9acadc2b |
1 | #include <stdio.h> |
2 | #include <errno.h> |
3 | #include <string.h> |
4 | |
5 | #define isbase64(c) ( ((c) >= 'A' && (c) <= 'Z') || \ |
6 | ((c) >= 'a' && (c) <= 'z') || \ |
7 | ((c) >= '0' && (c) <= '9') || \ |
8 | (c) == '+' || (c) == '/' || (c) == '=' \ |
9 | ) |
10 | |
11 | int base64_decode_atom(char *atom, unsigned char *out) { |
12 | int vals[4]; |
13 | int i, v, len; |
14 | unsigned word; |
15 | char c; |
16 | |
17 | for (i = 0; i < 4; i++) { |
18 | c = atom[i]; |
19 | if (c >= 'A' && c <= 'Z') |
20 | v = c - 'A'; |
21 | else if (c >= 'a' && c <= 'z') |
22 | v = c - 'a' + 26; |
23 | else if (c >= '0' && c <= '9') |
24 | v = c - '0' + 52; |
25 | else if (c == '+') |
26 | v = 62; |
27 | else if (c == '/') |
28 | v = 63; |
29 | else if (c == '=') |
30 | v = -1; |
31 | else |
32 | return 0; /* invalid atom */ |
33 | vals[i] = v; |
34 | } |
35 | |
36 | if (vals[0] == -1 || vals[1] == -1) |
37 | return 0; |
38 | if (vals[2] == -1 && vals[3] != -1) |
39 | return 0; |
40 | |
41 | if (vals[3] != -1) |
42 | len = 3; |
43 | else if (vals[2] != -1) |
44 | len = 2; |
45 | else |
46 | len = 1; |
47 | |
48 | word = ((vals[0] << 18) | |
49 | (vals[1] << 12) | |
50 | ((vals[2] & 0x3F) << 6) | |
51 | (vals[3] & 0x3F)); |
52 | out[0] = (word >> 16) & 0xFF; |
53 | if (len > 1) |
54 | out[1] = (word >> 8) & 0xFF; |
55 | if (len > 2) |
56 | out[2] = word & 0xFF; |
57 | return len; |
58 | } |
59 | |
60 | void base64_encode_atom(unsigned char *data, int n, char *out) { |
61 | static const char base64_chars[] = |
62 | "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; |
63 | |
64 | unsigned word; |
65 | |
66 | word = data[0] << 16; |
67 | if (n > 1) |
68 | word |= data[1] << 8; |
69 | if (n > 2) |
70 | word |= data[2]; |
71 | out[0] = base64_chars[(word >> 18) & 0x3F]; |
72 | out[1] = base64_chars[(word >> 12) & 0x3F]; |
73 | if (n > 1) |
74 | out[2] = base64_chars[(word >> 6) & 0x3F]; |
75 | else |
76 | out[2] = '='; |
77 | if (n > 2) |
78 | out[3] = base64_chars[word & 0x3F]; |
79 | else |
80 | out[3] = '='; |
81 | } |
82 | |
83 | const char usagemsg[] = |
84 | "usage: base64 [-d] [filename] decode from a file or from stdin\n" |
85 | " or: base64 -e [-cNNN] [filename] encode from a file or from stdin\n" |
86 | " also: base64 --version report version number\n" |
87 | " and: base64 --help display this help text\n" |
88 | "where: -d decode mode (default)\n" |
89 | " -e encode mode\n" |
90 | " -cNNN set number of chars per line for encoded output\n" |
91 | ; |
92 | |
93 | void usage(void) { |
94 | fputs(usagemsg, stdout); |
95 | } |
96 | |
97 | void version(void) { |
98 | #define SVN_REV "$Revision$" |
99 | char rev[sizeof(SVN_REV)]; |
100 | char *p, *q; |
101 | |
102 | strcpy(rev, SVN_REV); |
103 | |
104 | for (p = rev; *p && *p != ':'; p++); |
105 | if (*p) { |
106 | p++; |
107 | while (*p && isspace(*p)) p++; |
108 | for (q = p; *q && *q != '$'; q++); |
109 | if (*q) *q = '\0'; |
110 | printf("base64 revision %s\n", p); |
111 | } else { |
112 | printf("base64: unknown version\n"); |
113 | } |
114 | } |
115 | |
116 | int main(int ac, char **av) { |
