Diff: embedded/Base64.cpp

Revision:

0:08606a13a816

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/embedded/Base64.cpp	Thu Jun 02 05:04:57 2016 +0000
@@ -0,0 +1,161 @@
+/*
+ * Base64.cpp
+ *
+ *  Created on: 2016/2/24
+ *      Author: D10307009
+ */
+
+//
+// Base64 Encoding and Decoding
+//
+// @note Copyright © 2013 by Smartware Computing, all rights reserved.
+//     Individuals may use this application for evaluation or non-commercial
+//     purposes. Within this restriction, changes may be made to this application
+//     as long as this copyright notice is retained. The user shall make
+//     clear that their work is a derived work, and not the original.
+//     Users of this application and sources accept this application "as is" and
+//     shall hold harmless Smartware Computing, for any undesired results while
+//     using this application - whether real or imagined.
+//
+// author David Smart, Smartware Computing
+//
+#ifndef WIN32
+#include "mbed.h"
+#else
+#include "windows.h"
+typedef unsigned int uint32_t;
+#endif
+#include "Base64.h"
+#include "FATFileSystem.h"
+
+static const char encoding_table[] = { '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 const int mod_table[] = { 0, 2, 1 };
+
+Base64::Base64() {
+	decoding_table = NULL;
+}
+
+Base64::~Base64() {
+	if (decoding_table)
+		free(decoding_table);
+}
+
+char * Base64::Encode(const char *data, size_t input_length,
+		size_t *output_length) {
+	*output_length = 4 * ((input_length + 2) / 3);
+
+	char *encoded_data = (char *) malloc(*output_length + 1); // often used for text, so add room for NULL
+	if (encoded_data == NULL)
+		return NULL;
+
+	for (unsigned int i = 0, j = 0; i < input_length;) {
+
+		uint32_t octet_a = i < input_length ? data[i++] : 0;
+		uint32_t octet_b = i < input_length ? data[i++] : 0;
+		uint32_t octet_c = i < input_length ? data[i++] : 0;
+
+		uint32_t triple = (octet_a << 0x10) + (octet_b << 0x08) + octet_c;
+
+		encoded_data[j++] = encoding_table[(triple >> 3 * 6) & 0x3F];
+		encoded_data[j++] = encoding_table[(triple >> 2 * 6) & 0x3F];
+		encoded_data[j++] = encoding_table[(triple >> 1 * 6) & 0x3F];
+		encoded_data[j++] = encoding_table[(triple >> 0 * 6) & 0x3F];
+	}
+
+	for (int i = 0; i < mod_table[input_length % 3]; i++)
+		encoded_data[*output_length - 1 - i] = '=';
+
+	encoded_data[*output_length] = '\0';    // as a courtesy to text users
+	return encoded_data;
+}
+
+int Base64::Encode(FILE *base, FILE *source) {
+
+	fseek(source, 0, SEEK_END);
+	size_t input_length = ftell(source);
+	fseek(source, 0, SEEK_SET);
+	size_t output_length = 4 * ((input_length + 2) / 3);
+
+	char buff_in[3];
+	char buff_out[4];
+	memset(buff_in, 0, 3);
+
+	size_t ret;
+	while ((ret = fread(buff_in, 1, 3, source)) > 0) {
+
+		uint32_t triple = (buff_in[0] << 0x10) + (buff_in[1] << 0x08)
+				+ buff_in[2];
+
+		buff_out[0] = encoding_table[(triple >> 3 * 6) & 0x3F];
+		buff_out[1] = encoding_table[(triple >> 2 * 6) & 0x3F];
+		buff_out[2] = encoding_table[(triple >> 1 * 6) & 0x3F];
+		buff_out[3] = encoding_table[(triple >> 0 * 6) & 0x3F];
+
+		fwrite(buff_out, 1, 4, base);
+		memset(buff_in, 0, 3);
+	}
+
+	memcpy(buff_out, "===", 3);
+	long int mt = mod_table[input_length % 3];
+	fseek(base, mt*-1, SEEK_CUR);
+	fwrite(buff_out, 1, mt, base);
+
+	return 0;
+}
+
+char * Base64::Decode(const char *data, size_t input_length,
+		size_t *output_length) {
+	if (decoding_table == NULL)
+		build_decoding_table();
+
+	if (input_length % 4 != 0)
+		return NULL;
+
+	*output_length = input_length / 4 * 3;
+	if (data[input_length - 1] == '=')
+		(*output_length)--;
+	if (data[input_length - 2] == '=')
+		(*output_length)--;
+
+	char *decoded_data = (char *) malloc(*output_length + 1); // often used for text, so add room for NULL
+	if (decoded_data == NULL)
+		return NULL;
+
+	for (unsigned int i = 0, j = 0; i < input_length;) {
+
+		uint32_t sextet_a =
+				data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
+		uint32_t sextet_b =
+				data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
+		uint32_t sextet_c =
+				data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
+		uint32_t sextet_d =
+				data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
+
+		uint32_t triple = (sextet_a << 3 * 6) + (sextet_b << 2 * 6)
+				+ (sextet_c << 1 * 6) + (sextet_d << 0 * 6);
+
+		if (j < *output_length)
+			decoded_data[j++] = (triple >> 2 * 8) & 0xFF;
+		if (j < *output_length)
+			decoded_data[j++] = (triple >> 1 * 8) & 0xFF;
+		if (j < *output_length)
+			decoded_data[j++] = (triple >> 0 * 8) & 0xFF;
+	}
+	decoded_data[*output_length] = '\0';    // as a courtesy to text users
+	return decoded_data;
+}
+
+void Base64::build_decoding_table() {
+	decoding_table = (char *) malloc(256);
+
+	for (int i = 0; i < 64; i++)
+		decoding_table[(unsigned char) encoding_table[i]] = i;
+}
+
+