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1 | #include <stdio.h> |
2 | #include <errno.h> |
3 | #include <string.h> |
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4 | #include <stdlib.h> |
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5 | #include <ctype.h> |
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6 | |
7 | #define isbase64(c) ( ((c) >= 'A' && (c) <= 'Z') || \ |
8 | ((c) >= 'a' && (c) <= 'z') || \ |
9 | ((c) >= '0' && (c) <= '9') || \ |
10 | (c) == '+' || (c) == '/' || (c) == '=' \ |
11 | ) |
12 | |
13 | int base64_decode_atom(char *atom, unsigned char *out) { |
14 | int vals[4]; |
15 | int i, v, len; |
16 | unsigned word; |
17 | char c; |
18 | |
19 | for (i = 0; i < 4; i++) { |
20 | c = atom[i]; |
21 | if (c >= 'A' && c <= 'Z') |
22 | v = c - 'A'; |
23 | else if (c >= 'a' && c <= 'z') |
24 | v = c - 'a' + 26; |
25 | else if (c >= '0' && c <= '9') |
26 | v = c - '0' + 52; |
27 | else if (c == '+') |
28 | v = 62; |
29 | else if (c == '/') |
30 | v = 63; |
31 | else if (c == '=') |
32 | v = -1; |
33 | else |
34 | return 0; /* invalid atom */ |
35 | vals[i] = v; |
36 | } |
37 | |
38 | if (vals[0] == -1 || vals[1] == -1) |
39 | return 0; |
40 | if (vals[2] == -1 && vals[3] != -1) |
41 | return 0; |
42 | |
43 | if (vals[3] != -1) |
44 | len = 3; |
45 | else if (vals[2] != -1) |
46 | len = 2; |
47 | else |
48 | len = 1; |
49 | |
50 | word = ((vals[0] << 18) | |
51 | (vals[1] << 12) | |
52 | ((vals[2] & 0x3F) << 6) | |
53 | (vals[3] & 0x3F)); |
54 | out[0] = (word >> 16) & 0xFF; |
55 | if (len > 1) |
56 | out[1] = (word >> 8) & 0xFF; |
57 | if (len > 2) |
58 | out[2] = word & 0xFF; |
59 | return len; |
60 | } |
61 | |
62 | void base64_encode_atom(unsigned char *data, int n, char *out) { |
63 | static const char base64_chars[] = |
64 | "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; |
65 | |
66 | unsigned word; |
67 | |
68 | word = data[0] << 16; |
69 | if (n > 1) |
70 | word |= data[1] << 8; |
71 | if (n > 2) |
72 | word |= data[2]; |
73 | out[0] = base64_chars[(word >> 18) & 0x3F]; |
74 | out[1] = base64_chars[(word >> 12) & 0x3F]; |
75 | if (n > 1) |
76 | out[2] = base64_chars[(word >> 6) & 0x3F]; |
77 | else |
78 | out[2] = '='; |
79 | if (n > 2) |
80 | out[3] = base64_chars[word & 0x3F]; |
81 | else |
82 | out[3] = '='; |
83 | } |
84 | |
85 | const char usagemsg[] = |
86 | "usage: base64 [-d] [filename] decode from a file or from stdin\n" |
87 | " or: base64 -e [-cNNN] [filename] encode from a file or from stdin\n" |
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88 | "where: -d decode mode (default)\n" |
89 | " -e encode mode\n" |
90 | " -cNNN set number of chars per line for encoded output\n" |
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91 | " also: base64 --version report version number\n" |
92 | " base64 --help display this help text\n" |
93 | " base64 --licence display the (MIT) licence text\n" |
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94 | ; |
95 | |
96 | void usage(void) { |
97 | fputs(usagemsg, stdout); |
98 | } |
99 | |
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100 | const char licencemsg[] = |
101 | "base64 is copyright 2001,2004 Simon Tatham.\n" |
102 | "\n" |
103 | "Permission is hereby granted, free of charge, to any person\n" |
104 | "obtaining a copy of this software and associated documentation files\n" |
105 | "(the \"Software\"), to deal in the Software without restriction,\n" |
106 | "including without limitation the rights to use, copy, modify, merge,\n" |
107 | "publish, distribute, sublicense, and/or sell copies of the Software,\n" |
108 | "and to permit persons to whom the Software is furnished to do so,\n" |
109 | "subject to the following conditions:\n" |
110 | "\n" |
111 | "The above copyright notice and this permission notice shall be\n" |
112 | "included in all copies or substantial portions of the Software.\n" |
113 | "\n" |
114 | "THE SOFTWARE IS PROVIDED \"AS IS\", WITHOUT WARRANTY OF ANY KIND,\n" |
115 | "EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF\n" |
116 | "MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND\n" |
117 | "NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS\n" |
118 | "BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN\n" |
119 | "ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN\n" |
120 | "CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE\n" |
