blob: 0619fdfa0a87795a56d572afa19ef3dd69f79eb7 [file] [log] [blame]
// Copyright 2023 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 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 "#bad scan count"
pub status "#missing Huffman table"
pub status "#missing Quantization table"
pub status "#rejected progressive JPEG"
pub status "#short SOS bitstream"
pub status "#truncated input"
pub status "#unsupported arithmetic coding"
pub status "#unsupported color model"
pub status "#unsupported fractional sampling"
pub status "#unsupported hierarchical coding"
pub status "#unsupported implicit height"
pub status "#unsupported lossless coding"
pub status "#unsupported marker"
pub status "#unsupported precision (12 bits)"
pub status "#unsupported precision (16 bits)"
pub status "#unsupported precision"
pub status "#unsupported scan count"
pri status "#internal error: inconsistent decoder state"
pub const DECODER_WORKBUF_LEN_MAX_INCL_WORST_CASE : base.u64 = 0xC_00C0_0300
pub struct decoder? implements base.image_decoder(
width : base.u32[..= 0xFFFF],
height : base.u32[..= 0xFFFF],
width_in_mcus : base.u32[..= 0x2000],
height_in_mcus : base.u32[..= 0x2000],
// The call sequence state machine is discussed in
// (/doc/std/image-decoders-call-sequence.md).
call_sequence : base.u8,
test_only_interrupt_decode_mcu : base.bool,
is_jfif : base.bool,
is_adobe : base.u8, // 0: no, 1: yes+RGB/CMYK, 2:yes+YCC/YCCK.
is_rgb_or_cmyk : base.bool,
sof_marker : base.u8,
next_restart_marker : base.u8[..= 7],
max_incl_components_h : base.u8[..= 4],
max_incl_components_v : base.u8[..= 4],
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[..= 3],
// components_workbuf_offsets[0 .. 5], indexed by (csel) and (csel +
// 1), is the i and j bounds in the workbuf[i .. j] slice holding 8-bit
// samples (post-IDCT values) for the csel'th component. The row width
// is components_workbuf_widths[csel], which is also the row stride.
// There is no slack.
//
// For example, a 4:2:0 chroma-subsampled, 36 pixels wide × 28 pixels
// high image has 6 blocks (4 Y, 1 Cb, 1 Cr; 8×8 samples each) per MCU.
// Each MCU is 16×16 pixels. The image is 3 MCUs wide × 2 MCUs high.
// The post-IDCT image dimensions round up to 48 × 32 pixels.
//
// The components_workbuf_widths array is:
// 0: 0x30 = 48 // Y
// 1: 0x18 = 24 // Cb
// 2: 0x18 = 24 // Cr
// 3: 0x00 = 0 // Unused
//
// The head of the components_workbuf_offsets array is:
// 0: 0x0000 = 0
// 1: 0x0600 = 1536 = previous + (48 * 32)
// 2: 0x0780 = 1920 = previous + (24 * 16)
// 3: 0x0900 = 2304 = previous + (24 * 16)
// 4: 0x0900 = 2304 = previous + ( 0 * 0)
//
// That's components_workbuf_offsets[0 .. 5], for to a csel ranging in
// [0 .. 4]. For sequential JPEGs, components_workbuf_offsets[5 .. 9]
// are all equal to components_workbuf_offsets[4]. The four tail
// elements are unused, other than components_workbuf_offsets[8] (equal
// to components_workbuf_offsets[4]) being the workbuf_len.
//
// For progressive JPEGs, these hold the pre-IDCT pre-dequantization
// coefficients that persist between and are incrementally built by
// multiple Scans. There are 64 16-bit coefficients per block, just
// like there are 64 8-bit samples per block, but 16-bit coefficients
// obviously occupy twice as many bytes. Hence, the deltas between the
// components_workbuf_offsets tail elements are twice the deltas
// between its head elements.
//
// A block's 64 coefficients also have a different workbuf layout
// (placed in 128 consecutive bytes), compared to a block's 64 samples
// (placed in 8 rows; the stride is components_workbuf_widths[csel]).
// The 16-bit coefficients are stored little-endian.
