| #ifndef DEFLATE_H_ |
| #define DEFLATE_H_ |
| /* deflate.h -- internal compression state |
| * Copyright (C) 1995-2016 Jean-loup Gailly |
| * For conditions of distribution and use, see copyright notice in zlib.h |
| */ |
| |
| /* WARNING: this file should *not* be used by applications. It is |
| part of the implementation of the compression library and is |
| subject to change. Applications should only use zlib.h. |
| */ |
| |
| #include "zutil.h" |
| #include "zendian.h" |
| #include "adler32_fold.h" |
| #include "crc32_fold.h" |
| |
| /* define NO_GZIP when compiling if you want to disable gzip header and |
| trailer creation by deflate(). NO_GZIP would be used to avoid linking in |
| the crc code when it is not needed. For shared libraries, gzip encoding |
| should be left enabled. */ |
| #ifndef NO_GZIP |
| # define GZIP |
| #endif |
| |
| /* =========================================================================== |
| * Internal compression state. |
| */ |
| |
| #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 BIT_BUF_SIZE 64 |
| /* size of bit buffer in bi_buf */ |
| |
| #define END_BLOCK 256 |
| /* end of block literal code */ |
| |
| #define INIT_STATE 42 /* zlib header -> BUSY_STATE */ |
| #ifdef GZIP |
| # define GZIP_STATE 57 /* gzip header -> BUSY_STATE | EXTRA_STATE */ |
| # define EXTRA_STATE 69 /* gzip extra block -> NAME_STATE */ |
| # define NAME_STATE 73 /* gzip file name -> COMMENT_STATE */ |
| # define COMMENT_STATE 91 /* gzip comment -> HCRC_STATE */ |
| # define HCRC_STATE 103 /* gzip header CRC -> BUSY_STATE */ |
| #endif |
| #define BUSY_STATE 113 /* deflate -> FINISH_STATE */ |
| #define FINISH_STATE 666 /* stream complete */ |
| /* Stream status */ |
| |
| #define HASH_BITS 16u /* log2(HASH_SIZE) */ |
| #ifndef HASH_SIZE |
| # define HASH_SIZE 65536u /* number of elements in hash table */ |
| #endif |
| #define HASH_MASK (HASH_SIZE - 1u) /* HASH_SIZE-1 */ |
| |
| |
| /* Data structure describing a single value and its code string. */ |
| typedef struct ct_data_s { |
| union { |
| uint16_t freq; /* frequency count */ |
| uint16_t code; /* bit string */ |
| } fc; |
| union { |
| uint16_t dad; /* father node in Huffman tree */ |
| uint16_t 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 */ |
| const static_tree_desc *stat_desc; /* the corresponding static tree */ |
| } tree_desc; |
| |
| typedef uint16_t Pos; |
| |
| /* A Pos is an index in the character window. We use short instead of int to |
| * save space in the various tables. |
| */ |
| /* Type definitions for hash callbacks */ |
| typedef struct internal_state deflate_state; |
| |
| typedef uint32_t (* update_hash_cb) (deflate_state *const s, uint32_t h, uint32_t val); |
| typedef void (* insert_string_cb) (deflate_state *const s, uint32_t str, uint32_t count); |
| typedef Pos (* quick_insert_string_cb)(deflate_state *const s, uint32_t str); |
| |
| struct internal_state { |
| PREFIX3(stream) *strm; /* pointer back to this zlib stream */ |
| unsigned char *pending_buf; /* output still pending */ |
| unsigned char *pending_out; /* next pending byte to output to the stream */ |
| uint32_t pending_buf_size; /* size of pending_buf */ |
| uint32_t pending; /* nb of bytes in the pending buffer */ |
| int wrap; /* bit 0 true for zlib, bit 1 true for gzip */ |
| uint32_t gzindex; /* where in extra, name, or comment */ |
| PREFIX(gz_headerp) gzhead; /* gzip header information to write */ |
| int status; /* as the name implies */ |
| int last_flush; /* value of flush param for previous deflate call */ |
| int reproducible; /* Whether reproducible compression results are required. */ |
| |
| int block_open; |
| /* Whether or not a block is currently open for the QUICK deflation scheme. |
| * This is set to 1 if there is an active block, or 0 if the block was just closed. |
| */ |
| |
| /* used by deflate.c: */ |
| |
| unsigned int w_size; /* LZ77 window size (32K by default) */ |
| unsigned int w_bits; /* log2(w_size) (8..16) */ |
| unsigned int w_mask; /* w_size - 1 */ |
