--- /dev/null
+/* base64_dec.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 decoder (RFC3548)
+ * Author: Daniel Otte
+ * License: GPLv3
+ *
+ *
+ */
+
+#include <stdint.h>
+#include "base64_dec.h"
+
+#include "test_src/cli.h"
+
+/*
+ #define USE_GCC_EXTENSION
+*/
+#if 1
+
+#ifdef USE_GCC_EXTENSION
+
+static
+int ascii2bit6(char a){
+ switch(a){
+ case 'A'...'Z':
+ return a-'A';
+ case 'a'...'z':
+ return a-'a'+26;
+ case '0'...'9':
+ return a-'0'+52;
+ case '+':
+ case '-':
+ return 62;
+ case '/':
+ case '_':
+ return 63;
+ default:
+ return -1;
+ }
+}
+
+#else
+
+static
+uint8_t ascii2bit6(char a){
+ int r;
+ switch(a>>4){
+ case 0x5:
+ case 0x4:
+ r=a-'A';
+ if(r<0 || r>25){
+ return -1;
+ } else {
+ return r;
+ }
+ case 0x7:
+ case 0x6:
+ r=a-'a';
+ if(r<0 || r>25){
+ return -1;
+ } else {
+ return r+26;
+ }
+ break;
+ case 0x3:
+ if(a>'9')
+ return -1;
+ return a-'0'+52;
+ default:
+ break;
+ }
+ switch (a){
+ case '+':
+ case '-':
+ return 62;
+ case '/':
+ case '_':
+ return 63;
+ default:
+ return 0xff;
+ }
+}
+
+#endif
+
+#else
+
+static
+uint8_t ascii2bit6(uint8_t a){
+ if(a>='A' && a<='Z'){
+ return a-'A';
+ } else {
+ if(a>='a' && a<= 'z'){
+ return a-'a'+26;
+ } else {
+ if(a>='0' && a<='9'){
+ return a-'0'+52;
+ } else {
+ if(a=='+' || a=='-'){
+ return 62;
+ } else {
+ if(a=='/' || a=='_'){
+ return 63;
+ } else {
+ return 0xff;
+ }
+ }
+ }
+ }
+ }
+}
+
+#endif
+
+int base64_binlength(char* str, uint8_t strict){
+ int l=0;
+ uint8_t term=0;
+ for(;;){
+ if(*str=='\0')
+ break;
+ if(*str=='\n' || *str=='\r'){
+ str++;
+ continue;
+ }
+ if(*str=='='){
+ term++;
+ str++;
+ if(term==2){
+ break;
+ }
+ continue;
+ }
+ if(term)
+ return -1;
+ if(ascii2bit6(*str)==-1){
+ if(strict)
+ return -1;
+ } else {
+ l++;
+ }
+ str++;
+ }
+ switch(term){
+ case 0:
+ if(l%4!=0)
+ return -1;
+ return l/4*3;
+ case 1:
+ if(l%4!=3)
+ return -1;
+ return (l+1)/4*3-1;
+ case 2:
+ if(l%4!=2)
+ return -1;
+ return (l+2)/4*3-2;
+ default:
+ return -1;
+ }
+}
+
+/*
+ |543210543210543210543210|
+ |765432107654321076543210|
+
+ . . . .
+ |54321054|32105432|10543210|
+ |76543210|76543210|76543210|
+
+*/
+
+int base64dec(void* dest, char* b64str, uint8_t strict){
+ uint8_t buffer[4];
+ uint8_t idx=0;
+ uint8_t term=0;
+ for(;;){
+// cli_putstr_P(PSTR("\r\n DBG: got 0x"));
+// cli_hexdump(b64str, 1);
+ buffer[idx]= ascii2bit6(*b64str);
+// cli_putstr_P(PSTR(" --> 0x"));
+// cli_hexdump(buffer+idx, 1);
+
+ if(buffer[idx]==0xFF){
+ if(*b64str=='='){
+ term++;
+ b64str++;
+ if(term==2)
+ goto finalize; /* definitly the end */
+ }else{
+ if(*b64str == '\0'){
+ goto finalize; /* definitly the end */
+ }else{
+ if(*b64str == '\r' || *b64str == '\n' || !(strict)){
+ b64str++; /* charcters that we simply ignore */
+ }else{
+ return -1;
+ }
+ }
+ }
+ }else{
+ if(term)
+ return -1; /* this happens if we get a '=' in the stream */
+ idx++;
+ b64str++;
+ }
+ if(idx==4){
+ ((uint8_t*)dest)[0] = buffer[0]<<2 | buffer[1]>>4;
+ ((uint8_t*)dest)[1] = buffer[1]<<4 | buffer[2]>>2;
+ ((uint8_t*)dest)[2] = buffer[2]<<6 | buffer[3];
+ dest = (uint8_t*)dest +3;
+ idx=0;
+ }
+ }
+ finalize:
+ /* the final touch */
+ if(idx==0)
+ return 0;
+ if(term==1){
+ ((uint8_t*)dest)[0] = buffer[0]<<2 | buffer[1]>>4;
+ ((uint8_t*)dest)[1] = buffer[1]<<4 | buffer[2]>>2;
+ return 0;
+ }
+ if(term==2){
+ ((uint8_t*)dest)[0] = buffer[0]<<2 | buffer[1]>>4;
+ return 0;
+ }
+ return -1;
+}
projects / avr-crypto-lib.git / blobdiff