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/* Buff to buff example - A test program for the lzlib library
Copyright (C) 2010, 2011, 2012, 2013 Antonio Diaz Diaz.
This program is free software: you have unlimited permission
to copy, distribute and modify it.
Usage is:
bbexample filename
This program is an example of how buffer-to-buffer
compression/decompression can be implemented using lzlib.
*/
#ifndef __cplusplus
#include <stdbool.h>
#endif
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "lzlib.h"
/* Compresses 'size' bytes from 'data'. Returns the address of a
malloc'd buffer containing the compressed data and its size in
'*out_sizep'.
In case of error, returns 0 and does not modify '*out_sizep'.
*/
uint8_t * bbcompress( const uint8_t * const data, const int size,
int * const out_sizep )
{
struct LZ_Encoder * encoder;
uint8_t * new_data;
const int match_len_limit = 36;
const unsigned long long member_size = INT64_MAX;
int delta_size, new_data_size;
int new_pos = 0;
int written = 0;
bool error = false;
int dict_size = 8 << 20; /* 8 MiB */
if( dict_size > size ) dict_size = size; /* saves memory */
if( dict_size < LZ_min_dictionary_size() )
dict_size = LZ_min_dictionary_size();
encoder = LZ_compress_open( dict_size, match_len_limit, member_size );
if( !encoder || LZ_compress_errno( encoder ) != LZ_ok )
{ LZ_compress_close( encoder ); return 0; }
delta_size = (size < 256) ? 64 : size / 4; /* size may be zero */
new_data_size = delta_size; /* initial size */
new_data = (uint8_t *)malloc( new_data_size );
if( !new_data )
{ LZ_compress_close( encoder ); return 0; }
while( true )
{
int rd;
if( LZ_compress_write_size( encoder ) > 0 )
{
if( written < size )
{
const int wr = LZ_compress_write( encoder, data + written,
size - written );
if( wr < 0 ) { error = true; break; }
written += wr;
}
if( written >= size ) LZ_compress_finish( encoder );
}
rd = LZ_compress_read( encoder, new_data + new_pos,
new_data_size - new_pos );
if( rd < 0 ) { error = true; break; }
new_pos += rd;
if( LZ_compress_finished( encoder ) == 1 ) break;
if( new_pos >= new_data_size )
{
uint8_t * const tmp =
(uint8_t *)realloc( new_data, new_data_size + delta_size );
if( !tmp ) { error = true; break; }
new_data = tmp;
new_data_size += delta_size;
}
}
if( LZ_compress_close( encoder ) < 0 ) error = true;
if( error ) { free( new_data ); return 0; }
*out_sizep = new_pos;
return new_data;
}
/* Decompresses 'size' bytes from 'data'. Returns the address of a
malloc'd buffer containing the decompressed data and its size in
'*out_sizep'.
In case of error, returns 0 and does not modify '*out_sizep'.
*/
uint8_t * bbdecompress( const uint8_t * const data, const int size,
int * const out_sizep )
{
struct LZ_Decoder * const decoder = LZ_decompress_open();
uint8_t * new_data;
const int delta_size = size; /* size must be > zero */
int new_data_size = delta_size; /* initial size */
int new_pos = 0;
int written = 0;
bool error = false;
if( !decoder || LZ_decompress_errno( decoder ) != LZ_ok )
{ LZ_decompress_close( decoder ); return 0; }
new_data = (uint8_t *)malloc( new_data_size );
if( !new_data )
{ LZ_decompress_close( decoder ); return 0; }
while( true )
{
int rd;
if( LZ_decompress_write_size( decoder ) > 0 )
{
if( written < size )
{
const int wr = LZ_decompress_write( decoder, data + written,
size - written );
if( wr < 0 ) { error = true; break; }
written += wr;
}
if( written >= size ) LZ_decompress_finish( decoder );
}
rd = LZ_decompress_read( decoder, new_data + new_pos,
new_data_size - new_pos );
if( rd < 0 ) { error = true; break; }
new_pos += rd;
if( LZ_decompress_finished( decoder ) == 1 ) break;
if( new_pos >= new_data_size )
{
uint8_t * const tmp =
(uint8_t *)realloc( new_data, new_data_size + delta_size );
if( !tmp ) { error = true; break; }
new_data = tmp;
new_data_size += delta_size;
}
}
if( LZ_decompress_close( decoder ) < 0 ) error = true;
if( error ) { free( new_data ); return 0; }
*out_sizep = new_pos;
return new_data;
}
int main( const int argc, const char * const argv[] )
{
FILE * file;
uint8_t * in_buffer, * mid_buffer, * out_buffer;
const int in_buffer_size = 1 << 20;
int in_size, mid_size = 0, out_size = 0;
if( argc < 2 )
{
fprintf( stderr, "Usage: bbexample filename\n" );
return 1;
}
file = fopen( argv[1], "rb" );
if( !file )
{
fprintf( stderr, "bbexample: Can't open file '%s' for reading\n", argv[1] );
return 1;
}
in_buffer = (uint8_t *)malloc( in_buffer_size );
if( !in_buffer )
{
fprintf( stderr, "bbexample: Not enough memory.\n" );
return 1;
}
in_size = fread( in_buffer, 1, in_buffer_size, file );
if( in_size >= in_buffer_size )
{
fprintf( stderr, "bbexample: Input file '%s' is too big.\n", argv[1] );
return 1;
}
fclose( file );
mid_buffer = bbcompress( in_buffer, in_size, &mid_size );
if( !mid_buffer )
{
fprintf( stderr, "bbexample: Not enough memory or compress error.\n" );
return 1;
}
out_buffer = bbdecompress( mid_buffer, mid_size, &out_size );
if( !out_buffer )
{
fprintf( stderr, "bbexample: Not enough memory or decompress error.\n" );
return 1;
}
if( in_size != out_size ||
( in_size > 0 && memcmp( in_buffer, out_buffer, in_size ) != 0 ) )
{
fprintf( stderr, "bbexample: Decompressed data differs from original.\n" );
return 1;
}
free( out_buffer );
free( mid_buffer );
free( in_buffer );
return 0;
}
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