Apply fix to QOI decoder as well.

core/image/qoi/qoi.odin

@@ -1,379 +1,378 @@
-/*
-	Copyright 2022 Jeroen van Rijn <[email protected]>.
-	Made available under Odin's BSD-3 license.
-
-	List of contributors:
-		Jeroen van Rijn: Initial implementation.
-*/
-
-
-// package qoi implements a QOI image reader
-//
-// The QOI specification is at https://qoiformat.org.
-package qoi
-
-import "core:image"
-import "core:compress"
-import "core:bytes"
-
-Error   :: image.Error
-Image   :: image.Image
-Options :: image.Options
-
-RGB_Pixel  :: image.RGB_Pixel
-RGBA_Pixel :: image.RGBA_Pixel
-
-save_to_buffer  :: proc(output: ^bytes.Buffer, img: ^Image, options := Options{}, allocator := context.allocator) -> (err: Error) {
-	context.allocator = allocator
-
-	if img == nil {
-		return .Invalid_Input_Image
-	}
-
-	if output == nil {
-		return .Invalid_Output
-	}
-
-	pixels := img.width * img.height
-	if pixels == 0 || pixels > image.MAX_DIMENSIONS {
-		return .Invalid_Input_Image
-	}
-
-	// QOI supports only 8-bit images with 3 or 4 channels.
-	if img.depth != 8 || img.channels < 3 || img.channels > 4 {
-		return .Invalid_Input_Image
-	}
-
-	if img.channels * pixels != len(img.pixels.buf) {
-		return .Invalid_Input_Image
-	}
-
-	written := 0
-
-	// Calculate and allocate maximum size. We'll reclaim space to actually written output at the end.
-	max_size := pixels * (img.channels + 1) + size_of(image.QOI_Header) + size_of(u64be)
-
-	if resize(&output.buf, max_size) != nil {
-		return .Unable_To_Allocate_Or_Resize
-	}
-
-	header := image.QOI_Header{
-		magic       = image.QOI_Magic,
-		width       = u32be(img.width),
-		height      = u32be(img.height),
-		channels    = u8(img.channels),
-		color_space = .Linear if .qoi_all_channels_linear in options else .sRGB,
-	}
-	header_bytes := transmute([size_of(image.QOI_Header)]u8)header
-
-	copy(output.buf[written:], header_bytes[:])
-	written += size_of(image.QOI_Header)
-
-	/*
-		Encode loop starts here.
-	*/
-	seen: [64]RGBA_Pixel
-	pix  := RGBA_Pixel{0, 0, 0, 255}
-	prev := pix
-
-	input := img.pixels.buf[:]
-	run   := u8(0)
-
-	for len(input) > 0 {
-		if img.channels == 4 {
-			pix     = (^RGBA_Pixel)(raw_data(input))^
-		} else {
-			pix.rgb = (^RGB_Pixel)(raw_data(input))^
-		}
-		input = input[img.channels:]
-
-		if pix == prev {
-			run += 1
-			// As long as the pixel matches the last one, accumulate the run total.
-			// If we reach the max run length or the end of the image, write the run.
-			if run == 62 || len(input) == 0 {
-				// Encode and write run
-				output.buf[written] = u8(QOI_Opcode_Tag.RUN) | (run - 1)
-				written += 1
-				run = 0
-			}
-		} else {
-			if run > 0 {
-				// The pixel differs from the previous one, but we still need to write the pending run.
-				// Encode and write run
-				output.buf[written] = u8(QOI_Opcode_Tag.RUN) | (run - 1)
-				written += 1
-				run = 0
-			}
-
-			index := qoi_hash(pix)
-
-			if seen[index] == pix {
-				// Write indexed pixel
-				output.buf[written] = u8(QOI_Opcode_Tag.INDEX) | index
-				written += 1
-			} else {
-				// Add pixel to index
-				seen[index] = pix
-
-				// If the alpha matches the previous pixel's alpha, we don't need to write a full RGBA literal.
