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-rw-r--r--lzip.h40
1 files changed, 24 insertions, 16 deletions
diff --git a/lzip.h b/lzip.h
index 291e3e3..e7afe3c 100644
--- a/lzip.h
+++ b/lzip.h
@@ -1,5 +1,5 @@
/* Lzip - LZMA lossless data compressor
- Copyright (C) 2008-2015 Antonio Diaz Diaz.
+ Copyright (C) 2008-2016 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
@@ -44,6 +44,7 @@ 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,
@@ -175,6 +176,11 @@ public:
extern const CRC32 crc32;
+inline bool isvalid_ds( const unsigned dictionary_size )
+ { return ( dictionary_size >= min_dictionary_size &&
+ dictionary_size <= max_dictionary_size ); }
+
+
inline int real_bits( unsigned value )
{
int bits = 0;
@@ -195,9 +201,15 @@ struct File_header
void set_magic() { std::memcpy( data, magic_string, 4 ); data[4] = 1; }
bool verify_magic() const
{ return ( std::memcmp( data, magic_string, 4 ) == 0 ); }
+ bool verify_prefix( const int size ) const // detect truncated header
+ {
+ for( int i = 0; i < size && i < 4; ++i )
+ if( data[i] != magic_string[i] ) return false;
+ return ( size > 0 );
+ }
uint8_t version() const { return data[4]; }
- bool verify_version() const { return ( data[4] <= 1 ); }
+ bool verify_version() const { return ( data[4] == 1 ); }
unsigned dictionary_size() const
{
@@ -209,20 +221,17 @@ struct File_header
bool dictionary_size( 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;
- for( int 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;
+ for( int i = 7; i >= 1; --i )
+ if( base_size - ( i * fraction ) >= sz )
+ { data[5] |= ( i << 5 ); break; }
}
- return false;
+ return true;
}
};
@@ -233,8 +242,7 @@ struct File_trailer
// 4-11 size of the uncompressed data
// 12-19 member size including header and trailer
- static int size( const int version = 1 )
- { return ( ( version >= 1 ) ? 20 : 12 ); }
+ enum { size = 20 };
unsigned data_crc() const
{