/[dynamips]/upstream/dynamips-0.2.5/base64.c
This is repository of my old source code which isn't updated any more. Go to git.rot13.org for current projects!
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Annotation of /upstream/dynamips-0.2.5/base64.c

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Revision 1 - (hide annotations)
Sat Oct 6 16:01:44 2007 UTC (12 years, 7 months ago) by dpavlin
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import 0.2.5 from upstream

1 dpavlin 1 /*
2     * base64.c -- base-64 conversion routines.
3     * Copyright (C)2002 by Eric S. Raymond.
4     *
5     * For license terms, see the file COPYING in this directory.
6     *
7     * This base 64 encoding is defined in RFC2045 section 6.8,
8     * "Base64 Content-Transfer-Encoding", but lines must not be broken in the
9     * scheme used here.
10     */
11    
12     #include <ctype.h>
13    
14     static const char base64digits[] =
15     "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
16    
17     #define BAD -1
18    
19     static const char base64val[] = {
20     BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD,
21     BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD,
22     BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD, 62, BAD,BAD,BAD, 63,
23     52, 53, 54, 55, 56, 57, 58, 59, 60, 61,BAD,BAD, BAD,BAD,BAD,BAD,
24     BAD, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
25     15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,BAD, BAD,BAD,BAD,BAD,
26     BAD, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
27     41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,BAD, BAD,BAD,BAD,BAD
28     };
29    
30     #define DECODE64(c) (isascii(c) ? base64val[c] : BAD)
31    
32     /* Encode into base64 */
33     void base64_encode(unsigned char *out,const unsigned char *in,int inlen)
34     {
35     /* raw bytes in quasi-big-endian order to base 64 string (NUL-terminated) */
36     for (; inlen >= 3; inlen -= 3) {
37     *out++ = base64digits[in[0] >> 2];
38     *out++ = base64digits[((in[0] << 4) & 0x30) | (in[1] >> 4)];
39     *out++ = base64digits[((in[1] << 2) & 0x3c) | (in[2] >> 6)];
40     *out++ = base64digits[in[2] & 0x3f];
41     in += 3;
42     }
43    
44     if (inlen > 0) {
45     unsigned char fragment;
46    
47     *out++ = base64digits[in[0] >> 2];
48     fragment = (in[0] << 4) & 0x30;
49     if (inlen > 1)
50     fragment |= in[1] >> 4;
51     *out++ = base64digits[fragment];
52     *out++ = (inlen < 2) ? '=' : base64digits[(in[1] << 2) & 0x3c];
53     *out++ = '=';
54     }
55     *out = '\0';
56     }
57    
58     /*
59     * Decode from base64.
60     *
61     * base 64 to raw bytes in quasi-big-endian order, returning count of bytes
62     * maxlen limits output buffer size, set to zero to ignore.
63     */
64     int base64_decode(unsigned char *out,const unsigned char *in,int maxlen)
65     {
66     register unsigned char digit1, digit2, digit3, digit4;
67     int len = 0;
68    
69     if (in[0] == '+' && in[1] == ' ')
70     in += 2;
71     if (*in == '\r')
72     return(0);
73    
74     do {
75     digit1 = in[0];
76     if (DECODE64(digit1) == BAD)
77     return(-1);
78     digit2 = in[1];
79     if (DECODE64(digit2) == BAD)
80     return(-1);
81     digit3 = in[2];
82     if (digit3 != '=' && DECODE64(digit3) == BAD)
83     return(-1);
84     digit4 = in[3];
85     if (digit4 != '=' && DECODE64(digit4) == BAD)
86     return(-1);
87     in += 4;
88     ++len;
89    
90     if (maxlen && len > maxlen)
91     return(-1);
92    
93     *out++ = (DECODE64(digit1) << 2) | (DECODE64(digit2) >> 4);
94     if (digit3 != '=')
95     {
96     ++len;
97     if (maxlen && (len > maxlen))
98     return(-1);
99    
100     *out++ = ((DECODE64(digit2) << 4) & 0xf0) | (DECODE64(digit3) >> 2);
101     if (digit4 != '=') {
102     ++len;
103     if (maxlen && (len > maxlen))
104     return(-1);
105     *out++ = ((DECODE64(digit3) << 6) & 0xc0) | DECODE64(digit4);
106     }
107     }
108     } while(*in && (*in != '\r') && (digit4 != '='));
109    
110     return(len);
111     }

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