/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 4 -*- */
/* vi: set expandtab shiftwidth=4 tabstop=4: */
/**
 * \file modp_b64.c
 * <PRE>
 * MODP_B64 - High performance base64 encoder/decoder
 * http://code.google.com/p/stringencoders/
 *
 * Copyright &copy; 2005, 2006, 2007  Nick Galbreath -- nickg [at] modp [dot] com
 * All rights reserved.
 *
 * Modified for inclusion in Phusion Passenger.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *   Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 *   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.
 *
 *   Neither the name of the modp.com 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 COPYRIGHT HOLDERS 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 COPYRIGHT
 * OWNER 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.
 *
 * This is the standard "new" BSD license:
 * http://www.opensource.org/licenses/bsd-license.php
 * </PRE>
 */

#include "modp_b64_data.h"

/* public header */
#include "modp_b64.h"

size_t modp_b64_encode(char* dest, const char* str, size_t len)
{
    size_t i = 0;
    const modp_uint8_t* s = (const modp_uint8_t*) str;
    modp_uint8_t* p = (modp_uint8_t*) dest;

    /* unsigned here is important! */
    /* modp_uint8_t is fastest on G4, amd */
    /* modp_uint32_t is fastest on Intel */
    modp_uint32_t t1, t2, t3;

    if (len > 2) {
        for (i = 0; i < len - 2; i += 3) {
            t1 = s[i]; t2 = s[i+1]; t3 = s[i+2];
            *p++ = e0[t1];
            *p++ = e1[((t1 & 0x03) << 4) | ((t2 >> 4) & 0x0F)];
            *p++ = e1[((t2 & 0x0F) << 2) | ((t3 >> 6) & 0x03)];
            *p++ = e2[t3];
        }
    }

    switch (len - i) {
    case 0:
        break;
    case 1:
        t1 = s[i];
        *p++ = e0[t1];
        *p++ = e1[(t1 & 0x03) << 4];
        *p++ = B64_CHARPAD;
        *p++ = B64_CHARPAD;
        break;
    default: /* case 2 */
        t1 = s[i]; t2 = s[i+1];
        *p++ = e0[t1];
        *p++ = e1[((t1 & 0x03) << 4) | ((t2 >> 4) & 0x0F)];
        *p++ = e2[(t2 & 0x0F) << 2];
        *p++ = B64_CHARPAD;
    }

    *p = '\0';
    return (size_t)(p - (modp_uint8_t*)dest);
}

#if defined(__x86_64__) || defined(__x86__)
/* INTEL & AMD */

#if defined(__has_feature)
    #if __has_feature(address_sanitizer)
        #define MODP_NO_SANITIZE(args) __attribute__((no_sanitize(args)))
    #endif
#endif
#ifndef MODP_NO_SANITIZE
    #define MODP_NO_SANITIZE(args)
#endif

MODP_NO_SANITIZE("undefined")
size_t modp_b64_decode(char* dest, const char* src, size_t len)
{
    size_t i;
    size_t leftover;
    size_t chunks;

    modp_uint8_t* p;
    modp_uint32_t x;
    modp_uint32_t* destInt;
    const modp_uint32_t* srcInt = (const modp_uint32_t*) src;
    modp_uint32_t y = *srcInt++;

    if (len == 0) return 0;

#ifdef B64_DOPAD
    /*
     * if padding is used, then the message must be at least
     * 4 chars and be a multiple of 4
     */
    if (len < 4 || (len % 4 != 0)) {
        return (size_t)-1; /* error */
    }
    /* there can be at most 2 pad chars at the end */
    if (src[len-1] == B64_CHARPAD) {
        len--;
        if (src[len -1] == B64_CHARPAD) {
            len--;
        }
    }
#endif

    leftover = len % 4;
    chunks = (leftover == 0) ? len / 4 - 1 : len /4;

    p = (modp_uint8_t*) dest;
    x = 0;
    destInt = (modp_uint32_t*) p;
    srcInt = (const modp_uint32_t*) src;
    y = *srcInt++;
    for (i = 0; i < chunks; ++i) {
        x = d0[y & 0xff] |
            d1[(y >> 8) & 0xff] |
            d2[(y >> 16) & 0xff] |
            d3[(y >> 24) & 0xff];

        if (x >= B64_BADCHAR) {
            return (size_t)-1;
        }
        *destInt = x ;
        p += 3;
        destInt = (modp_uint32_t*)p;
        y = *srcInt++;}


    switch (leftover) {
    case 0:
        x = d0[y & 0xff] |
            d1[(y >> 8) & 0xff] |
            d2[(y >> 16) & 0xff] |
            d3[(y >> 24) & 0xff];

        if (x >= B64_BADCHAR) {
            return (size_t)-1;
        }
        *p++ =  ((modp_uint8_t*)(&x))[0];
        *p++ =  ((modp_uint8_t*)(&x))[1];
        *p =    ((modp_uint8_t*)(&x))[2];
        return (chunks+1)*3;
#ifndef B64_DOPAD
    case 1:  /* with padding this is an impossible case */
        x = d0[y & 0xff];
        *p = *((modp_uint8_t*)(&x)); /* i.e. first char/byte in int */
        break;
#endif
    case 2: /* case 2, 1  output byte */
        x = d0[y & 0xff] | d1[y >> 8 & 0xff];
        *p = *((modp_uint8_t*)(&x)); /* i.e. first char */
        break;
    default: /* case 3, 2 output bytes */
        x = d0[y & 0xff] |
            d1[y >> 8 & 0xff ] |
            d2[y >> 16 & 0xff];  /* 0x3c */
        *p++ =  ((modp_uint8_t*)(&x))[0];
        *p =  ((modp_uint8_t*)(&x))[1];
        break;
    }

    if (x >= B64_BADCHAR) {
        return (size_t)-1;
    }

    return 3*chunks + (6*leftover)/8;
}

#endif