commit b4ac11e701ddfb012b25d6f77f75ab8aa4db405e
parent f1d863cbfb093d47c811a5b2ea668c7990e91645
Author: nsz <nszabolcs@gmail.com>
Date: Sat, 1 Aug 2009 19:15:39 +0200
inflate dynamic decode state fix, state->err, nice interface
Diffstat:
| Makefile | | | 7 | ++++--- |
| inflate.c | | | 253 | ++++++++++++++++++++++++++++++++++++++----------------------------------------- |
2 files changed, 125 insertions(+), 135 deletions(-)
diff --git a/Makefile b/Makefile
@@ -1,12 +1,13 @@
#CFLAGS=-g -Wall -ansi -pedantic
CFLAGS=-O3 -Wall -ansi -pedantic
LDFLAGS=
-SRC=inflate.c inflate_simple.c inflate_callback.c deflate.c deflate_simple.c
+SRC=inflate.c inflate_simple.c inflate_example.c inflate_callback.c \
+ deflate.c deflate_simple.c
OBJ=${SRC:.c=.o}
-EXE=${SRC:.c=}
+EXE=inflate inflate_simple deflate deflate_simple
all: ${EXE}
-inflate: inflate.o
+inflate: inflate.o inflate_example.o
${CC} -o $@ $^ ${LDFLAGS}
inflate_simple: inflate_simple.o
${CC} -o $@ $^ ${LDFLAGS}
diff --git a/inflate.c b/inflate.c
@@ -1,8 +1,6 @@
#include <stdlib.h>
-
-typedef unsigned char uchar;
-typedef unsigned short ushort;
-typedef unsigned int uint;
+#include <string.h>
+#include "inflate.h"
enum {
CodeBits = 16, /* max number of bits in a code + 1 */
@@ -15,18 +13,9 @@ enum {
Nlitlen = Nlit+Nlen+3, /* litlen codes + block end + 2 unused */
Ndist = 30, /* number of distance codes */
Nclen = 19, /* number of code length codes */
- SrcSize = 1 << 12, /* input buffer size */
WinSize = 1 << 15 /* output window size */
};
-/* return values */
-enum {
- FlateOk = 0,
- FlateError = -1,
- FlateNeedInput = -2,
- FlateHasOutput = -3
-};
-
/* states */
enum {
BlockHead,
@@ -59,28 +48,30 @@ typedef struct {
} Huff;
typedef struct {
- uchar *src; /* input buffer pointer */
+ uchar *src; /* input buffer pointer */
uchar *srcend;
uint bits;
uint nbits;
- uchar *win; /* output window */
- uint pos; /* window pos */
+ uchar win[WinSize]; /* output window */
+ uint pos; /* window pos */
+ uint posout; /* used for flushing win */
+
+ int state; /* decode state */
+ int final; /* last block flag */
+ char *err; /* error message */
- int state; /* decode state */
- int final; /* last block flag */
-
/* for decoding dynamic code trees in inflate() */
int nlit;
int ndist;
- int nclen; /* also used in decode_block() */
- int lenpos; /* also used in decode_block() */
+ int nclen; /* also used in decode_block() */
+ int lenpos; /* also used in decode_block() */
uchar lens[Nlitlen + Ndist];
- int fixed; /* fixed code tree flag */
- Huff lhuff; /* dynamic lit/len huffman code tree */
- Huff dhuff; /* dynamic distance huffman code tree */
+ int fixed; /* fixed code tree flag */
+ Huff lhuff; /* dynamic lit/len huffman code tree */
+ Huff dhuff; /* dynamic distance huffman code tree */
} State;
/* TODO: globals.. initialization is not thread safe */
@@ -285,7 +276,7 @@ static uint decode_symbol_long(State *s, Huff *huff, uint bits, uint nbits, int
cur <<= 1;
count++;
if (count == huff->count + CodeBits)
- return FlateError;
+ return s->err = "symbol decoding failed.", FlateError;
}
s->bits = bits;
s->nbits = nbits;
@@ -337,7 +328,7 @@ static uint decode_symbol(State *s, Huff *huff) {
s->nbits = nbits - entry.len;
return entry.sym;
} else if (entry.len == 0)
- return FlateError;
+ return s->err = "symbol decoding failed.", FlateError;
return decode_symbol_long(s, huff, bits, nbits, entry.sym);
}
