sl@0: /* inffast.c -- process literals and length/distance pairs fast sl@0: * Copyright (C) 1995-2002 Mark Adler sl@0: * For conditions of distribution and use, see copyright notice in zlib.h sl@0: */ sl@0: sl@0: #include "zutil.h" sl@0: #include "inftrees.h" sl@0: #include "infblock.h" sl@0: #include "infcodes.h" sl@0: #include "infutil.h" sl@0: #include "inffast.h" sl@0: sl@0: struct inflate_codes_state {int dummy;}; /* for buggy compilers */ sl@0: sl@0: /* simplify the use of the inflate_huft type with some defines */ sl@0: #define exop word.what.Exop sl@0: #define bits word.what.Bits sl@0: sl@0: /* macros for bit input with no checking and for returning unused bytes */ sl@0: #define GRABBITS(j) {while(k<(j)){b|=((uLong)NEXTBYTE)<avail_in-n;c=(k>>3)>3:c;n+=c;p-=c;k-=c<<3;} sl@0: sl@0: /* Called with number of bytes left to write in window at least 258 sl@0: (the maximum string length) and number of input bytes available sl@0: at least ten. The ten bytes are six bytes for the longest length/ sl@0: distance pair plus four bytes for overloading the bit buffer. */ sl@0: sl@0: int inflate_fast( sl@0: uInt bl, uInt bd, sl@0: const inflate_huft *tl, sl@0: const inflate_huft *td, /* need separate declaration for Borland C++ */ sl@0: inflate_blocks_statef *s, sl@0: z_streamp z) sl@0: { sl@0: const inflate_huft *t; /* temporary pointer */ sl@0: uInt e; /* extra bits or operation */ sl@0: uLong b; /* bit buffer */ sl@0: uInt k; /* bits in bit buffer */ sl@0: Bytef *p; /* input data pointer */ sl@0: uInt n; /* bytes available there */ sl@0: Bytef *q; /* output window write pointer */ sl@0: uInt m; /* bytes to end of window or read pointer */ sl@0: uInt ml; /* mask for literal/length tree */ sl@0: uInt md; /* mask for distance tree */ sl@0: uInt c; /* bytes to copy */ sl@0: uInt d; /* distance back to copy from */ sl@0: Bytef *r; /* copy source pointer */ sl@0: int alwaysTrue = 1; /* Added by Markr Symbian 9/11/99 to get rid of warnings */ sl@0: /* load input, output, bit values */ sl@0: LOAD sl@0: sl@0: /* initialize masks */ sl@0: ml = inflate_mask[bl]; sl@0: md = inflate_mask[bd]; sl@0: sl@0: /* do until not enough input or output space for fast loop */ sl@0: do { /* assume called with m >= 258 && n >= 10 */ sl@0: /* get literal/length code */ sl@0: GRABBITS(20) /* max bits for literal/length code */ sl@0: if ((e = (t = tl + ((uInt)b & ml))->exop) == 0) sl@0: { sl@0: DUMPBITS(t->bits) sl@0: Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ? sl@0: "inflate: * literal '%c'\n" : sl@0: "inflate: * literal 0x%02x\n", t->base)); sl@0: *q++ = (Byte)t->base; sl@0: m--; sl@0: continue; sl@0: } sl@0: do { sl@0: DUMPBITS(t->bits) sl@0: if (e & 16) sl@0: { sl@0: /* get extra bits for length */ sl@0: e &= 15; sl@0: c = t->base + ((uInt)b & inflate_mask[e]); sl@0: DUMPBITS(e) sl@0: Tracevv((stderr, "inflate: * length %u\n", c)); sl@0: sl@0: /* decode distance base of block to copy */ sl@0: GRABBITS(15); /* max bits for distance code */ sl@0: e = (t = td + ((uInt)b & md))->exop; sl@0: do { sl@0: DUMPBITS(t->bits) sl@0: if (e & 16) sl@0: { sl@0: /* get extra bits to add to distance base */ sl@0: e &= 15; sl@0: GRABBITS(e) /* get extra bits (up to 13) */ sl@0: d = t->base + ((uInt)b & inflate_mask[e]); sl@0: DUMPBITS(e) sl@0: Tracevv((stderr, "inflate: * distance %u\n", d)); sl@0: sl@0: /* do the copy */ sl@0: m -= c; sl@0: r = q - d; sl@0: if (r < s->window) /* wrap if needed */ sl@0: { sl@0: do { sl@0: r += s->end - s->window; /* force pointer in window */ sl@0: } while (r < s->window); /* covers invalid distances */ sl@0: e = s->end - r; sl@0: if (c > e) sl@0: { sl@0: c -= e; /* wrapped copy */ sl@0: do { sl@0: *q++ = *r++; sl@0: } while (--e); sl@0: r = s->window; sl@0: do { sl@0: *q++ = *r++; sl@0: } while (--c); sl@0: } sl@0: else /* normal copy */ sl@0: { sl@0: *q++ = *r++; c--; sl@0: *q++ = *r++; c--; sl@0: do { sl@0: *q++ = *r++; sl@0: } while (--c); sl@0: } sl@0: } sl@0: else /* normal copy */ sl@0: { sl@0: *q++ = *r++; c--; sl@0: *q++ = *r++; c--; sl@0: do { sl@0: *q++ = *r++; sl@0: } while (--c); sl@0: } sl@0: break; sl@0: } sl@0: else if ((e & 64) == 0) sl@0: { sl@0: t += t->base; sl@0: e = (t += ((uInt)b & inflate_mask[e]))->exop; sl@0: } sl@0: else sl@0: { sl@0: z->msg = (char*)"invalid distance code"; sl@0: UNGRAB sl@0: UPDATE sl@0: return Z_DATA_ERROR; sl@0: } sl@0: } while (alwaysTrue); // Changed by Markr to alleviate warning sl@0: break; sl@0: } sl@0: if ((e & 64) == 0) sl@0: { sl@0: t += t->base; sl@0: if ((e = (t += ((uInt)b & inflate_mask[e]))->exop) == 0) sl@0: { sl@0: DUMPBITS(t->bits) sl@0: Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ? sl@0: "inflate: * literal '%c'\n" : sl@0: "inflate: * literal 0x%02x\n", t->base)); sl@0: *q++ = (Byte)t->base; sl@0: m--; sl@0: break; sl@0: } sl@0: } sl@0: else if (e & 32) sl@0: { sl@0: Tracevv((stderr, "inflate: * end of block\n")); sl@0: UNGRAB sl@0: UPDATE sl@0: return Z_STREAM_END; sl@0: } sl@0: else sl@0: { sl@0: z->msg = (char*)"invalid literal/length code"; sl@0: UNGRAB sl@0: UPDATE sl@0: return Z_DATA_ERROR; sl@0: } sl@0: } while (alwaysTrue); // Changed by Markr to alleviate warning sl@0: } while (m >= 258 && n >= 10); sl@0: sl@0: /* not enough input or output--restore pointers and return */ sl@0: UNGRAB sl@0: UPDATE sl@0: return Z_OK; sl@0: }