Split bitstream.h, put the bitstream writer stuff in the new file

put_bits.h.

Originally committed as revision 18461 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 311 insertions, 0 deletions

diff --git a/libavcodec/put_bits.h b/libavcodec/put_bits.h
new file mode 100644
index 0000000000..3bddd44ac0
--- /dev/null
+++ b/libavcodec/put_bits.h
@@ -0,0 +1,311 @@
+/*
+ * copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * 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
+ */
+
+/**
+ * @file libavcodec/put_bits.h
+ * bitstream writer API
+ */
+
+#ifndef AVCODEC_PUT_BITS_H
+#define AVCODEC_PUT_BITS_H
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <assert.h>
+#include "libavutil/bswap.h"
+#include "libavutil/common.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/log.h"
+#include "mathops.h"
+
+//#define ALT_BITSTREAM_WRITER
+//#define ALIGNED_BITSTREAM_WRITER
+
+/* buf and buf_end must be present and used by every alternative writer. */
+typedef struct PutBitContext {
+#ifdef ALT_BITSTREAM_WRITER
+    uint8_t *buf, *buf_end;
+    int index;
+#else
+    uint32_t bit_buf;
+    int bit_left;
+    uint8_t *buf, *buf_ptr, *buf_end;
+#endif
+    int size_in_bits;
+} PutBitContext;
+
+/**
+ * Initializes the PutBitContext \p s.
+ *
+ * @param buffer the buffer where to put bits
+ * @param buffer_size the size in bytes of \p buffer
+ */
+static inline void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
+{
+    if(buffer_size < 0) {
+        buffer_size = 0;
+        buffer = NULL;
+    }
+
+    s->size_in_bits= 8*buffer_size;
+    s->buf = buffer;
+    s->buf_end = s->buf + buffer_size;
+#ifdef ALT_BITSTREAM_WRITER
+    s->index=0;
+    ((uint32_t*)(s->buf))[0]=0;
+//    memset(buffer, 0, buffer_size);
+#else
+    s->buf_ptr = s->buf;
+    s->bit_left=32;
+    s->bit_buf=0;
+#endif
+}
+
+/**
+ * Returns the total number of bits written to the bitstream.
+ */
+static inline int put_bits_count(PutBitContext *s)
+{
+#ifdef ALT_BITSTREAM_WRITER
+    return s->index;
+#else
+    return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left;
+#endif
+}
+
+/**
+ * Pads the end of the output stream with zeros.
+ */
+static inline void flush_put_bits(PutBitContext *s)
+{
+#ifdef ALT_BITSTREAM_WRITER
+    align_put_bits(s);
+#else
+#ifndef BITSTREAM_WRITER_LE
+    s->bit_buf<<= s->bit_left;
+#endif
+    while (s->bit_left < 32) {
+        /* XXX: should test end of buffer */
+#ifdef BITSTREAM_WRITER_LE
+        *s->buf_ptr++=s->bit_buf;
+        s->bit_buf>>=8;
+#else
+        *s->buf_ptr++=s->bit_buf >> 24;
+        s->bit_buf<<=8;
+#endif
+        s->bit_left+=8;
+    }
+    s->bit_left=32;
+    s->bit_buf=0;
+#endif
+}
+
+/**
+ * Pads the bitstream with zeros up to the next byte boundary.
+ */
+void align_put_bits(PutBitContext *s);
+
+/**
+ * Puts the string \p s in the bitstream.
+ *
+ * @param terminate_string 0-terminates the written string if value is 1
+ */
+void ff_put_string(PutBitContext * pbc, const char *s, int terminate_string);
+
+/**
+ * Copies the content of \p src to the bitstream.
+ *
+ * @param length the number of bits of \p src to copy
+ */
+void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length);
+
+static inline void put_bits(PutBitContext *s, int n, unsigned int value)
+#ifndef ALT_BITSTREAM_WRITER
+{
+    unsigned int bit_buf;
+    int bit_left;
+
+    //    printf("put_bits=%d %x\n", n, value);
+    assert(n == 32 || value < (1U << n));
+
+    bit_buf = s->bit_buf;
+    bit_left = s->bit_left;
+
+    //    printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);
+    /* XXX: optimize */
+#ifdef BITSTREAM_WRITER_LE
+    bit_buf |= value << (32 - bit_left);
+    if (n >= bit_left) {
+#if !HAVE_FAST_UNALIGNED
+        if (3 & (intptr_t) s->buf_ptr) {
+            AV_WL32(s->buf_ptr, bit_buf);
+        } else
+#endif
+        *(uint32_t *)s->buf_ptr = le2me_32(bit_buf);
+        s->buf_ptr+=4;
+        bit_buf = (bit_left==32)?0:value >> bit_left;
+        bit_left+=32;
+    }
+    bit_left-=n;
+#else
+    if (n < bit_left) {
+        bit_buf = (bit_buf<<n) | value;
