152 lines
5.7 KiB
C
152 lines
5.7 KiB
C
#include "common.h"
|
|
#include "api_int.h"
|
|
|
|
|
|
// decoding tables for dynamic blocks
|
|
#define LITERAL_TABLE_BITS 9
|
|
#define LITERAL_TABLE_MASK ((1 << LITERAL_TABLE_BITS)-1)
|
|
|
|
#define DISTANCE_TABLE_BITS 7
|
|
#define DISTANCE_TABLE_MASK ((1 << DISTANCE_TABLE_BITS)-1)
|
|
|
|
#define PRETREE_TABLE_BITS 7
|
|
#define PRETREE_TABLE_MASK ((1 << PRETREE_TABLE_BITS)-1)
|
|
|
|
|
|
// decoding tables for static blocks
|
|
#define STATIC_BLOCK_LITERAL_TABLE_BITS 9
|
|
#define STATIC_BLOCK_LITERAL_TABLE_MASK ((1 << STATIC_BLOCK_LITERAL_TABLE_BITS)-1)
|
|
#define STATIC_BLOCK_LITERAL_TABLE_SIZE (1 << STATIC_BLOCK_LITERAL_TABLE_BITS)
|
|
|
|
#define STATIC_BLOCK_DISTANCE_TABLE_BITS 5
|
|
#define STATIC_BLOCK_DISTANCE_TABLE_MASK ((1 << STATIC_BLOCK_DISTANCE_TABLE_BITS)-1)
|
|
#define STATIC_BLOCK_DISTANCE_TABLE_SIZE (1 << STATIC_BLOCK_DISTANCE_TABLE_BITS)
|
|
|
|
|
|
|
|
// Various possible states
|
|
|
|
typedef enum
|
|
{
|
|
STATE_READING_GZIP_HEADER, // Only applies to GZIP
|
|
STATE_READING_BFINAL_NEED_TO_INIT_BITBUF, // Start of block, need to init bit buffer
|
|
STATE_READING_BFINAL, // About to read bfinal bit
|
|
STATE_READING_BTYPE, // About to read btype bits
|
|
STATE_READING_NUM_LIT_CODES, // About to read # literal codes
|
|
STATE_READING_NUM_DIST_CODES, // About to read # dist codes
|
|
STATE_READING_NUM_CODE_LENGTH_CODES,// About to read # code length codes
|
|
STATE_READING_CODE_LENGTH_CODES, // In the middle of reading the code length codes
|
|
STATE_READING_TREE_CODES_BEFORE, // In the middle of reading tree codes (loop top)
|
|
STATE_READING_TREE_CODES_AFTER, // In the middle of reading tree codes (extension; code > 15)
|
|
STATE_DECODE_TOP, // About to decode a literal (char/match) in a compressed block
|
|
STATE_HAVE_INITIAL_LENGTH, // Decoding a match, have the literal code (base length)
|
|
STATE_HAVE_FULL_LENGTH, // Ditto, now have the full match length (incl. extra length bits)
|
|
STATE_HAVE_DIST_CODE, // Ditto, now have the distance code also, need extra dist bits
|
|
STATE_INTERRUPTED_MATCH, // In the middle of a match, but output buffer filled up
|
|
|
|
/* uncompressed blocks */
|
|
STATE_UNCOMPRESSED_ALIGNING,
|
|
STATE_UNCOMPRESSED_1,
|
|
STATE_UNCOMPRESSED_2,
|
|
STATE_UNCOMPRESSED_3,
|
|
STATE_UNCOMPRESSED_4,
|
|
STATE_DECODING_UNCOMPRESSED,
|
|
|
|
// These three apply only to GZIP
|
|
STATE_START_READING_GZIP_FOOTER, // (Initialisation for reading footer)
|
|
STATE_READING_GZIP_FOOTER,
|
|
STATE_VERIFYING_GZIP_FOOTER,
|
|
|
|
STATE_DONE // Finished
|
|
|
|
} t_decoder_state;
|
|
|
|
|
|
typedef struct
|
|
{
|
|
byte window[WINDOW_SIZE];
|
|
|
|
// output buffer
|
|
byte * output_curpos; // current output pos
|
|
byte * end_output_buffer; // ptr to end of output buffer
|
|
byte * output_buffer; // ptr to start of output buffer
|
|
|
|
// input buffer
|
|
const byte * input_curpos; // current input pos
|
|
const byte * end_input_buffer; // ptr to end of input buffer
|
|
|
|
int num_literal_codes;
|
|
int num_dist_codes;
|
|
int num_code_length_codes;
|
|
int temp_code_array_size;
|
|
byte temp_code_list[MAX_LITERAL_TREE_ELEMENTS + MAX_DIST_TREE_ELEMENTS];
|
|
|
|
// is this the last block?
|
|
int bfinal;
|
|
|
|
// type of current block
|
|
int btype;
|
|
|
|
// state information
|
|
t_decoder_state state;
|
|
long state_loop_counter;
|
|
byte state_code;
|
|
BOOL using_gzip;
|
|
|
|
// gzip-specific stuff
|
|
byte gzip_header_substate;
|
|
byte gzip_header_flag;
|
|
byte gzip_header_xlen1_byte; // first byte of XLEN
|
|
unsigned int gzip_header_xlen; // xlen (0...65535)
|
|
unsigned int gzip_header_loop_counter;
|
|
|
|
byte gzip_footer_substate;
|
|
unsigned int gzip_footer_loop_counter;
|
|
unsigned long gzip_footer_crc32; // what we're supposed to end up with
|
|
unsigned long gzip_footer_output_stream_size; // what we're supposed to end up with
|
|
|
|
unsigned long gzip_crc32; // running counter
|
|
unsigned long gzip_output_stream_size; // running counter
|
|
// end of gzip-specific stuff
|
|
|
|
int length;
|
|
int dist_code;
|
|
long offset;
|
|
|
|
// bit buffer and # bits available in buffer
|
|
unsigned long bitbuf;
|
|
int bitcount;
|
|
|
|
// position in the window
|
|
long bufpos;
|
|
|
|
// for decoding the uncompressed block header
|
|
byte unc_buffer[4];
|
|
|
|
// bit lengths of tree codes
|
|
byte literal_tree_code_length[MAX_LITERAL_TREE_ELEMENTS];
|
|
byte distance_tree_code_length[MAX_DIST_TREE_ELEMENTS];
|
|
byte pretree_code_length[NUM_PRETREE_ELEMENTS];
|
|
|
|
// tree decoding tables
|
|
short distance_table[1 << DISTANCE_TABLE_BITS];
|
|
short literal_table[1 << LITERAL_TABLE_BITS];
|
|
|
|
short literal_left[MAX_LITERAL_TREE_ELEMENTS*2];
|
|
short literal_right[MAX_LITERAL_TREE_ELEMENTS*2];
|
|
|
|
short distance_left[MAX_DIST_TREE_ELEMENTS*2];
|
|
short distance_right[MAX_DIST_TREE_ELEMENTS*2];
|
|
|
|
short pretree_table[1 << PRETREE_TABLE_BITS];
|
|
short pretree_left[NUM_PRETREE_ELEMENTS*2];
|
|
short pretree_right[NUM_PRETREE_ELEMENTS*2];
|
|
|
|
} t_decoder_context;
|
|
|
|
|
|
#include "infproto.h"
|
|
|
|
#include "infdata.h"
|
|
#include "comndata.h"
|