| // Copyright 2020 The Wuffs Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // https://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| // |
| // SPDX-License-Identifier: Apache-2.0 OR MIT |
| |
| pub status "#bad header" |
| pub status "#truncated input" |
| |
| pub const DECODER_WORKBUF_LEN_MAX_INCL_WORST_CASE : base.u64 = 0 |
| |
| pub struct decoder? implements base.image_decoder( |
| width : base.u32[..= 0xFF_FFFF], |
| height : base.u32[..= 0xFF_FFFF], |
| |
| // The call sequence state machine is discussed in |
| // (/doc/std/image-decoders-call-sequence.md). |
| call_sequence : base.u8, |
| |
| frame_config_io_position : base.u64, |
| |
| swizzler : base.pixel_swizzler, |
| util : base.utility, |
| ) |
| |
| pub func decoder.get_quirk(key: base.u32) base.u64 { |
| return 0 |
| } |
| |
| 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."$short read") and args.src.is_closed() { |
| return "#truncated input" |
| } |
| yield? status |
| } endwhile |
| } |
| |
| pri func decoder.do_decode_image_config?(dst: nptr base.image_config, src: base.io_reader) { |
| var c8 : base.u8 |
| var i : base.u32 |
| var p : base.u32[..= 0xFF_FFFF] |
| |
| if this.call_sequence <> 0x00 { |
| return base."#bad call sequence" |
| } |
| |
| // TypeField, FixHeaderField. |
| i = 0 |
| while i < 2 { |
| c8 = args.src.read_u8?() |
| if c8 <> 0 { |
| return "#bad header" |
| } |
| i += 1 |
| } endwhile |
| |
| // Width, height. |
| i = 0 |
| while i < 2 { |
| p = 0 |
| |
| while true, |
| inv i < 2, |
| { |
| c8 = args.src.read_u8?() |
| p |= (c8 & 0x7F) as base.u32 |
| if (c8 >> 7) == 0 { |
| break |
| } else if p > 0x1_FFFF { |
| return base."#unsupported image dimension" |
| } |
| p <<= 7 |
| } endwhile |
| |
| if i == 0 { |
| this.width = p |
| } else { |
| this.height = p |
| } |
| i += 1 |
| } endwhile |
| |
| this.frame_config_io_position = args.src.position() |
| |
| if args.dst <> nullptr { |
| args.dst.set!( |
| pixfmt: base.PIXEL_FORMAT__INDEXED__BGRA_BINARY, |
| pixsub: 0, |
| width: this.width, |
| height: this.height, |
| first_frame_io_position: this.frame_config_io_position, |
| first_frame_is_opaque: true) |
| } |
| |
| this.call_sequence = 0x20 |
| } |
| |
| pub func decoder.decode_frame_config?(dst: nptr base.frame_config, src: base.io_reader) { |
| var status : base.status |
| |
| while true { |
| status =? this.do_decode_frame_config?(dst: args.dst, src: args.src) |
| if (status == base."$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.u64[..= 32] |
| var dst_x_in_bytes : base.u64 |
| var dst_x : base.u32 |
| var dst_y : base.u32 |
| var tab : table base.u8 |
| var dst : slice base.u8 |
| var src : array[1] base.u8 |
| var c8 : base.u8 |
| |
| 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(), |
| src_pixfmt: this.util.make_pixel_format(repr: base.PIXEL_FORMAT__Y), |
| 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) as base.u64 |
| |
| // TODO: be more efficient than reading one byte at a time. |
| if this.width > 0 { |
| tab = args.dst.plane(p: 0) |
| while dst_y < this.height { |
| assert dst_y < 0xFF_FFFF via "a < b: a < c; c <= b"(c: this.height) |
| dst = tab.row_u32(y: dst_y) |
| dst_x = 0 |
| |
| while dst_x < this.width, |
| inv dst_y < 0xFF_FFFF, |
| { |
| assert dst_x < 0xFF_FFFF via "a < b: a < c; c <= b"(c: this.width) |
| |
| if (dst_x & 7) == 0 { |
| while args.src.length() <= 0, |
| inv dst_x < 0xFF_FFFF, |
| inv dst_y < 0xFF_FFFF, |
| post args.src.length() > 0, |
| { |
| yield? base."$short read" |
| tab = args.dst.plane(p: 0) |
| dst = tab.row_u32(y: dst_y) |
| dst_x_in_bytes = (dst_x as base.u64) * dst_bytes_per_pixel |
| if dst_x_in_bytes <= dst.length() { |
| dst = dst[dst_x_in_bytes ..] |
| } |
| } endwhile |
| c8 = args.src.peek_u8() |
| args.src.skip_u32_fast!(actual: 1, worst_case: 1) |
| } |
| if (c8 & 0x80) == 0 { |
| src[0] = 0x00 |
| } else { |
| src[0] = 0xFF |
| } |
| // TODO: this should just be "c8 ~mod<<= 1", but that generates: |
| // |
| // error: conversion to ‘uint8_t {aka unsigned char}’ from |
| // ‘int’ may alter its value [-Werror=conversion] |
| // v_c <<= 1; |
| c8 = (((c8 as base.u32) << 1) & 0xFF) as base.u8 |
| |
| this.swizzler.swizzle_interleaved_from_slice!( |
| dst: dst, dst_palette: this.util.empty_slice_u8(), src: src[..]) |
| |
| if dst_bytes_per_pixel <= dst.length() { |
| dst = dst[dst_bytes_per_pixel ..] |
| } |
| |
| dst_x += 1 |
| } endwhile |
| dst_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) { |
| // No-op. WBMP doesn't support metadata. |
| } |
| |
| 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) |
| } |
