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/*
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;
signed 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 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;
}
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