| unsigned int lookahead; /* number of valid bytes ahead in window */ |
| |
| unsigned int high_water; |
| /* High water mark offset in window for initialized bytes -- bytes above |
| * this are set to zero in order to avoid memory check warnings when |
| * longest match routines access bytes past the input. This is then |
| * updated to the new high water mark. |
| */ |
| |
| unsigned int window_size; |
| /* Actual size of window: 2*wSize, except when the user input buffer |
| * is directly used as sliding window. |
| */ |
| |
| unsigned char *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-STD_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. |
| */ |
| |
| 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 0. */ |
| |
| uint32_t ins_h; /* hash index of string to be inserted */ |
| |
| int block_start; |
| /* Window position at the beginning of the current output block. Gets |
| * negative when the window is moved backwards. |
| */ |
| |
| unsigned int match_length; /* length of best match */ |
| Pos prev_match; /* previous match */ |
| int match_available; /* set if previous match exists */ |
| unsigned int strstart; /* start of string to insert */ |
| unsigned int match_start; /* start of matching string */ |
| |
| unsigned int 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. |
| */ |
| |
| unsigned int 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. |
| */ |
| |
| unsigned int 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. |
| */ |
| |
| update_hash_cb update_hash; |
| insert_string_cb insert_string; |
| quick_insert_string_cb quick_insert_string; |
| /* Hash function callbacks that can be configured depending on the deflate |
| * algorithm being used */ |
| |
| int level; /* compression level (1..9) */ |
| int strategy; /* favor or force Huffman coding*/ |
| |
| unsigned int good_match; |
| /* Use a faster search when the previous match is longer than this */ |
| |
| int nice_match; /* Stop searching when current match exceeds this */ |
| |
| struct crc32_fold_s ALIGNED_(16) crc_fold; |
| |
| /* 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 */ |
| |
| uint16_t 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. |
| */ |
| |
| unsigned char depth[2*L_CODES+1]; |
| /* Depth of each subtree used as tie breaker for trees of equal frequency |
| */ |
| |
| unsigned int 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 |
| */ |
| |
| unsigned char *sym_buf; /* buffer for distances and literals/lengths */ |
| unsigned int sym_next; /* running index in sym_buf */ |
| unsigned int sym_end; /* symbol table full when sym_next reaches this */ |
| |
| unsigned long opt_len; /* bit length of current block with optimal trees */ |
| unsigned long static_len; /* bit length of current block with static trees */ |
| unsigned int matches; /* number of string matches in current block */ |
| unsigned int insert; /* bytes at end of window left to insert */ |
| |
| /* compressed_len and bits_sent are only used if ZLIB_DEBUG is defined */ |
| unsigned long compressed_len; /* total bit length of compressed file mod 2^32 */ |
| unsigned long bits_sent; /* bit length of compressed data sent mod 2^32 */ |
| |
| /* Reserved for future use and alignment purposes */ |
| char *reserved_p; |
| |
| uint64_t bi_buf; |
| /* Output buffer. bits are inserted starting at the bottom (least significant bits). */ |
| |
| int32_t bi_valid; |
| /* Number of valid bits in bi_buf. All bits above the last valid bit are always zero. */ |
| |
| /* Reserved for future use and alignment purposes */ |
| int32_t reserved[11]; |
| } ALIGNED_(8); |
| |
| typedef enum { |
| need_more, /* block not completed, need more input or more output */ |
| block_done, /* block flush performed */ |
| finish_started, /* finish started, need only more output at next deflate */ |
| finish_done /* finish done, accept no more input or output */ |
| } block_state; |
| |
| /* 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++] = (unsigned char)(c); \ |
| } |
| |
