Add compress and image to core.

core/compress/gzip/example.odin

@@ -0,0 +1,70 @@
+//+ignore
+package gzip
+
+import "core:compress/gzip"
+import "core:bytes"
+import "core:os"
+
+// Small GZIP file with fextra, fname and fcomment present.
+@private
+TEST: []u8 = {
+	0x1f, 0x8b, 0x08, 0x1c, 0xcb, 0x3b, 0x3a, 0x5a,
+	0x02, 0x03, 0x07, 0x00, 0x61, 0x62, 0x03, 0x00,
+	0x63, 0x64, 0x65, 0x66, 0x69, 0x6c, 0x65, 0x6e,
+	0x61, 0x6d, 0x65, 0x00, 0x54, 0x68, 0x69, 0x73,
+	0x20, 0x69, 0x73, 0x20, 0x61, 0x20, 0x63, 0x6f,
+	0x6d, 0x6d, 0x65, 0x6e, 0x74, 0x00, 0x2b, 0x48,
+	0xac, 0xcc, 0xc9, 0x4f, 0x4c, 0x01, 0x00, 0x15,
+	0x6a, 0x2c, 0x42, 0x07, 0x00, 0x00, 0x00,
+};
+
+main :: proc() {
+	// Set up output buffer.
+	buf: bytes.Buffer;
+	defer bytes.buffer_destroy(&buf);
+
+	stdout :: proc(s: string) {
+		os.write_string(os.stdout, s);
+	}
+	stderr :: proc(s: string) {
+		os.write_string(os.stderr, s);
+	}
+
+	args := os.args;
+
+	if len(args) < 2 {
+		stderr("No input file specified.\n");
+		err := gzip.load(&TEST, &buf);
+		if gzip.is_kind(err, gzip.E_General.OK) {
+			stdout("Displaying test vector: ");
+			stdout(bytes.buffer_to_string(&buf));
+			stdout("\n");
+		}
+	}
+
+	// The rest are all files.
+	args = args[1:];
+	err: gzip.Error;
+
+	for file in args {
+		if file == "-" {
+			// Read from stdin
+			s := os.stream_from_handle(os.stdin);
+			err = gzip.load(&s, &buf);
+		} else {
+			err = gzip.load(file, &buf);
+		}
+		if !gzip.is_kind(err, gzip.E_General.OK) {
+			if gzip.is_kind(err, gzip.E_General.File_Not_Found) {
+				stderr("File not found: ");
+				stderr(file);
+				stderr("\n");
+				os.exit(1);
+			}
+			stderr("GZIP returned an error.\n");
+			os.exit(2);
+		}
+		stdout(bytes.buffer_to_string(&buf));
+	}
+	os.exit(0);
+}