commit 8357a25a970d35e014c98530be0d853a24a3b37c
parent d374cb0ffda5de8dbdf8d084f37d3118e582a282
Author: nsz <nszabolcs@gmail.com>
Date: Tue, 18 Aug 2009 19:55:00 +0200
fix callback, s/hist/win/, clean up match
Diffstat:
| deflate.c | | | 80 | ++++++++++++++++++++++++++++++++++++++----------------------------------------- |
1 file changed, 38 insertions(+), 42 deletions(-)
diff --git a/deflate.c b/deflate.c
@@ -21,7 +21,6 @@ enum {
MaxDist = WinSize - MaxMatch + 1, /* worst case available history */
StartPos = WinSize - MaxMatch + 1, /* block start position */
EndPos = 2*WinSize - MaxMatch + 1, /* block end position */
- HistSize = 2*WinSize, /* history buffer size (64K, indexed with ushort) */
DstSize = WinSize + MaxMatch + 6, /* worst case compressed block size */
LzSize = 1 << 13, /* lz buffer size */
LzEnd = LzSize - 2, /* guard that lzbuf does not overflow in the next iteration */
@@ -45,13 +44,13 @@ typedef struct {
int startpos; /* block start pos in input win */
int avail; /* available in input win */
Match prevm; /* previous (deferred) match */
- uchar *src; /* input data (not yet in hist) */
+ uchar *src; /* input data (not yet in win) */
uchar *srcend;
uchar *dst; /* compressed output (position in dstbuf) */
uchar *dstbegin; /* start position of unflushed data in dstbuf */
uint bits;
int nbits;
- uchar hist[HistSize]; /* history (input buffer) */
+ uchar win[2*WinSize]; /* input window */
ushort head[HashSize]; /* position of hash chain heads */
ushort chain[WinSize]; /* hash chain */
LzCode lzbuf[LzSize]; /* literal run length, match len, match dist */
@@ -297,14 +296,14 @@ static int clencodes(uchar *codes, uchar *extra, uchar *llen, int nlit, uchar *d
static void putblock(State *s, ushort *lcode, uchar *llen, ushort *dcode, uchar *dlen) {
int n;
LzCode *lz;
- uchar *h;
+ uchar *p;
- for (lz = s->lzbuf, h = s->hist + s->startpos; lz != s->lz; lz++)
+ for (lz = s->lzbuf, p = s->win + s->startpos; lz != s->lz; lz++)
if (lz->bits & LzLitFlag)
- for (n = lz->n; n > 0; n--, h++)
- putbits(s, lcode[*h], llen[*h]);
+ for (n = lz->n; n > 0; n--, p++)
+ putbits(s, lcode[*p], llen[*p]);
else {
- h += lenbase[lz->n] + lz->bits;
+ p += lenbase[lz->n] + lz->bits;
putbits(s, lcode[Nlit + lz->n + 1], llen[Nlit + lz->n + 1]);
putbits(s, lz->bits, lenbits[lz->n]);
lz++;
@@ -324,7 +323,7 @@ static void deflate_block(State *s) {
int i, c, n, ncodes;
int nlit, ndist, nclen;
LzCode *lz;
- uchar *h;
+ uchar *p;
int dynsize, fixsize, uncsize;
int blocklen = s->pos - s->startpos;
/* int dyntree; */
@@ -359,14 +358,14 @@ static void deflate_block(State *s) {
dynsize += 7;
}
/* dyntree = dynsize - 3; */
- for (lz = s->lzbuf, h = s->hist + s->startpos; lz != s->lz; lz++)
+ for (lz = s->lzbuf, p = s->win + s->startpos; lz != s->lz; lz++)
if (lz->bits & LzLitFlag)
- for (n = lz->n; n > 0; n--, h++) {
- fixsize += fixllen[*h];
- dynsize += llen[*h];
+ for (n = lz->n; n > 0; n--, p++) {
+ fixsize += fixllen[*p];
+ dynsize += llen[*p];
}
else {
- h += lenbase[lz->n] + lz->bits;
+ p += lenbase[lz->n] + lz->bits;
fixsize += fixllen[Nlit + lz->n + 1];
dynsize += llen[Nlit + lz->n + 1];
fixsize += lenbits[lz->n];
@@ -412,7 +411,7 @@ static void deflate_block(State *s) {
s->nbits = 0;
putbits(s, blocklen, 16);
putbits(s, ~blocklen & 0xffff, 16);
- memcpy(s->dst, s->hist + s->startpos, blocklen);
+ memcpy(s->dst, s->win + s->startpos, blocklen);
s->dst += blocklen;
}
/*
@@ -480,10 +479,9 @@ static int gethash(uchar *p) {
static int updatechain(State *s) {
int h, i;
- /* eliminating this check didn't make the code faster */
if (s->avail < MinMatch)
return 0;
- h = gethash(s->hist + s->pos);
+ h = gethash(s->win + s->pos);
i = s->head[h];
s->head[h] = s->pos;
if (i >= s->pos || s->pos - i > MaxDist)
@@ -496,29 +494,28 @@ static int updatechain(State *s) {
static Match getmatch(State *s, int mpos) {
Match m = {0, MinMatch-1};
