| // Copyright 2023 The Wuffs Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| pub status "#bad DHT marker" |
| pub status "#bad DQT marker" |
| pub status "#bad DRI marker" |
| pub status "#bad SOF marker" |
| pub status "#bad SOS marker" |
| pub status "#bad header" |
| pub status "#bad marker" |
| pub status "#truncated input" |
| pub status "#unsupported arithmetic coding" |
| pub status "#unsupported hierarchical coding" |
| pub status "#unsupported lossless coding" |
| pub status "#unsupported implicit height" |
| pub status "#unsupported marker" |
| pub status "#unsupported precision" |
| pub status "#unsupported precision (12 bits)" |
| pub status "#unsupported precision (16 bits)" |
| |
| pub const DECODER_WORKBUF_LEN_MAX_INCL_WORST_CASE : base.u64 = 0 |
| |
| pub struct decoder? implements base.image_decoder( |
| width : base.u32[..= 0xFFFF], |
| height : base.u32[..= 0xFFFF], |
| |
| // The call sequence state machine is discussed in |
| // (/doc/std/image-decoders-call-sequence.md). |
| call_sequence : base.u8, |
| |
| sof_marker : base.u8, |
| |
| num_components : base.u32[..= 4], |
| components_c : array[4] base.u8, |
| components_h : array[4] base.u8[..= 4], |
| components_v : array[4] base.u8[..= 4], |
| components_tq : array[4] base.u8[..= 4], |
| |
| payload_length : base.u32[..= 0xFFFF], |
| |
| restart_interval : base.u32[..= 0xFFFF], |
| |
| frame_config_io_position : base.u64, |
| |
| seen_dqt : array[4] base.bool, |
| |
| quant_tables : array[4] array[64] base.u8, |
| |
| swizzler : base.pixel_swizzler, |
| util : base.utility, |
| ) + ( |
| dst_palette : array[4 * 256] base.u8, |
| ) |
| |
| pub func decoder.set_quirk!(key: base.u32, value: base.u64) base.status { |
| return base."#unsupported option" |
| } |
| |
| pub func decoder.decode_image_config?(dst: nptr base.image_config, src: base.io_reader) { |
| var status : base.status |
| |
| while true { |
| status =? this.do_decode_image_config?(dst: args.dst, src: args.src) |
| if (status == base."$short read") and args.src.is_closed() { |
| return "#truncated input" |
| } |
| yield? status |
| } endwhile |
| } |
| |
| pri func decoder.do_decode_image_config?(dst: nptr base.image_config, src: base.io_reader) { |
| var c : base.u8 |
| var marker : base.u8 |
| |
| if this.call_sequence <> 0x00 { |
| return base."#bad call sequence" |
| } |
| |
| c = args.src.read_u8?() |
| if c <> 0xFF { |
| return "#bad header" |
| } |
| c = args.src.read_u8?() |
| if c <> 0xD8 { // SOI (Start Of Image). |
| return "#bad header" |
| } |
| |
| // Process chunks (markers and their payloads). |
| while true { |
| // Read the marker (a two-byte 0xFF 0x?? sequence). |
| while true { |
| c = args.src.read_u8?() |
| if c == 0xFF { |
| break |
| } |
| // Getting here is invalid according to the JPEG spec, but libjpeg |
| // treats this as a warning (JWRN_EXTRANEOUS_DATA), not an error. |
| } endwhile |
| while true { |
| c = args.src.read_u8?() |
| if c <> 0xFF { |
| marker = c |
| break |
| } |
| // Section B.1.1.2: "Any marker may optionally be preceded by any |
| // number of [0xFF] fill bytes". |
| } endwhile |
| |
| if marker == 0x00 { |
| // Ignore byte stuffing. |
| continue |
| } else if (0xD0 <= marker) and (marker <= 0xD7) { |
| // RSTn (Restart) markers have no payload. |
| continue |
| } |
| |
| // Payload length includes the 2 bytes for the u16be payload length. |
| this.payload_length = args.src.read_u16be_as_u32?() |
| if this.payload_length < 2 { |
| return "#bad marker" |
| } |
