/* PipeWire */
/* SPDX-FileCopyrightText: Copyright © 2021 Wim Taymans */
/* SPDX-License-Identifier: MIT */

static inline void base64_encode(const uint8_t *data, size_t len, char *enc, char pad)
{
	static const char tab[] =
	    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
	size_t i;
	for (i = 0; i < len; i += 3) {
		uint32_t v;
		v  =              data[i+0]      << 16;
		v |= (i+1 < len ? data[i+1] : 0) << 8;
		v |= (i+2 < len ? data[i+2] : 0);
		*enc++ =             tab[(v >> (3*6)) & 0x3f];
		*enc++ =             tab[(v >> (2*6)) & 0x3f];
		*enc++ = i+1 < len ? tab[(v >> (1*6)) & 0x3f] : pad;
		*enc++ = i+2 < len ? tab[(v >> (0*6)) & 0x3f] : pad;
	}
	*enc = '\0';
}

static inline size_t base64_decode(const char *data, size_t len, uint8_t *dec)
{
	uint8_t tab[] = {
		62, -1, -1, -1, 63, 52, 53, 54, 55, 56,
		57, 58, 59, 60, 61, -1, -1, -1, -1, -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 };
	size_t i, j;
	for (i = 0, j = 0; i < len; i += 4) {
		uint32_t v;
		v =                          tab[data[i+0]-43]  << (3*6);
		v |=                         tab[data[i+1]-43]  << (2*6);
		v |= (data[i+2] == '=' ? 0 : tab[data[i+2]-43]) << (1*6);
		v |= (data[i+3] == '=' ? 0 : tab[data[i+3]-43]);
		                      dec[j++] = (v >> 16) & 0xff;
		if (data[i+2] != '=') dec[j++] = (v >> 8)  & 0xff;
		if (data[i+3] != '=') dec[j++] =  v        & 0xff;
	}
	return j;
}