int len;
+ int maxlen = s->avail < MaxMatch ? s->avail : MaxMatch;
int limit = s->pos - MaxDist;
int chainlen = MaxChainLen;
uchar *q;
- uchar *p = s->hist + s->pos;
- uchar *end = p + MaxMatch;
+ uchar *p = s->win + s->pos;
+ uchar *end = p + maxlen;
do {
- q = s->hist + mpos;
+ q = s->win + mpos;
/* next match should be at least m.len+1 long */
if (q[m.len] != p[m.len] || q[m.len-1] != p[m.len-1] || q[0] != p[0])
continue;
while (++p != end && *++q == *p);
- len = MaxMatch - (end - p);
+ len = maxlen - (end - p);
p -= len;
if (len > m.len) {
m.dist = s->pos - mpos;
- if (len >= s->avail || len == MaxMatch) {
- m.len = s->avail < MaxMatch ? s->avail : MaxMatch;
- return m;
- }
m.len = len;
+ if (len == maxlen)
+ return m;
}
- /* >= limit can be allowed except if limit == 0 */
+ /* >= limit can be allowed except when limit == 0 */
} while ((mpos = s->chain[mpos % WinSize]) > limit && --chainlen);
if (m.len < MinMatch || (m.len == MinMatch && m.dist > BigDist))
m.len = 0;
@@ -551,7 +548,7 @@ static int endblock(State *s) {
return 1;
}
/* shift input window */
- memcpy(s->hist, s->hist + WinSize, WinSize);
+ memcpy(s->win, s->win + WinSize, WinSize);
for (n = 0; n < HashSize; n++)
s->head[n] = s->head[n] > WinSize ? s->head[n] - WinSize : 0;
for (n = 0; n < WinSize; n++)
@@ -562,6 +559,7 @@ static int endblock(State *s) {
return 0;
}
+/* fill input window */
static int fillwin(State *s) {
int n, k;
@@ -571,7 +569,7 @@ static int fillwin(State *s) {
n = 2*WinSize - s->pos - s->avail; /* s->avail + n >= MaxMatch */
if (k > n)
k = n;
- memcpy(s->hist + s->pos + s->avail, s->src, k);
+ memcpy(s->win + s->pos + s->avail, s->src, k);
s->src += k;
s->avail += k;
if (s->avail < MaxMatch) /* s->srcend == s->src */
@@ -580,7 +578,7 @@ static int fillwin(State *s) {
return 1;
}
-/* deflate from s->src into s->dstbuf */
+/* deflate compress from s->src into s->dstbuf */
static int deflate_state(State *s) {
Match m;
int head;
@@ -610,7 +608,7 @@ static int deflate_state(State *s) {
m = getmatch(s, head);
if (head && m.len > s->prevm.len) {
if (s->prevm.len)
- recordlit(s, s->hist[s->pos-1]);
+ recordlit(s, s->win[s->pos-1]);
s->prevm = m;
} else if (s->prevm.len) {
recordmatch(s, s->prevm);
@@ -621,7 +619,7 @@ static int deflate_state(State *s) {
updatechain(s);
} while (--s->prevm.len);
} else
- recordlit(s, s->hist[s->pos]);
+ recordlit(s, s->win[s->pos]);
s->pos++;
s->avail--;
}
@@ -649,6 +647,8 @@ static State *alloc_state(void) {
fixdlen[i] = 5;
huffcodes(fixlcode, fixllen, Nlitlen);
huffcodes(fixdcode, fixdlen, Ndist);
+ s->state = FlateOut;
+ s->src = s->srcend = 0;
s->dst = s->dstbegin = s->dstbuf;
s->pos = s->startpos = StartPos;
s->eof = 0;
@@ -673,8 +673,6 @@ int deflate(FlateStream *stream) {
s = stream->state = alloc_state();
if (!s)
return stream->err = "no mem.", FlateErr;
- s->state = FlateOut;
- s->src = s->srcend = 0;
}
if (stream->nin) {
s->src = stream->in;
@@ -698,27 +696,25 @@ int deflate(FlateStream *stream) {
int deflate_callback(int (*r)(void *, int, void *), void *rdata, int (*w)(void *, int, void *), void *wdata) {
State *s;
+ uchar *src;
int len, n;
- enum {SrcSize = 1 << 12};
+ enum {SrcSize = 1 << 13};
s = alloc_state();
if (!s)
return FlateErr;
- s->src = s->srcend = malloc(SrcSize);
- if (!s->src) {
+ src = s->src = s->srcend = malloc(SrcSize);
+ if (!src) {
free(s);
return FlateErr;
}
- s->state = FlateOut;
for (;;) {
n = deflate_state(s);
switch (n) {
case FlateIn:
+ s->src = src;
len = r(s->src, SrcSize, rdata);
- if (len > 0)
- s->srcend = s->src + len;
- else
- s->state = FlateErr;
+ s->srcend = s->src + len;
break;
case FlateOut:
len = w(s->dstbegin, s->dst - s->dstbegin, wdata);
@@ -729,7 +725,7 @@ int deflate_callback(int (*r)(void *, int, void *), void *rdata, int (*w)(void *
break;
case FlateOk:
case FlateErr:
- free(s->src);
+ free(src);
free(s);
return n;
}
