TEST-2: Implement parser for Tiled tileset files

tiled_parser.odin

@@ -41,6 +41,45 @@ Tileset :: struct {
 	source:    string `json:"source"`,
 }
 
+Tileset_File :: struct {
+	columns:       int    `json:"columns"`,
+	image:         string `json:"image"`,
+	image_height:  int    `json:"imageheight"`,
+	image_width:   int    `json:"imagewidth"`,
+	margin:        int    `json:"margin"`,
+	name:          string `json:"name"`,
+	spacing:       int    `json:"spacing"`,
+	tile_count:    int    `json:"tilecount"`,
+	tiled_version: string `json:"tiledversion"`,
+	tile_height:   int    `json:"tileheight"`,
+	tile_width:    int    `json:"tilewidth"`,
+	type:          string `json:"type"`,
+	version:       string `json:"version"`,
+}
+
+Tileset_Load_Error_Type :: enum {
+	None,
+	Err_Loading_File,
+	Err_Unmarshal,
+}
+
+Tileset_Load_Error :: struct {
+	type: Tileset_Load_Error_Type,
+	msg:  string,
+}
+
+Tileset_Data :: struct {
+	name:        string,
+	image:       string,
+	tile_width:  i32,
+	tile_height: i32,
+	columns:     i32,
+	rows:        i32,
+	margin:      i32,
+	spacing:     i32,
+	tile_count:  i32,
+}
+
 Map_Load_Error_Type :: enum {
 	None,
 	Err_Loading_File,
@@ -137,3 +176,46 @@ load_map :: proc(
 
 	return
 }
+
+load_tileset :: proc(
+	path: string,
+	allocator: runtime.Allocator,
+) -> (
+	tileset_out: Tileset_Data,
+	err: Tileset_Load_Error,
+) {
+
+	context.allocator = allocator
+
+	cfg_data, os_err := os.read_entire_file(path, context.allocator)
+	if os_err != os.General_Error.None {
+		return {}, Tileset_Load_Error{type = .Err_Loading_File, msg = fmt.aprintf("Error reading file: %v (%v)", path, os_err)}
+	}
+
+	unm: Tileset_File
+	unm_err := json.unmarshal(cfg_data, &unm)
+	if unm_err != nil {
+		return {}, Tileset_Load_Error{type = .Err_Unmarshal, msg = fmt.aprintf("Error unmarshalling file: %v (%v)\nOnly Tiled version 1.11.2 is supported", path, unm_err)}
+	}
+
+	assert(unm.type == "tileset", "Only files with type 'tileset' are supported")
+	assert(
+		unm.tile_height > 0 && unm.tile_width > 0,
+		"Only positive tile sizes are supported",
+	)
+	assert(unm.columns > 0, "Tileset must have at least one column")
+
+	tileset_out.name = unm.name
+	tileset_out.image = unm.image
+	tileset_out.tile_width = i32(unm.tile_width)
+	tileset_out.tile_height = i32(unm.tile_height)
+	tileset_out.columns = i32(unm.columns)
+	tileset_out.rows = i32(
+		(unm.image_height - 2 * unm.margin + unm.spacing) / (unm.tile_height + unm.spacing),
+	)
+	tileset_out.margin = i32(unm.margin)
+	tileset_out.spacing = i32(unm.spacing)
+	tileset_out.tile_count = i32(unm.tile_count)
+
+	return
+}