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261 lines
7.4 KiB
C
261 lines
7.4 KiB
C
/* MODP_B64 - High performance base64 encoder/decoder
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* Version 1.3 -- 17-Mar-2006
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* http://modp.com/release/base64
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*
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* Copyright (C) 2005, 2006 Nick Galbreath -- nickg [at] modp [dot] com
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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 are
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* met:
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*
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* 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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* 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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* Neither the name of the modp.com nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* This is the standard "new" BSD license:
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* http://www.opensource.org/licenses/bsd-license.php
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*/
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/* public header */
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#include "modp_b64.h"
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/*
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* If you are ripping this out of the library, comment out the next
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* line and uncomment the next lines as approrpiate
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*/
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/* #include "config.h" */
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/* if on motoral, sun, ibm; uncomment this */
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/* #define WORDS_BIGENDIAN 1 */
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/* else for Intel, Amd; uncomment this */
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/* #undef WORDS_BIGENDIAN */
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#include "modp_b64_data.h"
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#define BADCHAR 0x01FFFFFF
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/**
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* you can control if we use padding by commenting out this
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* next line. However, I highly recommend you use padding and not
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* using it should only be for compatability with a 3rd party.
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* Also, 'no padding' is not tested!
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*/
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#define DOPAD 1
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/*
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* if we aren't doing padding
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* set the pad character to NULL
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*/
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#ifndef DOPAD
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#undef CHARPAD
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#define CHARPAD '\0'
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#endif
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size_t modp_b64_encode(char* dest, const char* str, size_t len)
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{
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size_t i = 0;
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uint8_t* p = (uint8_t*) dest;
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/* unsigned here is important! */
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uint8_t t1, t2, t3;
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if (len > 2) {
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for (; i < len - 2; i += 3) {
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t1 = str[i]; t2 = str[i+1]; t3 = str[i+2];
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*p++ = e0[t1];
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*p++ = e1[((t1 & 0x03) << 4) | ((t2 >> 4) & 0x0F)];
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*p++ = e1[((t2 & 0x0F) << 2) | ((t3 >> 6) & 0x03)];
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*p++ = e2[t3];
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}
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}
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switch (len - i) {
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case 0:
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break;
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case 1:
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t1 = str[i];
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*p++ = e0[t1];
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*p++ = e1[(t1 & 0x03) << 4];
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*p++ = CHARPAD;
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*p++ = CHARPAD;
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break;
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default: /* case 2 */
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t1 = str[i]; t2 = str[i+1];
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*p++ = e0[t1];
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*p++ = e1[((t1 & 0x03) << 4) | ((t2 >> 4) & 0x0F)];
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*p++ = e2[(t2 & 0x0F) << 2];
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*p++ = CHARPAD;
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}
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*p = '\0';
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return p - (uint8_t*)dest;
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}
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#ifdef WORDS_BIGENDIAN /* BIG ENDIAN -- SUN / IBM / MOTOROLA */
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size_t modp_b64_decode(char* dest, const char* src, size_t len)
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{
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if (len == 0) return 0;
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#ifdef DOPAD
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/* if padding is used, then the message must be at least
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4 chars and be a multiple of 4.
