modified structure

[avr-crypto-lib.git] / base64 / base64_enc.c

diff --git a/base64/base64_enc.c b/base64/base64_enc.c
new file mode 100644 (file)
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+++ b/base64/base64_enc.c
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+/* base64_enc.c */
+/*
+ *   This file is part of the AVR-Crypto-Lib.
+ *   Copyright (C) 2006, 2007, 2008  Daniel Otte (daniel.otte@rub.de)
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program 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 General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+/**
+ * base64 encoder (RFC3548)
+ * Author: Daniel Otte
+ * License: GPLv3
+ * 
+ * 
+ */
+
+#include <stdint.h>
+#include "base64_enc.h"
+
+#if 1
+#include <avr/pgmspace.h>
+
+char base64_alphabet[64] PROGMEM = {
+       'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 
+       'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 
+       'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 
+       'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 
+       'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 
+       'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 
+       'w', 'x', 'y', 'z', '0', '1', '2', '3', 
+       '4', '5', '6', '7', '8', '9', '+', '/' }; 
+
+static 
+char bit6toAscii(uint8_t a){
+       a &= (uint8_t)0x3F;
+       return pgm_read_byte(base64_alphabet+a);
+}
+
+#else
+
+static 
+char bit6toAscii(uint8_t a){
+       a &= (uint8_t)0x3F;
+       
+       if(a<=25){
+               return a+'A';
+       } else {
+               if(a<=51){
+                       return a-26+'a';
+               } else {
+                       if(a<=61){
+                               return a-52+'0';
+                       } else {
+                               if(a==62){
+                                       return '+';
+                               } else {
+                                       return '/'; /* a == 63 */
+                               }
+                       }
+               }
+       }
+}
+
+#endif
+
+void base64enc(char* dest, void* src, uint16_t length){
+       uint16_t i,j;
+       uint8_t a[4];
+       for(i=0; i<length/3; ++i){
+               a[0]= (((uint8_t*)src)[i*3+0])>>2;
+               a[1]= (((((uint8_t*)src)[i*3+0])<<4) | ((((uint8_t*)src)[i*3+1])>>4)) & 0x3F;
+               a[2]= (((((uint8_t*)src)[i*3+1])<<2) | ((((uint8_t*)src)[i*3+2])>>6)) & 0x3F;
+               a[3]= (((uint8_t*)src)[i*3+2]) & 0x3F;
+               for(j=0; j<4; ++j){
+                       *dest++=bit6toAscii(a[j]);
+               }
+       }
+       /* now we do the rest */
+       switch(length%3){
+               case 0: 
+                       break;
+               case 1:
+                       a[0]=(((uint8_t*)src)[i*3+0])>>2;
+                       a[1]=((((uint8_t*)src)[i*3+0])<<4)&0x3F;
+                       *dest++ = bit6toAscii(a[0]);
+                       *dest++ = bit6toAscii(a[1]);
+                       *dest++ = '=';
+                       *dest++ = '=';
+                       break;
+               case 2:         
+                       a[0]= (((uint8_t*)src)[i*3+0])>>2;
+                       a[1]= (((((uint8_t*)src)[i*3+0])<<4) | ((((uint8_t*)src)[i*3+1])>>4)) & 0x3F;
+                       a[2]= ((((uint8_t*)src)[i*3+1])<<2) & 0x3F;
+                       *dest++ = bit6toAscii(a[0]);
+                       *dest++ = bit6toAscii(a[1]);
+                       *dest++ = bit6toAscii(a[2]);
+                       *dest++ = '=';
+                       break;
+               default: /* this will not happen! */
+                       break;  
+       }
+/*  finalize: */
+       *dest='\0';
+}
+