File: /usr/src/linux/fs/cramfs/inflate/infutil.c

1     /* inflate_util.c -- data and routines common to blocks and codes
2      * Copyright (C) 1995-1998 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     struct inflate_codes_state {int dummy;}; /* for buggy compilers */
13     
14     /* And'ing with mask[n] masks the lower n bits */
15     uInt cramfs_inflate_mask[17] = {
16         0x0000,
17         0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
18         0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
19     };
20     
21     
22     /* copy as much as possible from the sliding window to the output area */
23     int cramfs_inflate_flush(s, z, r)
24     inflate_blocks_statef *s;
25     z_streamp z;
26     int r;
27     {
28       uInt n;
29       Bytef *p;
30       Bytef *q;
31     
32       /* local copies of source and destination pointers */
33       p = z->next_out;
34       q = s->read;
35     
36       /* compute number of bytes to copy as far as end of window */
37       n = (uInt)((q <= s->write ? s->write : s->end) - q);
38       if (n > z->avail_out) n = z->avail_out;
39       if (n && r == Z_BUF_ERROR) r = Z_OK;
40     
41       /* update counters */
42       z->avail_out -= n;
43       z->total_out += n;
44     
45       /* update check information */
46       if (s->checkfn != Z_NULL)
47         z->adler = s->check = (*s->checkfn)(s->check, q, n);
48     
49       /* copy as far as end of window */
50       memcpy(p, q, n);
51       p += n;
52       q += n;
53     
54       /* see if more to copy at beginning of window */
55       if (q == s->end)
56       {
57         /* wrap pointers */
58         q = s->window;
59         if (s->write == s->end)
60           s->write = s->window;
61     
62         /* compute bytes to copy */
63         n = (uInt)(s->write - q);
64         if (n > z->avail_out) n = z->avail_out;
65         if (n && r == Z_BUF_ERROR) r = Z_OK;
66     
67         /* update counters */
68         z->avail_out -= n;
69         z->total_out += n;
70     
71         /* update check information */
72         if (s->checkfn != Z_NULL)
73           z->adler = s->check = (*s->checkfn)(s->check, q, n);
74     
75         /* copy */
76         memcpy(p, q, n);
77         p += n;
78         q += n;
79       }
80     
81       /* update pointers */
82       z->next_out = p;
83       s->read = q;
84     
85       /* done */
86       return r;
87     }
88