in contrib/libz/deflate.c [804:1116]
int ZEXPORT deflate (strm, flush)
z_streamp 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 && s->wrap == 0)
s->status = BUSY_STATE;
if (s->status == INIT_STATE) {
/* zlib header */
uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
uInt 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, (uInt)(strm->adler >> 16));
putShortMSB(s, (uInt)(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, (Byte)(s->gzhead->time & 0xff));
put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
put_byte(s, (Byte)((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 */
uInt left = (s->gzhead->extra_len & 0xffff) - s->gzindex;
while (s->pending + left > s->pending_buf_size) {
uInt 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, (Byte)(strm->adler & 0xff));
put_byte(s, (Byte)((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, (Byte)(strm->adler & 0xff));
put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
put_byte(s, (Byte)(strm->total_in & 0xff));
put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
}
else
#endif
{
putShortMSB(s, (uInt)(strm->adler >> 16));
putShortMSB(s, (uInt)(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;
}