Merge pull request #8 from inkyblackness/master

Sync with upstream

AllocatedGlyphRanges.go

@@ -31,7 +31,7 @@ func (builder *GlyphRangesBuilder) Build() AllocatedGlyphRanges {
 	const uint16PerRangeEntry = 2
 	ranges := builder.mergedRanges()
 	raw := C.malloc(C.size_t(bytesPerUint16 * ((len(ranges) * uint16PerRangeEntry) + 1)))
-	rawSlice := (*[1 << 30]uint16)(raw)[:]
+	rawSlice := ptrToUint16Slice(raw)
 	outIndex := 0
 	for _, r := range ranges {
 		rawSlice[outIndex+0] = r.from

CONTRIBUTING.md

@@ -21,6 +21,9 @@ If you can and want to make use of this library in your own projects, you are ha
 * Public Go API is documented. Copied documentation from **Dear ImGui** is acceptable and recommended, assuming it is adapted regarding type names. If there is no documentation in the original, try to spend some time figuring it out. In any case, please make the comments readable as complete English sentences, as recommended by Go.
 * API and version philosophies are respected (see README.md)
 
+_Ideally_, please also extend the demo window(s) of [inkyblackness/imgui-go-examples](https://github.com/inkyblackness/imgui-go-examples) - see `internal/demo/Window.go`.
+This way we also grow a Go-based demonstrator. 
+
 #### Clarification on API naming and signatures
 
 If a **Dear ImGui** function has the signature of

FontAtlas.go

@@ -103,9 +103,9 @@ func (atlas FontAtlas) AddFontFromMemoryTTFV(
 	}
 
 	fontDataC := C.malloc(C.size_t(len(fontData)))
-	cBuf := (*[1 << 30]byte)(fontDataC)
+	cBuf := ptrToByteSlice(fontDataC)
 
-	copy(cBuf[:], fontData)
+	copy(cBuf, fontData)
 
 	fontHandle := C.iggAddFontFromMemoryTTF(atlas.handle(), (*C.char)(fontDataC), C.int(len(fontData)), C.float(sizePixels),
 		config.handle(), glyphRange.handle())

GlyphRanges.go

@@ -21,7 +21,7 @@ func (glyphs GlyphRanges) extract() (result []glyphRange) {
 	if glyphs == 0 {
 		return
 	}
-	rawSlice := (*[1 << 30]uint16)(unsafe.Pointer(glyphs.handle()))[:]
+	rawSlice := ptrToUint16Slice(unsafe.Pointer(glyphs.handle()))
 	index := 0
 	// iterate until end of list or an arbitrary paranoia limit, should the list not be proper.
 	for (rawSlice[index] != 0) && (index < 1000) {

InputTextCallbackData.go

@@ -125,7 +125,7 @@ func (data InputTextCallbackData) Buffer() []byte {
 		return nil
 	}
 	textLen := data.bufTextLen()
-	return ((*[1 << 30]byte)(unsafe.Pointer(ptr)))[:textLen]
+	return ptrToByteSlice(unsafe.Pointer(ptr))[:textLen]
 }
 
 // MarkBufferModified indicates that the content of the buffer was modified during a callback.

WrapperConverter.go

@@ -77,8 +77,9 @@ func newStringBuffer(initialValue string) *stringBuffer {
 	bufSize := len(rawText) + 1
 	newPtr := C.malloc(C.size_t(bufSize))
 	zeroOffset := bufSize - 1
-	copy(((*[1 << 30]byte)(newPtr))[:zeroOffset], rawText)
-	((*[1 << 30]byte)(newPtr))[zeroOffset] = 0
+	buf := ptrToByteSlice(newPtr)
+	copy(buf[:zeroOffset], rawText)
+	buf[zeroOffset] = 0
 
 	return &stringBuffer{ptr: newPtr, size: bufSize}
 }
@@ -101,7 +102,7 @@ func (buf *stringBuffer) resizeTo(requestedSize int) {
 	if copySize > 0 {
 		C.memcpy(newPtr, buf.ptr, C.size_t(copySize))
 	}
-	((*[1 << 30]byte)(newPtr))[bufSize-1] = 0
+	ptrToByteSlice(newPtr)[bufSize-1] = 0
 	C.free(buf.ptr)
 	buf.ptr = newPtr
 	buf.size = bufSize
@@ -111,6 +112,21 @@ func (buf stringBuffer) toGo() string {
 	if (buf.ptr == nil) || (buf.size < 1) {
 		return ""
 	}
-	((*[1 << 30]byte)(buf.ptr))[buf.size-1] = 0
+	ptrToByteSlice(buf.ptr)[buf.size-1] = 0
 	return C.GoString((*C.char)(buf.ptr))
 }
+
+// unrealisticLargePointer is used to cast an arbitrary native pointer to a slice.
+// Its value is chosen to fit into a 32bit architecture, and still be large
+// enough to cover "any" data blob. Note that this value is in bytes.
+// Should an array of larger primitives be addressed, be sure to divide the value
+// by the size of the elements.
+const unrealisticLargePointer = 1 << 30
+
+func ptrToByteSlice(p unsafe.Pointer) []byte {
+	return (*[unrealisticLargePointer]byte)(p)[:]
+}
+
+func ptrToUint16Slice(p unsafe.Pointer) []uint16 {
+	return (*[unrealisticLargePointer / 2]uint16)(p)[:]
+}