diff options
Diffstat (limited to 'cbuffer.c')
| -rw-r--r-- | cbuffer.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/cbuffer.c b/cbuffer.c new file mode 100644 index 0000000..d4dbeb9 --- /dev/null +++ b/cbuffer.c @@ -0,0 +1,134 @@ +/* Lzlib - A compression library for lzip files + Copyright (C) 2009, 2010, 2011, 2012, 2013 Antonio Diaz Diaz. + + This library is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This library 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this library. If not, see <http://www.gnu.org/licenses/>. + + As a special exception, you may use this file as part of a free + software library without restriction. Specifically, if other files + instantiate templates or use macros or inline functions from this + file, or you compile this file and link it with other files to + produce an executable, this file does not by itself cause the + resulting executable to be covered by the GNU General Public + License. This exception does not however invalidate any other + reasons why the executable file might be covered by the GNU General + Public License. +*/ + +struct Circular_buffer + { + uint8_t * buffer; + int buffer_size; /* capacity == buffer_size - 1 */ + int get; /* buffer is empty when get == put */ + int put; + }; + +static inline void Cb_reset( struct Circular_buffer * const cb ) + { cb->get = 0; cb->put = 0; } + +static inline bool Cb_init( struct Circular_buffer * const cb, + const int buf_size ) + { + cb->buffer = (uint8_t *)malloc( buf_size + 1 ); + cb->buffer_size = buf_size + 1; + cb->get = 0; + cb->put = 0; + return ( cb->buffer != 0 ); + } + +static inline void Cb_free( struct Circular_buffer * const cb ) + { free( cb->buffer ); cb->buffer = 0; } + +static inline int Cb_used_bytes( const struct Circular_buffer * const cb ) + { return ( (cb->get <= cb->put) ? 0 : cb->buffer_size ) + cb->put - cb->get; } + +static inline int Cb_free_bytes( const struct Circular_buffer * const cb ) + { return ( (cb->get <= cb->put) ? cb->buffer_size : 0 ) - cb->put + cb->get - 1; } + +static inline uint8_t Cb_get_byte( struct Circular_buffer * const cb ) + { + const uint8_t b = cb->buffer[cb->get]; + if( ++cb->get >= cb->buffer_size ) cb->get = 0; + return b; + } + +static inline void Cb_put_byte( struct Circular_buffer * const cb, + const uint8_t b ) + { + cb->buffer[cb->put] = b; + if( ++cb->put >= cb->buffer_size ) cb->put = 0; + } + + +/* Copies up to 'out_size' bytes to 'out_buffer' and updates 'get'. + Returns the number of bytes copied. +*/ +static int Cb_read_data( struct Circular_buffer * const cb, + uint8_t * const out_buffer, const int out_size ) + { + int size = 0; + if( out_size < 0 ) return 0; + if( cb->get > cb->put ) + { + size = min( cb->buffer_size - cb->get, out_size ); + if( size > 0 ) + { + memcpy( out_buffer, cb->buffer + cb->get, size ); + cb->get += size; + if( cb->get >= cb->buffer_size ) cb->get = 0; + } + } + if( cb->get < cb->put ) + { + const int size2 = min( cb->put - cb->get, out_size - size ); + if( size2 > 0 ) + { + memcpy( out_buffer + size, cb->buffer + cb->get, size2 ); + cb->get += size2; + size += size2; + } + } + return size; + } + + +/* Copies up to 'in_size' bytes from 'in_buffer' and updates 'put'. + Returns the number of bytes copied. +*/ +static int Cb_write_data( struct Circular_buffer * const cb, + const uint8_t * const in_buffer, const int in_size ) + { + int size = 0; + if( in_size < 0 ) return 0; + if( cb->put >= cb->get ) + { + size = min( cb->buffer_size - cb->put - (cb->get == 0), in_size ); + if( size > 0 ) + { + memcpy( cb->buffer + cb->put, in_buffer, size ); + cb->put += size; + if( cb->put >= cb->buffer_size ) cb->put = 0; + } + } + if( cb->put < cb->get ) + { + const int size2 = min( cb->get - cb->put - 1, in_size - size ); + if( size2 > 0 ) + { + memcpy( cb->buffer + cb->put, in_buffer + size, size2 ); + cb->put += size2; + size += size2; + } + } + return size; + } |