121 | "SOFTWARE.\n" |
122 | ; |
123 | |
124 | void licence(void) { |
125 | fputs(licencemsg, stdout); |
126 | } |
127 | |
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128 | void version(void) { |
129 | #define SVN_REV "$Revision$" |
130 | char rev[sizeof(SVN_REV)]; |
131 | char *p, *q; |
132 | |
133 | strcpy(rev, SVN_REV); |
134 | |
135 | for (p = rev; *p && *p != ':'; p++); |
136 | if (*p) { |
137 | p++; |
138 | while (*p && isspace(*p)) p++; |
139 | for (q = p; *q && *q != '$'; q++); |
140 | if (*q) *q = '\0'; |
141 | printf("base64 revision %s\n", p); |
142 | } else { |
143 | printf("base64: unknown version\n"); |
144 | } |
145 | } |
146 | |
147 | int main(int ac, char **av) { |
148 | int encoding = 0; |
149 | int cpl = 64; |
150 | FILE *fp; |
151 | char *fname; |
152 | char *eptr; |
153 | |
154 | fname = NULL; |
155 | |
156 | while (--ac) { |
157 | char *v, *p = *++av; |
158 | if (*p == '-') { |
159 | while (*p) { |
160 | char c = *++p; |
161 | switch (c) { |
162 | case '-': |
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163 | p++; |
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164 | if (!strcmp(p, "version")) { |
165 | version(); |
166 | exit(0); |
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167 | } else if (!strcmp(p, "help")) { |
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168 | usage(); |
169 | exit(0); |
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170 | } else if (!strcmp(p, "licence") || |
171 | !strcmp(p, "license")) { |
172 | licence(); |
173 | exit(0); |
174 | } else { |
175 | fprintf(stderr, "base64: unknown long option '--%s'\n", |
176 | p); |
177 | exit(1); |
178 | } |
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179 | break; |
180 | case 'v': |
181 | case 'V': |
182 | version(); |
183 | exit(0); |
184 | break; |
185 | case 'h': |
186 | case 'H': |
187 | usage(); |
188 | exit(0); |
189 | break; |
190 | case 'd': |
191 | encoding = 0; |
192 | break; |
193 | case 'e': |
194 | encoding = 1; |
195 | break; |
196 | case 'c': |
197 | /* |
198 | * Options requiring values. |
199 | */ |
200 | v = p+1; |
201 | if (!*v && ac > 1) { |
202 | --ac; |
203 | v = *++av; |
204 | } |
205 | if (!*v) { |
206 | fprintf(stderr, "base64: option '-%c' expects" |
207 | " an argument\n", c); |
208 | exit(1); |
209 | } |
210 | switch (c) { |
211 | case 'c': |
212 | cpl = strtol(v, &eptr, 10); |
213 | if (eptr && *eptr) { |
214 | fprintf(stderr, "base64: option -c expects" |
215 | " a numeric argument\n"); |
216 | exit(1); |
217 | } |
218 | if (cpl % 4) { |
219 | fprintf(stderr, "base64: chars per line should be" |
220 | " divisible by 4\n"); |
221 | exit(1); |
222 | } |
223 | break; |
224 | } |
225 | p = ""; |
226 | break; |
227 | } |
228 | } |
229 | } else { |
230 | if (!fname) |
231 | fname = p; |
232 | else { |
233 | fprintf(stderr, "base64: expected only one filename\n"); |
234 | exit(0); |
235 | } |
236 | } |
237 | } |
238 | |
239 | if (fname) { |
240 | fp = fopen(fname, encoding ? "rb" : "r"); |
241 | if (!fp) { |
242 | fprintf(stderr, "base64: unable to open '%s': %s\n", fname, |
243 | strerror(errno)); |
244 | exit(1); |
245 | } |
246 | } else |
247 | fp = stdin; |
248 | |
249 | if (encoding) { |
250 | unsigned char in[3]; |
251 | char out[4]; |
252 | int column; |
253 | int n; |
254 | |
255 | column = 0; |
256 | while (1) { |
257 | if (cpl && column >= cpl) { |
258 | putchar('\n'); |
259 | column = 0; |
260 | } |
261 | n = fread(in, 1, 3, fp); |
262 | if (n == 0) break; |
263 | base64_encode_atom(in, n, out); |
264 | fwrite(out, 1, 4, stdout); |
265 | column += 4; |
266 | } |
267 | |
268 | putchar('\n'); |
269 | } else { |
270 | char in[4]; |
271 | unsigned char out[3]; |
272 | int c, i, n, eof; |
273 | |
274 | eof = 0; |
275 | do { |
276 | for (i = 0; i < 4; i++) { |
277 | do { |
278 | c = fgetc(fp); |
279 | } while (c != EOF && !isbase64(c)); |
280 | if (c == EOF) { |
281 | eof = 1; |
282 | break; |
283 | } |
284 | in[i] = c; |
285 | } |
286 | if (i > 0) { |
287 | if (i < 4) { |
288 | fprintf(stderr, "base64: warning: number of base64" |
289 | " characters was not a multiple of 4\n"); |
290 | while (i < 4) in[i++] = '='; |
291 | } |
292 | n = base64_decode_atom(in, out); |
293 | fwrite(out, 1, n, stdout); |
294 | } |
295 | } while (!eof); |
296 | } |
297 | |
298 | if (fname) |
299 | fclose(fp); |
300 | |
301 | return 0; |
302 | } |