-				if pix.a == prev.a {
-					// Delta
-					d  := pix.rgb - prev.rgb
-
-					// DIFF, biased and modulo 256
-					_d := d + 2
-
-					// LUMA, biased and modulo 256
-					_l := RGB_Pixel{ d.r - d.g + 8, d.g + 32, d.b - d.g + 8 }
-
-					if _d.r < 4 && _d.g < 4 && _d.b < 4 {
-						// Delta is between -2 and 1 inclusive
-						output.buf[written] = u8(QOI_Opcode_Tag.DIFF) | _d.r << 4 | _d.g << 2 | _d.b
-						written += 1
-					} else if _l.r < 16 && _l.g < 64 && _l.b < 16 {
-						// Biased luma is between {-8..7, -32..31, -8..7}
-						output.buf[written    ] = u8(QOI_Opcode_Tag.LUMA) | _l.g
-						output.buf[written + 1] = _l.r << 4 | _l.b
-						written += 2
-					} else {
-						// Write RGB literal
-						output.buf[written] = u8(QOI_Opcode_Tag.RGB)
-						pix_bytes := transmute([4]u8)pix
-						copy(output.buf[written + 1:], pix_bytes[:3])
-						written += 4
-					}
-				} else {
-					// Write RGBA literal
-					output.buf[written] = u8(QOI_Opcode_Tag.RGBA)
-					pix_bytes := transmute([4]u8)pix
-					copy(output.buf[written + 1:], pix_bytes[:])
-					written += 5
-				}
-			}
-		}
-		prev = pix
-	}
-
-	trailer := []u8{0, 0, 0, 0, 0, 0, 0, 1}
-	copy(output.buf[written:], trailer[:])
-	written += len(trailer)
-
-	resize(&output.buf, written)
-	return nil
-}
-
-load_from_bytes :: proc(data: []byte, options := Options{}, allocator := context.allocator) -> (img: ^Image, err: Error) {
-	ctx := &compress.Context_Memory_Input{
-		input_data = data,
-	}
-
-	img, err = load_from_context(ctx, options, allocator)
-	return img, err
-}
-
-@(optimization_mode="speed")
-load_from_context :: proc(ctx: ^$C, options := Options{}, allocator := context.allocator) -> (img: ^Image, err: Error) {
-	context.allocator = allocator
-	options := options
-
-	if .info in options {
-		options |= {.return_metadata, .do_not_decompress_image}
-		options -= {.info}
-	}
-
-	if .return_header in options && .return_metadata in options {
-		options -= {.return_header}
-	}
-
-	header := image.read_data(ctx, image.QOI_Header) or_return
-	if header.magic != image.QOI_Magic {
-		return img, .Invalid_Signature
-	}
-
-	if img == nil {
-		img = new(Image)
-	}
-	img.which = .QOI
-
-	if .return_metadata in options {
-		info := new(image.QOI_Info)
-		info.header  = header
-		img.metadata = info		
-	}
-
-	if header.channels != 3 && header.channels != 4 {
-		return img, .Invalid_Number_Of_Channels
-	}
-
-	if header.color_space != .sRGB && header.color_space != .Linear {
-		return img, .Invalid_Color_Space
-	}
-
-	if header.width == 0 || header.height == 0 {
-		return img, .Invalid_Image_Dimensions
-	}
-
-	total_pixels := header.width * header.height
-	if total_pixels > image.MAX_DIMENSIONS {
-		return img, .Image_Dimensions_Too_Large
-	}
-
-	img.width    = int(header.width)
-	img.height   = int(header.height)
-	img.channels = 4 if .alpha_add_if_missing in options else int(header.channels)
-	img.depth    = 8
-
-	if .do_not_decompress_image in options {
-		img.channels = int(header.channels)
-		return
-	}
-
-	bytes_needed := image.compute_buffer_size(int(header.width), int(header.height), img.channels, 8)
-
-	if resize(&img.pixels.buf, bytes_needed) != nil {
-	 	return img, .Unable_To_Allocate_Or_Resize
-	}
-
-	/*
-		Decode loop starts here.
