gobject: Make enum/flags value lookups case-insensitive

Make g_enum_get_value_by_name(), g_flags_get_value_by_name(),
g_enum_get_value_by_nick() and g_flags_get_value_by_nick() perform ASCII
case-insensitive comparisons when matching names and nicks. This aligns
behavior with common expectations for user-visible nicks and reduces
rejections of mixed-case inputs.

Implementation switches from strcmp() to strcmp_ignore_case() when
comparing the provided name/nick to registered values.

This is a minor behavior change that only broadens accepted input. Types
with values that differ only by case are now allowed.

Tests: Extend gobject/tests/enums.c to cover mixed-case lookups for both
enums and flags (names and nicks).

Fixes: #74

gobject/genums.c

@@ -351,6 +351,33 @@ g_flags_class_init (GFlagsClass *class,
     }
 }
 
+/* Internal function to compare strings without taking into account
+ * character case and more... in order to ease the look ups. */
+static int
+strcmp_ignore_case (const char *str1, const char *str2)
+{
+  const char *ptr1 = str1, *ptr2 = str2;
+  char c1, c2;
+
+  do
+    {
+      /* Normalize to lower case */
+      c1 = g_ascii_tolower (*ptr1++);
+      c2 = g_ascii_tolower (*ptr2++);
+
+      /* End of either string */
+      if (c1 == '\0' || c2 == '\0')
+        return c1 - c2;
+
+      /* Normalize '-' to '_' */
+      c1 = (c1 == '-') ? '_' : c1;
+      c2 = (c2 == '-') ? '_' : c2;
+    }
+  while (c1 == c2);
+
+  return c1 - c2;
+}
+
 /**
  * g_enum_get_value_by_name:
  * @enum_class: a #GEnumClass
@@ -374,8 +401,8 @@ g_enum_get_value_by_name (GEnumClass  *enum_class,
       GEnumValue *enum_value;
       
       for (enum_value = enum_class->values; enum_value->value_name; enum_value++)
-	if (strcmp (name, enum_value->value_name) == 0)
-	  return enum_value;
+        if (strcmp_ignore_case (name, enum_value->value_name) == 0)
+          return enum_value;
     }
   
   return NULL;
@@ -403,8 +430,8 @@ g_flags_get_value_by_name (GFlagsClass *flags_class,
       GFlagsValue *flags_value;
       
       for (flags_value = flags_class->values; flags_value->value_name; flags_value++)
-	if (strcmp (name, flags_value->value_name) == 0)
-	  return flags_value;
+        if (strcmp_ignore_case (name, flags_value->value_name) == 0)
+          return flags_value;
     }
   
   return NULL;
@@ -433,8 +460,8 @@ g_enum_get_value_by_nick (GEnumClass  *enum_class,
       GEnumValue *enum_value;
       
       for (enum_value = enum_class->values; enum_value->value_name; enum_value++)
-	if (enum_value->value_nick && strcmp (nick, enum_value->value_nick) == 0)
-	  return enum_value;
+        if (enum_value->value_nick && strcmp_ignore_case (nick, enum_value->value_nick) == 0)
+          return enum_value;
     }
   
   return NULL;
@@ -462,8 +489,8 @@ g_flags_get_value_by_nick (GFlagsClass *flags_class,
       GFlagsValue *flags_value;
       
       for (flags_value = flags_class->values; flags_value->value_nick; flags_value++)
-	if (flags_value->value_nick && strcmp (nick, flags_value->value_nick) == 0)
-	  return flags_value;
+        if (flags_value->value_nick && strcmp_ignore_case (nick, flags_value->value_nick) == 0)
+          return flags_value;
     }
   
   return NULL;

gobject/tests/enums.c

@@ -41,12 +41,14 @@ test_enum_basic (void)
   val = g_enum_get_value_by_name (class, "the third value");
   g_assert_nonnull (val);
   g_assert_cmpint (val->value, ==, 3);
+  g_assert_true (g_enum_get_value_by_name (class, "The Third Value") == val);
   val = g_enum_get_value_by_name (class, "the color purple");
   g_assert_null (val);
 
   val = g_enum_get_value_by_nick (class, "one");
   g_assert_nonnull (val);
   g_assert_cmpint (val->value, ==, 1);
+  g_assert_true (g_enum_get_value_by_nick (class, "One") == val);
   val = g_enum_get_value_by_nick (class, "purple");
   g_assert_null (val);
 
@@ -118,6 +120,7 @@ test_flags_basic (void)
 
   val = g_flags_get_value_by_name (class, "the third flag");
   g_assert_nonnull (val);
+  g_assert_true (g_flags_get_value_by_name (class, "The Third Flag") == val);
   g_assert_cmpint (val->value, ==, 8);
   val = g_flags_get_value_by_name (class, "the color purple");
   g_assert_null (val);
@@ -125,6 +128,7 @@ test_flags_basic (void)
   val = g_flags_get_value_by_nick (class, "one");
   g_assert_nonnull (val);
   g_assert_cmpint (val->value, ==, 1);
+  g_assert_true (g_flags_get_value_by_nick (class, "One") == val);
   val = g_flags_get_value_by_nick (class, "purple");
   g_assert_null (val);