@@ -356,7 +347,7 @@ static int decode_block(State *s, Huff *lhuff, Huff *dhuff) {
if (sym < 256) {
win[pos++] = sym;
if (pos == WinSize) {
- s->pos = pos;
+ s->pos = WinSize;
s->state = DecodeBlock;
return FlateHasOutput;
}
@@ -422,7 +413,7 @@ static int decode_block(State *s, Huff *lhuff, Huff *dhuff) {
win[pos] = win[(pos - dist) % WinSize];
pos++;
if (pos == WinSize) {
- s->pos = pos;
+ s->pos = WinSize;
s->lenpos = len;
s->nclen = dist; /* using nclen to store dist */
s->state = DecodeBlockCopy;
@@ -436,42 +427,23 @@ static int decode_block(State *s, Huff *lhuff, Huff *dhuff) {
}
} /* for (;;) */
} /* switch () */
- return FlateError;
-}
-
-
-/* extern */
-
-int inflate_init(State *s) {
- /* TODO */
- if (lhuff.nbits == 0)
- init_fixed_huffs();
- s->pos = 0;
- s->win = malloc(WinSize);
- if (!s->win)
- return FlateError;
- s->bits = 0;
- s->nbits = 0;
-
- s->state = BlockHead;
- s->final = 0;
- return FlateOk;
+ return s->err = "corrupted state.", FlateError;
}
-/* inflate, returns: short src, short dst, error, ok */
-int inflate(State *s) {
+/* inflate state machine (decodes s->src into s->win) */
+static int inflate_state(State *s) {
int n;
+ if (s->posout)
+ return FlateHasOutput;
for (;;) {
switch (s->state) {
case BlockHead:
if (s->final) {
if (s->pos)
return FlateHasOutput;
- else {
- free(s->win);
+ else
return FlateOk;
- }
}
if (!fillbits(s, 3))
return FlateNeedInput;
@@ -484,7 +456,7 @@ int inflate(State *s) {
else if (n == 2)
s->state = DynamicHuff;
else
- goto error;
+ return s->err = "corrupt block header.", FlateError;
break;
case UncompressedBlock:
/* start block on a byte boundary */
@@ -495,10 +467,10 @@ int inflate(State *s) {
s->lenpos = getbits(s, 16);
n = getbits(s, 16);
if (s->lenpos != (~n & 0xffff))
- goto error;
+ return s->err = "corrupt uncompressed length.", FlateError;
s->state = CopyUncompressed;
case CopyUncompressed:
- /* TODO: untested, slow */
+ /* TODO: untested, slow, memcpy etc */
/* s->nbits should be 0 here */
while (s->lenpos) {
if (s->src == s->srcend)
@@ -522,7 +494,7 @@ int inflate(State *s) {
s->ndist = 1 + getbits(s, 5);
s->nclen = 4 + getbits(s, 4);
if (s->nlit > Nlitlen || s->ndist > Ndist)
- goto error;
+ return s->err = "corrupt code tree.", FlateError;
/* build code length tree */
for (n = 0; n < Nclen; n++)
s->lens[n] = 0;
@@ -539,7 +511,7 @@ int inflate(State *s) {
}
/* using lhuff for code length huff code */
if (build_huff(&s->lhuff, s->lens, Nclen, ClenTableBits) < 0)
- goto error;
+ return s->err = "building clen tree failed.", FlateError;
s->state = DynamicHuffLitlenDist;
s->lenpos = 0;
case DynamicHuffLitlenDist:
@@ -558,17 +530,17 @@ int inflate(State *s) {
case DynamicHuffContinue:
n = s->lenpos;
sym = s->nclen;
+ s->state = DynamicHuffLitlenDist;
}
if (!fillbits(s, 7)) {
- /* TODO: 7 is too much */
+ /* TODO: 7 is too much when an almost empty block is at the end */
if (sym == (uint)FlateError)
- goto error;
+ return FlateError;
s->nclen = sym;
s->lenpos = n;
s->state = DynamicHuffContinue;
return FlateNeedInput;
}
-
/* TODO: bound check s->lens */
if (sym == 16) {
/* copy previous code length 3-6 times */
@@ -584,13 +556,13 @@ int inflate(State *s) {
for (len = 11 + getbits(s, 7); len; len--)
s->lens[n++] = 0;
} else
- goto error;
+ return s->err = "corrupt code tree.", FlateError;
}
/* build dynamic huffman code trees */
if (build_huff(&s->lhuff, s->lens, s->nlit, LitlenTableBits) < 0)
- goto error;
