AuroraMiddleware/zlib
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Enable dictionary setting in middle of stream, and keeping the dictionary.

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This patch adds the deflateResetKeep() function to retain the sliding
window for the next deflate operation, and fixes an inflateResetKeep()
problem that came from inflate() not updating the window when the
stream completed.  This enables constructing and decompressing a series
of concatenated deflate streams where each can depend on the history of
uncompressed data that precedes it.

This generalizes deflateSetDictionary() and inflateSetDictionary() to
permit setting the dictionary in the middle of a stream for raw deflate
and inflate.  This in combination with the Keep functions enables a
scheme for updating files block by block with the transmission of
compressed data, where blocks are sent with deflateResetKeep() to
retain history for better compression, and deflateSetDictionary() is
used for blocks already present at the receiver to skip compression but
insert that data in the history, again for better compression.  The
corresponding inflate calls are done on the receiver side.
This commit is contained in:
Mark Adler 2011-12-07 23:57:37 -08:00
parent fbac04f666
commit afe7cf78d5
12 changed files with 108 additions and 49 deletions
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1
as400/bndsrc
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@ -33,6 +33,7 @@ STRPGMEXP PGMLVL(*CURRENT) SIGNATURE('ZLIB')
EXPORT SYMBOL("deflateSetDictionary")
EXPORT SYMBOL("deflateCopy")
EXPORT SYMBOL("deflateReset")
EXPORT SYMBOL("deflateResetKeep")
EXPORT SYMBOL("deflateParams")
EXPORT SYMBOL("deflatePending")
EXPORT SYMBOL("deflatePrime")

4
as400/zlib.inc
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@ -433,6 +433,10 @@
*
D inflateResetKeep...
D PR 10I 0 extproc('inflateResetKeep') End and init. stream
D strm like(z_stream) Expansion stream
*
D deflateResetKeep...
D PR 10I 0 extproc('deflateResetKeep') End and init. stream
D strm like(z_stream) Expansion stream
*
D gzflags PR 10U 0 extproc('gzflags')

1
contrib/vstudio/vc10/zlibvc.def
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@ -133,3 +133,4 @@ EXPORTS
gzgetc_ @30
gzflags @162
inflateResetKeep @163
deflateResetKeep @164

1
contrib/vstudio/vc9/zlibvc.def
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@ -133,3 +133,4 @@ EXPORTS
gzgetc_ @30
gzflags @162
inflateResetKeep @163
deflateResetKeep @164

88
deflate.c
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@ -323,43 +323,68 @@ int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
uInt dictLength;
{
deflate_state *s;
uInt length = dictLength;
uInt n;
IPos hash_head = 0;
uInt str, n;
int wrap;
unsigned avail;
unsigned char *next;
if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
strm->state->wrap == 2 ||
(strm->state->wrap == 1 && strm->state->status != INIT_STATE))
if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL)
return Z_STREAM_ERROR;
s = strm->state;
wrap = s->wrap;
if (wrap == 2 || (wrap == 1 && s->status != INIT_STATE) || s->lookahead)
return Z_STREAM_ERROR;
s = strm->state;
if (s->wrap)
/* when using zlib wrappers, compute Adler-32 for provided dictionary */
if (wrap == 1)
strm->adler = adler32(strm->adler, dictionary, dictLength);
s->wrap = 0; /* avoid computing Adler-32 in read_buf */
if (length < MIN_MATCH) return Z_OK;
if (length > s->w_size) {
length = s->w_size;
dictionary += dictLength - length; /* use the tail of the dictionary */
/* if dictionary would fill window, just replace the history */
if (dictLength >= s->w_size) {
if (wrap == 0) { /* already empty otherwise */
CLEAR_HASH(s);
s->strstart = 0;
s->block_start = 0L;
}
dictionary += dictLength - s->w_size; /* use the tail */
dictLength = s->w_size;
}
zmemcpy(s->window, dictionary, length);
s->strstart = length;
s->block_start = (long)length;
/* Insert all strings in the hash table (except for the last two bytes).
* s->lookahead stays null, so s->ins_h will be recomputed at the next
* call of fill_window.
*/
s->ins_h = s->window[0];
UPDATE_HASH(s, s->ins_h, s->window[1]);
for (n = 0; n <= length - MIN_MATCH; n++) {
INSERT_STRING(s, n, hash_head);
/* insert dictionary into window and hash */
avail = strm->avail_in;
next = strm->next_in;
strm->avail_in = dictLength;
strm->next_in = (Bytef *)dictionary;
fill_window(s);
while (s->lookahead >= MIN_MATCH) {
str = s->strstart;
n = s->lookahead - (MIN_MATCH-1);
do {
UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
#ifndef FASTEST
s->prev[str & s->w_mask] = s->head[s->ins_h];
#endif
s->head[s->ins_h] = (Pos)str;
str++;
} while (--n);
s->strstart = str;
s->lookahead = MIN_MATCH-1;
fill_window(s);
}
if (hash_head) hash_head = 0; /* to make compiler happy */
s->strstart += s->lookahead;
s->block_start = (long)s->strstart;
s->lookahead = 0;
s->match_length = s->prev_length = MIN_MATCH-1;
s->match_available = 0;
strm->next_in = next;
strm->avail_in = avail;
s->wrap = wrap;
return Z_OK;
}
/* ========================================================================= */
int ZEXPORT deflateReset (strm)
int ZEXPORT deflateResetKeep (strm)
z_streamp strm;
{
deflate_state *s;
@ -389,11 +414,22 @@ int ZEXPORT deflateReset (strm)
s->last_flush = Z_NO_FLUSH;
_tr_init(s);
lm_init(s);
return Z_OK;
}
/* ========================================================================= */
int ZEXPORT deflateReset (strm)
z_streamp strm;
{
int ret;
ret = deflateResetKeep(strm);
if (ret == Z_OK)
lm_init(strm->state);
return ret;
}
/* ========================================================================= */
int ZEXPORT deflateSetHeader (strm, head)
z_streamp strm;

