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static const char rcsid[] = "#(@) $Id$";
/*
Encode or decode file as MIME base64 (RFC 1341)
by John Walker
http://www.fourmilab.ch/
This program is in the public domain.
*/
#include <stdio.h>
/* ENCODE -- Encode binary file into base64. */
#include <stdlib.h>
#include <ctype.h>
#include "base64.h"
static unsigned char dtable[512];
void buffer_new(struct buffer_st *b)
{
b->length = 512;
b->data = malloc(sizeof(char)*(b->length));
b->data[0] = 0;
b->ptr = b->data;
b->offset = 0;
}
void buffer_add(struct buffer_st *b, char c)
{
*(b->ptr++) = c;
b->offset++;
if (b->offset == b->length) {
b->length += 512;
b->data = realloc(b->data, b->length);
b->ptr = b->data + b->offset;
}
}
void buffer_delete(struct buffer_st *b)
{
free(b->data);
b->length = 0;
b->offset = 0;
b->ptr = NULL;
b->data = NULL;
}
void base64_encode(struct buffer_st *b, const char *source, int length)
{
int i, hiteof = 0;
int offset = 0;
int olen;
olen = 0;
buffer_new(b);
/* Fill dtable with character encodings. */
for (i = 0; i < 26; i++) {
dtable[i] = 'A' + i;
dtable[26 + i] = 'a' + i;
}
for (i = 0; i < 10; i++) {
dtable[52 + i] = '0' + i;
}
dtable[62] = '+';
dtable[63] = '/';
while (!hiteof) {
unsigned char igroup[3], ogroup[4];
int c, n;
igroup[0] = igroup[1] = igroup[2] = 0;
for (n = 0; n < 3; n++) {
c = *(source++);
offset++;
if (offset > length) {
hiteof = 1;
break;
}
igroup[n] = (unsigned char) c;
}
if (n > 0) {
ogroup[0] = dtable[igroup[0] >> 2];
ogroup[1] = dtable[((igroup[0] & 3) << 4) | (igroup[1] >> 4)];
ogroup[2] = dtable[((igroup[1] & 0xF) << 2) | (igroup[2] >> 6)];
ogroup[3] = dtable[igroup[2] & 0x3F];
/* Replace characters in output stream with "=" pad
characters if fewer than three characters were
read from the end of the input stream. */
if (n < 3) {
ogroup[3] = '=';
if (n < 2) {
ogroup[2] = '=';
}
}
for (i = 0; i < 4; i++) {
buffer_add(b, ogroup[i]);
if (!(b->offset % 72)) {
// buffer_add(b, '\r');
buffer_add(b, '\n');
}
}
}
}
// buffer_add(b, '\r');
buffer_add(b, '\n');
}
void base64_decode(struct buffer_st *bfr, const char *source, int length)
{
int i;
int offset = 0;
int endoffile;
int count;
buffer_new(bfr);
for (i = 0; i < 255; i++) {
dtable[i] = 0x80;
}
for (i = 'A'; i <= 'Z'; i++) {
dtable[i] = 0 + (i - 'A');
}
for (i = 'a'; i <= 'z'; i++) {
dtable[i] = 26 + (i - 'a');
}
for (i = '0'; i <= '9'; i++) {
dtable[i] = 52 + (i - '0');
}
dtable['+'] = 62;
dtable['/'] = 63;
dtable['='] = 0;
endoffile = 0;
/*CONSTANTCONDITION*/
while (1) {
unsigned char a[4], b[4], o[3];
for (i = 0; i < 4; i++) {
int c;
while (1) {
c = *(source++);
offset++;
if (offset > length) endoffile = 1;
if (isspace(c) || c == '\n' || c == '\r') continue;
break;
}
if (endoffile) {
/*
if (i > 0) {
fprintf(stderr, "Input file incomplete.\n");
exit(1);
}
*/
return;
}
if (dtable[c] & 0x80) {
/*
fprintf(stderr, "Offset %i length %i\n", offset, length);
fprintf(stderr, "character '%c:%x:%c' in input file.\n", c, c, dtable[c]);
exit(1);
*/
i--;
continue;
}
a[i] = (unsigned char) c;
b[i] = (unsigned char) dtable[c];
}
o[0] = (b[0] << 2) | (b[1] >> 4);
o[1] = (b[1] << 4) | (b[2] >> 2);
o[2] = (b[2] << 6) | b[3];
i = a[2] == '=' ? 1 : (a[3] == '=' ? 2 : 3);
count = 0;
while (count < i) {
buffer_add(bfr, o[count++]);
}
if (i < 3) {
return;
}
}
}
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