commit 6ee26d56c3e3e39af131e339290495825e8951a3
parent 0a06e6487a7525f7cb49d3b211c551abe56e596c
Author: nsz <nszabolcs@gmail.com>
Date: Sat, 4 Jul 2009 20:15:24 +0200
decode simple +multiple blocks
Diffstat:
2 files changed, 81 insertions(+), 56 deletions(-)
diff --git a/deflate_simple.c b/deflate_simple.c
@@ -30,11 +30,6 @@ typedef struct {
ushort len;
} Match;
-typedef struct {
- uchar *len; /* bit length of the code */
- ushort *code;
-} Huff;
-
enum {
SymLitlen,
SymDist,
@@ -65,19 +60,12 @@ typedef struct {
int firstblock;
int lastblock;
int finished;
-
- Huff fixed_litlen;
- Huff fixed_dist;
- Huff litlen;
- Huff dist;
- Huff clen;
} State;
-#if 0
-/* TODO: globals.. */
-static Huff lhuff; /* fixed lit/len huffman code tree */
-static Huff dhuff; /* fixed distance huffman code tree */
-#endif
+static uchar fixed_llen[Nlitlen]; /* fixed lit/len huffman code tree */
+static ushort fixed_lcode[Nlitlen];
+static uchar fixed_dlen[Ndist]; /* fixed distance huffman code tree */
+static ushort fixed_dcode[Ndist];
/* base offset and extra bits tables */
static uchar lenbits[Nlen] = {
@@ -102,16 +90,6 @@ static short gethash(uchar *p) {
return (257 * p[0] + 263 * p[1] + 269 * p[2]) % HashSize;
}
-static void lzinit(State *s) {
- int i;
-
- for (i = 0; i < WinSize; i++)
- s->chain[i] = 0;
- for (i = 0; i < HashSize; i++)
- s->head[i] = 0;
- s->pos = 0;
-}
-
static Match getmatch(State *s, uchar *src, int len) {
int i, j;
int pos;
@@ -395,7 +373,9 @@ static void hufflenslimit(uchar *lens, int *freqs, int nsym, int limit) {
/* adding < 16 bits to dst */
static void outbits(State *s, uint bits, int nbits) {
+/*
fprintf(stderr, "b:%3d n:%3d\n", bits, nbits);
+*/
s->bits |= bits << s->nbits;
s->nbits += nbits;
while (s->nbits >= 8) {
@@ -414,8 +394,12 @@ static Sym makesym(int type, int len, int sym) {
return s;
}
+static void chooseblock(State *s);
+
static void putsym(State *s, Sym sym) {
s->symbuf[(s->symstart + s->symlen++) % SymSize] = sym;
+ if (s->symlen == SymSize)
+ chooseblock(s);
}
static Sym getsym(State *s, int i) {
@@ -487,15 +471,13 @@ static void block(State *s, int dynlen, int fixlen) {
Sym sym;
int nsym;
int i, nlit, ndist, nclen;
- int dynsize;
+ int dynsize, fixsize;
int blocklen;
- int dynamic;
- int lastblock;
memset(lfreq, 0, sizeof(lfreq));
memset(dfreq, 0, sizeof(dfreq));
lfreq[256] = 1; /* EOB */
- for (i = 0; i < s->symlen; i++) {
+ for (i = 0; i < dynlen; i++) {
sym = getsym(s, i);
if (sym.type == SymLitlen)
lfreq[sym.n]++;
@@ -530,6 +512,7 @@ static void block(State *s, int dynlen, int fixlen) {
if (sym.type == SymExtra)
dynsize += sym.len;
}
+fprintf(stderr, "tree len: %d bits: %d\n", nsym, dynsize);
for (i = 0; i < dynlen; i++) {
sym = getsym(s, i);
if (sym.type == SymLitlen)
@@ -540,16 +523,22 @@ static void block(State *s, int dynlen, int fixlen) {
dynsize += sym.len;
}
dynsize += llen[256]; /* EOB */
-/*
- dynamic = (long long)fsize * dynlen > (long long)dsize * fixlen;
- blocklen = dynamic ? dlen : fixlen;
-*/
- dynamic = 1;
- blocklen = dynlen;
- lastblock = 1;
- outbits(s, lastblock ? 1 : 0, 1);
- if (dynamic) {
+ fixsize = 3;
+ for (i = 0; i < fixlen; i++) {
+ sym = getsym(s, i);
+ if (sym.type == SymLitlen)
+ fixsize += fixed_llen[sym.n];
+ if (sym.type == SymDist)
+ fixsize += fixed_dlen[sym.n];
+ if (sym.type == SymExtra)
+ fixsize += sym.len;
+ }
+ fixsize += fixed_llen[256]; /* EOB */
+
+ outbits(s, s->lastblock, 1);
+ if ((long long)fixsize * dynlen > (long long)dynsize * fixlen) {
+ blocklen = dynlen;
outbits(s, 2, 2);
outbits(s, nlit - 257, 5);
outbits(s, ndist - 1, 5);
@@ -577,9 +566,23 @@ static void block(State *s, int dynlen, int fixlen) {
}
/* EOB */
