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// SPDX-License-Identifier: NONE
/*
* This is part of the libb64 project, and has been placed in the public domain.
* For details, see http://sourceforge.net/projects/libb64
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "base64.h"
#include "compiler.h"
static const int CHARS_PER_LINE = 72;
static const char *ENCODING =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
void base64_init_encodestate(struct base64_encodestate *state_in)
{
state_in->step = step_A;
state_in->result = 0;
state_in->stepcount = 0;
}
char base64_encode_value(char value_in)
{
if (value_in > 63)
return '=';
return ENCODING[(int)value_in];
}
int base64_encode_block(const char *plaintext_in, int length_in, char *code_out,
struct 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) {
fallthrough;
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;
fallthrough;
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;
fallthrough;
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, struct 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;
}
signed char base64_decode_value(signed char value_in)
{
static const signed char decoding[] = {
62, -1, -1, -1, 63, 52, 53, 54,
55, 56, 57, 58, 59, 60, 61, -1,
-1, -1, -2, -1, -1, -1, 0, 1,
2, 3, 4, 5, 6, 7, 8, 9,
10, 11, 12, 13, 14, 15, 16, 17,
18, 19, 20, 21, 22, 23, 24, 25,
-1, -1, -1, -1, -1, -1, 26, 27,
28, 29, 30, 31, 32, 33, 34, 35,
36, 37, 38, 39, 40, 41, 42, 43,
44, 45, 46, 47, 48, 49, 50, 51
};
value_in -= 43;
if (value_in < 0 || value_in >= 80)
return -1;
return decoding[(int)value_in];
}
void base64_init_decodestate(struct base64_decodestate *state_in)
{
state_in->step = step_a;
state_in->plainchar = 0;
}
int base64_decode_block(const char *code_in, int length_in, char *plaintext_out,
struct base64_decodestate *state_in)
{
const char *codec = code_in;
char *plainc = plaintext_out;
signed char fragmt;
*plainc = state_in->plainchar;
switch (state_in->step) {
while (1) {
fallthrough;
case step_a:
do {
if (codec == code_in+length_in) {
state_in->step = step_a;
state_in->plainchar = *plainc;
return plainc - plaintext_out;
}
fragmt = base64_decode_value(*codec++);
} while (fragmt < 0);
*plainc = (fragmt & 0x03f) << 2;
fallthrough;
case step_b:
do {
if (codec == code_in+length_in) {
state_in->step = step_b;
state_in->plainchar = *plainc;
return plainc - plaintext_out;
}
fragmt = base64_decode_value(*codec++);
} while (fragmt < 0);
*plainc++ |= (fragmt & 0x030) >> 4;
*plainc = (fragmt & 0x00f) << 4;
fallthrough;
case step_c:
do {
if (codec == code_in+length_in) {
state_in->step = step_c;
state_in->plainchar = *plainc;
return plainc - plaintext_out;
}
fragmt = base64_decode_value(*codec++);
} while (fragmt < 0);
*plainc++ |= (fragmt & 0x03c) >> 2;
*plainc = (fragmt & 0x003) << 6;
fallthrough;
case step_d:
do {
if (codec == code_in+length_in) {
state_in->step = step_d;
state_in->plainchar = *plainc;
return plainc - plaintext_out;
}
fragmt = base64_decode_value(*codec++);
} while (fragmt < 0);
*plainc++ |= (fragmt & 0x03f);
}
}
/* control should not reach here */
return plainc - plaintext_out;
}
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