base: use reference for ascii_to output argument

Issue #1477

repos/base/include/util/string.h

@@ -27,7 +27,7 @@ namespace Genode {
 
 
 /**
- * Wrapper of 'size_t' for selecting 'ascii_to' specialization
+ * Wrapper of 'size_t' for selecting the 'ascii_to' function to parse byte values
  */
 class Genode::Number_of_bytes
 {
@@ -266,8 +266,18 @@ namespace Genode {
 
 	/**
 	 * Read unsigned long value from string
+	 *
+	 * \param s       source string
+	 * \param result  destination variable
+	 * \param base    integer base
+	 * \return        number of consumed characters
+	 *
+	 * If the base argument is 0, the integer base is detected based on the
+	 * characters in front of the number. If the number is prefixed with "0x",
+	 * a base of 16 is used, otherwise a base of 10.
 	 */
-	inline size_t ascii_to(const char *s, unsigned long *result, unsigned base = 0)
+	inline size_t ascii_to_unsigned_long(const char *s, unsigned long &result,
+	                                     unsigned base)
 	{
 		unsigned long i = 0, value = 0;
 
@@ -294,27 +304,42 @@ namespace Genode {
 			value = value*base + d;
 		}
 
-		*result = value;
+		result = value;
 		return i;
 	}
 
 
 	/**
-	 * Read unsigned int value from string
+	 * Read unsigned long value from string
+	 *
+	 * \return number of consumed characters
 	 */
-	inline size_t ascii_to(const char *s, unsigned int *result, unsigned base = 10)
+	inline size_t ascii_to(const char *s, unsigned long &result)
+	{
+		return ascii_to_unsigned_long(s, result, 0);
+	}
+
+
+	/**
+	 * Read unsigned int value from string
+	 *
+	 * \return number of consumed characters
+	 */
+	inline size_t ascii_to(const char *s, unsigned int &result)
 	{
 		unsigned long result_long = 0;
-		size_t ret = ascii_to(s, &result_long, base);
-		*result = result_long;
+		size_t ret = ascii_to_unsigned_long(s, result_long, 0);
+		result = result_long;
 		return ret;
 	}
 
 
 	/**
 	 * Read signed long value from string
+	 *
+	 * \return number of consumed characters
 	 */
-	inline size_t ascii_to(const char *s, long *result, unsigned base = 10)
+	inline size_t ascii_to(const char *s, long &result)
 	{
 		int i = 0;
 
@@ -326,11 +351,11 @@ namespace Genode {
 		int j = 0;
 		unsigned long value = 0;
 
-		j = ascii_to(s, &value, base);
+		j = ascii_to_unsigned_long(s, value, 10);
 
 		if (!j) return i;
 
-		*result = sign*value;
+		result = sign*value;
 		return i + j;
 	}
 
@@ -340,13 +365,15 @@ namespace Genode {
 	 *
 	 * This function scales the resulting size value according to the suffixes
 	 * for G (2^30), M (2^20), and K (2^10) if present.
+	 *
+	 * \return number of consumed characters
 	 */
-	inline size_t ascii_to(const char *s, Number_of_bytes *result, unsigned base = 0)
+	inline size_t ascii_to(const char *s, Number_of_bytes &result)
 	{
 		unsigned long res = 0;
 
 		/* convert numeric part of string */
-		int i = ascii_to(s, &res, 0);
+		int i = ascii_to_unsigned_long(s, res, 0);
 
 		/* handle suffixes */
 		if (i > 0)
@@ -357,15 +384,17 @@ namespace Genode {
 			default: break;
 			}
 
-		*result = res;
+		result = res;
 		return i;
 	}
 
 
 	/**
 	 * Read double float value from string
+	 *
+	 * \return number of consumed characters
 	 */
-	inline size_t ascii_to(const char *s, double *result, unsigned base = 0)
+	inline size_t ascii_to(const char *s, double &result)
 	{
 		double v = 0.0;    /* decimal part              */
 		double d = 0.1;    /* power of fractional digit */
@@ -383,7 +412,7 @@ namespace Genode {
 
 		/* if no fractional part exists, return current value */
 		if (s[i] != '.') {
-			*result = neg ? -v : v;
+			result = neg ? -v : v;
 			return i;
 		}
 
@@ -394,7 +423,7 @@ namespace Genode {
 		for (; s[i] && is_digit(s[i]); i++, d *= 0.1)
 			v += d*digit(s[i], false);
 
-		*result = neg ? -v : v;
+		result = neg ? -v : v;
 		return i;
 	}