flate

commit 9de8fb994bd9a86f1f0948249d5fe49d6a9ea97d
parent cb7adc2901ab8582b02d3a77e9139c3fb70c6a49
Author: nsz@tpx <unknown>
Date:   Sat,  8 Aug 2009 19:57:03 +0200

deflate cleanup (wip)
Diffstat:
deflate.c
 | 
112
++++++++++++++++++++++++++++++++++++++-----------------------------------------

1 file changed, 54 insertions(+), 58 deletions(-)
diff --git a/deflate.c b/deflate.c
@@ -64,7 +64,7 @@ typedef struct {
 	int state;
 	int pos;
 	int avail;
-	int blockstart;
+	int startpos;
 	int lastblock;
 	Match prevm;
 	uchar *src;             /* input (block start) */
@@ -320,7 +320,7 @@ static void putblock(State *s, ushort *lcode, uchar *llen, ushort *dcode, uchar 
 	Runlen *r;
 	uchar *pc;
 
-	for (r = s->rbuf, pc = s->win + s->blockstart; r != s->rend; r++)
+	for (r = s->rbuf, pc = s->win + s->startpos; r != s->rend; r++)
 		if (r->bits & RunlenFlag)
 			for (n = r->n; n > 0; n--, pc++)
 				putbits(s, lcode[*pc], llen[*pc]);
@@ -377,7 +377,7 @@ int dyntree;
 			dynsize += 7;
 	}
 dyntree = dynsize - 3;
-	for (r = s->rbuf, pc = s->win + s->blockstart; r != s->rend; r++)
+	for (r = s->rbuf, pc = s->win + s->startpos; r != s->rend; r++)
 		if (r->bits & RunlenFlag)
 			for (n = r->n; n > 0; n--, pc++) {
 				fixsize += fixllen[*pc];
@@ -430,7 +430,7 @@ dyntree = dynsize - 3;
 		s->nbits = 0;
 		putbits(s, blocklen, 16);
 		putbits(s, ~blocklen & 0xffff, 16);
-		memcpy(s->dst, s->win + s->blockstart, blocklen);
+		memcpy(s->dst, s->win + s->startpos, blocklen);
 		s->dst += blocklen;
 	}
 fprintf(stderr, "blocklen: %d lzlen: %d dynsize: %d (tree: %d, rate: %.3f) fixsize: %d (rate: %.3f) uncsize: %d (rate: %.3f)\n", blocklen, s->rend - s->rbuf,
@@ -539,6 +539,7 @@ static Match getmatch(State *s, ushort pos, ushort mpos) {
 }
 
 static void newblock(State *s) {
+	s->startpos = s->pos;
 	s->dst = s->dstbegin = s->dstbuf;
 	s->rend = s->rbuf;
 	s->run = 0;
@@ -557,7 +558,7 @@ static int fillwin(State *s) {
 			s->head[n] = s->head[n] > WinSize ? s->head[n] - WinSize : 0;
 		for (n = WinSize; n--;)
 			s->chain[n] = s->chain[n] > WinSize ? s->chain[n] - WinSize : 0;
-		s->blockstart -= WinSize;
+		s->startpos -= WinSize;
 		s->pos -= WinSize;
 	}
 	k = 2*WinSize - s->pos - s->avail;
@@ -574,80 +575,75 @@ static int fillwin(State *s) {
 
 static int deflate_state(State *s) {
 	Match m;
-	Match prevm = {0, 0};
-	int pos;
 	int head;
 
