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Diffstat (limited to 'src/libspeex/include/speex/speex_bits.h')
-rw-r--r-- | src/libspeex/include/speex/speex_bits.h | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/src/libspeex/include/speex/speex_bits.h b/src/libspeex/include/speex/speex_bits.h new file mode 100644 index 0000000..a26fb4c --- /dev/null +++ b/src/libspeex/include/speex/speex_bits.h @@ -0,0 +1,174 @@ +/* Copyright (C) 2002 Jean-Marc Valin */ +/** + @file speex_bits.h + @brief Handles bit packing/unpacking +*/ +/* + 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. + + - Neither the name of the Xiph.org Foundation nor the names of its + contributors may be used to endorse or promote products derived from + this software without specific prior written permission. + + 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 FOUNDATION 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. + +*/ + +#ifndef BITS_H +#define BITS_H +/** @defgroup SpeexBits SpeexBits: Bit-stream manipulations + * This is the structure that holds the bit-stream when encoding or decoding + * with Speex. It allows some manipulations as well. + * @{ + */ + +#ifdef __cplusplus +extern "C" { +#endif + +/** Bit-packing data structure representing (part of) a bit-stream. */ +typedef struct SpeexBits { + char *chars; /**< "raw" data */ + int nbBits; /**< Total number of bits stored in the stream*/ + int charPtr; /**< Position of the byte "cursor" */ + int bitPtr; /**< Position of the bit "cursor" within the current char */ + int owner; /**< Does the struct "own" the "raw" buffer (member "chars") */ + int overflow;/**< Set to one if we try to read past the valid data */ + int buf_size;/**< Allocated size for buffer */ + int reserved1; /**< Reserved for future use */ + void *reserved2; /**< Reserved for future use */ +} SpeexBits; + +/** Initializes and allocates resources for a SpeexBits struct */ +void speex_bits_init(SpeexBits *bits); + +/** Initializes SpeexBits struct using a pre-allocated buffer*/ +void speex_bits_init_buffer(SpeexBits *bits, void *buff, int buf_size); + +/** Sets the bits in a SpeexBits struct to use data from an existing buffer (for decoding without copying data) */ +void speex_bits_set_bit_buffer(SpeexBits *bits, void *buff, int buf_size); + +/** 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.*/ +void speex_bits_destroy(SpeexBits *bits); + +/** Resets bits to initial value (just after initialization, erasing content)*/ +void speex_bits_reset(SpeexBits *bits); + +/** Rewind the bit-stream to the beginning (ready for read) without erasing the content */ +void speex_bits_rewind(SpeexBits *bits); + +/** Initializes the bit-stream from the data in an area of memory */ +void speex_bits_read_from(SpeexBits *bits, char *bytes, int len); + +/** Append bytes to the bit-stream + * + * @param bits Bit-stream to operate on + * @param bytes pointer to the bytes what will be appended + * @param len Number of bytes of append + */ +void speex_bits_read_whole_bytes(SpeexBits *bits, char *bytes, int len); + +/** Write the content of a bit-stream to an area of memory + * + * @param bits Bit-stream to operate on + * @param bytes Memory location where to write the bits + * @param max_len Maximum number of bytes to write (i.e. size of the "bytes" buffer) + * @return Number of bytes written to the "bytes" buffer +*/ +int speex_bits_write(SpeexBits *bits, char *bytes, int max_len); + +/** Like speex_bits_write, but writes only the complete bytes in the stream. Also removes the written bytes from the stream */ +int speex_bits_write_whole_bytes(SpeexBits *bits, char *bytes, int max_len); + +/** Append bits to the bit-stream + * @param bits Bit-stream to operate on + * @param data Value to append as integer + * @param nbBits number of bits to consider in "data" + */ +void speex_bits_pack(SpeexBits *bits, int data, int nbBits); + +/** Interpret the next bits in the bit-stream as a signed integer + * + * @param bits Bit-stream to operate on + * @param nbBits Number of bits to interpret + * @return A signed integer represented by the bits read + */ +int speex_bits_unpack_signed(SpeexBits *bits, int nbBits); + +/** Interpret the next bits in the bit-stream as an unsigned integer + * + * @param bits Bit-stream to operate on + * @param nbBits Number of bits to interpret + * @return An unsigned integer represented by the bits read + */ +unsigned int speex_bits_unpack_unsigned(SpeexBits *bits, int nbBits); + +/** Returns the number of bytes in the bit-stream, including the last one even if it is not "full" + * + * @param bits Bit-stream to operate on + * @return Number of bytes in the stream + */ +int speex_bits_nbytes(SpeexBits *bits); + +/** Same as speex_bits_unpack_unsigned, but without modifying the cursor position + * + * @param bits Bit-stream to operate on + * @param nbBits Number of bits to look for + * @return Value of the bits peeked, interpreted as unsigned + */ +unsigned int speex_bits_peek_unsigned(SpeexBits *bits, int nbBits); + +/** Get the value of the next bit in the stream, without modifying the + * "cursor" position + * + * @param bits Bit-stream to operate on + * @return Value of the bit peeked (one bit only) + */ +int speex_bits_peek(SpeexBits *bits); + +/** Advances the position of the "bit cursor" in the stream + * + * @param bits Bit-stream to operate on + * @param n Number of bits to advance + */ +void speex_bits_advance(SpeexBits *bits, int n); + +/** Returns the number of bits remaining to be read in a stream + * + * @param bits Bit-stream to operate on + * @return Number of bits that can still be read from the stream + */ +int speex_bits_remaining(SpeexBits *bits); + +/** Insert a terminator so that the data can be sent as a packet while auto-detecting + * the number of frames in each packet + * + * @param bits Bit-stream to operate on + */ +void speex_bits_insert_terminator(SpeexBits *bits); + +#ifdef __cplusplus +} +#endif + +/* @} */ +#endif |