+        bit_left-=n;
+    } else {
+        bit_buf<<=bit_left;
+        bit_buf |= value >> (n - bit_left);
+#if !HAVE_FAST_UNALIGNED
+        if (3 & (intptr_t) s->buf_ptr) {
+            AV_WB32(s->buf_ptr, bit_buf);
+        } else
+#endif
+        *(uint32_t *)s->buf_ptr = be2me_32(bit_buf);
+        //printf("bitbuf = %08x\n", bit_buf);
+        s->buf_ptr+=4;
+        bit_left+=32 - n;
+        bit_buf = value;
+    }
+#endif
+
+    s->bit_buf = bit_buf;
+    s->bit_left = bit_left;
+}
+#else  /* ALT_BITSTREAM_WRITER defined */
+{
+#    ifdef ALIGNED_BITSTREAM_WRITER
+#        if ARCH_X86
+    __asm__ volatile(
+        "movl %0, %%ecx                 \n\t"
+        "xorl %%eax, %%eax              \n\t"
+        "shrdl %%cl, %1, %%eax          \n\t"
+        "shrl %%cl, %1                  \n\t"
+        "movl %0, %%ecx                 \n\t"
+        "shrl $3, %%ecx                 \n\t"
+        "andl $0xFFFFFFFC, %%ecx        \n\t"
+        "bswapl %1                      \n\t"
+        "orl %1, (%2, %%ecx)            \n\t"
+        "bswapl %%eax                   \n\t"
+        "addl %3, %0                    \n\t"
+        "movl %%eax, 4(%2, %%ecx)       \n\t"
+        : "=&r" (s->index), "=&r" (value)
+        : "r" (s->buf), "r" (n), "0" (s->index), "1" (value<<(-n))
+        : "%eax", "%ecx"
+    );
+#        else
+    int index= s->index;
+    uint32_t *ptr= ((uint32_t *)s->buf)+(index>>5);
+
+    value<<= 32-n;
+
+    ptr[0] |= be2me_32(value>>(index&31));
+    ptr[1]  = be2me_32(value<<(32-(index&31)));
+//if(n>24) printf("%d %d\n", n, value);
+    index+= n;
+    s->index= index;
+#        endif
+#    else //ALIGNED_BITSTREAM_WRITER
+#        if ARCH_X86
+    __asm__ volatile(
+        "movl $7, %%ecx                 \n\t"
+        "andl %0, %%ecx                 \n\t"
+        "addl %3, %%ecx                 \n\t"
+        "negl %%ecx                     \n\t"
+        "shll %%cl, %1                  \n\t"
+        "bswapl %1                      \n\t"
+        "movl %0, %%ecx                 \n\t"
+        "shrl $3, %%ecx                 \n\t"
+        "orl %1, (%%ecx, %2)            \n\t"
+        "addl %3, %0                    \n\t"
+        "movl $0, 4(%%ecx, %2)          \n\t"
+        : "=&r" (s->index), "=&r" (value)
+        : "r" (s->buf), "r" (n), "0" (s->index), "1" (value)
+        : "%ecx"
+    );
+#        else
+    int index= s->index;
+    uint32_t *ptr= (uint32_t*)(((uint8_t *)s->buf)+(index>>3));
+
+    ptr[0] |= be2me_32(value<<(32-n-(index&7) ));
+    ptr[1] = 0;
+//if(n>24) printf("%d %d\n", n, value);
+    index+= n;
+    s->index= index;
+#        endif
+#    endif //!ALIGNED_BITSTREAM_WRITER
+}
+#endif
+
+static inline void put_sbits(PutBitContext *pb, int bits, int32_t val)
+{
+    assert(bits >= 0 && bits <= 31);
+
+    put_bits(pb, bits, val & ((1<<bits)-1));
+}
+
+
+static inline uint8_t* pbBufPtr(PutBitContext *s)
+{
+#ifdef ALT_BITSTREAM_WRITER
+        return s->buf + (s->index>>3);
+#else
+        return s->buf_ptr;
+#endif
+}
+
+/**
+ * Skips the given number of bytes.
+ * PutBitContext must be flushed & aligned to a byte boundary before calling this.
+ */
+static inline void skip_put_bytes(PutBitContext *s, int n){
+        assert((put_bits_count(s)&7)==0);
+#ifdef ALT_BITSTREAM_WRITER
+        FIXME may need some cleaning of the buffer
+        s->index += n<<3;
+#else
+        assert(s->bit_left==32);
+        s->buf_ptr += n;
+#endif
+}
+
+/**
+ * Skips the given number of bits.
+ * Must only be used if the actual values in the bitstream do not matter.
+ * If \p n is 0 the behavior is undefined.
+ */
+static inline void skip_put_bits(PutBitContext *s, int n){
+#ifdef ALT_BITSTREAM_WRITER
+    s->index += n;
+#else
+    s->bit_left -= n;
+    s->buf_ptr-= s->bit_left>>5;
+    s->bit_left &= 31;
+#endif
+}
+
+/**
+ * Changes the end of the buffer.
+ *
+ * @param size the new size in bytes of the buffer where to put bits
+ */
+static inline void set_put_bits_buffer_size(PutBitContext *s, int size){
+    s->buf_end= s->buf + size;
+}
+
+#endif /* AVCODEC_PUT_BITS_H */