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-rw-r--r--lzip.h49
1 files changed, 28 insertions, 21 deletions
diff --git a/lzip.h b/lzip.h
index 9ef5913..73fc7f1 100644
--- a/lzip.h
+++ b/lzip.h
@@ -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
@@ -60,6 +60,7 @@ enum {
max_dictionary_bits = 29,
max_dictionary_size = 1 << max_dictionary_bits,
literal_context_bits = 3,
+ literal_pos_state_bits = 0, /* not used */
pos_state_bits = 2,
pos_states = 1 << pos_state_bits,
pos_state_mask = pos_states - 1,
@@ -100,8 +101,8 @@ typedef int Bit_model;
static inline void Bm_init( Bit_model * const probability )
{ *probability = bit_model_total / 2; }
-static inline void Bm_array_init( Bit_model * const p, const int size )
- { int i = 0; while( i < size ) p[i++] = bit_model_total / 2; }
+static inline void Bm_array_init( Bit_model bm[], const int size )
+ { int i; for( i = 0; i < size; ++i ) Bm_init( &bm[i] ); }
struct Len_model
{
@@ -183,6 +184,11 @@ static inline void CRC32_update_buf( uint32_t * const crc,
}
+static inline bool isvalid_ds( const unsigned dictionary_size )
+ { return ( dictionary_size >= min_dictionary_size &&
+ dictionary_size <= max_dictionary_size ); }
+
+
static inline int real_bits( unsigned value )
{
int bits = 0;
@@ -204,6 +210,14 @@ static inline void Fh_set_magic( File_header data )
static inline bool Fh_verify_magic( const File_header data )
{ return ( memcmp( data, magic_string, 4 ) == 0 ); }
+/* detect truncated header */
+static inline bool Fh_verify_prefix( const File_header data, const int size )
+ {
+ int i; for( i = 0; i < size && i < 4; ++i )
+ if( data[i] != magic_string[i] ) return false;
+ return ( size > 0 );
+ }
+
static inline uint8_t Fh_version( const File_header data )
{ return data[4]; }
@@ -220,31 +234,24 @@ static inline unsigned Fh_get_dictionary_size( const File_header data )
static inline bool Fh_set_dictionary_size( File_header data, const unsigned sz )
{
- if( sz >= min_dictionary_size && sz <= max_dictionary_size )
+ if( !isvalid_ds( sz ) ) return false;
+ data[5] = real_bits( sz - 1 );
+ if( sz > min_dictionary_size )
{
- data[5] = real_bits( sz - 1 );
- if( sz > min_dictionary_size )
- {
- const unsigned base_size = 1 << data[5];
- const unsigned fraction = base_size / 16;
- int i;
- for( i = 7; i >= 1; --i )
- if( base_size - ( i * fraction ) >= sz )
- { data[5] |= ( i << 5 ); break; }
- }
- return true;
+ const unsigned base_size = 1 << data[5];
+ const unsigned fraction = base_size / 16;
+ int i;
+ for( i = 7; i >= 1; --i )
+ if( base_size - ( i * fraction ) >= sz )
+ { data[5] |= ( i << 5 ); break; }
}
- return false;
+ return true;
}
static inline bool Fh_verify( const File_header data )
{
if( Fh_verify_magic( data ) && Fh_verify_version( data ) )
- {
- const unsigned dictionary_size = Fh_get_dictionary_size( data );
- return ( dictionary_size >= min_dictionary_size &&
- dictionary_size <= max_dictionary_size );
- }
+ return isvalid_ds( Fh_get_dictionary_size( data ) );
return false;
}