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there can be at most 2 pad chars at the end */
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if (len < 4 || (len % 4 != 0)) return MODP_B64_ERROR;
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if (src[len-1] == CHARPAD) {
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len--;
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if (src[len -1] == CHARPAD) {
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len--;
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}
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}
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#endif /* DOPAD */
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size_t i;
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int leftover = len % 4;
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size_t chunks = (leftover == 0) ? len / 4 - 1 : len /4;
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uint8_t* p = (uint8_t*) dest;
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uint32_t x = 0;
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uint32_t* destInt = (uint32_t*) p;
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uint32_t* srcInt = (uint32_t*) src;
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uint32_t y = *srcInt++;
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for (i = 0; i < chunks; ++i) {
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x = d0[y >> 24 & 0xff] | d1[y >> 16 & 0xff] |
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d2[y >> 8 & 0xff] | d3[y & 0xff];
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if (x >= BADCHAR) return MODP_B64_ERROR;
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*destInt = x << 8;
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p += 3;
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destInt = (uint32_t*)p;
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y = *srcInt++;
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}
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switch (leftover) {
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case 0:
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x = d0[y >> 24 & 0xff] | d1[y >> 16 & 0xff] |
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d2[y >> 8 & 0xff] | d3[y & 0xff];
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if (x >= BADCHAR) return MODP_B64_ERROR;
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*p++ = ((uint8_t*)&x)[1];
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*p++ = ((uint8_t*)&x)[2];
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*p = ((uint8_t*)&x)[3];
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return (chunks+1)*3;
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case 1:
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x = d3[y >> 24];
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*p = (uint8_t)x;
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break;
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case 2:
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x = d3[y >> 24] *64 + d3[(y >> 16) & 0xff];
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*p = (uint8_t)(x >> 4);
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break;
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default: /* case 3 */
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x = (d3[y >> 24] *64 + d3[(y >> 16) & 0xff])*64 +
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d3[(y >> 8) & 0xff];
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*p++ = (uint8_t) (x >> 10);
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*p = (uint8_t) (x >> 2);
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break;
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}
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if (x >= BADCHAR) return MODP_B64_ERROR;
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return 3*chunks + (6*leftover)/8;
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}
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#else /* LITTLE ENDIAN -- INTEL AND FRIENDS */
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size_t modp_b64_decode(char* dest, const char* src, size_t len)
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{
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if (len == 0) return 0;
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#ifdef DOPAD
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/*
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* if padding is used, then the message must be at least
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* 4 chars and be a multiple of 4
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*/
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if (len < 4 || (len % 4 != 0)) return MODP_B64_ERROR; /* error */
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/* there can be at most 2 pad chars at the end */
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if (src[len-1] == CHARPAD) {
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len--;
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if (src[len -1] == CHARPAD) {
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len--;
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}
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}
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#endif
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size_t i;
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int leftover = len % 4;
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size_t chunks = (leftover == 0) ? len / 4 - 1 : len /4;
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uint8_t* p = (uint8_t*)dest;
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uint32_t x = 0;
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uint32_t* destInt = (uint32_t*) p;
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uint32_t* srcInt = (uint32_t*) src;
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uint32_t y = *srcInt++;
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for (i = 0; i < chunks; ++i) {
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x = d0[y & 0xff] |
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d1[(y >> 8) & 0xff] |
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d2[(y >> 16) & 0xff] |
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d3[(y >> 24) & 0xff];
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if (x >= BADCHAR) return MODP_B64_ERROR;
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*destInt = x ;
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p += 3;
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destInt = (uint32_t*)p;
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y = *srcInt++;}
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switch (leftover) {
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case 0:
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x = d0[y & 0xff] |
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d1[(y >> 8) & 0xff] |
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d2[(y >> 16) & 0xff] |
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d3[(y >> 24) & 0xff];
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if (x >= BADCHAR) return MODP_B64_ERROR;
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*p++ = ((uint8_t*)(&x))[0];
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*p++ = ((uint8_t*)(&x))[1];
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*p = ((uint8_t*)(&x))[2];
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return (chunks+1)*3;
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break;
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case 1: /* with padding this is an impossible case */
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x = d0[y & 0xff];
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*p = *((uint8_t*)(&x)); // i.e. first char/byte in int
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break;
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case 2: // * case 2, 1 output byte */
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x = d0[y & 0xff] | d1[y >> 8 & 0xff];
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*p = *((uint8_t*)(&x)); // i.e. first char
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break;
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default: /* case 3, 2 output bytes */
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x = d0[y & 0xff] |
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d1[y >> 8 & 0xff ] |
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d2[y >> 16 & 0xff]; /* 0x3c */
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*p++ = ((uint8_t*)(&x))[0];
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*p = ((uint8_t*)(&x))[1];
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break;
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}
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if (x >= BADCHAR) return MODP_B64_ERROR;
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return 3*chunks + (6*leftover)/8;
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}
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#endif /* if bigendian / else / endif */
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