27
inflate.c
View File

@ -1232,7 +1232,7 @@ int flush;
*/
inf_leave:
RESTORE();
if (state->wsize || (state->mode < CHECK && out != strm->avail_out))
if (state->wsize || (state->mode < BAD && out != strm->avail_out))
if (updatewindow(strm, out)) {
state->mode = MEM;
return Z_MEM_ERROR;
@ -1274,6 +1274,9 @@ uInt dictLength;
{
struct inflate_state FAR *state;
unsigned long id;
unsigned char *next;
unsigned avail;
int ret;
/* check state */
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
@ -1289,21 +1292,19 @@ uInt dictLength;
return Z_DATA_ERROR;
}
/* copy dictionary to window */
if (updatewindow(strm, strm->avail_out)) {
/* copy dictionary to window using updatewindow(), which will amend the
existing dictionary if appropriate */
next = strm->next_out;
avail = strm->avail_out;
strm->next_out = (Bytef *)dictionary + dictLength;
strm->avail_out = 0;
ret = updatewindow(strm, dictLength);
strm->avail_out = avail;
strm->next_out = next;
if (ret) {
state->mode = MEM;
return Z_MEM_ERROR;
}
if (dictLength > state->wsize) {
zmemcpy(state->window, dictionary + dictLength - state->wsize,
state->wsize);
state->whave = state->wsize;
}
else {
zmemcpy(state->window + state->wsize - dictLength, dictionary,
dictLength);
state->whave = dictLength;
}
state->havedict = 1;
Tracev((stderr, "inflate: dictionary set\n"));
return Z_OK;

1
win32/zlib.def
View File

@ -78,5 +78,6 @@ EXPORTS
get_crc_table
inflateUndermine
inflateResetKeep
deflateResetKeep
gzgetc_
gzflags

1
zconf.h
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@ -46,6 +46,7 @@
# define deflatePending z_deflatePending
# define deflatePrime z_deflatePrime
# define deflateReset z_deflateReset
# define deflateResetKeep z_deflateResetKeep
# define deflateSetDictionary z_deflateSetDictionary
# define deflateSetHeader z_deflateSetHeader
# define deflateTune z_deflateTune

1
zconf.h.cmakein
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@ -48,6 +48,7 @@
# define deflatePending z_deflatePending
# define deflatePrime z_deflatePrime
# define deflateReset z_deflateReset
# define deflateResetKeep z_deflateResetKeep
# define deflateSetDictionary z_deflateSetDictionary
# define deflateSetHeader z_deflateSetHeader
# define deflateTune z_deflateTune

1
zconf.h.in
View File

@ -46,6 +46,7 @@
# define deflatePending z_deflatePending
# define deflatePrime z_deflatePrime
# define deflateReset z_deflateReset
# define deflateResetKeep z_deflateResetKeep
# define deflateSetDictionary z_deflateSetDictionary
# define deflateSetHeader z_deflateSetHeader
# define deflateTune z_deflateTune

27
zlib.h
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@ -581,10 +581,15 @@ ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
uInt dictLength));
/*
Initializes the compression dictionary from the given byte sequence
without producing any compressed output. This function must be called
immediately after deflateInit, deflateInit2 or deflateReset, before any call
of deflate. The compressor and decompressor must use exactly the same
dictionary (see inflateSetDictionary).
without producing any compressed output. When using the zlib format, this
function must be called immediately after deflateInit, deflateInit2 or
deflateReset, and before any call of deflate. When doing raw deflate, this
function must be called either before any call of deflate, or immediately
after the completion of a deflate block, i.e. after all input has been
consumed and all output has been delivered when using any of the flush
options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The
compressor and decompressor must use exactly the same dictionary (see
inflateSetDictionary).
The dictionary should consist of strings (byte sequences) that are likely
to be encountered later in the data to be compressed, with the most commonly
@ -611,8 +616,8 @@ ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
inconsistent (for example if deflate has already been called for this stream
or if the compression method is bsort). deflateSetDictionary does not
perform any compression: this will be done by deflate().
or if not at a block boundary for raw deflate). deflateSetDictionary does
not perform any compression: this will be done by deflate().
*/
ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
@ -810,10 +815,11 @@ ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
can be determined from the adler32 value returned by that call of inflate.
The compressor and decompressor must use exactly the same dictionary (see
deflateSetDictionary). For raw inflate, this function can be called
immediately after inflateInit2() or inflateReset() and before any call of
inflate() to set the dictionary. The application must insure that the
dictionary that was used for compression is provided.
deflateSetDictionary). For raw inflate, this function can be called at any
time to set the dictionary. If the provided dictionary is smaller than the
window and there is already data in the window, then the provided dictionary
will amend what's there. The application must insure that the dictionary
that was used for compression is provided.
inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
@ -1694,6 +1700,7 @@ ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp));
ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void));
ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int));
ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp));
ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp));
#ifndef Z_SOLO
ZEXTERN unsigned long ZEXPORT gzflags OF((void));
#endif

4
zlib.map
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@ -76,3 +76,7 @@ ZLIB_1.2.5.2 {
gzgetc_;
inflateResetKeep;
} ZLIB_1.2.5.1;
ZLIB_1.2.5.3 {
deflateResetKeep;
} ZLIB_1.2.5.2;