const z_stream = struct { /// next input byte */ next_in: &const u8, /// number of bytes available at next_in avail_in: u16, /// total number of input bytes read so far total_in: u32, /// next output byte will go here next_out: u8, /// remaining free space at next_out avail_out: u16, /// total number of bytes output so far total_out: u32, /// last error message, NULL if no error msg: ?&const u8, /// not visible by applications state: struct internal_state FAR *state; // not visible by applications */ alloc_func zalloc; // used to allocate the internal state */ free_func zfree; // used to free the internal state */ voidpf opaque; // private data object passed to zalloc and zfree */ int data_type; // best guess about the data type: binary or text // for deflate, or the decoding state for inflate */ uint32_t adler; // Adler-32 or CRC-32 value of the uncompressed data */ uint32_t reserved; // reserved for future use */ }; typedef struct internal_state { z_stream * strm; /* pointer back to this zlib stream */ int status; /* as the name implies */ uint8_t *pending_buf; /* output still pending */ ulg pending_buf_size; /* size of pending_buf */ uint8_t *pending_out; /* next pending byte to output to the stream */ ulg pending; /* nb of bytes in the pending buffer */ int wrap; /* bit 0 true for zlib, bit 1 true for gzip */ gz_headerp gzhead; /* gzip header information to write */ ulg gzindex; /* where in extra, name, or comment */ uint8_t method; /* can only be DEFLATED */ int last_flush; /* value of flush param for previous deflate call */ /* used by deflate.c: */ uint16_t w_size; /* LZ77 window size (32K by default) */ uint16_t w_bits; /* log2(w_size) (8..16) */ uint16_t w_mask; /* w_size - 1 */ uint8_t *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. */ Posf *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. */ Posf *head; /* Heads of the hash chains or NIL. */ uint16_t ins_h; /* hash index of string to be inserted */ uint16_t hash_size; /* number of elements in hash table */ uint16_t hash_bits; /* log2(hash_size) */ uint16_t hash_mask; /* hash_size-1 */ uint16_t 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. */ uint16_t match_length; /* length of best match */ IPos prev_match; /* previous match */ int match_available; /* set if previous match exists */ uint16_t strstart; /* start of string to insert */ uint16_t match_start; /* start of matching string */ uint16_t lookahead; /* number of valid bytes ahead in window */ uint16_t 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. */ uint16_t 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. */ uint16_t 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*/ uint16_t 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 */ uchf *l_buf; /* buffer for literals or lengths */ uint16_t 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 */ uint16_t last_lit; /* running index in l_buf */ ushf *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 */ uint16_t matches; /* number of string matches in current block */ uint16_t insert; /* bytes at end of window left to insert */ #ifdef ZLIB_DEBUG ulg compressed_len; /* total bit length of compressed file mod 2^32 */ ulg bits_sent; /* bit length of compressed data sent mod 2^32 */ #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. */ ulg 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. */ } FAR deflate_state; fn deflate(strm: &z_stream, flush: int) -> %void { } int deflate (z_stream * strm, int flush) { int old_flush; /* value of flush param for previous deflate call */ deflate_state *s; if (deflateStateCheck(strm) || flush > Z_BLOCK || flush < 0) { return Z_STREAM_ERROR; } s = strm->state; if (strm->next_out == Z_NULL || (strm->avail_in != 0 && strm->next_in == Z_NULL) || (s->status == FINISH_STATE && flush != Z_FINISH)) { ERR_RETURN(strm, Z_STREAM_ERROR); } if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); old_flush = s->last_flush; s->last_flush = flush; /* Flush as much pending output as possible */ if (s->pending != 0) { flush_pending(strm); if (strm->avail_out == 0) { /* Since avail_out is 0, deflate will be called again with * more output space, but possibly with both pending and * avail_in equal to zero. There won't be anything to do, * but this is not an error situation so make sure we * return OK instead of BUF_ERROR at next call of deflate: */ s->last_flush = -1; return Z_OK; } /* Make sure there is something to do and avoid duplicate consecutive * flushes. For repeated and useless calls with Z_FINISH, we keep * returning Z_STREAM_END instead of Z_BUF_ERROR. */ } else if (strm->avail_in == 0 && RANK(flush) <= RANK(old_flush) && flush != Z_FINISH) { ERR_RETURN(strm, Z_BUF_ERROR); } /* User must not provide more input after the first FINISH: */ if (s->status == FINISH_STATE && strm->avail_in != 0) { ERR_RETURN(strm, Z_BUF_ERROR); } /* Write the header */ if (s->status == INIT_STATE) { /* zlib header */ uint16_t header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; uint16_t level_flags; if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) level_flags = 0; else if (s->level < 6) level_flags = 1; else if (s->level == 6) level_flags = 2; else level_flags = 3; header |= (level_flags << 6); if (s->strstart != 0) header |= PRESET_DICT; header += 31 - (header % 31); putShortMSB(s, header); /* Save the adler32 of the preset dictionary: */ if (s->strstart != 0) { putShortMSB(s, (uint16_t)(strm->adler >> 16)); putShortMSB(s, (uint16_t)(strm->adler & 0xffff)); } strm->adler = adler32(0L, Z_NULL, 0); s->status = BUSY_STATE; /* Compression must start with an empty pending buffer */ flush_pending(strm); if (s->pending != 0) { s->last_flush = -1; return Z_OK; } } #ifdef GZIP if (s->status == GZIP_STATE) { /* gzip header */ strm->adler = crc32(0L, Z_NULL, 0); put_byte(s, 31); put_byte(s, 139); put_byte(s, 8); if (s->gzhead == Z_NULL) { put_byte(s, 0); put_byte(s, 0); put_byte(s, 0); put_byte(s, 0); put_byte(s, 0); put_byte(s, s->level == 9 ? 2 : (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? 4 : 0)); put_byte(s, OS_CODE); s->status = BUSY_STATE; /* Compression must start with an empty pending buffer */ flush_pending(strm); if (s->pending != 0) { s->last_flush = -1; return Z_OK; } } else { put_byte(s, (s->gzhead->text ? 1 : 0) + (s->gzhead->hcrc ? 2 : 0) + (s->gzhead->extra == Z_NULL ? 0 : 4) + (s->gzhead->name == Z_NULL ? 0 : 8) + (s->gzhead->comment == Z_NULL ? 0 : 16) ); put_byte(s, (uint8_t)(s->gzhead->time & 0xff)); put_byte(s, (uint8_t)((s->gzhead->time >> 8) & 0xff)); put_byte(s, (uint8_t)((s->gzhead->time >> 16) & 0xff)); put_byte(s, (uint8_t)((s->gzhead->time >> 24) & 0xff)); put_byte(s, s->level == 9 ? 2 : (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? 4 : 0)); put_byte(s, s->gzhead->os & 0xff); if (s->gzhead->extra != Z_NULL) { put_byte(s, s->gzhead->extra_len & 0xff); put_byte(s, (s->gzhead->extra_len >> 8) & 0xff); } if (s->gzhead->hcrc) strm->adler = crc32(strm->adler, s->pending_buf, s->pending); s->gzindex = 0; s->status = EXTRA_STATE; } } if (s->status == EXTRA_STATE) { if (s->gzhead->extra != Z_NULL) { ulg beg = s->pending; /* start of bytes to update crc */ uint16_t left = (s->gzhead->extra_len & 0xffff) - s->gzindex; while (s->pending + left > s->pending_buf_size) { uint16_t copy = s->pending_buf_size - s->pending; zmemcpy(s->pending_buf + s->pending, s->gzhead->extra + s->gzindex, copy); s->pending = s->pending_buf_size; HCRC_UPDATE(beg); s->gzindex += copy; flush_pending(strm); if (s->pending != 0) { s->last_flush = -1; return Z_OK; } beg = 0; left -= copy; } zmemcpy(s->pending_buf + s->pending, s->gzhead->extra + s->gzindex, left); s->pending += left; HCRC_UPDATE(beg); s->gzindex = 0; } s->status = NAME_STATE; } if (s->status == NAME_STATE) { if (s->gzhead->name != Z_NULL) { ulg beg = s->pending; /* start of bytes to update crc */ int val; do { if (s->pending == s->pending_buf_size) { HCRC_UPDATE(beg); flush_pending(strm); if (s->pending != 0) { s->last_flush = -1; return Z_OK; } beg = 0; } val = s->gzhead->name[s->gzindex++]; put_byte(s, val); } while (val != 0); HCRC_UPDATE(beg); s->gzindex = 0; } s->status = COMMENT_STATE; } if (s->status == COMMENT_STATE) { if (s->gzhead->comment != Z_NULL) { ulg beg = s->pending; /* start of bytes to update crc */ int val; do { if (s->pending == s->pending_buf_size) { HCRC_UPDATE(beg); flush_pending(strm); if (s->pending != 0) { s->last_flush = -1; return Z_OK; } beg = 0; } val = s->gzhead->comment[s->gzindex++]; put_byte(s, val); } while (val != 0); HCRC_UPDATE(beg); } s->status = HCRC_STATE; } if (s->status == HCRC_STATE) { if (s->gzhead->hcrc) { if (s->pending + 2 > s->pending_buf_size) { flush_pending(strm); if (s->pending != 0) { s->last_flush = -1; return Z_OK; } } put_byte(s, (uint8_t)(strm->adler & 0xff)); put_byte(s, (uint8_t)((strm->adler >> 8) & 0xff)); strm->adler = crc32(0L, Z_NULL, 0); } s->status = BUSY_STATE; /* Compression must start with an empty pending buffer */ flush_pending(strm); if (s->pending != 0) { s->last_flush = -1; return Z_OK; } } #endif /* Start a new block or continue the current one. */ if (strm->avail_in != 0 || s->lookahead != 0 || (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { block_state bstate; bstate = s->level == 0 ? deflate_stored(s, flush) : s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) : s->strategy == Z_RLE ? deflate_rle(s, flush) : (*(configuration_table[s->level].func))(s, flush); if (bstate == finish_started || bstate == finish_done) { s->status = FINISH_STATE; } if (bstate == need_more || bstate == finish_started) { if (strm->avail_out == 0) { s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ } return Z_OK; /* If flush != Z_NO_FLUSH && avail_out == 0, the next call * of deflate should use the same flush parameter to make sure * that the flush is complete. So we don't have to output an * empty block here, this will be done at next call. This also * ensures that for a very small output buffer, we emit at most * one empty block. */ } if (bstate == block_done) { if (flush == Z_PARTIAL_FLUSH) { _tr_align(s); } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */ _tr_stored_block(s, (char*)0, 0L, 0); /* For a full flush, this empty block will be recognized * as a special marker by inflate_sync(). */ if (flush == Z_FULL_FLUSH) { CLEAR_HASH(s); /* forget history */ if (s->lookahead == 0) { s->strstart = 0; s->block_start = 0L; s->insert = 0; } } } flush_pending(strm); if (strm->avail_out == 0) { s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ return Z_OK; } } } if (flush != Z_FINISH) return Z_OK; if (s->wrap <= 0) return Z_STREAM_END; /* Write the trailer */ #ifdef GZIP if (s->wrap == 2) { put_byte(s, (uint8_t)(strm->adler & 0xff)); put_byte(s, (uint8_t)((strm->adler >> 8) & 0xff)); put_byte(s, (uint8_t)((strm->adler >> 16) & 0xff)); put_byte(s, (uint8_t)((strm->adler >> 24) & 0xff)); put_byte(s, (uint8_t)(strm->total_in & 0xff)); put_byte(s, (uint8_t)((strm->total_in >> 8) & 0xff)); put_byte(s, (uint8_t)((strm->total_in >> 16) & 0xff)); put_byte(s, (uint8_t)((strm->total_in >> 24) & 0xff)); } else #endif { putShortMSB(s, (uint16_t)(strm->adler >> 16)); putShortMSB(s, (uint16_t)(strm->adler & 0xffff)); } flush_pending(strm); /* If avail_out is zero, the application will call deflate again * to flush the rest. */ if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ return s->pending != 0 ? Z_OK : Z_STREAM_END; }