outbits(s, lcode[256], llen[256]);
+ } else {
+ blocklen = fixlen;
+ outbits(s, 1, 2);
+ /* block data */
+ for (i = 0; i < fixlen; i++) {
+ sym = getsym(s, i);
+ if (sym.type == SymLitlen)
+ outbits(s, fixed_lcode[sym.n], fixed_llen[sym.n]);
+ if (sym.type == SymDist)
+ outbits(s, fixed_dcode[sym.n], fixed_dlen[sym.n]);
+ if (sym.type == SymExtra)
+ outbits(s, sym.n, sym.len);
+ }
+ /* EOB */
+ outbits(s, fixed_lcode[256], fixed_llen[256]);
}
-
-fprintf(stderr, "blocklen: %d symlen: %d dynsize: %d\n", blocklen, s->symlen, dynsize);
+fprintf(stderr, "blocklen: %d symlen: %d dynsize: %d dynlen: %d fixsize: %d fixlen:%d\n", blocklen, s->symlen, dynsize, dynlen, fixsize, fixlen);
s->symstart = (s->symstart + blocklen) % SymSize;
s->symlen -= blocklen;
}
@@ -621,11 +624,11 @@ static void chooseblock(State *s) {
memset(lfreq, 0, sizeof(lfreq));
memset(dfreq, 0, sizeof(dfreq));
- lfreq[256] = 1; /* we're bound to need one EOB */
+ lfreq[256] = 1; /* we're bound to need one EOB */
ltotal = 1;
dtotal = longestlen = bestvfm = 0;
bestlen = -1;
- len = 300 * 8; /* very approximate size of the Huffman trees */
+ len = 400 * 8; /* approximate size of the Huffman trees */
for (i = 0; i < s->symlen; i++) {
sym = getsym(s, i);
if (sym.type == SymLitlen) {
@@ -645,8 +648,6 @@ static void chooseblock(State *s) {
len -= lfreq[sym.n] * log2_8(lfreq[sym.n]);
len += ltotal * log2_8(ltotal);
}
- if (sym.type == SymExtra)
- len += 8 * sym.len;
if (sym.type == SymDist) {
len += dfreq[sym.n] * log2_8(dfreq[sym.n]);
len -= dtotal * log2_8(dtotal);
@@ -655,17 +656,18 @@ static void chooseblock(State *s) {
len -= dfreq[sym.n] * log2_8(dfreq[sym.n]);
len += dtotal * log2_8(dtotal);
}
+ if (sym.type == SymExtra)
+ len += 8 * sym.len;
}
-/* block(s, bestlen, longestlen);*/
- block(s, s->symlen, longestlen);
+ block(s, bestlen, longestlen);
}
static int count = 0;
static void emitlit(State *s, ushort lit) {
- if (s->symlen == SymSize)
- chooseblock(s);
+/*
fprintf(stderr, "%3d %c\n", lit, lit);
+*/
count++;
putsym(s, makesym(SymLitlen, 0, lit));
}
@@ -686,9 +688,9 @@ static int bisect(ushort *base, int len, int n) {
}
static void emitmatch(State *s, Match m) {
- if (s->symlen + 5 >= SymSize)
- chooseblock(s);
+/*
fprintf(stderr, "m %d, %d\n", m.dist, m.len);
+*/
count++;
while (m.len > 0) {
int len;
@@ -708,6 +710,29 @@ count++;
}
}
+static void lzinit(State *s) {
+ int i;
+
+ for (i = 0; i < WinSize; i++)
+ s->chain[i] = 0;
+ for (i = 0; i < HashSize; i++)
+ s->head[i] = 0;
+ s->pos = 0;
+
+ for (i = 0; i < 144; i++)
+ fixed_llen[i] = 8;
+ for (; i < 256; i++)
+ fixed_llen[i] = 9;
+ for (; i < 280; i++)
+ fixed_llen[i] = 7;
+ for (; i < Nlitlen; i++)
+ fixed_llen[i] = 8;
+ huffcodes(fixed_lcode, fixed_llen, Nlitlen);
+ for (i = 0; i < Ndist; i++)
+ fixed_dlen[i] = 5;
+ huffcodes(fixed_dcode, fixed_dlen, Ndist);
+}
+
int deflate(uchar *src, int len, uchar *dst) {
State s;
@@ -720,8 +745,8 @@ int deflate(uchar *src, int len, uchar *dst) {
s.dst = dst;
lzcompress(&s, src, len);
chooseblock(&s);
- if (s.symlen)
- block(&s, s.symlen, s.symlen);
+ s.lastblock = 1;
+ block(&s, s.symlen, s.symlen);
outbits(&s, 0, 7);
return s.dst - dst;
}
diff --git a/inflate.c b/inflate.c
@@ -71,11 +71,11 @@ typedef struct {
int state; /* decode state */
int final; /* last block flag */
- /* for decoding dynamic code trees */
+ /* for decoding dynamic code trees in inflate() */
int nlit;
int ndist;
- int nclen; /* also used for saving decoded symbol */
- int lenpos; /* also used for copy length */
+ int nclen; /* also used in decode_block() */
+ int lenpos; /* also used in decode_block() */
uchar lens[Nlitlen + Ndist];
int fixed; /* fixed code tree flag */