 	/* messy.. */
 	switch (s->state) {
+	case FlateOut:
+		if (s->dstbegin < s->dst)
+			return FlateOut;
+		if (s->lastblock)
+			return FlateOk;
+		newblock(s);
+		if (s->prevm.len)
+			s->pos++;
+		if (fillwin(s)) {
+			s->state = FlateIn;
+			return FlateIn;
+		}
+		break;
+	case FlateIn:
+		fillwin(s);
+		break;
+	}
 	for (;;) {
+		head = addtochain(s, s->pos);
+		if (head >= s->pos || s->pos - head >= MaxDist)
+			head = 0;
+		if (head)
+			m = getmatch(s, s->pos, head);
+		if (head && m.len > s->prevm.len) {
+			if (s->prevm.len)
+				recordlit(s, s->win[s->pos-1]);
+			s->prevm = m;
+		} else if (s->prevm.len) {
+			recordmatch(s, s->prevm);
+			/* tricky.. */
+			s->prevm.len -= 2;
+			do {
+				s->pos++;
+				s->avail--;
+				addtochain(s, s->pos);
+			} while (--s->prevm.len);
+		} else
+			recordlit(s, s->win[s->pos]);
+		s->pos++;
+		s->avail--;
+
 		if (s->avail < MaxMatch || s->rend - s->rbuf >= RbufSize - 2) {
 			if (s->avail == 0) {
 				flushlit(s);
 				s->lastblock = 1;
 				s->state = FlateOut;
-				deflate_block(s, pos - s->blockstart);
+				deflate_block(s, s->pos - s->startpos);
 				putbits(s, 0, 7);
 				return FlateOut;
 			}
-			if (pos - s->blockstart > MaxDist || s->rend - s->rbuf >= RbufSize - 2) {
+			if (s->pos - s->startpos > MaxDist || s->rend - s->rbuf >= RbufSize - 2) {
 				flushlit(s);
-				if (prevm.len)
-					pos--;
-fprintf(stderr, "avail %d pos %d lastpos %d srcavail %d\n", s->avail, pos, s->pos, s->srcend - s->src);
-				deflate_block(s, pos - s->blockstart);
-				s->pos = pos;
-				s->prevm = prevm;
+				if (s->prevm.len)
+					s->pos--;
+fprintf(stderr, "avail %d pos %d srcavail %d\n", s->avail, s->pos, s->srcend - s->src);
+				deflate_block(s, s->pos - s->startpos);
 				s->state = FlateOut;
 				return FlateOut;
-	case FlateOut:
-				if (s->dstbegin < s->dst)
-					return FlateOut;
-				if (s->lastblock)
-					return FlateOk;
-				newblock(s);
-				s->blockstart = pos = s->pos;
-				prevm = s->prevm;
-				if (prevm.len)
-					pos++;
 			}
-			s->pos = pos;
 			if (fillwin(s)) {
-				s->prevm = prevm;
 				s->state = FlateIn;
 				return FlateIn;
-	case FlateIn:
-				fillwin(s);
-				prevm = s->prevm;
 			}
-			pos = s->pos;
-fprintf(stderr, "avail %d pos %d srcavail %d\n", s->avail, s->pos, s->srcend - s->src);
 		}
-		head = addtochain(s, pos);
-		if (head >= pos || pos - head >= MaxDist)
-			head = 0;
-		if (head)
-			m = getmatch(s, pos, head);
-		if (head && m.len > prevm.len) {
-			if (prevm.len)
-				recordlit(s, s->win[pos-1]);
-			prevm = m;
-		} else if (prevm.len) {
-			recordmatch(s, prevm);
-			/* too tricky.. */
-			prevm.len -= 2;
-			do {
-				pos++;
-				s->avail--;
-				addtochain(s, pos);
-			} while (--prevm.len);
-		} else
-			recordlit(s, s->win[pos]);
-		pos++;
-		s->avail--;
-	} /* for(;;) */
-	} /* switch */
-	return FlateErr; /* unreachable */
+	}
 }
 
 static State *alloc_state(void) {
@@ -673,7 +669,7 @@ static State *alloc_state(void) {
 	huffcodes(fixdcode, fixdlen, Ndist);
 
 	s->dst = s->dstbegin = s->dstbuf;
-	s->pos = s->blockstart = WinSize;
+	s->pos = s->startpos = WinSize;
 	s->avail = 0;
 	return s;
 }