1/*
2 * Copyright 2011-2013 Haiku, Inc. All rights reserved.
3 * Copyright 2001-2003 Dr. Zoidberg Enterprises. All rights reserved.
4 */
5
6
7#include <mail_encoding.h>
8
9#include <ctype.h>
10#include <string.h>
11#include <SupportDefs.h>
12
13
14static const char kBase64Alphabet[64] = {
15	'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',
16	'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
17	'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',
18	'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
19	'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
20	'+',
21	'/'
22};
23
24
25ssize_t
26encode_base64(char *out, const char *in, off_t length, int headerMode)
27{
28	uint32 concat;
29	int i = 0;
30	int k = 0;
31	int lineLength = 4;
32		// Stop before it actually gets too long
33
34	while (i < length) {
35		concat = ((in[i] & 0xff) << 16);
36
37		if ((i+1) < length)
38			concat |= ((in[i+1] & 0xff) << 8);
39		if ((i+2) < length)
40			concat |= (in[i+2] & 0xff);
41
42		i += 3;
43
44		out[k++] = kBase64Alphabet[(concat >> 18) & 63];
45		out[k++] = kBase64Alphabet[(concat >> 12) & 63];
46		out[k++] = kBase64Alphabet[(concat >> 6) & 63];
47		out[k++] = kBase64Alphabet[concat & 63];
48
49		if (i >= length) {
50			int v;
51			for (v = 0; v <= (i - length); v++)
52				out[k-v] = '=';
53		}
54
55		lineLength += 4;
56
57		// No line breaks in header mode, since the text is part of a Subject:
58		// line or some other single header line.  The header code will do word
59		// wrapping separately from this encoding stuff.
60		if (!headerMode && lineLength > BASE64_LINELENGTH) {
61			out[k++] = '\r';
62			out[k++] = '\n';
63
64			lineLength = 4;
65		}
66	}
67
68	return k;
69}
70
71
72ssize_t
73decode_base64(char *out, const char *in, off_t length)
74{
75	uint32 concat, value;
76	int lastOutLine = 0;
77	int i, j;
78	int outIndex = 0;
79
80	for (i = 0; i < length; i += 4) {
81		concat = 0;
82
83		for (j = 0; j < 4 && (i + j) < length; j++) {
84			value = in[i + j];
85
86			if (value == '\n' || value == '\r') {
87				// jump over line breaks
88				lastOutLine = outIndex;
89				i++;
90				j--;
91				continue;
92			}
93
94			if ((value >= 'A') && (value <= 'Z'))
95				value -= 'A';
96			else if ((value >= 'a') && (value <= 'z'))
97				value = value - 'a' + 26;
98			else if ((value >= '0') && (value <= '9'))
99				value = value - '0' + 52;
100			else if (value == '+')
101				value = 62;
102			else if (value == '/')
103				value = 63;
104			else if (value == '=')
105				break;
106			else {
107				// there is an invalid character in this line - we will
108				// ignore the whole line and go to the next
109				outIndex = lastOutLine;
110				while (i < length && in[i] != '\n' && in[i] != '\r')
111					i++;
112				concat = 0;
113			}
114
115			value = value << ((3-j)*6);
116
117			concat |= value;
118		}
119
120		if (j > 1)
121			out[outIndex++] = (concat & 0x00ff0000) >> 16;
122		if (j > 2)
123			out[outIndex++] = (concat & 0x0000ff00) >> 8;
124		if (j > 3)
125			out[outIndex++] = (concat & 0x000000ff);
126	}
127
128	return outIndex;
129}
130
131
132#if __GNUC__ <= 2
133	// BeOS-ABI compatible wrappers.
134	ssize_t encode_base64(char *out, char *in, off_t length)
135	{
136		return encode_base64(out, in, length, 0);
137	}
138
139	ssize_t	decode_base64(char *out, const char *in, off_t length,
140		bool /*replace_cr*/)
141	{
142		return decode_base64(out, in, length);
143	}
144#endif	//  __GNUC__ <= 2
145