Keymap: Add a method to get modified characters for a key

This method fills out the passed-in BList of modified utf-8 characters for
a given utf-8 character and set of modifiers.

For example if you pass in "=" and B_SHIFT_KEY the list will get filled
out with each character in the shift map that has "=" in the normal map.

Each supported keymap modifier combination is available.

The reason this is useful will soon become apparent.

A BList is used because the character might be mapped multiple times,
for example if you have a Mac keyboard you've got two "=" keys, one in
0x1d and one in 0x6a.

The caller is responsible for creating the BList and destroying it as well as
freeing the resulting character strings.

headers/private/shared/Keymap.h

@@ -14,6 +14,8 @@
 #include <InterfaceDefs.h>
 
 
+class BList;
+
 class BKeymap {
 public:
 								BKeymap();
@@ -38,6 +40,9 @@ public:
 			void				GetChars(uint32 keyCode, uint32 modifiers,
 									uint8 activeDeadKey, char** chars,
 									int32* numBytes) const;
+			status_t			GetModifiedCharacters(const char* normal,
+									int32 modifiers,
+									BList* _modifiedCharacters);
 
 			const key_map&		Map() const { return fKeys; }
 

src/kits/shared/Keymap.cpp

@@ -19,6 +19,7 @@
 
 #include <ByteOrder.h>
 #include <File.h>
+#include <List.h>
 
 #ifdef HAIKU_TARGET_PLATFORM_HAIKU
 #	include "SystemKeymap.h"
@@ -441,6 +442,60 @@ BKeymap::GetChars(uint32 keyCode, uint32 modifiers, uint8 activeDeadKey,
 }
 
 
+status_t
+BKeymap::GetModifiedCharacters(const char* normal, int32 modifiers,
+	BList* _modifiedCharacters)
+{
+	if (normal == NULL || strcmp(normal, "") == 0
+		|| _modifiedCharacters == NULL) {
+		return B_BAD_VALUE;
+	}
+
+	int32 normalOffset;
+	int32 modifiedOffset;
+
+	for(uint32 i = 0; i < 128; i++) {
+		normalOffset = fKeys.normal_map[i];
+		size_t sizeNormal = fChars[normalOffset++];
+		if (sizeNormal == 0
+			|| memcmp(normal, fChars + normalOffset, sizeNormal) != 0) {
+			// this character isn't mapped or doesn't match
+			continue;
+		}
+
+		if (modifiers == B_SHIFT_KEY)
+			modifiedOffset = fKeys.shift_map[i];
+		else if (modifiers == B_CONTROL_KEY)
+			modifiedOffset = fKeys.control_map[i];
+		else if (modifiers == B_OPTION_KEY)
+			modifiedOffset = fKeys.option_map[i];
+		else if (modifiers == (B_OPTION_KEY | B_SHIFT_KEY))
+			modifiedOffset = fKeys.option_shift_map[i];
+		else if (modifiers == B_CAPS_LOCK)
+			modifiedOffset = fKeys.caps_map[i];
+		else if (modifiers == (B_CAPS_LOCK | B_SHIFT_KEY))
+			modifiedOffset = fKeys.caps_shift_map[i];
+		else if (modifiers == (B_OPTION_KEY | B_CAPS_LOCK))
+			modifiedOffset = fKeys.option_caps_map[i];
+		else if (modifiers == (B_OPTION_KEY | B_CAPS_LOCK | B_SHIFT_KEY))
+			modifiedOffset = fKeys.option_caps_shift_map[i];
+		else
+			return B_BAD_VALUE;
+
+		size_t sizeModified = fChars[modifiedOffset++];
+		char* modified = (char*)malloc(sizeModified + 1);
+		if (modified == NULL)
+			return B_NO_MEMORY;
+
+		memcpy(modified, fChars + modifiedOffset, sizeModified);
+		modified[sizeModified] = '\0';
+		_modifiedCharacters->AddItem(modified);
+	}
+
+	return B_OK;
+}
+
+
 bool
 BKeymap::operator==(const BKeymap& other) const
 {