Add Int8 support (since gdal>=3.7.0)

doc_test.go

@@ -289,6 +289,19 @@ func Example_rasterTutorial() {
 	poDstDS.Bands()[0].Write(0, 0, abyRaster, 512, 512)
 	poDstDS.Close()
 
+	poDstDSInt8, err := godal.Create(godal.GTiff, pszDstFilename, 1, godal.Int8, 512, 512)
+	if godal.CheckMinVersion(3, 7, 0) {
+		if err != nil {
+			panic(err)
+		}
+		defer poDstDSInt8.Close() //Close can be defered / called more than once (second+ calls are no-ops)
+
+		// ... now populate with data
+		poDstDSInt8.Bands()[0].Write(0, 0, abyRaster, 512, 512)
+		poDstDSInt8.Close()
+	} else if err == nil {
+		panic("godal.Int8 is not supported with GDAL<3.7.0, but godal.Create returns no error")
+	}
 	// Output:
 	// Size is 10x10x3
 	// Projection is 'GEOGCS["WGS 84",DATU...'

godal.go

@@ -45,6 +45,9 @@ const (
 	Byte = DataType(C.GDT_Byte)
 	//UInt16 DataType
 	UInt16 = DataType(C.GDT_UInt16)
+	//Int8 DataType (GDAL>=3.7.0)
+	// [RFC 87]: https://gdal.org/development/rfc/rfc87_signed_int8.html
+	Int8 = DataType(C.GDT_Int8)
 	//Int16 DataType
 	Int16 = DataType(C.GDT_Int16)
 	//UInt32 DataType
@@ -89,7 +92,7 @@ func (dtype DataType) String() string {
 // Size retruns the number of bytes needed for one instance of DataType
 func (dtype DataType) Size() int {
 	switch dtype {
-	case Byte:
+	case Byte, Int8:
 		return 1
 	case Int16, UInt16:
 		return 2
@@ -1780,6 +1783,8 @@ func bufferType(buffer interface{}) DataType {
 	switch buffer.(type) {
 	case []byte:
 		return Byte
+	case []int8:
+		return Int8
 	case []int16:
 		return Int16
 	case []uint16:
@@ -1813,6 +1818,9 @@ func cBuffer(buffer interface{}, minsize int) unsafe.Pointer {
 	case []byte:
 		sizecheck(len(buf))
 		return unsafe.Pointer(&buf[0])
+	case []int8:
+		sizecheck(len(buf))
+		return unsafe.Pointer(&buf[0])
 	case []int16:
 		sizecheck(len(buf))
 		return unsafe.Pointer(&buf[0])

godal.h

@@ -25,6 +25,10 @@
 
 #if GDAL_VERSION_NUM < 3000000
 	#error "this code is only compatible with gdal version >= 3.0"
+#elif GDAL_VERSION_NUM < GDAL_COMPUTE_VERSION(3, 7, 0)
+typedef enum {
+    /*! 8-bit signed integer (GDAL >= 3.7) */ GDT_Int8 = 14
+} FutureGDALDataType;
 #endif
 
 #ifdef __cplusplus

godal_test.go

@@ -77,6 +77,12 @@ func TestCBuffer(t *testing.T) {
 	assert.Equal(t, 1, bufferType(buf).Size())
 	assert.Panics(t, func() { cBuffer(buf, 101) })
 
+	buf = make([]int8, 100)
+	_ = cBuffer(buf, 100)
+	assert.Equal(t, Int8, bufferType(buf))
+	assert.Equal(t, 1, bufferType(buf).Size())
+	assert.Panics(t, func() { cBuffer(buf, 101) })
+
 	buf = make([]int16, 100)
 	_ = cBuffer(buf, 100)
 	assert.Equal(t, Int16, bufferType(buf))