/*      $NetBSD: base64.c,v 1.2 2017/04/18 17:28:18 maya Exp $  */

/*-
* Copyright (c) 2005,2006,2011 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Wasabi Systems, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Adapted for kernel mode use with minimal changes from
* /usr/src/crypto/dist/heimdal/lib/roken/base64.c
*
* Original:
* Copyright (c) 1995-2001 Kungliga Tekniska H�gskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the Institute nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include "iscsi_globals.h"
#include "base64.h"

static char base64_chars[] =
       "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

static int
pos(char c)
{
       char *p;

       for (p = base64_chars; *p; p++) {
               if (*p == c) {
                       return (int)(p - base64_chars);
               }
       }
       return -1;
}

int
base64_encode(const void *data, int size, uint8_t * buffer)
{
       uint8_t *p;
       int i;
       int c;
       const uint8_t *q;

       p = buffer;
       q = (const uint8_t *) data;
       *p++ = '0';
       *p++ = 'b';

       for (i = 0; i < size;) {
               c = q[i++];
               c *= 256;
               if (i < size) {
                       c += q[i];
               }
               i++;
               c *= 256;
               if (i < size) {
                       c += q[i];
               }
               i++;
               p[0] = base64_chars[(c & 0x00fc0000) >> 18];
               p[1] = base64_chars[(c & 0x0003f000) >> 12];
               p[2] = base64_chars[(c & 0x00000fc0) >> 6];
               p[3] = base64_chars[(c & 0x0000003f) >> 0];
               if (i > size) {
                       p[3] = '=';
               }
               if (i > size + 1) {
                       p[2] = '=';
               }
               p += 4;
       }
       *p = 0;
       return strlen(buffer);
}

#define DECODE_ERROR 0xffffffff

static uint32_t
token_decode(uint8_t * token)
{
       int i;
       uint32_t val = 0;
       int marker = 0;

       if (strlen(token) < 4) {
               return DECODE_ERROR;
       }
       for (i = 0; i < 4; i++) {
               val *= 64;
               if (token[i] == '=') {
                       marker++;
               } else if (marker > 0) {
                       return DECODE_ERROR;
               } else {
                       val += pos(token[i]);
               }
       }
       if (marker > 2) {
               return DECODE_ERROR;
       }
       return (marker << 24) | val;
}


uint8_t *
base64_decode(uint8_t * str, void *data, int *datalen)
{
       uint8_t *p, *q;
       uint32_t marker = 0;

       q = data;
       for (p = str; *p; p += 4) {
               uint32_t val = token_decode(p);
               marker = (val >> 24) & 0xff;
               if (val == DECODE_ERROR) {
                       return NULL;
               }
               *q++ = (val >> 16) & 0xff;
               if (marker < 2) {
                       *q++ = (val >> 8) & 0xff;
               }
               if (marker < 1) {
                       *q++ = val & 0xff;
               }
       }
       *datalen = (int)(q - (uint8_t *) data);

       return p - marker + 1;
}