FUNC(show_val)(bc, n);
+}
+
+/**
+ * Return n bits from the buffer as a signed integer,
+ * do not change the buffer state.
+ * n has to be in the 0-32 range.
+ */
+static inline int BS_FUNC(bitstream_peek_signed)(BitstreamContext *bc, unsigned int n)
+{
+ return sign_extend(BS_FUNC(bitstream_peek)(bc, n), n);
+}
+
+static inline void BS_FUNC(skip_remaining)(BitstreamContext *bc, unsigned int n)
+{
+#ifdef BITSTREAM_LE
+ bc->bits >>= n;
+#else
+ bc->bits <<= n;
+#endif
+ bc->bits_left -= n;
+}
+
+/**
+ * Skip n bits in the buffer.
+ */
+static inline void BS_FUNC(bitstream_skip)(BitstreamContext *bc, unsigned int n)
+{
+ if (n < bc->bits_left)
+ BS_FUNC(skip_remaining)(bc, n);
+ else {
+ n -= bc->bits_left;
+ bc->bits = 0;
+ bc->bits_left = 0;
+
+ if (n >= 64) {
+ unsigned int skip = n / 8;
+
+ n -= skip * 8;
+ bc->ptr += skip;
+ }
+ BS_FUNC(refill_64)(bc);
+ if (n)
+ BS_FUNC(skip_remaining)(bc, n);
+ }
+}
+
+/**
+ * Seek to the given bit position.
+ */
+static inline void BS_FUNC(bitstream_seek)(BitstreamContext *bc, unsigned pos)
+{
+ bc->ptr = bc->buffer;
+ bc->bits = 0;
+ bc->bits_left = 0;
+
+ BS_FUNC(bitstream_skip)(bc, pos);
+}
+
+/**
+ * Skip bits to a byte boundary.
+ */
+static inline const uint8_t *BS_FUNC(bitstream_align)(BitstreamContext *bc)
+{
+ unsigned int n = -bitstream_tell(bc) & 7;
+ if (n)
+ BS_FUNC(bitstream_skip)(bc, n);
+ return bc->buffer + (bitstream_tell(bc) >> 3);
+}
+
+/**
+ * Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB).
+ * If MSB not set it is negative.
+ * @param n length in bits
+ */
+static inline int BS_FUNC(bitstream_read_xbits)(BitstreamContext *bc, unsigned int n)
+{
+ int32_t cache = BS_FUNC(bitstream_peek)(bc, 32);
+ int sign = ~cache >> 31;
+ BS_FUNC(skip_remaining)(bc, n);
+
+ return ((((uint32_t)(sign ^ cache)) >> (32 - n)) ^ sign) - sign;
+}
+
+/**
+ * Return decoded truncated unary code for the values 0, 1, 2.
+ */
+static inline int BS_FUNC(bitstream_decode012)(BitstreamContext *bc)
+{
+ if (!BS_FUNC(bitstream_read_bit)(bc))
+ return 0;
+ else
+ return BS_FUNC(bitstream_read_bit)(bc) + 1;
+}
+
+/**
+ * Return decoded truncated unary code for the values 2, 1, 0.
+ */
+static inline int BS_FUNC(bitstream_decode210)(BitstreamContext *bc)
+{
+ if (BS_FUNC(bitstream_read_bit)(bc))
+ return 0;
+ else
+ return 2 - BS_FUNC(bitstream_read_bit)(bc);
+}
+
+/* Read sign bit and flip the sign of the provided value accordingly. */
+static inline int BS_FUNC(bitstream_apply_sign)(BitstreamContext *bc, int val)
+{
+ int sign = BS_FUNC(bitstream_read_signed)(bc, 1);
+ return (val ^ sign) - sign;
+}
+
+static inline int BS_FUNC(bitstream_skip_1stop_8data)(BitstreamContext *s)
+{
+ if (bitstream_bits_left(s) <= 0)
+ return AVERROR_INVALIDDATA;
+
+ while (BS_FUNC(bitstream_read)(s, 1)) {
+ BS_FUNC(bitstream_skip)(s, 8);
+ if (bitstream_bits_left(s) <= 0)
+ return AVERROR_INVALIDDATA;
+ }
+
+ return 0;
+}
+
+/**
+ * Return the LUT element for the given bitstream configuration.
+ */
+static inline int BS_FUNC(set_idx)(BitstreamContext *bc, int code, int *n, int *nb_bits,
+ const VLCElem *table)
+{
+ unsigned idx;
+
+ *nb_bits = -*n;
+ idx = BS_FUNC(bitstream_peek)(bc, *nb_bits) + code;
+ *n = table[idx].len;
+
+ return table[idx].sym;
+}
+
+/**
+ * Parse a vlc code.
+ * @param bits is the number of bits which will be read at once, must be
+ * identical to nb_bits in init_vlc()
+ * @param max_depth is the number of times bits bits must be read to completely
+ * read the longest vlc code
+ * = (max_vlc_length + bits - 1) / bits
+ * If the vlc code is invalid and max_depth=1, then no bits will be removed.
+ * If the vlc code is invalid and max_depth>1, then the number of bits removed
+ * is undefined.
+ */
+static inline int BS_FUNC(bitstream_read_vlc)(BitstreamContext *bc, const VLCElem *table,
+ int bits, int max_depth)
+{
+ int nb_bits;
+ unsigned idx = BS_FUNC(bitstream_peek)(bc, bits);
+ int code = table[idx].sym;
+ int n = table[idx].len;
+
+ if (max_depth > 1 && n < 0) {
+ BS_FUNC(skip_remaining)(bc, bits);
+ code = BS_FUNC(set_idx)(bc, code, &n, &nb_bits, table);
+ if (max_depth > 2 && n < 0) {
+ BS_FUNC(skip_remaining)(bc, nb_bits);
+ code = BS_FUNC(set_idx)(bc, code, &n, &nb_bits, table);
+ }
+ }
+ BS_FUNC(skip_remaining)(bc, n);
+
+ return code;
+}
+
+#undef BS_FUNC
+#undef BS_FUNC2
+#undef BS_JOIN
+#undef BS_SUFFIX
diff --git a/tests/ref/fate/source b/tests/ref/fate/source
index 16ea7ef9c1..3b7ea9c379 100644
--- a/tests/ref/fate/source
+++ b/tests/ref/fate/source
@@ -21,6 +21,7 @@ Headers without standard inclusion guards:
compat/djgpp/math.h
compat/float/float.h
compat/float/limits.h
+libavcodec/bitstream_template.h
tools/decode_simple.h
Use of av_clip() where av_clip_uintp2() could be used:
Use of av_clip() where av_clip_intp2() could be used:
--
2.34.1
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