Repository navigation
Expand file tree
/
Copy pathinffast.cpp
More file actions
179 lines (167 loc) · 5.77 KB
/
Copy pathinffast.cpp
File metadata and controls
179 lines (167 loc) · 5.77 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
/* 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 "stdafx.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(uInt bl, uInt bd, inflate_huft *tl, inflate_huft *td, 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;
}