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1 /* inflate_util.c -- data and routines common to blocks and codes
2  * Copyright (C) 1995-2002 Mark Adler
3  * For conditions of distribution and use, see copyright notice in zlib.h
4  */
5 
6 #include "zutil.h"
7 #include "infblock.h"
8 #include "inftrees.h"
9 #include "infcodes.h"
10 #include "infutil.h"
11 
12 
13 /* And'ing with mask[n] masks the lower n bits */
14 local const uInt inflate_mask[17] = {
15     0x0000,
16     0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
17     0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
18 };
19 
20 
21 /* copy as much as possible from the sliding window to the output area */
inflate_flush(inflate_blocks_statef * s,z_streamp z,int r)22 local int inflate_flush( /* s, z, r) */
23 inflate_blocks_statef *s,
24 z_streamp z,
25 int r )
26 {
27   uInt n;
28   Bytef *p;
29   Bytef *q;
30 
31   /* local copies of source and destination pointers */
32   p = z->next_out;
33   q = s->read;
34 
35   /* compute number of bytes to copy as far as end of window */
36   n = (uInt)((q <= s->write ? s->write : s->end) - q);
37   if (n > z->avail_out) n = z->avail_out;
38   if (n && r == Z_BUF_ERROR) r = Z_OK;
39 
40   /* update counters */
41   z->avail_out -= n;
42   z->total_out += n;
43 
44   /* update check information */
45   if (s->checkfn != Z_NULL)
46     z->adler = s->check = (*s->checkfn)(s->check, q, n);
47 
48   /* copy as far as end of window */
49   zmemcpy(p, q, n);
50   p += n;
51   q += n;
52 
53   /* see if more to copy at beginning of window */
54   if (q == s->end)
55   {
56     /* wrap pointers */
57     q = s->window;
58     if (s->write == s->end)
59       s->write = s->window;
60 
61     /* compute bytes to copy */
62     n = (uInt)(s->write - q);
63     if (n > z->avail_out) n = z->avail_out;
64     if (n && r == Z_BUF_ERROR) r = Z_OK;
65 
66     /* update counters */
67     z->avail_out -= n;
68     z->total_out += n;
69 
70     /* update check information */
71     if (s->checkfn != Z_NULL)
72       z->adler = s->check = (*s->checkfn)(s->check, q, n);
73 
74     /* copy */
75     zmemcpy(p, q, n);
76     p += n;
77     q += n;
78   }
79 
80   /* update pointers */
81   z->next_out = p;
82   s->read = q;
83 
84   /* done */
85   return r;
86 }
87