base64.c

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/*
 * base64.c: Base64 converting functions
 *
 * Copyright (C) 2001, 2002  Juha Yrj鰈?<[e-mail]>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */


#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>
#include "secure_serial.h"
#include "base64.h"

static const unsigned char base64_table[66] =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" "0123456789+/=";

static const unsigned char bin_table[128] = {
	0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
	0xFF, 0xE0, 0xD0, 0xFF, 0xFF, 0xD0, 0xFF, 0xFF,
	0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
	0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
	0xE0, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
	0xFF, 0xFF, 0xFF, 0x3E, 0xFF, 0xF2, 0xFF, 0x3F,
	0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B,
	0x3C, 0x3D, 0xFF, 0xFF, 0xFF, 0xC0, 0xFF, 0xFF,
	0xFF, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
	0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
	0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
	0x17, 0x18, 0x19, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
	0xFF, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20,
	0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28,
	0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F, 0x30,
	0x31, 0x32, 0x33, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
};

static void to_base64(unsigned int i, unsigned char *out, unsigned int fillers) {
	unsigned int s = 18, c;

	for (c = 0; c < 4; c++) {
		if (fillers >= 4 - c) *out = base64_table[64];
		else *out = base64_table[(i >> s) & 0x3f];
		out++;
		s -= 6;
	}
}

static int from_base64(const char *in, unsigned int *out, int *skip) {
	unsigned int res = 0, c, s = 18;
	const char *in0 = in;

	for (c = 0; c < 4; c++, in++) {
		unsigned char b;
		int k = *in;

		if (k < 0) return -1;
		if (k == 0 && c == 0) return 0;
		b = bin_table[k];
		if (b == 0xC0)	/* '=' */ break;
		switch (b) {
		case 0xD0:	/* '\n' or '\r' */
			c--;
			continue;
		}
		if (b > 0x3f) return -1;

		res |= b << s;
		s -= 6;
	}
	*skip = in - in0;
	*out = res;
	return c * 6 / 8;
}

int base64_encode(const unsigned char *in, size_t len, unsigned char **outPtr) {
	unsigned int chars = 0;
	size_t i, c;
	unsigned char *out;
	
	*outPtr = malloc(len * 2);  // this is over kill
	
	if (*outPtr == NULL)
		return(-1);
	
	out = *outPtr;

	while (len >= 3) {
		i = in[2] + (in[1] << 8) + (in[0] << 16);
		in += 3;
		len -= 3;
		
		to_base64(i, out, 0);
		out += 4;
		chars += 4;

	}
	i = c = 0;
	while (c < len) i |= *in++ << ((2 - c++) << 3);
	if (len) {

		to_base64(i, out, 3 - len);
		out += 4;
		chars += 4;
	}

	*out = 0;

	return 0;
}
int base64_decode(const char *in, unsigned char *out, size_t outlen) {
	int len = 0, r, skip;
	unsigned int i;

	while ((r = from_base64(in, &i, &skip)) > 0) {
		int finished = 0, s = 16;

		if (r < 3) finished = 1;
		while (r--) {
			if (outlen <= 0) return -1;
			*out++ = i >> s;
			s -= 8;
			outlen--;
			len++;
		}
		in += skip;
		if (finished || *in == 0) return len;
	}
	if (r == 0) return len;
	return -1;
}




/* end of file */