X-Git-Url: https://git.cryptolib.org/?a=blobdiff_plain;ds=sidebyside;f=hmac-md5%2Fbase64_dec.c;fp=hmac-md5%2Fbase64_dec.c;h=f057f54f1c4b4cdf8f129f4e1461b9dafaad3f41;hb=d32eba56ce10ea6b9eff123b50d9842673b38f2b;hp=0000000000000000000000000000000000000000;hpb=8f855d283a31a468ea014774c4723a8b77b81644;p=avr-crypto-lib.git

diff --git a/hmac-md5/base64_dec.c b/hmac-md5/base64_dec.c
new file mode 100644
index 0000000..f057f54
--- /dev/null
+++ b/hmac-md5/base64_dec.c
@@ -0,0 +1,246 @@
+/* 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;
+}