-	*/
-	seen: [64]RGBA_Pixel
-	pix := RGBA_Pixel{0, 0, 0, 255}
-	seen[qoi_hash(pix)] = pix
-	pixels := img.pixels.buf[:]
-
-	decode: for len(pixels) > 0 {
-		data := image.read_u8(ctx) or_return
-
-		tag := QOI_Opcode_Tag(data)
-		#partial switch tag {
-		case .RGB:
-			pix.rgb = image.read_data(ctx, RGB_Pixel) or_return
-
-			#no_bounds_check {
-				seen[qoi_hash(pix)] = pix	
-			}
-
-		case .RGBA:
-			pix = image.read_data(ctx, RGBA_Pixel) or_return
-
-			#no_bounds_check {
-				seen[qoi_hash(pix)] = pix	
-			}
-
-		case:
-			// 2-bit tag
-			tag = QOI_Opcode_Tag(data & QOI_Opcode_Mask)
-			#partial switch tag {
-				case .INDEX:
-					pix = seen[data & 63]
-
-				case .DIFF:
-					diff_r := ((data >> 4) & 3) - 2
-					diff_g := ((data >> 2) & 3) - 2
-					diff_b := ((data >> 0) & 3) - 2
-
-					pix += {diff_r, diff_g, diff_b, 0}
-
-					#no_bounds_check {
-						seen[qoi_hash(pix)] = pix	
-					}
-
-				case .LUMA:
-					data2 := image.read_u8(ctx) or_return
-
-					diff_g := (data & 63) - 32
-					diff_r := diff_g - 8 + ((data2 >> 4) & 15)
-					diff_b := diff_g - 8 + (data2 & 15)
-
-					pix += {diff_r, diff_g, diff_b, 0}
-
-					#no_bounds_check {
-						seen[qoi_hash(pix)] = pix	
-					}
-
-				case .RUN:
-					if length := int(data & 63) + 1; (length * img.channels) > len(pixels) {
-						return img, .Corrupt
-					} else {
-						#no_bounds_check for _ in 0..<length {
-							copy(pixels, pix[:img.channels])
-							pixels = pixels[img.channels:]
-						}
-					}
-
-					continue decode
-
-				case:
-					unreachable()
-			}
-		}
-
-		#no_bounds_check {
-			copy(pixels, pix[:img.channels])
-			pixels = pixels[img.channels:]
-		}
-	}
-
-	// The byte stream's end is marked with 7 0x00 bytes followed by a single 0x01 byte.
-	trailer, trailer_err := compress.read_data(ctx, u64be)
-	if trailer_err != nil || trailer != 0x1 {
-		return img, .Missing_Or_Corrupt_Trailer
-	}
-
-	if .alpha_premultiply in options && !image.alpha_drop_if_present(img, options) {
-		return img, .Post_Processing_Error
-	}
-
-	return
-}
-
-/*
-	Cleanup of image-specific data.
-*/
-destroy :: proc(img: ^Image) {
-	if img == nil {
-		/*
-			Nothing to do.
-			Load must've returned with an error.
-		*/
-		return
-	}
-
-	bytes.buffer_destroy(&img.pixels)
-
-	if v, ok := img.metadata.(^image.QOI_Info); ok {
-	 	free(v)
-	}
-	free(img)
-}
-
-QOI_Opcode_Tag :: enum u8 {
-	// 2-bit tags
-	INDEX = 0b0000_0000, // 6-bit index into color array follows
-	DIFF  = 0b0100_0000, // 3x (RGB) 2-bit difference follows (-2..1), bias of 2.
-	LUMA  = 0b1000_0000, // Luma difference
-	RUN   = 0b1100_0000, // Run length encoding, bias -1
-
-	// 8-bit tags
-	RGB   = 0b1111_1110, // Raw RGB  pixel follows
-	RGBA  = 0b1111_1111, // Raw RGBA pixel follows
-}
-
-QOI_Opcode_Mask :: 0b1100_0000
-QOI_Data_Mask   :: 0b0011_1111
-
-qoi_hash :: #force_inline proc(pixel: RGBA_Pixel) -> (index: u8) {
-	i1 := u16(pixel.r) * 3
-	i2 := u16(pixel.g) * 5
-	i3 := u16(pixel.b) * 7
-	i4 := u16(pixel.a) * 11
-
-	return u8((i1 + i2 + i3 + i4) & 63)
-}
-
-@(init, private)
-_register :: proc() {
-	image.register(.QOI, load_from_bytes, destroy)
+/*
+	Copyright 2022 Jeroen van Rijn <[email protected]>.
