Add strtof native (bug 5909, r=Nextra)

plugins/include/string.inc

@@ -109,7 +109,7 @@ native str_to_num(const string[]);
  * @param string    The string to parse.
  * @param endPos    The position of the first character following the number.
  *                  On success and when containing only numbers, position is at the end of string, meaning equal to 'string' length.
- *                  On failure, position is sets always to -1.
+ *                  On failure, position is sets always to 0.
  * @param base      The numerical base (radix) that determines the valid characters and their interpretation.
  *                  If this is 0, the base used is determined by the format in the sequence.
  * @return          On success, the function returns the converted integral number as integer value.
@@ -117,7 +117,32 @@ native str_to_num(const string[]);
  *                  If the value read is out of the range of representable values by a cell, 
  *                  the function returns 'cellmin' or 'cellmax'.
  */
-native strtol(const string[], &endPos = -1, base = 0);
+native strtol(const string[], &endPos = 0, base = 0);
+
+/**
+ * Parses the 'string' interpreting its content as an floating point number and returns its value as a float.
+ * The function also sets the value of 'endPos' to point to the position of the first character after the number.
+ * 
+ * This is the same as C++ strtod function with a difference on second param.
+ * 
+ * The function first discards as many whitespace characters as necessary until the first 
+ * non-whitespace character is found. Then, starting from this character, takes as many 
+ * characters as possible that are valid and interprets them as a numerical value. 
+ * Finally, a position of the first character following the float representation in 'string' 
+ * is stored in 'endPos'.
+ * 
+ * If the first sequence of non-whitespace characters in 'string' is not a valid float number
+ * as defined above, or if no such sequence exists because either 'string' is empty or it contains
+ * only whitespace characters, no conversion is performed.
+ *
+ * @param string    The string to parse.
+ * @param endPos    The position of the first character following the number.
+ *                  On success and when containing only numbers, position is at the end of string, meaning equal to 'string' length.
+ *                  On failure, position is sets always to 0.
+ * @return          On success, the function returns the converted floating point number as float value.
+ *                  If no valid conversion could be performed, a zero value is returned.
+ */
+native Float:strtof(const string[], &endPos = 0);
 
 /* Converts float to string. */
 native float_to_str(Float:fl, string[], len);