Initial

src/wrapper/base64_wrapper.cpp

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+/*
+Copyright (C) 2016 Arturo Guadalupi. All right reserved.
+
+This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.
+
+This library 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 Lesser General Public License for more details.
+*/
+
+#include <Arduino.h>
+#include "base64_wrapper.h"
+#if (defined(__AVR__))
+#include <avr/pgmspace.h>
+#else
+#include <pgmspace.h>
+#endif
+
+const char PROGMEM _Base64AlphabetTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+		"abcdefghijklmnopqrstuvwxyz"
+		"0123456789+/";
+
+int Base64Class::encode(char *output, char *input, int inputLength) {
+	int i = 0, j = 0;
+	int encodedLength = 0;
+	unsigned char A3[3];
+	unsigned char A4[4];
+
+	while(inputLength--) {
+		A3[i++] = *(input++);
+		if(i == 3) {
+			fromA3ToA4(A4, A3);
+
+			for(i = 0; i < 4; i++) {
+				output[encodedLength++] = pgm_read_byte(&_Base64AlphabetTable[A4[i]]);
+			}
+
+			i = 0;
+		}
+	}
+
+	if(i) {
+		for(j = i; j < 3; j++) {
+			A3[j] = '\0';
+		}
+
+		fromA3ToA4(A4, A3);
+
+		for(j = 0; j < i + 1; j++) {
+			output[encodedLength++] = pgm_read_byte(&_Base64AlphabetTable[A4[j]]);
+		}
+
+		while((i++ < 3)) {
+			output[encodedLength++] = '=';
+		}
+	}
+	output[encodedLength] = '\0';
+	return encodedLength;
+}
+
+int Base64Class::decode(char * output, char * input, int inputLength) {
+	int i = 0, j = 0;
+	int decodedLength = 0;
+	unsigned char A3[3];
+	unsigned char A4[4];
+
+
+	while (inputLength--) {
+		if(*input == '=') {
+			break;
+		}
+
+		A4[i++] = *(input++);
+		if (i == 4) {
+			for (i = 0; i <4; i++) {
+				A4[i] = lookupTable(A4[i]);
+			}
+
+			fromA4ToA3(A3,A4);
+
+			for (i = 0; i < 3; i++) {
+				output[decodedLength++] = A3[i];
+			}
+			i = 0;
+		}
+	}
+
+	if (i) {
+		for (j = i; j < 4; j++) {
+			A4[j] = '\0';
+		}
+
+		for (j = 0; j <4; j++) {
+			A4[j] = lookupTable(A4[j]);
+		}
+
+		fromA4ToA3(A3,A4);
+
+		for (j = 0; j < i - 1; j++) {
+			output[decodedLength++] = A3[j];
+		}
+	}
+	output[decodedLength] = '\0';
+	return decodedLength;
+}
+
+int Base64Class::encodedLength(int plainLength) {
+	int n = plainLength;
+	return (n + 2 - ((n + 2) % 3)) / 3 * 4;
+}
+
+int Base64Class::decodedLength(char * input, int inputLength) {
+	int i = 0;
+	int numEq = 0;
+	for(i = inputLength - 1; input[i] == '='; i--) {
+		numEq++;
+	}
+
+	return ((6 * inputLength) / 8) - numEq;
+}
+
+//Private utility functions
+inline void Base64Class::fromA3ToA4(unsigned char * A4, unsigned char * A3) {
+	A4[0] = (A3[0] & 0xfc) >> 2;
+	A4[1] = ((A3[0] & 0x03) << 4) + ((A3[1] & 0xf0) >> 4);
+	A4[2] = ((A3[1] & 0x0f) << 2) + ((A3[2] & 0xc0) >> 6);
+	A4[3] = (A3[2] & 0x3f);
+}
+
+inline void Base64Class::fromA4ToA3(unsigned char * A3, unsigned char * A4) {
+	A3[0] = (A4[0] << 2) + ((A4[1] & 0x30) >> 4);
+	A3[1] = ((A4[1] & 0xf) << 4) + ((A4[2] & 0x3c) >> 2);
+	A3[2] = ((A4[2] & 0x3) << 6) + A4[3];
+}
+
+inline unsigned char Base64Class::lookupTable(char c) {
+	if(c >='A' && c <='Z') return c - 'A';
+	if(c >='a' && c <='z') return c - 71;
+	if(c >='0' && c <='9') return c + 4;
+	if(c == '+') return 62;
+	if(c == '/') return 63;
+	return -1;
+}
+
+Base64Class Base64;