flate

commit 6c48e7f91f57a70b1b4ff6ee6c6aeb4f71bcfd14
parent 65e244b895a0227983d92b1bf8ed98795fa67845
Author: nsz@tpx <unknown>
Date:   Thu,  6 Aug 2009 09:42:43 +0200

deflate cleaning
Diffstat:
deflate.c
 | 
78
++++++++++++++++++++++--------------------------------------------------------

1 file changed, 22 insertions(+), 56 deletions(-)
diff --git a/deflate.c b/deflate.c
@@ -22,6 +22,7 @@ TODO:
 	alloc bufs on heap?
 	overlap freq/code, rbuf/dstwin ?
 	fix match (loopunroll near end)
+	dstsize
 
 spec case tests:
 	empty block
@@ -53,12 +54,6 @@ enum {
 	Nclen       = 19   /* number of code length codes */
 };
 
-/* state */
-enum {
-	FillWin,
-	Block
-};
-
 typedef struct {
 	ushort dist;
 	ushort len;
@@ -69,18 +64,17 @@ typedef struct {
 	ushort bits;
 } Runlen;
 
-/* TODO: alloc buffers on heap */
 typedef struct {
 	int state;
 	int pos;
 	int avail;
 	int blockstart;
 	int lastblock;
-	Match m;
+	Match prevm;
 	uchar *src;             /* input (block start) */
 	uchar *srcend;
 	uchar *dst;             /* compressed output */
-	uchar *dstpos;
+	uchar *dstbegin;
 	uint bits;
 	int nbits;
 	int lfreq[Nlitlen];
@@ -91,7 +85,6 @@ typedef struct {
 	Runlen rbuf[RbufSize];  /* literal run length, match len, match dist */
 	Runlen *rend;           /* current pos in rbuf */
 	int run;                /* literal count */
-
 	uchar dstbuf[DstSize];
 } State;
 
@@ -552,7 +545,7 @@ static Match getmatch(State *s, ushort pos, ushort mpos) {
 }
 
 static void newblock(State *s) {
-	s->dst = s->dstpos = s->dstbuf;
+	s->dst = s->dstbegin = s->dstbuf;
 	s->rend = s->rbuf;
 	s->run = 0;
 	memset(s->lfreq, 0, sizeof(s->lfreq));
@@ -592,15 +585,15 @@ static int deflate_state(State *s) {
 	int pos = s->pos;
 	int head;
 
-
-	if (s->state == Block) {
-		if (s->lastblock && s->dstpos == s->dstbuf) /* todo.. */
+	switch (s->state) {
+	case FlateHasOutput:
+		if (s->lastblock && s->dstbegin == s->dst) /* todo.. */
 			return FlateOk;
 		else
 			goto block;
-	}
-	if (s->state == FillWin)
+	case FlateNeedInput:
 		goto filled;
+	}
 	do {
 		/* messy.. */
 		if (s->avail < MaxMatch || s->rend - s->rbuf >= RbufSize - 2) {
@@ -612,22 +605,22 @@ static int deflate_state(State *s) {
 					prevm.len = 0;
 				}
 fprintf(stderr, "avail %d pos %d lastpos %d srcavail %d\n", s->avail, pos, s->pos, s->srcend - s->src);
-				s->state = Block;
 				s->pos = pos;
-				s->m = prevm;
+				s->prevm = prevm;
+				s->state = FlateHasOutput;
 				deflate_block(s, pos - s->blockstart);
 				return FlateHasOutput;
 block:
-				if (s->dstpos != s->dstbuf)
+				if (s->dstbegin < s->dst)
 					return FlateHasOutput;
 				newblock(s);
 				pos = s->pos;
-				prevm = s->m;
+				prevm = s->prevm;
 				s->blockstart = pos;
 			}
 			s->pos = pos;
-			s->m = prevm;
-			s->state = FillWin;
+			s->prevm = prevm;
+			s->state = FlateNeedInput;
 			if (fillwin(s))
 				return FlateNeedInput;
 /* TODO: .. */
@@ -636,7 +629,7 @@ filled:
 				/* tralala */;
 fprintf(stderr, "avail %d pos %d srcavail %d\n", s->avail, s->pos, s->srcend - s->src);
 			pos = s->pos;
-			prevm = s->m;
+			prevm = s->prevm;
 		}
 		head = addtochain(s, pos);
 		if (head >= pos || pos - head >= MaxDist)
@@ -662,7 +655,7 @@ fprintf(stderr, "avail %d pos %d srcavail %d\n", s->avail, s->pos, s->srcend - s
 	} while (s->avail);
 	flushlit(s);
 	s->lastblock = 1;
-	s->state = Block;
+	s->state = FlateHasOutput;
 	deflate_block(s, pos - s->blockstart);
 	putbits(s, 0, 7);
 	return FlateHasOutput;
@@ -690,7 +683,7 @@ static State *alloc_state(void) {
 	huffcodes(fixlcode, fixllen, Nlitlen);
 	huffcodes(fixdcode, fixdlen, Ndist);
 
-	s->dstpos = s->dstbuf;
+	s->dst = s->dstbegin = s->dstbuf;
 	s->pos = s->blockstart = WinSize;
 	s->avail = 0;
 	return s;
@@ -709,7 +702,7 @@ int deflate(FlateStream *stream) {
 		s = stream->state = alloc_state();
 		if (!s)
 			return stream->err = "no mem.", FlateError;
-		s->state = Block;
+		s->state = FlateHasOutput;
 	}
 	if (stream->nin) {
 		s->src = stream->in;
@@ -718,13 +711,11 @@ int deflate(FlateStream *stream) {
 	}
 	n = deflate_state(s);
 	if (n == FlateHasOutput) {
-		k = s->dst - s->dstpos;
+		k = s->dst - s->dstbegin;
 		if (k < stream->nout)
 			stream->nout = k;
-		memcpy(stream->out, s->dstpos, stream->nout);
-		s->dstpos += stream->nout;
-		if (s->dstpos == s->dst)
-			s->dstpos = s->dstbuf;
+		memcpy(stream->out, s->dstbegin, stream->nout);
+		s->dstbegin += stream->nout;
 	}
 	if (n == FlateOk) {
 		free(s);
@@ -732,28 +723,3 @@ int deflate(FlateStream *stream) {
 	}
 	return n;
 }
-
-/*
-#include <stdlib.h>
-#include <stdio.h>
-
-enum {Siz = 1<<24};
-
-int main() {
-	FlateStream s;
-	int n;
-
-	s.in = malloc(Siz);
-	s.nin = fread(s.in, 1, Siz, stdin);
-	s.out = malloc(Siz);
-	s.nout = Siz;
-	s.err = 0;
-	s.state = 0;
-	n = deflate(&s);
-	fwrite(s.out, 1, s.nout, stdout);
-	fprintf(stderr, "compressed: %d return: %d\n", s.nout, n);
-	free(s.in);
-	free(s.out);
-	return 0;
-}
-*/