1 static const char rcsid[] = "#(@) $Id$";
5 Encode or decode file as MIME base64 (RFC 1341)
8 http://www.fourmilab.ch/
10 This program is in the public domain.
15 /* ENCODE -- Encode binary file into base64. */
21 static unsigned char dtable[512];
23 void buffer_new(struct buffer_st *b)
26 b->data = malloc(sizeof(char)*(b->length));
32 void buffer_add(struct buffer_st *b, char c)
36 if (b->offset == b->length) {
38 b->data = realloc(b->data, b->length);
39 b->ptr = b->data + b->offset;
43 void buffer_delete(struct buffer_st *b)
52 void base64_encode(struct buffer_st *b, const char *source, int length)
62 /* Fill dtable with character encodings. */
64 for (i = 0; i < 26; i++) {
66 dtable[26 + i] = 'a' + i;
68 for (i = 0; i < 10; i++) {
69 dtable[52 + i] = '0' + i;
75 unsigned char igroup[3], ogroup[4];
78 igroup[0] = igroup[1] = igroup[2] = 0;
79 for (n = 0; n < 3; n++) {
82 if (offset > length) {
86 igroup[n] = (unsigned char) c;
89 ogroup[0] = dtable[igroup[0] >> 2];
90 ogroup[1] = dtable[((igroup[0] & 3) << 4) | (igroup[1] >> 4)];
91 ogroup[2] = dtable[((igroup[1] & 0xF) << 2) | (igroup[2] >> 6)];
92 ogroup[3] = dtable[igroup[2] & 0x3F];
94 /* Replace characters in output stream with "=" pad
95 characters if fewer than three characters were
96 read from the end of the input stream. */
104 for (i = 0; i < 4; i++) {
105 buffer_add(b, ogroup[i]);
106 if (!(b->offset % 72)) {
107 /* buffer_add(b, '\r'); */
113 /* buffer_add(b, '\r'); */
117 void base64_decode(struct buffer_st *bfr, const char *source, int length)
126 for (i = 0; i < 255; i++) {
129 for (i = 'A'; i <= 'Z'; i++) {
130 dtable[i] = 0 + (i - 'A');
132 for (i = 'a'; i <= 'z'; i++) {
133 dtable[i] = 26 + (i - 'a');
135 for (i = '0'; i <= '9'; i++) {
136 dtable[i] = 52 + (i - '0');
144 /*CONSTANTCONDITION*/
146 unsigned char a[4], b[4], o[3];
148 for (i = 0; i < 4; i++) {
153 if (offset > length) endoffile = 1;
154 if (isspace(c) || c == '\n' || c == '\r') continue;
161 fprintf(stderr, "Input file incomplete.\n");
168 if (dtable[c] & 0x80) {
170 fprintf(stderr, "Offset %i length %i\n", offset, length);
171 fprintf(stderr, "character '%c:%x:%c' in input file.\n", c, c, dtable[c]);
177 a[i] = (unsigned char) c;
178 b[i] = (unsigned char) dtable[c];
180 o[0] = (b[0] << 2) | (b[1] >> 4);
181 o[1] = (b[1] << 4) | (b[2] >> 2);
182 o[2] = (b[2] << 6) | b[3];
183 i = a[2] == '=' ? 1 : (a[3] == '=' ? 2 : 3);
186 buffer_add(bfr, o[count++]);