+++ /dev/null
-/* inffast.c -- process literals and length/distance pairs fast
- * Copyright (C) 1995-2002 Mark Adler
- * For conditions of distribution and use, see copyright notice in zlib.h
- */
-
-#include "zutil.h"
-#include "inftrees.h"
-#include "infblock.h"
-#include "infcodes.h"
-#include "infutil.h"
-#include "inffast.h"
-
-struct inflate_codes_state {int dummy;}; /* for buggy compilers */
-
-/* simplify the use of the inflate_huft type with some defines */
-#define exop word.what.Exop
-#define bits word.what.Bits
-
-/* macros for bit input with no checking and for returning unused bytes */
-#define GRABBITS(j) {while(k<(j)){b|=((uLong)NEXTBYTE)<<k;k+=8;}}
-#define UNGRAB {c=z->avail_in-n;c=(k>>3)<c?k>>3:c;n+=c;p-=c;k-=c<<3;}
-
-/* Called with number of bytes left to write in window at least 258
- (the maximum string length) and number of input bytes available
- at least ten. The ten bytes are six bytes for the longest length/
- distance pair plus four bytes for overloading the bit buffer. */
-
-int inflate_fast(bl, bd, tl, td, s, z)
-uInt bl, bd;
-inflate_huft *tl;
-inflate_huft *td; /* need separate declaration for Borland C++ */
-inflate_blocks_statef *s;
-z_streamp z;
-{
- inflate_huft *t; /* temporary pointer */
- uInt e; /* extra bits or operation */
- uLong b; /* bit buffer */
- uInt k; /* bits in bit buffer */
- Bytef *p; /* input data pointer */
- uInt n; /* bytes available there */
- Bytef *q; /* output window write pointer */
- uInt m; /* bytes to end of window or read pointer */
- uInt ml; /* mask for literal/length tree */
- uInt md; /* mask for distance tree */
- uInt c; /* bytes to copy */
- uInt d; /* distance back to copy from */
- Bytef *r; /* copy source pointer */
-
- /* load input, output, bit values */
- LOAD
-
- /* initialize masks */
- ml = inflate_mask[bl];
- md = inflate_mask[bd];
-
- /* do until not enough input or output space for fast loop */
- do { /* assume called with m >= 258 && n >= 10 */
- /* get literal/length code */
- GRABBITS(20) /* max bits for literal/length code */
- if ((e = (t = tl + ((uInt)b & ml))->exop) == 0)
- {
- DUMPBITS(t->bits)
- Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ?
- "inflate: * literal '%c'\n" :
- "inflate: * literal 0x%02x\n", t->base));
- *q++ = (Byte)t->base;
- m--;
- continue;
- }
- do {
- DUMPBITS(t->bits)
- if (e & 16)
- {
- /* get extra bits for length */
- e &= 15;
- c = t->base + ((uInt)b & inflate_mask[e]);
- DUMPBITS(e)
- Tracevv((stderr, "inflate: * length %u\n", c));
-
- /* decode distance base of block to copy */
- GRABBITS(15); /* max bits for distance code */
- e = (t = td + ((uInt)b & md))->exop;
- do {
- DUMPBITS(t->bits)
- if (e & 16)
- {
- /* get extra bits to add to distance base */
- e &= 15;
- GRABBITS(e) /* get extra bits (up to 13) */
- d = t->base + ((uInt)b & inflate_mask[e]);
- DUMPBITS(e)
- Tracevv((stderr, "inflate: * distance %u\n", d));
-
- /* do the copy */
- m -= c;
- r = q - d;
- if (r < s->window) /* wrap if needed */
- {
- do {
- r += s->end - s->window; /* force pointer in window */
- } while (r < s->window); /* covers invalid distances */
- e = s->end - r;
- if (c > e)
- {
- c -= e; /* wrapped copy */
- do {
- *q++ = *r++;
- } while (--e);
- r = s->window;
- do {
- *q++ = *r++;
- } while (--c);
- }
- else /* normal copy */
- {
- *q++ = *r++; c--;
- *q++ = *r++; c--;
- do {
- *q++ = *r++;
- } while (--c);
- }
- }
- else /* normal copy */
- {
- *q++ = *r++; c--;
- *q++ = *r++; c--;
- do {
- *q++ = *r++;
- } while (--c);
- }
- break;
- }
- else if ((e & 64) == 0)
- {
- t += t->base;
- e = (t += ((uInt)b & inflate_mask[e]))->exop;
- }
- else
- {
- z->msg = (char*)"invalid distance code";
- UNGRAB
- UPDATE
- return Z_DATA_ERROR;
- }
- } while (1);
- break;
- }
- if ((e & 64) == 0)
- {
- t += t->base;
- if ((e = (t += ((uInt)b & inflate_mask[e]))->exop) == 0)
- {
- DUMPBITS(t->bits)
- Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ?
- "inflate: * literal '%c'\n" :
- "inflate: * literal 0x%02x\n", t->base));
- *q++ = (Byte)t->base;
- m--;
- break;
- }
- }
- else if (e & 32)
- {
- Tracevv((stderr, "inflate: * end of block\n"));
- UNGRAB
- UPDATE
- return Z_STREAM_END;
- }
- else
- {
- z->msg = (char*)"invalid literal/length code";
- UNGRAB
- UPDATE
- return Z_DATA_ERROR;
- }
- } while (1);
- } while (m >= 258 && n >= 10);
-
- /* not enough input or output--restore pointers and return */
- UNGRAB
- UPDATE
- return Z_OK;
-}
projects / rrdtool.git / blobdiff