| this.payload_length -= 2 |
| |
| // Switch on the marker. |
| if marker < 0xC0 { |
| return "#unsupported marker" |
| |
| } else if marker < 0xD0 { // SOFn (Start of Frame) and friends. |
| if marker <= 0xC2 { |
| if this.sof_marker <> 0 { |
| return "#bad SOF marker" |
| } |
| this.sof_marker = marker |
| this.decode_sof?(src: args.src) |
| break |
| |
| } else if marker == 0xC3 { |
| return "#unsupported lossless coding" |
| |
| } else if marker == 0xC4 { // DHT (Define Huffman Table). |
| // We shouldn't see DHT before SOF. |
| return "#bad DHT marker" |
| |
| } else if (0xC5 <= marker) and (marker <= 0xC7) { |
| return "#unsupported hierarchical coding" |
| |
| } else if marker == 0xC8 { // JPG (JPEG extension). |
| return "#unsupported marker" |
| |
| } else { |
| return "#unsupported arithmetic coding" |
| } |
| |
| } else if marker < 0xE0 { |
| if marker < 0xDA { |
| // RSTn markers are already handled above. We either have 0xD8 |
| // (SOI: Start Of Image) or 0xD9 (EOI: End Of Image), neither |
| // of which are valid here. |
| return "#bad marker" |
| |
| } else if marker == 0xDA { // SOS (Start Of Scan). |
| // We shouldn't see SOS before SOF. |
| return "#bad SOS marker" |
| |
| } else if marker == 0xDB { // DQT (Define Quantization Table). |
| this.decode_dqt?(src: args.src) |
| continue |
| |
| } else if marker == 0xDD { // DRI (Define Restart Interval). |
| this.decode_dri?(src: args.src) |
| continue |
| |
| } else { |
| // 0xDC (DNL: Define Number of Lines). |
| // 0xDE (DHP: Define Hierarchical Progression). |
| // 0xDF (EXP: Expand Reference Components). |
| return "#unsupported marker" |
| } |
| |
| } else if marker < 0xF0 { // APPn (Application specific). |
| // No-op. |
| |
| } else { |
| if marker == 0xFE { // COM (Comment). |
| // No-op. |
| |
| } else { |
| return "#unsupported marker" |
| } |
| } |
| |
| args.src.skip_u32?(n: this.payload_length) |
| this.payload_length = 0 |
| } endwhile |
| |
| this.frame_config_io_position = args.src.position() |
| |
| if args.dst <> nullptr { |
| args.dst.set!( |
| // TODO: base.PIXEL_FORMAT__YCBCR is probably more correct, |
| // although possibly less convenient for the caller. |
| pixfmt: base.PIXEL_FORMAT__BGRX, |
| pixsub: 0, |
| width: this.width, |
| height: this.height, |
| first_frame_io_position: this.frame_config_io_position, |
| first_frame_is_opaque: true) |
| } |
| |
| this.call_sequence = 0x20 |
| } |
| |
| pri func decoder.decode_dqt?(src: base.io_reader) { |
| var c : base.u8 |
| var q : base.u8[..= 3] |
| var i : base.u32 |
| |
| while this.payload_length > 0 { |
| this.payload_length -= 1 |
| c = args.src.read_u8?() |
| if (c & 0x0F) > 3 { |
| return "#bad DQT marker" |
| } |
| q = c & 0x0F |
| if (c >> 4) == 1 { |
| return "#unsupported precision" |
| } else if ((c >> 4) > 1) or (this.payload_length < 64) { |
| return "#bad DQT marker" |
| } |
| this.payload_length -= 64 |
| |
| i = 0 |
| while i < 64 { |
| this.quant_tables[q][UNZIG[i]] = args.src.read_u8?() |
| i += 1 |
| } endwhile |
| this.seen_dqt[q] = true |
| } endwhile |
| } |
| |
| pri func decoder.decode_dri?(src: base.io_reader) { |
| if this.payload_length <> 2 { |
| return "#bad DRI marker" |
| } |
| this.payload_length = 0 |
| |
| this.restart_interval = args.src.read_u16be_as_u32?() |
| } |
| |
| pri func decoder.decode_sof?(src: base.io_reader) { |
| var c : base.u8 |
| var comp_h : base.u8 |
| var comp_v : base.u8 |
| var i : base.u32 |
| var j : base.u32 |
| |
| if this.payload_length < 6 { |
| return "#bad SOF marker" |
