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-rw-r--r--cbuffer.c134
1 files changed, 134 insertions, 0 deletions
diff --git a/cbuffer.c b/cbuffer.c
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+++ b/cbuffer.c
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+/* 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;
+ }