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comparison base64.c @ 3:7faae8f46238 libtomcrypt-orig

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Branch renaming
author Matt Johnston <matt@ucc.asn.au>
date Mon, 31 May 2004 18:25:41 +0000
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-1:000000000000 3:7faae8f46238
1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 *
9 * Tom St Denis, [email protected], http://libtomcrypt.org
10 */
11 /* compliant base64 code donated by Wayne Scott ([email protected]) */
12 #include "mycrypt.h"
13
14 #ifdef BASE64
15
16 static const char *codes =
17 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
18
19 static const unsigned char map[256] = {
20 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
21 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
22 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
23 255, 255, 255, 255, 255, 255, 255, 62, 255, 255, 255, 63,
24 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255,
25 255, 254, 255, 255, 255, 0, 1, 2, 3, 4, 5, 6,
26 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
27 19, 20, 21, 22, 23, 24, 25, 255, 255, 255, 255, 255,
28 255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,
29 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
30 49, 50, 51, 255, 255, 255, 255, 255, 255, 255, 255, 255,
31 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
32 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
33 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
34 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
35 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
36 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
37 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
38 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
39 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
40 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
41 255, 255, 255, 255 };
42
43 int base64_encode(const unsigned char *in, unsigned long len,
44 unsigned char *out, unsigned long *outlen)
45 {
46 unsigned long i, len2, leven;
47 unsigned char *p;
48
49 _ARGCHK(in != NULL);
50 _ARGCHK(out != NULL);
51 _ARGCHK(outlen != NULL);
52
53 /* valid output size ? */
54 len2 = 4 * ((len + 2) / 3);
55 if (*outlen < len2 + 1) {
56 return CRYPT_BUFFER_OVERFLOW;
57 }
58 p = out;
59 leven = 3*(len / 3);
60 for (i = 0; i < leven; i += 3) {
61 *p++ = codes[(in[0] >> 2) & 0x3F];
62 *p++ = codes[(((in[0] & 3) << 4) + (in[1] >> 4)) & 0x3F];
63 *p++ = codes[(((in[1] & 0xf) << 2) + (in[2] >> 6)) & 0x3F];
64 *p++ = codes[in[2] & 0x3F];
65 in += 3;
66 }
67 /* Pad it if necessary... */
68 if (i < len) {
69 unsigned a = in[0];
70 unsigned b = (i+1 < len) ? in[1] : 0;
71
72 *p++ = codes[(a >> 2) & 0x3F];
73 *p++ = codes[(((a & 3) << 4) + (b >> 4)) & 0x3F];
74 *p++ = (i+1 < len) ? codes[(((b & 0xf) << 2)) & 0x3F] : '=';
75 *p++ = '=';
76 }
77
78 /* append a NULL byte */
79 *p = '\0';
80
81 /* return ok */
82 *outlen = p - out;
83 return CRYPT_OK;
84 }
85
86 int base64_decode(const unsigned char *in, unsigned long len,
87 unsigned char *out, unsigned long *outlen)
88 {
89 unsigned long t, x, y, z;
90 unsigned char c;
91 int g;
92
93 _ARGCHK(in != NULL);
94 _ARGCHK(out != NULL);
95 _ARGCHK(outlen != NULL);
96
97 g = 3;
98 for (x = y = z = t = 0; x < len; x++) {
99 c = map[in[x]&0xFF];
100 if (c == 255) continue;
101 if (c == 254) { c = 0; g--; }
102 t = (t<<6)|c;
103 if (++y == 4) {
104 if (z + g > *outlen) {
105 return CRYPT_BUFFER_OVERFLOW;
106 }
107 out[z++] = (unsigned char)((t>>16)&255);
108 if (g > 1) out[z++] = (unsigned char)((t>>8)&255);
109 if (g > 2) out[z++] = (unsigned char)(t&255);
110 y = t = 0;
111 }
112 }
113 if (y != 0) {
114 return CRYPT_INVALID_PACKET;
115 }
116 *outlen = z;
117 return CRYPT_OK;
118 }
119
120 #endif
121