helpers.cpp: Add new functions

- readFile()
 - parseJsonFromFile()
 - parseJsonFromString()

 parseJsonFromString() and parseJsonFromFile() use Json::CharReader
 instead of the obsolete function Json::Reader


Origin commit data
------------------
Commit: 05d8ed4105
Author: Michael Liebmann <tuxcode.bbg@gmail.com>
Date: 2017-09-19 (Tue, 19 Sep 2017)

Origin message was:
------------------
helpers.cpp: Add new functions

 - readFile()
 - parseJsonFromFile()
 - parseJsonFromString()

 parseJsonFromString() and parseJsonFromFile() use Json::CharReader
 instead of the obsolete function Json::Reader

src/system/helpers-json.h

@@ -0,0 +1,31 @@
+#ifndef __system_helpers_json__
+#define __system_helpers_json__
+
+/*
+	Neutrino-HD
+
+	License: GPL
+
+	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 2 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, write to the Free Software
+	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include <json/json.h>
+
+using namespace std;
+
+bool parseJsonFromFile(string& jFile, Json::Value *root, string *errMsg);
+bool parseJsonFromString(string& jData, Json::Value *root, string *errMsg);
+
+#endif

src/system/helpers.cpp

@@ -42,6 +42,7 @@
 #include <stdarg.h>
 #include <algorithm>
 #include <mntent.h>
+#include <fstream>
 #include <linux/hdreg.h>
 #include <linux/fs.h>
 #include "debug.h"
@@ -49,6 +50,7 @@
 #include <driver/fontrenderer.h>
 //#include <driver/framebuffer.h>
 #include <system/helpers.h>
+#include <system/helpers-json.h>
 #include <gui/update_ext.h>
 #include <libmd5sum.h>
 #define MD5_DIGEST_LENGTH 16
@@ -1445,3 +1447,51 @@ string readLink(string lnk)
 
 	return "";
 }
+
+string readFile(string file)
+{
+	string ret_s;
+	ifstream tmpData(file.c_str(), ifstream::binary);
+	if (tmpData.is_open()) {
+		tmpData.seekg(0, tmpData.end);
+		int length = tmpData.tellg();
+		tmpData.seekg(0, tmpData.beg);
+		char* buffer = new char[length+1];
+		tmpData.read(buffer, length);
+		tmpData.close();
+		buffer[length] = '\0';
+		ret_s = (string)buffer;
+		delete [] buffer;
+	}
+	else {
+		cerr << "Error read " << file << endl;
+		return "";
+	}
+
+	return ret_s;
+}
+
+bool parseJsonFromFile(string& jFile, Json::Value *root, string *errMsg)
+{
+	string jData = readFile(jFile);
+	bool ret = parseJsonFromString(jData, root, errMsg);
+	jData.clear();
+	return ret;
+}
+
+bool parseJsonFromString(string& jData, Json::Value *root, string *errMsg)
+{
+	Json::CharReaderBuilder builder;
+	Json::CharReader* reader(builder.newCharReader());
+	JSONCPP_STRING errs = "";
+	const char* jData_c = jData.c_str();
+
+	bool ret = reader->parse(jData_c, jData_c + strlen(jData_c), root, &errs);
+	if (!ret || (!errs.empty())) {
+		ret = false;
+		if (errMsg != NULL)
+			*errMsg = errs;
+	}
+	delete reader;
+	return ret;
+}

src/system/helpers.h

@@ -152,4 +152,6 @@ std::string filehash(const char * file);
 std::string get_path(const char * path);
 inline bool file_exists(const std::string file) { return file_exists(file.c_str()); }
 
+std::string readFile(std::string file);
+
 #endif