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/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
* base64.c
*
* Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
*/
#include "config.h"
#include "internal.h"
static uint8_t convert(char in)
{
if (isupper(in))
return in - 'A';
if (islower(in))
return in - 'a' + 26;
if (isdigit(in))
return in - '0' + 52;
if (in == '+')
return 62;
if (in == '/' || in == '-')
return 63;
return 0;
}
void base64_decode(uint8_t *out, const char *in)
{
char temp[4];
while (*in != '\0' && *in != '=') {
temp[0] = *in == '\0' ? 0 : convert(*(in++));
temp[1] = *in == '\0' ? 0 : convert(*(in++));
temp[2] = *in == '\0' ? 0 : convert(*(in++));
temp[3] = *in == '\0' ? 0 : convert(*(in++));
*(out++) = ((temp[0] << 2) & 0xFC) | ((temp[1] >> 4) & 0x03);
*(out++) = ((temp[1] << 4) & 0xF0) | ((temp[2] >> 2) & 0x0F);
*(out++) = ((temp[2] << 6) & 0xC0) | ( temp[3] & 0x3F);
}
}
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