1 files changed, 27 insertions, 21 deletions

diff --git a/decoder.h b/decoder.h
index 833701b..662aaf9 100644
--- a/decoder.h
+++ b/decoder.h
@@ -1,5 +1,5 @@
 /*  Clzip - LZMA lossless data compressor
-    Copyright (C) 2010-2015 Antonio Diaz Diaz.
+    Copyright (C) 2010-2016 Antonio Diaz Diaz.
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -60,7 +60,8 @@ static inline void Rd_reset_member_position( struct Range_decoder * const rdec )
 
 static inline uint8_t Rd_get_byte( struct Range_decoder * const rdec )
   {
-  if( Rd_finished( rdec ) ) return 0xAA;	/* make code != 0 */
+  /* 0xFF avoids decoder error if member is truncated at EOS marker */
+  if( Rd_finished( rdec ) ) return 0xFF;
   return rdec->buffer[rdec->pos++];
   }
 
@@ -232,12 +233,12 @@ struct LZ_decoder
   unsigned long long partial_data_pos;
   struct Range_decoder * rdec;
   unsigned dictionary_size;
-  int buffer_size;
   uint8_t * buffer;		/* output buffer */
-  int pos;			/* current pos in buffer */
-  int stream_pos;		/* first byte not yet written to file */
+  unsigned pos;			/* current pos in buffer */
+  unsigned stream_pos;		/* first byte not yet written to file */
   uint32_t crc;
   int outfd;			/* output file descriptor */
+  bool pos_wrapped;
 
   Bit_model bm_literal[1<<literal_context_bits][0x300];
   Bit_model bm_match[states][pos_states];
@@ -258,56 +259,61 @@ void LZd_flush_data( struct LZ_decoder * const d );
 
 static inline uint8_t LZd_peek_prev( const struct LZ_decoder * const d )
   {
-  const int i = ( ( d->pos > 0 ) ? d->pos : d->buffer_size ) - 1;
+  const unsigned i = ( ( d->pos > 0 ) ? d->pos : d->dictionary_size ) - 1;
   return d->buffer[i];
   }
 
 static inline uint8_t LZd_peek( const struct LZ_decoder * const d,
-                                const int distance )
+                                const unsigned distance )
   {
-  int i = d->pos - distance - 1;
-  if( i < 0 ) i += d->buffer_size;
+  unsigned i = d->pos - distance - 1;
+  if( d->pos <= distance ) i += d->dictionary_size;
   return d->buffer[i];
   }
 
 static inline void LZd_put_byte( struct LZ_decoder * const d, const uint8_t b )
   {
   d->buffer[d->pos] = b;
-  if( ++d->pos >= d->buffer_size ) LZd_flush_data( d );
+  if( ++d->pos >= d->dictionary_size ) LZd_flush_data( d );
   }
 
 static inline void LZd_copy_block( struct LZ_decoder * const d,
-                                   const int distance, int len )
+                                   const unsigned distance, unsigned len )
   {
-  int i = d->pos - distance - 1;
-  if( i < 0 ) i += d->buffer_size;
-  if( len < d->buffer_size - max( d->pos, i ) && len <= abs( d->pos - i ) )
+  unsigned i = d->pos - distance - 1;
+  bool fast;
+  if( d->pos <= distance )
+    { i += d->dictionary_size;
+      fast = ( len <= d->dictionary_size - i && len <= i - d->pos ); }
+  else
+    fast = ( len < d->dictionary_size - d->pos && len <= d->pos - i );
+  if( fast )					/* no wrap, no overlap */
     {
-    memcpy( d->buffer + d->pos, d->buffer + i, len );	/* no wrap, no overlap */
+    memcpy( d->buffer + d->pos, d->buffer + i, len );
     d->pos += len;
     }
   else for( ; len > 0; --len )
     {
     d->buffer[d->pos] = d->buffer[i];
-    if( ++d->pos >= d->buffer_size ) LZd_flush_data( d );
-    if( ++i >= d->buffer_size ) i = 0;
+    if( ++d->pos >= d->dictionary_size ) LZd_flush_data( d );
+    if( ++i >= d->dictionary_size ) i = 0;
     }
   }
 
 static inline bool LZd_init( struct LZ_decoder * const d,
                              struct Range_decoder * const rde,
-                             const int dict_size, const int ofd )
+                             const unsigned dict_size, const int ofd )
   {
   d->partial_data_pos = 0;
   d->rdec = rde;
   d->dictionary_size = dict_size;
-  d->buffer_size = max( 65536U, d->dictionary_size );
-  d->buffer = (uint8_t *)malloc( d->buffer_size );
+  d->buffer = (uint8_t *)malloc( d->dictionary_size );
   if( !d->buffer ) return false;
   d->pos = 0;
   d->stream_pos = 0;
   d->crc = 0xFFFFFFFFU;
   d->outfd = ofd;
+  d->pos_wrapped = false;
 
   Bm_array_init( d->bm_literal[0], (1 << literal_context_bits) * 0x300 );
   Bm_array_init( d->bm_match[0], states * pos_states );
@@ -321,7 +327,7 @@ static inline bool LZd_init( struct LZ_decoder * const d,
   Bm_array_init( d->bm_align, dis_align_size );
   Lm_init( &d->match_len_model );
   Lm_init( &d->rep_len_model );
-  d->buffer[d->buffer_size-1] = 0;		/* prev_byte of first byte */
+  d->buffer[d->dictionary_size-1] = 0;		/* prev_byte of first byte */
   return true;
   }