117 | int encoding = 0; |
118 | int cpl = 64; |
119 | FILE *fp; |
120 | char *fname; |
121 | char *eptr; |
122 | |
123 | fname = NULL; |
124 | |
125 | while (--ac) { |
126 | char *v, *p = *++av; |
127 | if (*p == '-') { |
128 | while (*p) { |
129 | char c = *++p; |
130 | switch (c) { |
131 | case '-': |
132 | if (!strcmp(p, "version")) { |
133 | version(); |
134 | exit(0); |
135 | } |
136 | if (!strcmp(p, "help")) { |
137 | usage(); |
138 | exit(0); |
139 | } |
140 | break; |
141 | case 'v': |
142 | case 'V': |
143 | version(); |
144 | exit(0); |
145 | break; |
146 | case 'h': |
147 | case 'H': |
148 | usage(); |
149 | exit(0); |
150 | break; |
151 | case 'd': |
152 | encoding = 0; |
153 | break; |
154 | case 'e': |
155 | encoding = 1; |
156 | break; |
157 | case 'c': |
158 | /* |
159 | * Options requiring values. |
160 | */ |
161 | v = p+1; |
162 | if (!*v && ac > 1) { |
163 | --ac; |
164 | v = *++av; |
165 | } |
166 | if (!*v) { |
167 | fprintf(stderr, "base64: option '-%c' expects" |
168 | " an argument\n", c); |
169 | exit(1); |
170 | } |
171 | switch (c) { |
172 | case 'c': |
173 | cpl = strtol(v, &eptr, 10); |
174 | if (eptr && *eptr) { |
175 | fprintf(stderr, "base64: option -c expects" |
176 | " a numeric argument\n"); |
177 | exit(1); |
178 | } |
179 | if (cpl % 4) { |
180 | fprintf(stderr, "base64: chars per line should be" |
181 | " divisible by 4\n"); |
182 | exit(1); |
183 | } |
184 | break; |
185 | } |
186 | p = ""; |
187 | break; |
188 | } |
189 | } |
190 | } else { |
191 | if (!fname) |
192 | fname = p; |
193 | else { |
194 | fprintf(stderr, "base64: expected only one filename\n"); |
195 | exit(0); |
196 | } |
197 | } |
198 | } |
199 | |
200 | if (fname) { |
201 | fp = fopen(fname, encoding ? "rb" : "r"); |
202 | if (!fp) { |
203 | fprintf(stderr, "base64: unable to open '%s': %s\n", fname, |
204 | strerror(errno)); |
205 | exit(1); |
206 | } |
207 | } else |
208 | fp = stdin; |
209 | |
210 | if (encoding) { |
211 | unsigned char in[3]; |
212 | char out[4]; |
213 | int column; |
214 | int n; |
215 | |
216 | column = 0; |
217 | while (1) { |
218 | if (cpl && column >= cpl) { |
219 | putchar('\n'); |
220 | column = 0; |
221 | } |
222 | n = fread(in, 1, 3, fp); |
223 | if (n == 0) break; |
224 | base64_encode_atom(in, n, out); |
225 | fwrite(out, 1, 4, stdout); |
226 | column += 4; |
227 | } |
228 | |
229 | putchar('\n'); |
230 | } else { |
231 | char in[4]; |
232 | unsigned char out[3]; |
233 | int c, i, n, eof; |
234 | |
235 | eof = 0; |
236 | do { |
237 | for (i = 0; i < 4; i++) { |
238 | do { |
239 | c = fgetc(fp); |
240 | } while (c != EOF && !isbase64(c)); |
241 | if (c == EOF) { |
242 | eof = 1; |
243 | break; |
244 | } |
245 | in[i] = c; |
246 | } |
247 | if (i > 0) { |
248 | if (i < 4) { |
249 | fprintf(stderr, "base64: warning: number of base64" |
250 | " characters was not a multiple of 4\n"); |
251 | while (i < 4) in[i++] = '='; |
252 | } |
253 | n = base64_decode_atom(in, out); |
254 | fwrite(out, 1, n, stdout); |
255 | } |
256 | } while (!eof); |
257 | } |
258 | |
259 | if (fname) |
260 | fclose(fp); |
261 | |
262 | return 0; |
263 | } |