Files
ustreamer/src/libs/base64.c
Maxim Devaev 2d6716aa47 refactoring
2024-02-26 20:28:09 +02:00

80 lines
3.0 KiB
C

/*****************************************************************************
# #
# uStreamer - Lightweight and fast MJPEG-HTTP streamer. #
# #
# Copyright (C) 2018-2023 Maxim Devaev <mdevaev@gmail.com> #
# #
# This program is free software: you can redistribute it and/or modify #
# it under the terms of the GNU General Public License as published by #
# the Free Software Foundation, either version 3 of the License, or #
# (at your option) any later version. #
# #
# This program is distributed in the hope that it will be useful, #
# but WITHOUT ANY WARRANTY; without even the implied warranty of #
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the #
# GNU General Public License for more details. #
# #
# You should have received a copy of the GNU General Public License #
# along with this program. If not, see <https://www.gnu.org/licenses/>. #
# #
*****************************************************************************/
#include "base64.h"
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include "types.h"
#include "tools.h"
static const char _ENCODING_TABLE[] = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
'w', 'x', 'y', 'z', '0', '1', '2', '3',
'4', '5', '6', '7', '8', '9', '+', '/',
};
static const uint _MOD_TABLE[] = {0, 2, 1};
void us_base64_encode(const u8 *data, uz size, char **encoded, uz *allocated) {
const uz encoded_size = 4 * ((size + 2) / 3) + 1; // +1 for '\0'
if (*encoded == NULL || (allocated && *allocated < encoded_size)) {
US_REALLOC(*encoded, encoded_size);
if (allocated) {
*allocated = encoded_size;
}
}
for (uint data_index = 0, encoded_index = 0; data_index < size;) {
# define OCTET(_name) uint _name = (data_index < size ? (u8)data[data_index++] : 0)
OCTET(octet_a);
OCTET(octet_b);
OCTET(octet_c);
# undef OCTET
const uint triple = (octet_a << 0x10) + (octet_b << 0x08) + octet_c;
# define ENCODE(_offset) (*encoded)[encoded_index++] = _ENCODING_TABLE[(triple >> _offset * 6) & 0x3F]
ENCODE(3);
ENCODE(2);
ENCODE(1);
ENCODE(0);
# undef ENCODE
}
for (uint index = 0; index < _MOD_TABLE[size % 3]; index++) {
(*encoded)[encoded_size - 2 - index] = '=';
}
(*encoded)[encoded_size - 1] = '\0';
}