#define Assert(err, str) #define Trace(dummy) #define Tracev(dummy) #define Tracecv(err, dummy) #define Tracevv(dummy) #define LENGTH_CODES 29 /* number of length codes, not counting the special END_BLOCK code */ #define LITERALS 256 /* number of literal bytes 0..255 */ #define L_CODES (LITERALS+1+LENGTH_CODES) /* number of Literal or Length codes, including the END_BLOCK code */ #define D_CODES 30 /* number of distance codes */ #define BL_CODES 19 /* number of codes used to transfer the bit lengths */ #define HEAP_SIZE (2*L_CODES+1) /* maximum heap size */ #define MAX_BITS 15 /* All codes must not exceed MAX_BITS bits */ #define INIT_STATE 42 #define BUSY_STATE 113 #define FINISH_STATE 666 /* Stream status */ /* Data structure describing a single value and its code string. */ typedef struct ct_data_s { union { ush freq; /* frequency count */ ush code; /* bit string */ } fc; union { ush dad; /* father node in Huffman tree */ ush len; /* length of bit string */ } dl; } ct_data; #define Freq fc.freq #define Code fc.code #define Dad dl.dad #define Len dl.len typedef struct static_tree_desc_s static_tree_desc; typedef struct tree_desc_s { ct_data *dyn_tree; /* the dynamic tree */ int max_code; /* largest code with non zero frequency */ static_tree_desc *stat_desc; /* the corresponding static tree */ } tree_desc; typedef ush Pos; typedef unsigned IPos; /* A Pos is an index in the character window. We use short instead of int to * save space in the various tables. IPos is used only for parameter passing. */ typedef struct deflate_state { z_streamp strm; /* pointer back to this zlib stream */ int status; /* as the name implies */ Byte *pending_buf; /* output still pending */ ulg pending_buf_size; /* size of pending_buf */ Byte *pending_out; /* next pending byte to output to the stream */ int pending; /* nb of bytes in the pending buffer */ int noheader; /* suppress zlib header and adler32 */ Byte data_type; /* UNKNOWN, BINARY or ASCII */ Byte method; /* STORED (for zip only) or DEFLATED */ int last_flush; /* value of flush param for previous deflate call */ /* used by deflate.c: */ uInt w_size; /* LZ77 window size (32K by default) */ uInt w_bits; /* log2(w_size) (8..16) */ uInt w_mask; /* w_size - 1 */ Byte *window; /* Sliding window. Input bytes are read into the second half of the window, * and move to the first half later to keep a dictionary of at least wSize * bytes. With this organization, matches are limited to a distance of * wSize-MAX_MATCH bytes, but this ensures that IO is always * performed with a length multiple of the block size. Also, it limits * the window size to 64K, which is quite useful on MSDOS. * To do: use the user input buffer as sliding window. */ ulg window_size; /* Actual size of window: 2*wSize, except when the user input buffer * is directly used as sliding window. */ Pos *prev; /* Link to older string with same hash index. To limit the size of this * array to 64K, this link is maintained only for the last 32K strings. * An index in this array is thus a window index modulo 32K. */ Pos *head; /* Heads of the hash chains or NIL. */ uInt ins_h; /* hash index of string to be inserted */ uInt hash_size; /* number of elements in hash table */ uInt hash_bits; /* log2(hash_size) */ uInt hash_mask; /* hash_size-1 */ uInt hash_shift; /* Number of bits by which ins_h must be shifted at each input * step. It must be such that after MIN_MATCH steps, the oldest * byte no longer takes part in the hash key, that is: * hash_shift * MIN_MATCH >= hash_bits */ long block_start; /* Window position at the beginning of the current output block. Gets * negative when the window is moved backwards. */ uInt match_length; /* length of best match */ IPos prev_match; /* previous match */ int match_available; /* set if previous match exists */ uInt strstart; /* start of string to insert */ uInt match_start; /* start of matching string */ uInt lookahead; /* number of valid bytes ahead in window */ uInt prev_length; /* Length of the best match at previous step. Matches not greater than this * are discarded. This is used in the lazy match evaluation. */ uInt max_chain_length; /* To speed up deflation, hash chains are never searched beyond this * length. A higher limit improves compression ratio but degrades the * speed. */ uInt max_lazy_match; /* Attempt to find a better match only when the current match is strictly * smaller than this value. This mechanism is used only for compression * levels >= 4. */ # define max_insert_length max_lazy_match /* Insert new strings in the hash table only if the match length is not * greater than this length. This saves time but degrades compression. * max_insert_length is used only for compression levels <= 3. */ int level; /* compression level (1..9) */ int strategy; /* favor or force Huffman coding*/ uInt good_match; /* Use a faster search when the previous match is longer than this */ int nice_match; /* Stop searching when current match exceeds this */ /* used by trees.c: */ /* Didn't use ct_data typedef below to suppress compiler warning */ struct ct_data_s dyn_ltree[HEAP_SIZE]; /* literal and length tree */ struct ct_data_s dyn_dtree[2*D_CODES+1]; /* distance tree */ struct ct_data_s bl_tree[2*BL_CODES+1]; /* Huffman