diff options
Diffstat (limited to 'decoder.h')
| -rw-r--r-- | decoder.h | 99 |
1 files changed, 48 insertions, 51 deletions
@@ -1,5 +1,5 @@ /* Lzlib - Compression library for the lzip format - Copyright (C) 2009-2015 Antonio Diaz Diaz. + Copyright (C) 2009-2016 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 @@ -58,75 +58,57 @@ static inline void Rd_finish( struct Range_decoder * const rdec ) { rdec->at_stream_end = true; } static inline bool Rd_enough_available_bytes( const struct Range_decoder * const rdec ) - { - return ( Cb_used_bytes( &rdec->cb ) >= rd_min_available_bytes || - ( rdec->at_stream_end && Cb_used_bytes( &rdec->cb ) > 0 ) ); - } + { return ( Cb_used_bytes( &rdec->cb ) >= rd_min_available_bytes ); } -static inline int Rd_available_bytes( const struct Range_decoder * const rdec ) +static inline unsigned Rd_available_bytes( const struct Range_decoder * const rdec ) { return Cb_used_bytes( &rdec->cb ); } -static inline int Rd_free_bytes( const struct Range_decoder * const rdec ) +static inline unsigned Rd_free_bytes( const struct Range_decoder * const rdec ) { if( rdec->at_stream_end ) return 0; return Cb_free_bytes( &rdec->cb ); } -static inline void Rd_purge( struct Range_decoder * const rdec ) - { rdec->at_stream_end = true; Cb_reset( &rdec->cb ); } +static inline unsigned long long Rd_purge( struct Range_decoder * const rdec ) + { + const unsigned long long size = + rdec->member_position + Cb_used_bytes( &rdec->cb ); + Cb_reset( &rdec->cb ); + rdec->member_position = 0; rdec->at_stream_end = true; + return size; + } static inline void Rd_reset( struct Range_decoder * const rdec ) - { rdec->at_stream_end = false; Cb_reset( &rdec->cb ); } + { Cb_reset( &rdec->cb ); + rdec->member_position = 0; rdec->at_stream_end = false; } -/* Seeks a member header and updates 'get'. - Returns true if it finds a valid header. +/* Seeks a member header and updates 'get'. '*skippedp' is set to the + number of bytes skipped. Returns true if it finds a valid header. */ -static bool Rd_find_header( struct Range_decoder * const rdec ) +static bool Rd_find_header( struct Range_decoder * const rdec, + int * const skippedp ) { + *skippedp = 0; while( rdec->cb.get != rdec->cb.put ) { if( rdec->cb.buffer[rdec->cb.get] == magic_string[0] ) { - int get = rdec->cb.get; + unsigned get = rdec->cb.get; int i; File_header header; for( i = 0; i < Fh_size; ++i ) { - if( get == rdec->cb.put ) return false; /* not enough data */ + if( get == rdec->cb.put ) return false; /* not enough data */ header[i] = rdec->cb.buffer[get]; if( ++get >= rdec->cb.buffer_size ) get = 0; } if( Fh_verify( header ) ) return true; } if( ++rdec->cb.get >= rdec->cb.buffer_size ) rdec->cb.get = 0; + ++*skippedp; } return false; } -/* Returns true, fills 'header', and updates 'get' if 'get' points to a - valid header. - Else returns false and leaves 'get' unmodified. -*/ -static bool Rd_read_header( struct Range_decoder * const rdec, - File_header header ) - { - int get = rdec->cb.get; - int i; - for( i = 0; i < Fh_size; ++i ) - { - if( get == rdec->cb.put ) return false; /* not enough data */ - header[i] = rdec->cb.buffer[get]; - if( ++get >= rdec->cb.buffer_size ) get = 0; - } - if( Fh_verify( header ) ) - { - rdec->cb.get = get; - rdec->member_position = Fh_size; - rdec->reload_pending = true; - return true; - } - return false; - } - static inline int Rd_write_data( struct Range_decoder * const rdec, const uint8_t * const inbuf, const int size ) { @@ -148,6 +130,15 @@ static inline int Rd_read_data( struct Range_decoder * const rdec, return sz; } +static inline bool Rd_unread_data( struct Range_decoder * const rdec, + const unsigned size ) + { + if( size > rdec->member_position || !Cb_unread_data( &rdec->cb, size ) ) + return false; + rdec->member_position -= size; + return true; + } + static bool Rd_try_reload( struct Range_decoder * const rdec, const bool force ) { if( force ) rdec->reload_pending = true; @@ -314,6 +305,7 @@ struct LZ_decoder uint32_t crc; bool member_finished; bool verify_trailer_pending; + bool pos_wrapped; unsigned rep0; /* rep[0-3] latest four distances */ unsigned rep1; /* used for efficient coding of */ unsigned rep2; /* repeated distances */ @@ -340,15 +332,15 @@ static inline bool LZd_enough_free_bytes( const struct LZ_decoder * const d ) static inline uint8_t LZd_peek_prev( const struct LZ_decoder * const d ) { - const int i = ( ( d->cb.put > 0 ) ? d->cb.put : d->cb.buffer_size ) - 1; + const unsigned i = ( ( d->cb.put > 0 ) ? d->cb.put : d->cb.buffer_size ) - 1; return d->cb.buffer[i]; } static inline uint8_t LZd_peek( const struct LZ_decoder * const d, - const int distance ) + const unsigned distance ) { - int i = d->cb.put - distance - 1; - if( i < 0 ) i += d->cb.buffer_size; + unsigned i = d->cb.put - distance - 1; + if( d->cb.put <= distance ) i += d->cb.buffer_size; return d->cb.buffer[i]; } @@ -357,16 +349,20 @@ static inline void LZd_put_byte( struct LZ_decoder * const d, const uint8_t b ) CRC32_update_byte( &d->crc, b ); d->cb.buffer[d->cb.put] = b; if( ++d->cb.put >= d->cb.buffer_size ) - { d->partial_data_pos += d->cb.put; d->cb.put = 0; } + { d->partial_data_pos += d->cb.put; d->cb.put = 0; d->pos_wrapped = true; } } static inline void LZd_copy_block( struct LZ_decoder * const d, - const int distance, int len ) + const unsigned distance, unsigned len ) { - int i = d->cb.put - distance - 1; - if( i < 0 ) i += d->cb.buffer_size; - if( len < d->cb.buffer_size - max( d->cb.put, i ) && - len <= abs( d->cb.put - i ) ) /* no wrap, no overlap */ + unsigned i = d->cb.put - distance - 1; + bool fast; + if( d->cb.put <= distance ) + { i += d->cb.buffer_size; + fast = ( len <= d->cb.buffer_size - i && len <= i - d->cb.put ); } + else + fast = ( len < d->cb.buffer_size - d->cb.put && len <= d->cb.put - i ); + if( fast ) /* no wrap, no overlap */ { CRC32_update_buf( &d->crc, d->cb.buffer + i, len ); memcpy( d->cb.buffer + d->cb.put, d->cb.buffer + i, len ); @@ -381,7 +377,7 @@ static inline void LZd_copy_block( struct LZ_decoder * const d, static inline bool LZd_init( struct LZ_decoder * const d, struct Range_decoder * const rde, - const int dict_size ) + const unsigned dict_size ) { if( !Cb_init( &d->cb, max( 65536, dict_size ) + lzd_min_free_bytes ) ) return false; @@ -391,6 +387,7 @@ static inline bool LZd_init( struct LZ_decoder * const d, d->crc = 0xFFFFFFFFU; d->member_finished = false; d->verify_trailer_pending = false; + d->pos_wrapped = false; d->rep0 = 0; d->rep1 = 0; d->rep2 = 0; |