+	Made available under Odin's BSD-3 license.
+
+	List of contributors:
+		Jeroen van Rijn: Initial implementation.
+*/
+
+
+// package qoi implements a QOI image reader
+//
+// The QOI specification is at https://qoiformat.org.
+package qoi
+
+import "core:image"
+import "core:compress"
+import "core:bytes"
+
+Error   :: image.Error
+Image   :: image.Image
+Options :: image.Options
+
+RGB_Pixel  :: image.RGB_Pixel
+RGBA_Pixel :: image.RGBA_Pixel
+
+save_to_buffer  :: proc(output: ^bytes.Buffer, img: ^Image, options := Options{}, allocator := context.allocator) -> (err: Error) {
+	context.allocator = allocator
+
+	if img == nil {
+		return .Invalid_Input_Image
+	}
+
+	if output == nil {
+		return .Invalid_Output
+	}
+
+	pixels := img.width * img.height
+	if pixels == 0 || pixels > image.MAX_DIMENSIONS {
+		return .Invalid_Input_Image
+	}
+
+	// QOI supports only 8-bit images with 3 or 4 channels.
+	if img.depth != 8 || img.channels < 3 || img.channels > 4 {
+		return .Invalid_Input_Image
+	}
+
+	if img.channels * pixels != len(img.pixels.buf) {
+		return .Invalid_Input_Image
+	}
+
+	written := 0
+
+	// Calculate and allocate maximum size. We'll reclaim space to actually written output at the end.
+	max_size := pixels * (img.channels + 1) + size_of(image.QOI_Header) + size_of(u64be)
+
+	if resize(&output.buf, max_size) != nil {
+		return .Unable_To_Allocate_Or_Resize
+	}
+
+	header := image.QOI_Header{
+		magic       = image.QOI_Magic,
+		width       = u32be(img.width),
+		height      = u32be(img.height),
+		channels    = u8(img.channels),
+		color_space = .Linear if .qoi_all_channels_linear in options else .sRGB,
+	}
+	header_bytes := transmute([size_of(image.QOI_Header)]u8)header
+
+	copy(output.buf[written:], header_bytes[:])
+	written += size_of(image.QOI_Header)
+
+	/*
+		Encode loop starts here.
+	*/
+	seen: [64]RGBA_Pixel
+	pix  := RGBA_Pixel{0, 0, 0, 255}
+	prev := pix
+
+	input := img.pixels.buf[:]
+	run   := u8(0)
+
+	for len(input) > 0 {
+		if img.channels == 4 {
+			pix     = (^RGBA_Pixel)(raw_data(input))^
+		} else {
+			pix.rgb = (^RGB_Pixel)(raw_data(input))^
+		}
+		input = input[img.channels:]
+
+		if pix == prev {
+			run += 1
+			// As long as the pixel matches the last one, accumulate the run total.
+			// If we reach the max run length or the end of the image, write the run.
+			if run == 62 || len(input) == 0 {
+				// Encode and write run
+				output.buf[written] = u8(QOI_Opcode_Tag.RUN) | (run - 1)
+				written += 1
+				run = 0
+			}
+		} else {
+			if run > 0 {
+				// The pixel differs from the previous one, but we still need to write the pending run.
+				// Encode and write run
+				output.buf[written] = u8(QOI_Opcode_Tag.RUN) | (run - 1)
+				written += 1
+				run = 0
+			}
+
+			index := qoi_hash(pix)
+
+			if seen[index] == pix {
+				// Write indexed pixel
+				output.buf[written] = u8(QOI_Opcode_Tag.INDEX) | index
+				written += 1
+			} else {
+				// Add pixel to index
+				seen[index] = pix
+
+				// If the alpha matches the previous pixel's alpha, we don't need to write a full RGBA literal.