tree for bit lengths */ struct tree_desc_s l_desc; /* desc. for literal tree */ struct tree_desc_s d_desc; /* desc. for distance tree */ struct tree_desc_s bl_desc; /* desc. for bit length tree */ ush bl_count[MAX_BITS+1]; /* number of codes at each bit length for an optimal tree */ int heap[2*L_CODES+1]; /* heap used to build the Huffman trees */ int heap_len; /* number of elements in the heap */ int heap_max; /* element of largest frequency */ /* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used. * The same heap array is used to build all trees. */ uch depth[2*L_CODES+1]; /* Depth of each subtree used as tie breaker for trees of equal frequency */ uch *l_buf; /* buffer for literals or lengths */ uInt lit_bufsize; /* Size of match buffer for literals/lengths. There are 4 reasons for * limiting lit_bufsize to 64K: * - frequencies can be kept in 16 bit counters * - if compression is not successful for the first block, all input * data is still in the window so we can still emit a stored block even * when input comes from standard input. (This can also be done for * all blocks if lit_bufsize is not greater than 32K.) * - if compression is not successful for a file smaller than 64K, we can * even emit a stored file instead of a stored block (saving 5 bytes). * This is applicable only for zip (not gzip or zlib). * - creating new Huffman trees less frequently may not provide fast * adaptation to changes in the input data statistics. (Take for * example a binary file with poorly compressible code followed by * a highly compressible string table.) Smaller buffer sizes give * fast adaptation but have of course the overhead of transmitting * trees more frequently. * - I can't count above 4 */ uInt last_lit; /* running index in l_buf */ ush *d_buf; /* Buffer for distances. To simplify the code, d_buf and l_buf have * the same number of elements. To use different lengths, an extra flag * array would be necessary. */ ulg opt_len; /* bit length of current block with optimal trees */ ulg static_len; /* bit length of current block with static trees */ ulg compressed_len; /* total bit length of compressed file */ uInt matches; /* number of string matches in current block */ int last_eob_len; /* bit length of EOB code for last block */ #ifdef DEBUG_ZLIB ulg bits_sent; /* bit length of the compressed data */ #endif ush bi_buf; /* Output buffer. bits are inserted starting at the bottom (least * significant bits). */ int bi_valid; /* Number of valid bits in bi_buf. All bits above the last valid bit * are always zero. */ } deflate_state; typedef struct deflate_workspace { /* State memory for the deflator */ deflate_state deflate_memory; Byte window_memory[2 * (1 << MAX_WBITS)]; Pos prev_memory[1 << MAX_WBITS]; Pos head_memory[1 << (MAX_MEM_LEVEL + 7)]; char overlay_memory[(1 << (MAX_MEM_LEVEL + 6)) * (sizeof(ush)+2)]; } deflate_workspace; /* Output a byte on the stream. * IN assertion: there is enough room in pending_buf. */ #define put_byte(s, c) {s->pending_buf[s->pending++] = (c);} #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1) /* Minimum amount of lookahead, except at the end of the input file. * See deflate.c for comments about the MIN_MATCH+1. */ #define MAX_DIST(s) ((s)->w_size-MIN_LOOKAHEAD) /* In order to simplify the code, particularly on 16 bit machines, match * distances are limited to MAX_DIST instead of WSIZE. */ /* in trees.c */ void zlib_tr_init (deflate_state *s); int zlib_tr_tally (deflate_state *s, unsigned dist, unsigned lc); ulg zlib_tr_flush_block (deflate_state *s, char *buf, ulg stored_len, int eof); void zlib_tr_align (deflate_state *s); void zlib_tr_stored_block (deflate_state *s, char *buf, ulg stored_len, int eof); void zlib_tr_stored_type_only (deflate_state *); /* =========================================================================== * Output a short LSB first on the stream. * IN assertion: there is enough room in pendingBuf. */ #define put_short(s, w) { \ put_byte(s, (uch)((w) & 0xff)); \ put_byte(s, (uch)((ush)(w) >> 8)); \ } /* =========================================================================== * Reverse the first len bits of a code, using straightforward code (a faster * method would use a table) * IN assertion: 1 <= len <= 15 */ static inline unsigned bi_reverse(unsigned code, /* the value to invert */ int len) /* its bit length */ { register unsigned res = 0; do { res |= code & 1; code >>= 1, res <<= 1; } while (--len > 0); return res >> 1; } /* =========================================================================== * Flush the bit buffer, keeping at most 7 bits in it. */ static inline void bi_flush(deflate_state *s) { if (s->bi_valid == 16) { put_short(s, s->bi_buf); s->bi_buf = 0; s->bi_valid = 0; } else if (s->bi_valid >= 8) { put_byte(s, (Byte)s->bi_buf); s->bi_buf >>= 8; s->bi_valid -= 8; } } /* =========================================================================== * Flush the bit buffer and align the output on a byte boundary */ static inline void bi_windup(deflate_state *s) { if (s->bi_valid > 8) { put_short(s, s->bi_buf); } else if (s->bi_valid > 0) { put_byte(s, (Byte)s->bi_buf); } s->bi_buf = 0; s->bi_valid = 0; #ifdef DEBUG_ZLIB s->bits_sent = (s->bits_sent+7) & ~7; #endif }