helpers.cpp: Add itoa() function

Origin commit data
------------------
Commit: 38470a8a80
Author: Michael Liebmann <tuxcode.bbg@gmail.com>
Date: 2016-09-03 (Sat, 03 Sep 2016)

src/system/helpers.cpp

@@ -951,6 +951,38 @@ std::string to_string(unsigned long long i)
 	return s.str();
 }
 
+/**
+ * C++ version 0.4 std::string style "itoa":
+ * Contributions from Stuart Lowe, Ray-Yuan Sheu,
+
+ * Rodrigo de Salvo Braz, Luc Gallant, John Maloney
+ * and Brian Hunt
+ */
+std::string itoa(int value, int base)
+{
+	std::string buf;
+
+	// check that the base if valid
+	if (base < 2 || base > 16) return buf;
+
+	enum { kMaxDigits = 35 };
+	buf.reserve( kMaxDigits ); // Pre-allocate enough space.
+
+	int quotient = value;
+
+	// Translating number to string with base:
+	do {
+		buf += "0123456789abcdef"[ std::abs( quotient % base ) ];
+		quotient /= base;
+	} while ( quotient );
+
+	// Append the negative sign
+	if ( value < 0) buf += '-';
+
+	std::reverse( buf.begin(), buf.end() );
+	return buf;
+}
+
 std::string getJFFS2MountPoint(int mtdPos)
 {
 	FILE* fd = fopen("/proc/mounts", "r");

src/system/helpers.h

@@ -105,6 +105,8 @@ std::string to_string(unsigned long);
 std::string to_string(long long);
 std::string to_string(unsigned long long);
 
+std::string itoa(int value, int base);
+
 inline int atoi(std::string &s) { return atoi(s.c_str()); }
 inline int atoi(const std::string &s) { return atoi(s.c_str()); }
 inline int access(std::string &s, int mode) { return access(s.c_str(), mode); }