1 /* vi: set sw=4 ts=4: */
3 * Copyright 2003, Glenn McGrath
4 * Copyright 2006, Rob Landley <rob@landley.net>
5 * Copyright 2010, Denys Vlasenko
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
12 /* Conversion table. for base 64 */
13 const char bb_uuenc_tbl_base64[65 + 1] ALIGN1 = {
14 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
15 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
16 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
17 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
18 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
19 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
20 'w', 'x', 'y', 'z', '0', '1', '2', '3',
21 '4', '5', '6', '7', '8', '9', '+', '/',
22 '=' /* termination character */,
23 '\0' /* needed for uudecode.c only */
26 const char bb_uuenc_tbl_std[65] ALIGN1 = {
27 '`', '!', '"', '#', '$', '%', '&', '\'',
28 '(', ')', '*', '+', ',', '-', '.', '/',
29 '0', '1', '2', '3', '4', '5', '6', '7',
30 '8', '9', ':', ';', '<', '=', '>', '?',
31 '@', 'A', 'B', 'C', 'D', 'E', 'F', 'G',
32 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',
33 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
34 'X', 'Y', 'Z', '[', '\\', ']', '^', '_',
35 '`' /* termination character */
39 * Encode bytes at S of length LENGTH to uuencode or base64 format and place it
40 * to STORE. STORE will be 0-terminated, and must point to a writable
41 * buffer of at least 1+BASE64_LENGTH(length) bytes.
42 * where BASE64_LENGTH(len) = (4 * ((LENGTH + 2) / 3))
44 void FAST_FUNC bb_uuencode(char *p, const void *src, int length, const char *tbl)
46 const unsigned char *s = src;
48 /* Transform the 3x8 bits to 4x6 bits */
52 /* Are s[1], s[2] valid or should be assumed 0? */
54 length -= 3; /* can be >=0, -1, -2 */
60 *p++ = tbl[s[0] >> 2];
61 *p++ = tbl[((s[0] & 3) << 4) + (s1 >> 4)];
62 *p++ = tbl[((s1 & 0xf) << 2) + (s2 >> 6)];
63 *p++ = tbl[s2 & 0x3f];
68 /* If length is -2 or -1, pad last char or two */
76 * Decode base64 encoded string. Stops on '\0'.
78 * Returns: pointer to the undecoded part of source.
79 * If points to '\0', then the source was fully decoded.
80 * (*pp_dst): advanced past the last written byte.
82 const char* FAST_FUNC decode_base64(char **pp_dst, const char *src)
88 unsigned char six_bit[4];
91 /* Fetch up to four 6-bit values */
97 /* Get next _valid_ character.
98 * bb_uuenc_tbl_base64[] contains this string:
100 * 01234567890123456789012345678901234567890123456789012345678901234
101 * "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="
108 * If we decode "QUJD <NUL>", we want
109 * to return ptr to NUL, not to ' ',
110 * because we did fully decode
111 * the string (to "ABC").
118 table_ptr = strchr(bb_uuenc_tbl_base64, ch);
119 //TODO: add BASE64_FLAG_foo to die on bad char?
120 } while (!table_ptr);
122 /* Convert encoded character to decimal */
123 ch = table_ptr - bb_uuenc_tbl_base64;
125 /* ch is 64 if char was '=', otherwise 0..63 */
132 /* Transform 6-bit values to 8-bit ones.
133 * count can be < 4 when we decode the tail:
134 * "eQ==" -> "y", not "y NUL NUL".
135 * Note that (count > 1) is always true,
136 * "x===" encoding is not valid:
137 * even a single zero byte encodes as "AA==".
138 * However, with current logic we come here with count == 1
139 * when we decode "==" tail.
142 *dst++ = six_bit[0] << 2 | six_bit[1] >> 4;
144 *dst++ = six_bit[1] << 4 | six_bit[2] >> 2;
146 *dst++ = six_bit[2] << 6 | six_bit[3];
147 /* Note that if we decode "AA==" and ate first '=',
148 * we just decoded one char (count == 2) and now we'll
149 * do the loop once more to decode second '='.
158 * Decode base64 encoded stream.
159 * Can stop on EOF, specified char, or on uuencode-style "====" line:
160 * flags argument controls it.
162 void FAST_FUNC read_base64(FILE *src_stream, FILE *dst_stream, int flags)
164 /* Note that EOF _can_ be passed as exit_char too */
165 #define exit_char ((int)(signed char)flags)
166 #define uu_style_end (flags & BASE64_FLAG_UU_STOP)
168 /* uuencoded files have 61 byte lines. Use 64 byte buffer
169 * to process line at a time.
171 enum { BUFFER_SIZE = 64 };
173 char in_buf[BUFFER_SIZE + 2];
174 char out_buf[BUFFER_SIZE / 4 * 3 + 2];
181 while (in_count < BUFFER_SIZE) {
182 int ch = fgetc(src_stream);
183 if (ch == exit_char) {
193 /* Prevent "====" line to be split: stop if we see '\n'.
194 * We can also skip other whitespace and skirt the problem
195 * of files with NULs by stopping on any control char or space:
199 in_buf[in_count++] = ch;
201 in_buf[in_count] = '\0';
203 /* Did we encounter "====" line? */
204 if (uu_style_end && strcmp(in_buf, "====") == 0)
208 in_tail = decode_base64(&out_tail, in_buf);
210 fwrite(out_buf, (out_tail - out_buf), 1, dst_stream);
213 /* Did we consume ALL characters? */
214 if (*in_tail == '\0')
217 bb_error_msg_and_die("truncated base64 input");
220 /* It was partial decode */
221 in_count = strlen(in_tail);
222 memmove(in_buf, in_tail, in_count);