bip/src/utils/base64.c

94 lines
2.2 KiB
C

/*
* Base64 encoding/decoding (RFC1341)
* Copyright (c) 2005-2011, Jouni Malinen <j@w1.fi>
* Copyright (c) 2022 Loïc Gomez
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include "base64.h"
static const unsigned char base64_table[65] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/**
* base64_encode - Base64 encode
* @src: Data to be encoded
* @len: Length of the data to be encoded
* @out_len: Pointer to output length variable, or %NULL if not used
* Returns: Allocated buffer of out_len bytes of encoded data,
* or %NULL on failure
*
* Caller is responsible for freeing the returned buffer. Returned buffer is
* nul terminated to make it easier to use as a C string. The nul terminator is
* not included in out_len.
*
* BIP change: remove line returns.
*/
unsigned char *base64_encode(const unsigned char *src, size_t len,
size_t *out_len)
{
unsigned char *out, *pos;
const unsigned char *end, *in;
size_t olen;
int line_len;
olen = len * 4 / 3 + 4; /* 3-byte blocks to 4-byte */
olen += olen / 72; /* line feeds */
olen++; /* nul termination */
if (olen < len)
return NULL; /* integer overflow */
out = malloc(olen);
if (out == NULL)
return NULL;
end = src + len;
in = src;
pos = out;
line_len = 0;
while (end - in >= 3) {
*pos++ = base64_table[in[0] >> 2];
*pos++ = base64_table[((in[0] & 0x03) << 4) | (in[1] >> 4)];
*pos++ = base64_table[((in[1] & 0x0f) << 2) | (in[2] >> 6)];
*pos++ = base64_table[in[2] & 0x3f];
in += 3;
line_len += 4;
/*
* BIP change: remove line returns.
if (line_len >= 72) {
*pos++ = '\n';
line_len = 0;
}
*/
}
if (end - in) {
*pos++ = base64_table[in[0] >> 2];
if (end - in == 1) {
*pos++ = base64_table[(in[0] & 0x03) << 4];
*pos++ = '=';
} else {
*pos++ = base64_table[((in[0] & 0x03) << 4)
| (in[1] >> 4)];
*pos++ = base64_table[(in[1] & 0x0f) << 2];
}
*pos++ = '=';
line_len += 4;
}
/*
* BIP change: remove line returns.
if (line_len)
*pos++ = '\n';
*/
*pos = '\0';
if (out_len)
*out_len = (size_t)(pos - out);
return out;
}