--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libavcodec/put_bits.h	Wed Nov 16 11:16:33 2016 +0200
@@ -0,0 +1,258 @@
+/*
+ * 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
+ * bitstream writer API
+ */
+
+#ifndef AVCODEC_PUT_BITS_H
+#define AVCODEC_PUT_BITS_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include <assert.h>
+
+#include "libavutil/intreadwrite.h"
+#include "libavutil/avassert.h"
+
+typedef struct PutBitContext {
+    uint32_t bit_buf;
+    int bit_left;
+    uint8_t *buf, *buf_ptr, *buf_end;
+    int size_in_bits;
+} PutBitContext;
+
+/**
+ * Initialize the PutBitContext s.
+ *
+ * @param buffer the buffer where to put bits
+ * @param buffer_size the size in bytes of 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;
+    s->buf_ptr      = s->buf;
+    s->bit_left     = 32;
+    s->bit_buf      = 0;
+}
+
+/**
+ * Rebase the bit writer onto a reallocated buffer.
+ *
+ * @param buffer the buffer where to put bits
+ * @param buffer_size the size in bytes of buffer,
+ *                    must be larger than the previous size
+ */
+static inline void rebase_put_bits(PutBitContext *s, uint8_t *buffer,
+                                   int buffer_size)
+{
+    av_assert0(8*buffer_size > s->size_in_bits);
+
+    s->buf_end = buffer + buffer_size;
+    s->buf_ptr = buffer + (s->buf_ptr - s->buf);
+    s->buf     = buffer;
+    s->size_in_bits = 8 * buffer_size;
+}
+
+/**
+ * @return the total number of bits written to the bitstream.
+ */
+static inline int put_bits_count(PutBitContext *s)
+{
+    return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left;
+}
+
+/**
+ * @return the number of bits available in the bitstream.
+ */
+static inline int put_bits_left(PutBitContext* s)
+{
+    return (s->buf_end - s->buf_ptr) * 8 - 32 + s->bit_left;
+}
+
+/**
+ * Pad the end of the output stream with zeros.
+ */
+static inline void flush_put_bits(PutBitContext *s)
+{
+#ifndef BITSTREAM_WRITER_LE
+    if (s->bit_left < 32)
+        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;
+}
+
+#ifdef BITSTREAM_WRITER_LE
+#define avpriv_align_put_bits align_put_bits_unsupported_here
+#define avpriv_put_string ff_put_string_unsupported_here
+#define avpriv_copy_bits avpriv_copy_bits_unsupported_here
+#else
+/**
+ * Pad the bitstream with zeros up to the next byte boundary.
+ */
+void avpriv_align_put_bits(PutBitContext *s);
+
+/**
+ * Put the string string in the bitstream.
+ *
+ * @param terminate_string 0-terminates the written string if value is 1
+ */
+void avpriv_put_string(PutBitContext *pb, const char *string,
+                       int terminate_string);
+
+/**
+ * Copy the content of src to the bitstream.
+ *
+ * @param length the number of bits of src to copy
+ */
+void avpriv_copy_bits(PutBitContext *pb, const uint8_t *src, int length);
+#endif
+
+/**
+ * Write up to 31 bits into a bitstream.
+ * Use put_bits32 to write 32 bits.
+ */
+static inline void put_bits(PutBitContext *s, int n, unsigned int value)
+{
+    unsigned int bit_buf;
+    int bit_left;
+
+    av_assert2(n <= 31 && value < (1U << n));
+
+    bit_buf  = s->bit_buf;
+    bit_left = s->bit_left;
+
+    /* XXX: optimize */
+#ifdef BITSTREAM_WRITER_LE
+    bit_buf |= value << (32 - bit_left);
+    if (n >= bit_left) {
+        av_assert2(s->buf_ptr+3<s->buf_end);
+        AV_WL32(s->buf_ptr, 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);
+        av_assert2(s->buf_ptr+3<s->buf_end);
+        AV_WB32(s->buf_ptr, bit_buf);
+        s->buf_ptr += 4;
+        bit_left   += 32 - n;
+        bit_buf     = value;
+    }
+#endif
+
+    s->bit_buf  = bit_buf;
+    s->bit_left = bit_left;
+}
+
+static inline void put_sbits(PutBitContext *pb, int n, int32_t value)
+{
+    av_assert2(n >= 0 && n <= 31);
+
+    put_bits(pb, n, value & ((1 << n) - 1));
+}
+
+/**
+ * Write exactly 32 bits into a bitstream.
+ */
+static void av_unused put_bits32(PutBitContext *s, uint32_t value)
+{
+    int lo = value & 0xffff;
+    int hi = value >> 16;
+#ifdef BITSTREAM_WRITER_LE
+    put_bits(s, 16, lo);
+    put_bits(s, 16, hi);
+#else
+    put_bits(s, 16, hi);
+    put_bits(s, 16, lo);
+#endif
+}
+
+/**
+ * Return the pointer to the byte where the bitstream writer will put
+ * the next bit.
+ */
+static inline uint8_t *put_bits_ptr(PutBitContext *s)
+{
+    return s->buf_ptr;
+}
+
+/**
+ * Skip 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)
+{
+    av_assert2((put_bits_count(s) & 7) == 0);
+    av_assert2(s->bit_left == 32);
+    s->buf_ptr += n;
+}
+
+/**
+ * Skip the given number of bits.
+ * Must only be used if the actual values in the bitstream do not matter.
+ * If n is 0 the behavior is undefined.
+ */
+static inline void skip_put_bits(PutBitContext *s, int n)
+{
+    s->bit_left -= n;
+    s->buf_ptr  -= 4 * (s->bit_left >> 5);
+    s->bit_left &= 31;
+}
+
+/**
+ * Change 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 */