//
// Continuing our 36 × 28 image example, if it was sequential encoded,
// the remaining four elements would all be 0x0900. If progressive
// encoded, the tail of the components_workbuf_offsets array is:
// 5: 0x1500 = 5376 = previous + (48 * 64)
// 6: 0x1800 = 6144 = previous + (24 * 32)
// 7: 0x1B00 = 6912 = previous + (24 * 32)
// 8: 0x1B00 = 6912 = previous + ( 0 * 0)
//
// The workbuf_len would be 0x0900 (baseline) or 0x1B00 (progressive).
components_workbuf_widths : array[4] base.u32[..= 0x1_0008],
components_workbuf_heights : array[4] base.u32[..= 0x1_0008],
components_workbuf_offsets : array[9] base.u64[..= 0xC_00C0_0300], // 12 * 0x1_0008 * 0x1_0008.
scan_count : base.u32,
scan_num_components : base.u32[..= 4],
scan_comps_cselector : array[4] base.u8[..= 3],
scan_comps_td : array[4] base.u8[..= 3],
scan_comps_ta : array[4] base.u8[..= 3],
// Every JPEG has a single SOI (Start Of Image) marker. Hierarchical
// JPEG images can have multiple Frames but this decoder does not
// support those. We thus expect a single SOF (Start Of Frame) for the
// single SOI.
//
// Sequential JPEGs have a single SOS (Start Of Scan) for the SOF.
// Their (Ss, Se, Ah, Al) below are effectively (0, 63, 0, 0).
//
// Progressive JPEGs have muliple Scans, incrementally building the 64
// coefficients (1 DC coefficient and 63 AC coefficients) of each
// pre-IDCT block. There are two independent aspects of progression.
//
// Spectral selection (the Ss and Se parameters) is when a subset of a
// 64 coefficients are in the scan. For example, three scans could hold
// coefficient 0 (the DC coefficient), coefficients 1 ..= 5 and then
// coefficients 6 ..= 63, in zig-zag order.
//
// Successive approximation (the Ah and Al parameters) is when a subset
// of the spectral-selected coefficients' 8 bits are in the scan
// (assuming 8-bit and not 12-bit or 16-bit JPEGs). For example, three
// scans could hold the 6 most significant bits, the second-least
// significant bit and then the least significant bit. A zero Ah value
// is a special case, meaning the scan holds (8 - Al) bits.
//
// The test/data/peacock.progressive.jpeg file has 10 scans:
// 0: Ss = 0 Se = 0 Ah = 0 Al = 1 3 components (Y, Cb, Cr)
// 1: Ss = 1 Se = 5 Ah = 0 Al = 2 1 component (Y)
// 2: Ss = 1 Se = 63 Ah = 0 Al = 1 1 component (Cr)
// 3: Ss = 1 Se = 63 Ah = 0 Al = 1 1 component (Cb)
// 4: Ss = 6 Se = 63 Ah = 0 Al = 2 1 component (Y)
// 5: Ss = 1 Se = 63 Ah = 2 Al = 1 1 component (Y)
// 6: Ss = 0 Se = 0 Ah = 1 Al = 0 3 components (Y, Cb, Cr)
// 7: Ss = 1 Se = 63 Ah = 1 Al = 0 1 component (Cr)
// 8: Ss = 1 Se = 63 Ah = 1 Al = 0 1 component (Cb)
// 9: Ss = 1 Se = 63 Ah = 1 Al = 0 1 component (Y)
//
// This matches /usr/bin/cjpeg's default script for progressive YCbCr:
// https://github.com/libjpeg-turbo/libjpeg-turbo/blob/2192560d74e6e6cf99dd05928885573be00a8208/jcparam.c#L517-L535
//
// The first scan holds the high 7 bits of all components' DC
// coefficients.
//
// The second scan holds the high 6 bits of the 1 ..= 5 AC coefficients
// of the Y component.
//
// The third and fourth scan give the high 7 bits of all of the AC
// coefficients of the Cr and Cb components.
//
// The fifth scan is like the second scan, but for the Y component's
// remaining AC coefficients.
//
// The sixth scan holds the second-least significant bit for the Y
// component's AC coefficients.
//
// The seventh scan holds the least significant bit for all components'
// DC coefficients.
//
// The last three scans hold the least significant bit for components'
// AC coefficients.
scan_ss : base.u8[..= 63],
scan_se : base.u8[..= 63],
scan_ah : base.u8[..= 14],
scan_al : base.u8[..= 13],
// These fields, the mx and my loop bounds in decode_sos, are usually
// measured "in MCUs" but, for progressive JPEGs' single-component
// scans, they're measured in blocks.
scan_width_in_mcus : base.u32[..= 0x2000],
scan_height_in_mcus : base.u32[..= 0x2000],
// The block's position within the MCU. For example, a 4:2:0 chroma-
// subsampled image has 6 blocks (4 Y, 1 Cb, 1 Cr) per MCU:
// 0: by = 0 bx = 0 Y
// 1: by = 0 bx = 1 Y
// 2: by = 1 bx = 0 Y
// 3: by = 1 bx = 1 Y
// 4: by = 0 bx = 0 Cb
// 5: by = 0 bx = 0 Cr
//
// The remaining (16 - mcu_num_blocks) elements are unused.
scan_comps_bx_offset : array[16] base.u8[..= 3],
scan_comps_by_offset : array[16] base.u8[..= 3],
mcu_num_blocks : base.u32[..= 10],
mcu_current_block : base.u32[..= 10],
mcu_zig_index : base.u32[..= 63],
mcu_blocks_sselector : array[16] base.u8[..= 3],
// (offset[b] + (mx_mul[b] * mx) + (my_mul[b] * my)) is the workbuf
// offset of the top-left sample of the b'th block in the (mx, my) MCU.