| } |
| this.payload_length -= 6 |
| c = args.src.read_u8?() |
| if c == 8 { |
| // No-op. |
| } else if c == 12 { |
| return "#unsupported precision (12 bits)" |
| } else if c == 16 { |
| return "#unsupported precision (16 bits)" |
| } else { |
| return "#unsupported precision" |
| } |
| this.height = args.src.read_u16be_as_u32?() |
| if this.height == 0 { |
| return "#unsupported implicit height" |
| } |
| this.width = args.src.read_u16be_as_u32?() |
| if this.width == 0 { |
| return base."#unsupported image dimension" |
| } |
| c = args.src.read_u8?() |
| if (c == 0) or (c > 4) { |
| return "#bad SOF marker" |
| } |
| this.num_components = c as base.u32 |
| if this.payload_length <> (3 * this.num_components) { |
| return "#bad SOF marker" |
| } |
| this.payload_length = 0 |
| |
| i = 0 |
| while i < this.num_components { |
| assert i < 4 via "a < b: a < c; c <= b"(c: this.num_components) |
| this.components_c[i] = args.src.read_u8?() |
| c = args.src.read_u8?() |
| comp_h = c >> 4 |
| comp_v = c & 0x0F |
| if (comp_h == 0) or (comp_h > 4) or (comp_v == 0) or (comp_v > 4) { |
| return "#bad SOF marker" |
| } |
| this.components_h[i] = comp_h |
| this.components_v[i] = comp_v |
| c = args.src.read_u8?() |
| if c > 4 { |
| return "#bad SOF marker" |
| } |
| this.components_tq[i] = c |
| |
| // Section B.2.2: "the value of C_i shall be different from the values |
| // of C_1 through C_(i-1)". |
| j = 0 |
| while j < i, |
| inv i < 4, |
| { |
| assert j < 4 via "a < b: a < c; c < b"(c: i) |
| if this.components_c[j] == this.components_c[i] { |
| return "#bad SOF marker" |
| } |
| j += 1 |
| } endwhile |
| |
| i += 1 |
| } endwhile |
| } |
| |
| pub func decoder.decode_frame_config?(dst: nptr base.frame_config, src: base.io_reader) { |
| var status : base.status |
| |
| while true { |
| status =? this.do_decode_frame_config?(dst: args.dst, src: args.src) |
| if (status == base."$short read") and args.src.is_closed() { |
| return "#truncated input" |
| } |
| yield? status |
| } endwhile |
| } |
| |
| pri func decoder.do_decode_frame_config?(dst: nptr base.frame_config, src: base.io_reader) { |
| if this.call_sequence == 0x20 { |
| // No-op. |
| } else if this.call_sequence < 0x20 { |
| this.do_decode_image_config?(dst: nullptr, src: args.src) |
| } else if this.call_sequence == 0x28 { |
| if this.frame_config_io_position <> args.src.position() { |
| return base."#bad restart" |
| } |
| } else if this.call_sequence == 0x40 { |
| this.call_sequence = 0x60 |
| return base."@end of data" |
| } else { |
| return base."@end of data" |
| } |
| |
| if args.dst <> nullptr { |
| args.dst.set!(bounds: this.util.make_rect_ie_u32( |
| min_incl_x: 0, |
| min_incl_y: 0, |
| max_excl_x: this.width, |
| max_excl_y: this.height), |
| duration: 0, |
| index: 0, |
| io_position: this.frame_config_io_position, |
| disposal: 0, |
| opaque_within_bounds: true, |
| overwrite_instead_of_blend: false, |
| background_color: 0xFF00_0000) |
| } |
| |
| this.call_sequence = 0x40 |
| } |
| |
| pub func decoder.decode_frame?(dst: ptr base.pixel_buffer, src: base.io_reader, blend: base.pixel_blend, workbuf: slice base.u8, opts: nptr base.decode_frame_options) { |
| var status : base.status |
| |
| while true { |
| status =? this.do_decode_frame?(dst: args.dst, src: args.src, blend: args.blend, workbuf: args.workbuf, opts: args.opts) |
| if (status == base."$short read") and args.src.is_closed() { |
| return "#truncated input" |
| } |
| yield? status |
| } endwhile |
| } |
| |
