moved string functions to their own file

settings.cpp

@@ -5,17 +5,7 @@
 #include "settings.h"
 
 #include <SD.h>
-
-bool is_whitespace(char const c)
-{
-    return c == ' ' || c == '\t';
-}
-
-bool is_printable(char const c)
-{
-    //cf. ASCII table
-    return c == '\n' || (c >= 0x20 && c <= 0x7E);
-}
+#include "string_helper.h"
 
 Settings::Settings()
 {

string_helper.cpp

@@ -0,0 +1,47 @@
+/**
+ * @file string.cpp
+ * @author n0m1s
+ */
+#include "./string.h"
+
+bool string_starts_by(char const* hay, char const* needle)
+{
+    if(needle == nullptr)
+        return true;
+    if(hay == nullptr)
+        return false;
+
+    for(unsigned int i = 0; needle[i] != '\0'; ++i)
+    {
+        if(hay[i] == '\0')
+            return false;
+        if(hay[i] != needle[i])
+            return false;
+    }
+
+    return true;
+}
+
+bool string_equals(char const* a, char const* b)
+{
+    if(a == nullptr) return b == nullptr;
+    if(b == nullptr) return false;
+
+    unsigned int i = 0;
+    for(; a[i] != '\0' && b[i] != '\0'; ++i)
+        if(a[i] != b[i]) return false;
+
+    //either a or b is finished, so we check that both are
+    return a[i] == b[i];
+}
+
+char* string_copy(char const* s)
+{
+    unsigned int const len = strlen(s)+1;
+
+    char * ret = new char[len];
+    for(unsigned int i = 0; i < len; ++i)
+        ret[i] = s[i];
+
+    return ret;
+}

string_helper.h

@@ -0,0 +1,30 @@
+#ifndef STRING_HELPER_H
+#define STRING_HELPER_H
+
+inline bool is_whitespace(char const c)
+{
+    return c == ' ' || c == '\t';
+}
+
+inline bool is_printable(char const c)
+{
+    //cf. ASCII table
+    return c == '\n' || (c >= 0x20 && c <= 0x7E);
+}
+
+/**
+ * @brief checks that if a string (hay) starts by a prefix (needle)
+ */
+bool string_starts_by(char const* hay, char const* needle);
+
+/**
+ * @brief checks that two strings have the same characters (and no others)
+ */
+bool string_equals(char const* a, char const* b);
+
+/**
+ * @brief copies a string
+ */
+char* string_copy(char const* s);
+
+#endif //STRING_HELPER_H