blob: a8c370897c9f4ee641373ba9245a5d833de07683 [file] [log] [blame]
#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 */
/* 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
#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 */
ulg bits_sent; /* bit length of the compressed data */
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;
Pos *prev_memory;
Pos *head_memory;
char *overlay_memory;
} deflate_workspace;
#define zlib_deflate_window_memsize(windowBits) \
(2 * (1 << (windowBits)) * sizeof(Byte))
#define zlib_deflate_prev_memsize(windowBits) \
((1 << (windowBits)) * sizeof(Pos))
#define zlib_deflate_head_memsize(memLevel) \
((1 << ((memLevel)+7)) * sizeof(Pos))
#define zlib_deflate_overlay_memsize(memLevel) \
((1 << ((memLevel)+6)) * (sizeof(ush)+2))
/* 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);}
/* 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)); \
/* ===========================================================================
* 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;
s->bits_sent = (s->bits_sent+7) & ~7;