| pri func decoder.do_decode_frame?(dst: ptr base.pixel_buffer, src: base.io_reader, blend: base.pixel_blend, workbuf: slice base.u8, opts: nptr base.decode_frame_options) { |
| var status : base.status |
| var dst_pixfmt : base.pixel_format |
| var dst_bits_per_pixel : base.u32[..= 256] |
| var dst_bytes_per_pixel : base.u32[..= 32] |
| var tab : table base.u8 |
| var dst : slice base.u8 |
| var src : array[4] base.u8 |
| var y : base.u32 |
| var x : base.u32 |
| var d : base.u64 |
| |
| if this.call_sequence == 0x40 { |
| // No-op. |
| } else if this.call_sequence < 0x40 { |
| this.do_decode_frame_config?(dst: nullptr, src: args.src) |
| } else { |
| return base."@end of data" |
| } |
| |
| status = this.swizzler.prepare!( |
| dst_pixfmt: args.dst.pixel_format(), |
| dst_palette: args.dst.palette_or_else(fallback: this.dst_palette[..]), |
| src_pixfmt: this.util.make_pixel_format(repr: base.PIXEL_FORMAT__BGRX), |
| src_palette: this.util.empty_slice_u8(), |
| blend: args.blend) |
| if not status.is_ok() { |
| return status |
| } |
| |
| // TODO: the dst_pixfmt variable shouldn't be necessary. We should be able |
| // to chain the two calls: "args.dst.pixel_format().bits_per_pixel()". |
| dst_pixfmt = args.dst.pixel_format() |
| dst_bits_per_pixel = dst_pixfmt.bits_per_pixel() |
| if (dst_bits_per_pixel & 7) <> 0 { |
| return base."#unsupported option" |
| } |
| dst_bytes_per_pixel = dst_bits_per_pixel / 8 |
| |
| // TODO: actually decode the pixels. Until then, fill with gradient tiles. |
| tab = args.dst.plane(p: 0) |
| y = 0 |
| while y < this.height { |
| assert y < 0xFFFF via "a < b: a < c; c <= b"(c: this.height) |
| x = 0 |
| while x < this.width, |
| inv y < 0xFFFF, |
| { |
| assert x < 0xFFFF via "a < b: a < c; c <= b"(c: this.width) |
| dst = tab.row_u32(y: y) |
| d = (x * dst_bytes_per_pixel) as base.u64 |
| if d < dst.length() { |
| src[0] = (x & 0xFF) as base.u8 |
| src[1] = 0x7F |
| src[2] = (y & 0xFF) as base.u8 |
| src[3] = 0xFF |
| this.swizzler.swizzle_interleaved_from_slice!( |
| dst: dst[d ..], |
| dst_palette: args.dst.palette_or_else(fallback: this.dst_palette[..]), |
| src: src[.. 4]) |
| } |
| x += 1 |
| } endwhile |
| y += 1 |
| } endwhile |
| |
| this.call_sequence = 0x60 |
| } |
| |
| pub func decoder.frame_dirty_rect() base.rect_ie_u32 { |
| return this.util.make_rect_ie_u32( |
| min_incl_x: 0, |
| min_incl_y: 0, |
| max_excl_x: this.width, |
| max_excl_y: this.height) |
| } |
| |
| pub func decoder.num_animation_loops() base.u32 { |
| return 0 |
| } |
| |
| pub func decoder.num_decoded_frame_configs() base.u64 { |
| if this.call_sequence > 0x20 { |
| return 1 |
| } |
| return 0 |
| } |
| |
| pub func decoder.num_decoded_frames() base.u64 { |
| if this.call_sequence > 0x40 { |
| return 1 |
| } |
| return 0 |
| } |
| |
| pub func decoder.restart_frame!(index: base.u64, io_position: base.u64) base.status { |
| if this.call_sequence < 0x20 { |
| return base."#bad call sequence" |
| } |
| if args.index <> 0 { |
| return base."#bad argument" |
| } |
| this.call_sequence = 0x28 |
| this.frame_config_io_position = args.io_position |
| return ok |
| } |
| |
| pub func decoder.set_report_metadata!(fourcc: base.u32, report: base.bool) { |
| // TODO: implement. |
| } |
| |
| pub func decoder.tell_me_more?(dst: base.io_writer, minfo: nptr base.more_information, src: base.io_reader) { |
| return base."#no more information" |
| } |
| |
| pub func decoder.workbuf_len() base.range_ii_u64 { |
| return this.util.make_range_ii_u64(min_incl: 0, max_incl: 0) |
| } |
