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154 lines
5.9 KiB
154 lines
5.9 KiB
/* Copyright (C) 2002 Jean-Marc Valin */ |
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/** |
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@file speex_bits.h |
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@brief Handles bit packing/unpacking |
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*/ |
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/* |
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Redistribution and use in source and binary forms, with or without |
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modification, are permitted provided that the following conditions |
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are met: |
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- Redistributions of source code must retain the above copyright |
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notice, this list of conditions and the following disclaimer. |
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- Redistributions in binary form must reproduce the above copyright |
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notice, this list of conditions and the following disclaimer in the |
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documentation and/or other materials provided with the distribution. |
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- Neither the name of the Xiph.org Foundation nor the names of its |
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contributors may be used to endorse or promote products derived from |
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this software without specific prior written permission. |
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR |
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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*/ |
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#ifndef BITS_H |
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#define BITS_H |
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#ifdef __cplusplus |
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extern "C" { |
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#endif |
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/** Maximum size of the bit-stream (for fixed-size allocation) */ |
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#define MAX_BYTES_PER_FRAME 2000 |
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/** Bit-packing data structure representing (part of) a bit-stream. */ |
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typedef struct SpeexBits { |
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char *bytes; /**< "raw" data */ |
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int nbBits; /**< Total number of bits stored in the stream*/ |
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int bytePtr; /**< Position of the byte "cursor" */ |
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int bitPtr; /**< Position of the bit "cursor" within the current byte */ |
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int owner; /**< Does the struct "own" the "raw" buffer (member "bytes") */ |
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int overflow;/**< Set to one if we try to read past the valid data */ |
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int buf_size;/**< Allocated size for buffer */ |
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int reserved1; /**< Reserved for future use */ |
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void *reserved2; /**< Reserved for future use */ |
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} SpeexBits; |
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/** Initializes and allocates resources for a SpeexBits struct */ |
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void speex_bits_init(SpeexBits *bits); |
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/** Initializes SpeexBits struct using a pre-allocated buffer*/ |
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void speex_bits_init_buffer(SpeexBits *bits, void *buff, int buf_size); |
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/** Frees all resources associated to a SpeexBits struct. Right now this does nothing since no resources are allocated, but this could change in the future.*/ |
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void speex_bits_destroy(SpeexBits *bits); |
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/** Resets bits to initial value (just after initialization, erasing content)*/ |
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void speex_bits_reset(SpeexBits *bits); |
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/** Rewind the bit-stream to the beginning (ready for read) without erasing the content */ |
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void speex_bits_rewind(SpeexBits *bits); |
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/** Initializes the bit-stream from the data in an area of memory */ |
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void speex_bits_read_from(SpeexBits *bits, char *bytes, int len); |
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/** Append bytes to the bit-stream |
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* @param bits Bit-stream to operate on |
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* @param bytes pointer to the bytes what will be appended |
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* @param len Number of bytes of append |
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*/ |
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void speex_bits_read_whole_bytes(SpeexBits *bits, char *bytes, int len); |
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/** Write the content of a bit-stream to an area of memory */ |
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int speex_bits_write(SpeexBits *bits, char *bytes, int max_len); |
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/** Like speex_bits_write, but writes only the complete bytes in the stream. Also removes the written bytes from the stream */ |
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int speex_bits_write_whole_bytes(SpeexBits *bits, char *bytes, int max_len); |
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/** Append bits to the bit-stream |
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* @param bits Bit-stream to operate on |
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* @param data Value to append as integer |
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* @param nbBits number of bits to consider in "data" |
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*/ |
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void speex_bits_pack(SpeexBits *bits, int data, int nbBits); |
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/** Interpret the next bits in the bit-stream as a signed integer |
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* |
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* @param bits Bit-stream to operate on |
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* @param nbBits Number of bits to interpret |
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* @return A signed integer represented by the bits read |
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*/ |
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int speex_bits_unpack_signed(SpeexBits *bits, int nbBits); |
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/** Interpret the next bits in the bit-stream as an unsigned integer |
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* |
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* @param bits Bit-stream to operate on |
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* @param nbBits Number of bits to interpret |
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* @return An unsigned integer represented by the bits read |
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*/ |
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unsigned int speex_bits_unpack_unsigned(SpeexBits *bits, int nbBits); |
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/** Returns the number of bytes in the bit-stream, including the last one even if it is not "full" |
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* |
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* @param bits Bit-stream to operate on |
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* @return Number of bytes in the stream |
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*/ |
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int speex_bits_nbytes(SpeexBits *bits); |
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/** Same as speex_bits_unpack_unsigned, but without modifying the cursor position */ |
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unsigned int speex_bits_peek_unsigned(SpeexBits *bits, int nbBits); |
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/** Get the value of the next bit in the stream, without modifying the |
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* "cursor" position |
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* |
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* @param bits Bit-stream to operate on |
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*/ |
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int speex_bits_peek(SpeexBits *bits); |
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/** Advances the position of the "bit cursor" in the stream |
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* |
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* @param bits Bit-stream to operate on |
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* @param n Number of bits to advance |
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*/ |
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void speex_bits_advance(SpeexBits *bits, int n); |
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/** Returns the number of bits remaining to be read in a stream |
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* |
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* @param bits Bit-stream to operate on |
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*/ |
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int speex_bits_remaining(SpeexBits *bits); |
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/** Insert a terminator so that the data can be sent as a packet while auto-detecting |
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* the number of frames in each packet |
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* |
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* @param bits Bit-stream to operate on |
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*/ |
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void speex_bits_insert_terminator(SpeexBits *bits); |
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#ifdef __cplusplus |
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} |
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#endif |
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#endif
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