| /* 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 |