+ return s->err = "building litlen tree failed.", FlateError;
if (build_huff(&s->dhuff, s->lens + s->nlit, s->ndist, DistTableBits) < 0)
- goto error;
+ return s->err = "building dist tree failed.", FlateError;
s->state = DecodeBlock;
case DecodeBlock:
case DecodeBlockLenBits:
@@ -603,93 +575,110 @@ int inflate(State *s) {
if (n == FlateHasOutput)
return FlateHasOutput;
if (n == FlateError)
- goto error;
+ return FlateError;
s->state = BlockHead;
break;
default:
- goto error;
+ return s->err = "corrupt state.", FlateError;
+ }
+ }
+}
+
+static State *alloc_state(void) {
+ State *s = malloc(sizeof(State));
+
+ if (s) {
+ s->final = s->pos = s->posout = s->bits = s->nbits = 0;
+ s->state = BlockHead;
+ s->src = s->srcend = 0;
+ s->err = 0;
+ /* TODO: globals.. */
+ if (lhuff.nbits == 0)
+ init_fixed_huffs();
+ }
+ return s;
+}
+
+
+/* extern */
+
+int inflate(FlateStream *stream) {
+ State *s = stream->state;
+ int n;
+
+ if (stream->err) {
+ if (s) {
+ free(s);
+ stream->state = 0;
}
+ return FlateError;
+ }
+ if (!s) {
+ s = stream->state = alloc_state();
+ if (!s)
+ return stream->err = "no mem.", FlateError;
+ }
+ if (stream->nin) {
+ s->src = stream->in;
+ s->srcend = s->src + stream->nin;
+ stream->nin = 0;
+ }
+ n = inflate_state(s);
+ if (n == FlateHasOutput) {
+ if (s->pos < stream->nout)
+ stream->nout = s->pos;
+ memcpy(stream->out, s->win + s->posout, stream->nout);
+ s->pos -= stream->nout;
+ if (s->pos)
+ s->posout += stream->nout;
+ else
+ s->posout = 0;
}
-error:
- free(s->win);
- return FlateError;
+ if (n == FlateOk || n == FlateError) {
+ stream->err = s->err;
+ free(s);
+ stream->state = 0;
+ }
+ return n;
}
int inflate_callback(int (*r)(void *, int, void *), void *rdata, int (*w)(void *, int, void *), void *wdata) {
- State s;
+ State *s;
uchar *src;
- int len;
+ int len, n;
+ enum {SrcSize = 4096};
- if (inflate_init(&s) != FlateOk)
+ s = alloc_state();
+ if (!s)
return FlateError;
- s.src = s.srcend = src = malloc(4096);
- if (src == NULL)
+ s->src = s->srcend = src = malloc(SrcSize);
+ if (!src) {
+ free(s);
return FlateError;
+ }
+ n = FlateNeedInput;
for (;;)
- switch (inflate(&s)) {
+ switch (n) {
case FlateNeedInput:
- len = r(src, 4096, rdata);
- if (len <= 0) {
- free(src);
- return FlateError;
- }
- s.src = src;
- s.srcend = src + len;
+ len = r(src, SrcSize, rdata);
+ if (len > 0) {
+ s->srcend = src + len;
+ n = inflate_state(s);
+ } else
+ n = FlateError;
break;
case FlateHasOutput:
- len = w(s.win, s.pos, wdata);
- if (len != s.pos) {
- free(src);
- return FlateError;
- }
- s.pos = 0; /* TODO: ouch */
+ len = w(s->win, s->pos, wdata);
+ if (len == s->pos) {
+ s->pos = 0;
+ n = inflate_state(s);
+ } else
+ n = FlateError;
break;
case FlateOk:
- free(src);
- return FlateOk;
case FlateError:
free(src);
- return FlateError;
+ free(s);
+ return n;
}
}
-
-/* simple test */
-
-#include <stdio.h>
-
-struct data {
- FILE *f;
- uint n;
-};
-
-int r(void *p, int siz, void *data) {
- uint n;
- struct data *d = data;
-
- n = fread(p, 1, siz, d->f);
- d->n += n;
- return n;
-}
-
-int w(void *p, int siz, void *data) {
- uint n;
- struct data *d = data;
-
- n = fwrite(p, 1, siz, d->f);
- d->n += n;
- return n;
-}
-
-int main() {
- struct data in, out;
- int err;
-
- in.f = stdin;
- in.n = 0;
- out.f = stdout;
- out.n = 0;
- err = inflate_callback(r, &in, w, &out);
- fprintf(stderr, "error: %d, decompressed %u bytes\n", err, out.n);
- return 0;
-}
-