+				if pix.a == prev.a {
+					// Delta
+					d  := pix.rgb - prev.rgb
+
+					// DIFF, biased and modulo 256
+					_d := d + 2
+
+					// LUMA, biased and modulo 256
+					_l := RGB_Pixel{ d.r - d.g + 8, d.g + 32, d.b - d.g + 8 }
+
+					if _d.r < 4 && _d.g < 4 && _d.b < 4 {
+						// Delta is between -2 and 1 inclusive
+						output.buf[written] = u8(QOI_Opcode_Tag.DIFF) | _d.r << 4 | _d.g << 2 | _d.b
+						written += 1
+					} else if _l.r < 16 && _l.g < 64 && _l.b < 16 {
+						// Biased luma is between {-8..7, -32..31, -8..7}
+						output.buf[written    ] = u8(QOI_Opcode_Tag.LUMA) | _l.g
+						output.buf[written + 1] = _l.r << 4 | _l.b
+						written += 2
+					} else {
+						// Write RGB literal
+						output.buf[written] = u8(QOI_Opcode_Tag.RGB)
+						pix_bytes := transmute([4]u8)pix
+						copy(output.buf[written + 1:], pix_bytes[:3])
+						written += 4
+					}
+				} else {
+					// Write RGBA literal
+					output.buf[written] = u8(QOI_Opcode_Tag.RGBA)
+					pix_bytes := transmute([4]u8)pix
+					copy(output.buf[written + 1:], pix_bytes[:])
+					written += 5
+				}
+			}
+		}
+		prev = pix
+	}
+
+	trailer := []u8{0, 0, 0, 0, 0, 0, 0, 1}
+	copy(output.buf[written:], trailer[:])
+	written += len(trailer)
+
+	resize(&output.buf, written)
+	return nil
+}
+
+load_from_bytes :: proc(data: []byte, options := Options{}, allocator := context.allocator) -> (img: ^Image, err: Error) {
+	ctx := &compress.Context_Memory_Input{
+		input_data = data,
+	}
+
+	img, err = load_from_context(ctx, options, allocator)
+	return img, err
+}
+
+@(optimization_mode="speed")
+load_from_context :: proc(ctx: ^$C, options := Options{}, allocator := context.allocator) -> (img: ^Image, err: Error) {
+	context.allocator = allocator
+	options := options
+
+	if .info in options {
+		options |= {.return_metadata, .do_not_decompress_image}
+		options -= {.info}
+	}
+
+	if .return_header in options && .return_metadata in options {
+		options -= {.return_header}
+	}
+
+	header := image.read_data(ctx, image.QOI_Header) or_return
+	if header.magic != image.QOI_Magic {
+		return img, .Invalid_Signature
+	}
+
+	if img == nil {
+		img = new(Image)
+	}
+	img.which = .QOI
+
+	if .return_metadata in options {
+		info := new(image.QOI_Info)
+		info.header  = header
+		img.metadata = info		
+	}
+
+	if header.channels != 3 && header.channels != 4 {
+		return img, .Invalid_Number_Of_Channels
+	}
+
+	if header.color_space != .sRGB && header.color_space != .Linear {
+		return img, .Invalid_Color_Space
+	}
+
+	if header.width == 0 || header.height == 0 {
+		return img, .Invalid_Image_Dimensions
+	}
+
+	total_pixels := header.width * header.height
+	if total_pixels > image.MAX_DIMENSIONS {
+		return img, .Image_Dimensions_Too_Large
+	}
+
+	img.width    = int(header.width)
+	img.height   = int(header.height)
+	img.channels = 4 if .alpha_add_if_missing in options else int(header.channels)
+	img.depth    = 8
+
+	if .do_not_decompress_image in options {
+		img.channels = int(header.channels)
+		return
+	}
+
+	bytes_needed := image.compute_buffer_size(int(header.width), int(header.height), img.channels, 8)
+
+	if resize(&img.pixels.buf, bytes_needed) != nil {
+	 	return img, .Unable_To_Allocate_Or_Resize
+	}
+
+	/*
+		Decode loop starts here.
