99 lines
2.5 KiB
C
99 lines
2.5 KiB
C
/*
|
|
cencoder.c - c source to a base64 encoding algorithm implementation
|
|
|
|
This is part of the libb64 project, and has been placed in the public domain.
|
|
For details, see http://sourceforge.net/projects/libb64
|
|
*/
|
|
|
|
#include "cencode.h"
|
|
|
|
const int CHARS_PER_LINE = 72;
|
|
|
|
void base64_init_encodestate(base64_encodestate* state_in) {
|
|
state_in->step = step_A;
|
|
state_in->result = 0;
|
|
state_in->stepcount = 0;
|
|
}
|
|
|
|
char base64_encode_value(char value_in) {
|
|
static const char* encoding = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
|
|
if (value_in > 63)
|
|
return '=';
|
|
return encoding[(int)value_in];
|
|
}
|
|
|
|
int base64_encode_block(const char* plaintext_in, int length_in, char* code_out, base64_encodestate* state_in) {
|
|
const char* plainchar = plaintext_in;
|
|
const char* const plaintextend = plaintext_in + length_in;
|
|
char* codechar = code_out;
|
|
char result;
|
|
char fragment;
|
|
|
|
result = state_in->result;
|
|
|
|
switch (state_in->step) {
|
|
while (1) {
|
|
case step_A:
|
|
if (plainchar == plaintextend) {
|
|
state_in->result = result;
|
|
state_in->step = step_A;
|
|
return codechar - code_out;
|
|
}
|
|
fragment = *plainchar++;
|
|
result = (fragment & 0x0fc) >> 2;
|
|
*codechar++ = base64_encode_value(result);
|
|
result = (fragment & 0x003) << 4;
|
|
case step_B:
|
|
if (plainchar == plaintextend) {
|
|
state_in->result = result;
|
|
state_in->step = step_B;
|
|
return (int)(codechar - code_out);
|
|
}
|
|
fragment = *plainchar++;
|
|
result |= (fragment & 0x0f0) >> 4;
|
|
*codechar++ = base64_encode_value(result);
|
|
result = (fragment & 0x00f) << 2;
|
|
case step_C:
|
|
if (plainchar == plaintextend) {
|
|
state_in->result = result;
|
|
state_in->step = step_C;
|
|
return codechar - code_out;
|
|
}
|
|
fragment = *plainchar++;
|
|
result |= (fragment & 0x0c0) >> 6;
|
|
*codechar++ = base64_encode_value(result);
|
|
result = (fragment & 0x03f) >> 0;
|
|
*codechar++ = base64_encode_value(result);
|
|
|
|
++(state_in->stepcount);
|
|
if (state_in->stepcount == CHARS_PER_LINE / 4) {
|
|
*codechar++ = '\n';
|
|
state_in->stepcount = 0;
|
|
}
|
|
}
|
|
}
|
|
/* control should not reach here */
|
|
return codechar - code_out;
|
|
}
|
|
|
|
int base64_encode_blockend(char* code_out, base64_encodestate* state_in) {
|
|
char* codechar = code_out;
|
|
|
|
switch (state_in->step) {
|
|
case step_B:
|
|
*codechar++ = base64_encode_value(state_in->result);
|
|
*codechar++ = '=';
|
|
*codechar++ = '=';
|
|
break;
|
|
case step_C:
|
|
*codechar++ = base64_encode_value(state_in->result);
|
|
*codechar++ = '=';
|
|
break;
|
|
case step_A:
|
|
break;
|
|
}
|
|
*codechar++ = '\n';
|
|
|
|
return codechar - code_out;
|
|
}
|