flate

commit a1f02b32650d405defac98da43ce6a4ca26dd202
parent 1642ddea0105b95c4b88e7dd794656a13d5a777d
Author: nsz <nszabolcs@gmail.com>
Date:   Sun, 23 Aug 2009 19:15:58 +0200

clean ups, -callback
Diffstat:
deflate.c
 | 
85
++++++++++++++++++++-----------------------------------------------------------

1 file changed, 21 insertions(+), 64 deletions(-)
diff --git a/deflate.c b/deflate.c
@@ -18,11 +18,12 @@ enum {
 	HashBits    = 13,
 	HashSize    = 1 << HashBits, /* hash table size */
 	BigDist     = 1 << 12, /* max match distance for short match length */
-	BlockSize   = (1 << 15) - 300, /* TODO */
 	MaxDist     = WinSize,
+	BlockSize   = 1 << 15, /* TODO */
 	SrcSize     = 2*WinSize + MaxMatch,
 	DstSize     = BlockSize + MaxMatch + 6, /* worst case compressed block size */
 	LzSize      = 1 << 13, /* lz buffer size */
+	LzGuard     = LzSize - 2,
 	LzLitFlag   = 1 << 15  /* marks literal run length in lz buffer */
 };
 
@@ -41,24 +42,24 @@ typedef struct {
 	int startpos;          /* block start pos in input src */
 	int endpos;            /* end of available bytes in src */
 	int skip;              /* skipped hash chain updates (until next iter) */
+	Match prevm;           /* previous (deferred) match */
 	int state;             /* prev return value */
 	int eof;               /* end of input */
-	Match prevm;           /* previous (deferred) match */
-	int nin;
 	uchar *in;             /* input data (not yet in src) */
+	uchar *inend;
+	uint bits;             /* for output */
+	int nbits;             /* for output */
 	uchar *dst;            /* compressed output (position in dstbuf) */
 	uchar *dstbegin;       /* start position of unflushed data in dstbuf */
-	uint bits;
-	int nbits;
-	uchar src[SrcSize];    /* input buf */
+	LzCode *lz;            /* current pos in lzbuf */
+	int nlit;              /* literal run length in lzbuf */
 	ushort head[HashSize]; /* position of hash chain heads */
 	ushort chain[WinSize]; /* hash chain */
-	LzCode lzbuf[LzSize];  /* literal run length, match len, match dist */
-	LzCode *lz;            /* current pos in lzbuf */
-	int nlit;              /* literal run length */
 	ushort lfreq[Nlitlen];
 	ushort dfreq[Ndist];
+	uchar src[SrcSize];    /* input buf */
 	uchar dstbuf[DstSize];
+	LzCode lzbuf[LzSize];  /* literal run length, match len, match dist */
 } State;
 
 static uchar fixllen[Nlitlen]; /* fixed lit/len huffman code tree */
@@ -558,10 +559,8 @@ static int shiftwin(State *s) {
 }
 
 static int endblock(State *s) {
-	LzCode *lzend = s->lzbuf + LzSize - 2;
-
 	if ((s->pos >= 2*WinSize && !shiftwin(s)) || s->pos - s->startpos >= BlockSize ||
-	  s->lz >= lzend || (s->eof && s->pos == s->endpos)) {
+	  s->lzbuf - s->lz >= LzGuard || (s->eof && s->pos == s->endpos)) {
 		/* deflate block */
 		flushlit(s);
 		if (s->prevm.len)
@@ -575,15 +574,15 @@ static int endblock(State *s) {
 }
 
 static int fillsrc(State *s) {
-	int n;
+	int n, k;
 
 	if (s->endpos < SrcSize && !s->eof) {
 		n = SrcSize - s->endpos;
-		if (n > s->nin)
-			n = s->nin;
+		k = s->inend - s->in;
+		if (n > k)
+			n = k;
 		memcpy(s->src + s->endpos, s->in, n);
 		s->in += n;
-		s->nin -= n;
 		s->endpos += n;
 		if (s->endpos < SrcSize)
 			return 0;
@@ -603,10 +602,9 @@ static int deflate_state(State *s) {
 	Match m;
 	int next;
 	int guard;
-	LzCode *lzend;
 
 	if (s->state == FlateIn)
-		s->eof = s->nin == 0;
+		s->eof = s->in == s->inend;
 	else if (s->state == FlateOut) {
 		if (s->dstbegin < s->dst)
 			return (s->state = FlateOut);
@@ -619,11 +617,10 @@ static int deflate_state(State *s) {
 		return s->state;
 
 	guard = calcguard(s);
-	lzend = s->lzbuf + LzSize - 2;
-/*fprintf(stderr,"guard:%d pos:%d nin:%d\n", guard, s->pos, s->nin);*/
+/*fprintf(stderr,"guard:%d pos:%d nin:%d\n", guard, s->pos, s->inend - s->in);*/
 	for (;;) {
-		if (s->pos >= guard || s->lz >= lzend) {
-/*fprintf(stderr,"guard:%d pos:%d len:%d end:%d start:%d nin:%d\n", guard, s->pos, s->pos - s->startpos, s->endpos, s->startpos, s->nin);*/
+		if (s->pos >= guard || s->lzbuf - s->lz >= LzGuard) {
+/*fprintf(stderr,"guard:%d pos:%d len:%d end:%d start:%d nin:%d\n", guard, s->pos, s->pos - s->startpos, s->endpos, s->startpos, s->inend - s->in);*/
 			if (endblock(s))
 				return (s->state = FlateOut);
 			if (!fillsrc(s))
@@ -671,7 +668,7 @@ static State *alloc_state(void) {
 	huffcodes(fixlcode, fixllen, Nlitlen);
 	huffcodes(fixdcode, fixdlen, Ndist);
 	s->state = FlateOut;
-	s->nin = 0;
+	s->in = s->inend = 0;
 	s->dst = s->dstbegin = s->dstbuf;
 	s->pos = s->startpos = s->endpos = WinSize;
 	s->eof = 0;
@@ -699,7 +696,7 @@ int deflate(FlateStream *stream) {
 	}
 	if (stream->nin) {
 		s->in = stream->in;
-		s->nin = stream->nin;
+		s->inend = s->in + stream->nin;
 		stream->nin = 0;
 	}
 	n = deflate_state(s);
@@ -716,43 +713,3 @@ int deflate(FlateStream *stream) {
 	}
 	return n;
 }
-
-/*
-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 << 13};
-	
-	s = alloc_state();
-	if (!s)
-		return FlateErr;
-	src = s->src = s->srcend = malloc(SrcSize);		
-	if (!src) {
-		free(s);
-		return FlateErr;
-	}
-	for (;;) {
-		n = deflate_state(s);
-		switch (n) {
-		case FlateIn:
-			s->src = src;
-			len = r(s->src, SrcSize, rdata);
-			s->srcend = s->src + len;
-			break;
-		case FlateOut:
-			len = w(s->dstbegin, s->dst - s->dstbegin, wdata);
-			if (len == s->dst - s->dstbegin)
-				s->dstbegin = s->dst;
-			else
-				s->state = FlateErr;
-			break;
-		case FlateOk:
-		case FlateErr:
-			free(src);
-			free(s);
-			return n;
-		}
-	}
-}
-*/