+	*/
+	seen: [64]RGBA_Pixel
+	pix    := RGBA_Pixel{0, 0, 0, 255}
+	pixels := img.pixels.buf[:]
+
+	decode: for len(pixels) > 0 {
+		data := image.read_u8(ctx) or_return
+
+		tag := QOI_Opcode_Tag(data)
+		#partial switch tag {
+		case .RGB:
+			pix.rgb = image.read_data(ctx, RGB_Pixel) or_return
+
+			#no_bounds_check {
+				seen[qoi_hash(pix)] = pix	
+			}
+
+		case .RGBA:
+			pix = image.read_data(ctx, RGBA_Pixel) or_return
+
+			#no_bounds_check {
+				seen[qoi_hash(pix)] = pix	
+			}
+
+		case:
+			// 2-bit tag
+			tag = QOI_Opcode_Tag(data & QOI_Opcode_Mask)
+			#partial switch tag {
+				case .INDEX:
+					pix = seen[data & 63]
+
+				case .DIFF:
+					diff_r := ((data >> 4) & 3) - 2
+					diff_g := ((data >> 2) & 3) - 2
+					diff_b := ((data >> 0) & 3) - 2
+
+					pix += {diff_r, diff_g, diff_b, 0}
+
+					#no_bounds_check {
+						seen[qoi_hash(pix)] = pix	
+					}
+
+				case .LUMA:
+					data2 := image.read_u8(ctx) or_return
+
+					diff_g := (data & 63) - 32
+					diff_r := diff_g - 8 + ((data2 >> 4) & 15)
+					diff_b := diff_g - 8 + (data2 & 15)
+
+					pix += {diff_r, diff_g, diff_b, 0}
+
+					#no_bounds_check {
+						seen[qoi_hash(pix)] = pix	
+					}
+
+				case .RUN:
+					if length := int(data & 63) + 1; (length * img.channels) > len(pixels) {
+						return img, .Corrupt
+					} else {
+						#no_bounds_check for _ in 0..<length {
+							copy(pixels, pix[:img.channels])
+							pixels = pixels[img.channels:]
+						}
+					}
+
+					continue decode
+
+				case:
+					unreachable()
+			}
+		}
+
+		#no_bounds_check {
+			copy(pixels, pix[:img.channels])
+			pixels = pixels[img.channels:]
+		}
+	}
+
+	// The byte stream's end is marked with 7 0x00 bytes followed by a single 0x01 byte.
+	trailer, trailer_err := compress.read_data(ctx, u64be)
+	if trailer_err != nil || trailer != 0x1 {
+		return img, .Missing_Or_Corrupt_Trailer
+	}
+
+	if .alpha_premultiply in options && !image.alpha_drop_if_present(img, options) {
+		return img, .Post_Processing_Error
+	}
+
+	return
+}
+
+/*
+	Cleanup of image-specific data.
+*/
+destroy :: proc(img: ^Image) {
+	if img == nil {
+		/*
+			Nothing to do.
+			Load must've returned with an error.
+		*/
+		return
+	}
+
+	bytes.buffer_destroy(&img.pixels)
+
+	if v, ok := img.metadata.(^image.QOI_Info); ok {
+	 	free(v)
+	}
+	free(img)
+}
+
+QOI_Opcode_Tag :: enum u8 {
+	// 2-bit tags
+	INDEX = 0b0000_0000, // 6-bit index into color array follows
+	DIFF  = 0b0100_0000, // 3x (RGB) 2-bit difference follows (-2..1), bias of 2.
+	LUMA  = 0b1000_0000, // Luma difference
+	RUN   = 0b1100_0000, // Run length encoding, bias -1
+
+	// 8-bit tags
+	RGB   = 0b1111_1110, // Raw RGB  pixel follows
+	RGBA  = 0b1111_1111, // Raw RGBA pixel follows
+}
+
+QOI_Opcode_Mask :: 0b1100_0000
+QOI_Data_Mask   :: 0b0011_1111
+
+qoi_hash :: #force_inline proc(pixel: RGBA_Pixel) -> (index: u8) {
+	i1 := u16(pixel.r) * 3
+	i2 := u16(pixel.g) * 5
+	i3 := u16(pixel.b) * 7
+	i4 := u16(pixel.a) * 11
+
+	return u8((i1 + i2 + i3 + i4) & 63)
+}
+
+@(init, private)
+_register :: proc() {
+	image.register(.QOI, load_from_bytes, destroy)
 }