base85.h

/*
 * This file is excerpted from base85.c in git, specifically:
 * https://github.com/git/git/blob/6fe1b1407ed91823daa5d487abe457ff37463349/base85.c
 * Git (and thus, this modified file) is distributed under the GPL 2.0 license.
 */

static const char en85[] = {
	'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
	'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',
	'!', '#', '$', '%', '&', '(', ')', '*', '+', '-',
	';', '<', '=', '>', '?', '@', '^', '_',	'`', '{',
	'|', '}', '~'
};

void encode_85(char *buf, const unsigned char *data, int bytes)
{
	while (bytes) {
		unsigned acc = 0;
		int cnt;
		for (cnt = 24; cnt >= 0; cnt -= 8) {
			unsigned ch = *data++;
			acc |= ch << cnt;
			if (--bytes == 0)
				break;
		}
		for (cnt = 4; cnt >= 0; cnt--) {
			int val = acc % 85;
			acc /= 85;
			buf[cnt] = en85[val];
		}
		buf += 5;
	}

	*buf = 0;
}