| /* =========================================================================== |
| * Output a short LSB first on the stream. |
| * IN assertion: there is enough room in pending_buf. |
| */ |
| static inline void put_short(deflate_state *s, uint16_t w) { |
| #if BYTE_ORDER == BIG_ENDIAN |
| w = ZSWAP16(w); |
| #endif |
| memcpy(&s->pending_buf[s->pending], &w, sizeof(w)); |
| s->pending += 2; |
| } |
| |
| /* =========================================================================== |
| * Output a short MSB first on the stream. |
| * IN assertion: there is enough room in pending_buf. |
| */ |
| static inline void put_short_msb(deflate_state *s, uint16_t w) { |
| #if BYTE_ORDER == LITTLE_ENDIAN |
| w = ZSWAP16(w); |
| #endif |
| memcpy(&s->pending_buf[s->pending], &w, sizeof(w)); |
| s->pending += 2; |
| } |
| |
| /* =========================================================================== |
| * Output a 32-bit unsigned int LSB first on the stream. |
| * IN assertion: there is enough room in pending_buf. |
| */ |
| static inline void put_uint32(deflate_state *s, uint32_t dw) { |
| #if BYTE_ORDER == BIG_ENDIAN |
| dw = ZSWAP32(dw); |
| #endif |
| memcpy(&s->pending_buf[s->pending], &dw, sizeof(dw)); |
| s->pending += 4; |
| } |
| |
| /* =========================================================================== |
| * Output a 32-bit unsigned int MSB first on the stream. |
| * IN assertion: there is enough room in pending_buf. |
| */ |
| static inline void put_uint32_msb(deflate_state *s, uint32_t dw) { |
| #if BYTE_ORDER == LITTLE_ENDIAN |
| dw = ZSWAP32(dw); |
| #endif |
| memcpy(&s->pending_buf[s->pending], &dw, sizeof(dw)); |
| s->pending += 4; |
| } |
| |
| /* =========================================================================== |
| * Output a 64-bit unsigned int LSB first on the stream. |
| * IN assertion: there is enough room in pending_buf. |
| */ |
| static inline void put_uint64(deflate_state *s, uint64_t lld) { |
| #if BYTE_ORDER == BIG_ENDIAN |
| lld = ZSWAP64(lld); |
| #endif |
| memcpy(&s->pending_buf[s->pending], &lld, sizeof(lld)); |
| s->pending += 8; |
| } |
| |
| #define MIN_LOOKAHEAD (STD_MAX_MATCH + STD_MIN_MATCH + 1) |
| /* Minimum amount of lookahead, except at the end of the input file. |
| * See deflate.c for comments about the STD_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. |
| */ |
| |
| #define WIN_INIT STD_MAX_MATCH |
| /* Number of bytes after end of data in window to initialize in order to avoid |
| memory checker errors from longest match routines */ |
| |
| |
| void Z_INTERNAL PREFIX(fill_window)(deflate_state *s); |
| void Z_INTERNAL slide_hash_c(deflate_state *s); |
| |
| /* in trees.c */ |
| void Z_INTERNAL zng_tr_init(deflate_state *s); |
| void Z_INTERNAL zng_tr_flush_block(deflate_state *s, char *buf, uint32_t stored_len, int last); |
| void Z_INTERNAL zng_tr_flush_bits(deflate_state *s); |
| void Z_INTERNAL zng_tr_align(deflate_state *s); |
| void Z_INTERNAL zng_tr_stored_block(deflate_state *s, char *buf, uint32_t stored_len, int last); |
| uint16_t Z_INTERNAL PREFIX(bi_reverse)(unsigned code, int len); |
| void Z_INTERNAL PREFIX(flush_pending)(PREFIX3(streamp) strm); |
| #define d_code(dist) ((dist) < 256 ? zng_dist_code[dist] : zng_dist_code[256+((dist)>>7)]) |
| /* Mapping from a distance to a distance code. dist is the distance - 1 and |
| * must not have side effects. zng_dist_code[256] and zng_dist_code[257] are never |
| * used. |
| */ |
| |
| /* Bit buffer and compress bits calculation debugging */ |
| #ifdef ZLIB_DEBUG |
| # define cmpr_bits_add(s, len) s->compressed_len += (len) |
| # define cmpr_bits_align(s) s->compressed_len = (s->compressed_len + 7) & ~7L |
| # define sent_bits_add(s, bits) s->bits_sent += (bits) |
| # define sent_bits_align(s) s->bits_sent = (s->bits_sent + 7) & ~7L |
| #else |
| # define cmpr_bits_add(s, len) Z_UNUSED(len) |
| # define cmpr_bits_align(s) |
| # define sent_bits_add(s, bits) Z_UNUSED(bits) |
| # define sent_bits_align(s) |
| #endif |
| |
| #endif /* DEFLATE_H_ */ |
