/*
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* This file is based on roken from the FreeBSD source. It has been modified
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* to not use malloc() and instead expect static buffers, and tabs have been
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* replaced with spaces. Also, instead of strlen() on the resulting string,
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* pointer arithmitic is done, as p represents the end of the buffer.
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*/
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/*
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* Copyright (c) 1995-2001 Kungliga Tekniska Högskolan
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* (Royal Institute of Technology, Stockholm, Sweden).
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <base64/base64.h>
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static const char base64_chars[] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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static int
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pos(char c)
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{
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const char *p;
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for (p = base64_chars; *p; p++)
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if (*p == c)
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return p - base64_chars;
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return -1;
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}
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int
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base64_encode(const void *data, int size, char *s, uint8_t should_pad)
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{
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char *p;
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int i;
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int c;
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const unsigned char *q;
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char *last;
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int diff;
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p = s;
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q = (const unsigned char *) data;
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last = NULL;
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i = 0;
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while (i < size) {
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c = q[i++];
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c *= 256;
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if (i < size)
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c += q[i];
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i++;
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c *= 256;
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if (i < size)
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c += q[i];
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i++;
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p[0] = base64_chars[(c & 0x00fc0000) >> 18];
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p[1] = base64_chars[(c & 0x0003f000) >> 12];
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p[2] = base64_chars[(c & 0x00000fc0) >> 6];
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p[3] = base64_chars[(c & 0x0000003f) >> 0];
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last = p;
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p += 4;
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}
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if (last) {
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diff = i - size;
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if (diff > 0) {
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if (should_pad) {
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memset(last + (4 - diff), '=', diff);
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} else {
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p = last + (4 - diff);
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}
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}
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}
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*p = 0;
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return (p - s);
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}
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int
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base64_pad(char *buf, int len)
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{
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int remainder;
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remainder = len % 4;
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if (remainder == 0) {
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return (0);
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}
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memset(buf, '=', 4 - remainder);
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return (4 - remainder);
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}
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#define DECODE_ERROR -1
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static int
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token_decode(const char *token, int len)
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{
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int i;
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unsigned int val = 0;
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int marker = 0;
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if (len < 4) {
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return DECODE_ERROR;
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}
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for (i = 0; i < 4; i++) {
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val *= 64;
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if (token[i] == '=') {
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marker++;
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} else if (marker > 0) {
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return DECODE_ERROR;
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} else {
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val += pos(token[i]);
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}
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}
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if (marker > 2) {
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return DECODE_ERROR;
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}
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return (marker << 24) | val;
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}
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int
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base64_decode(const char *str, void *data)
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{
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struct base64_decoder dec = {
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.src = str,
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.dst = data,
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};
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return base64_decoder_go(&dec);
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}
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int
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base64_decode_maxlen(const char *str, void *data, int len)
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{
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struct base64_decoder dec = {
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.src = str,
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.dst = data,
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.dst_len = len,
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};
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return base64_decoder_go(&dec);
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}
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int
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base64_decode_len(const char *str)
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{
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int len;
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len = strlen(str);
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while (len && str[len - 1] == '=') {
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len--;
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}
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return len * 3 / 4;
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}
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int
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base64_decoder_go(struct base64_decoder *dec)
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{
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unsigned int marker;
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int val;
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uint8_t *dst;
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char sval;
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int read_len;
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int src_len;
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int src_rem;
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int src_off;
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int dst_len;
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int dst_off;
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int i;
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dst = dec->dst;
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dst_off = 0;
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src_off = 0;
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/* A length <= 0 means "unbounded". */
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if (dec->src_len <= 0) {
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src_len = INT_MAX;
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} else {
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src_len = dec->src_len;
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}
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if (dec->dst_len <= 0) {
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dst_len = INT_MAX;
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} else {
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dst_len = dec->dst_len;
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}
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while (1) {
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src_rem = src_len - src_off;
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if (src_rem == 0) {
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/* End of source input. */
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break;
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}
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if (dec->src[src_off] == '\0') {
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/* End of source string. */
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break;
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}
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/* Account for possibility of partial token from previous call. */
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read_len = 4 - dec->buf_len;
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/* Detect invalid input. */
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for (i = 0; i < read_len; i++) {
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sval = dec->src[src_off + i];
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if (sval == '\0') {
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/* Incomplete input. */
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return -1;
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}
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if (sval != '=' && strchr(base64_chars, sval) == NULL) {
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/* Invalid base64 character. */
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return -1;
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}
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}
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if (src_rem < read_len) {
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/* Input contains a partial token. Stash it for use during the
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* next call.
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*/
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memcpy(&dec->buf[dec->buf_len], &dec->src[src_off], src_rem);
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dec->buf_len += src_rem;
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break;
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}
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/* Copy full token into buf and decode it. */
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memcpy(&dec->buf[dec->buf_len], &dec->src[src_off], read_len);
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val = token_decode(dec->buf, read_len);
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if (val == DECODE_ERROR) {
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return -1;
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}
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src_off += read_len;
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dec->buf_len = 0;
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marker = (val >> 24) & 0xff;
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if (dst_off >= dst_len) {
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break;
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}
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dst[dst_off] = (val >> 16) & 0xff;
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dst_off++;
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if (marker < 2) {
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if (dst_off >= dst_len) {
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break;
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}
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dst[dst_off] = (val >> 8) & 0xff;
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dst_off++;
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}
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if (marker < 1) {
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if (dst_off >= dst_len) {
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break;
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}
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dst[dst_off] = val & 0xff;
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dst_off++;
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}
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}
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return dst_off;
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}
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