// The block's 64 samples are arranged in 8 rows, each separated by a
// stride equal to components_workbuf_widths[csel].
//
// For single-component scans, its calculation depends on:
// - components_workbuf_offsets
// - components_workbuf_widths
//
// For multi-component scans, its calculation depends on:
// - components_workbuf_offsets
// - components_workbuf_widths
// - scan_comps_bx_offset
// - scan_comps_by_offset
// - components_h
// - components_v
//
// Continuing our 4:2:0 chroma-subsampled, 36 × 28 sequential example:
// 0: my_mul = 768 mx_mul = 16 offset = 0x0000 + 0x0000 = 0
// 1: my_mul = 768 mx_mul = 16 offset = 0x0000 + 0x0008 = 8
// 2: my_mul = 768 mx_mul = 16 offset = 0x0000 + 0x0180 = 384
// 3: my_mul = 768 mx_mul = 16 offset = 0x0000 + 0x0188 = 392
// 4: my_mul = 192 mx_mul = 8 offset = 0x0600 + 0x0000 = 1536
// 5: my_mul = 192 mx_mul = 8 offset = 0x0780 + 0x0000 = 1920
mcu_blocks_offset : array[10] base.u64[..= 0xC_00D8_03D8], // (8 * 3 * (0x1_0008 + 1)) + 0xC_00C0_0300
mcu_blocks_mx_mul : array[10] base.u32[..= 0x00_0020], // 8 * 4.
mcu_blocks_my_mul : array[10] base.u32[..= 0x20_0100], // 8 * 4 * 0x1_0008.
mcu_blocks_dc_hselector : array[10] base.u8[..= 3],
mcu_blocks_ac_hselector : array[10] base.u8[..= 7],
mcu_previous_dc_values : array[4] base.u16,
block_smoothing_lowest_scan_al : array[4] array[10] base.u8[..= 16],
block_smoothing_dc_values : array[5] array[5] base.u16,
block_smoothing_mx_max_incl : base.u32[..= 0x1FFF],
block_smoothing_my_max_incl : base.u32[..= 0x1FFF],
restart_interval : base.u16,
saved_restart_interval : base.u16,
restarts_remaining : base.u16,
// End-Of-Band run count, per Section G.1.2.2: "Progressive encoding of
// AC coefficients with Huffman coding... An EOB run of length 5 means
// that the current block and the next four blocks have an end-of-band
// with no intervening non-zero coefficients".
eob_run : base.u16,
frame_config_io_position : base.u64,
payload_length : base.u32[..= 0xFFFF],
seen_dqt : array[4] base.bool,
saved_seen_dqt : array[4] base.bool,
seen_dht : array[8] base.bool,
// These fields yield bitstream bits in Most Significant Bits order.
bitstream_bits : base.u64,
bitstream_n_bits : base.u32,
bitstream_ri : base.u32[..= 0x800],
bitstream_wi : base.u32[..= 0x800],
bitstream_is_closed : base.bool,
expect_multiple_scans : base.bool,
use_lower_quality : base.bool,
reject_progressive_jpegs : base.bool,
swizzle_immediately : base.bool,
swizzle_immediately_status : base.status,
swizzle_immediately_b_offsets : array[10] base.u32[..= 576],
swizzle_immediately_c_offsets : array[5] base.u32,
// bitstream_padding is the number (per restart) of implicit zeroes
// remaining at the end of the bitstream. Its initial 12345 value is
// arbitrary.
bitstream_padding : base.u32[..= 12345],
quant_tables : array[4] array[64] base.u16[..= 0xFF],
saved_quant_tables : array[4] array[64] base.u16[..= 0xFF],
// huff_tables_symbols[(tc*4)|th][i] is the i'th Huffman code's symbol.
huff_tables_symbols : array[8] array[256] base.u8,
// huff_tables_slow[(tc*4)|th][n] is a u32 such that:
// - the high 24 bits hold the maximum (exclusive) bit-string of the
// codes of bit-length (n+1).
// - the low 8 bits hold a huff_tables_symbols[(tc*4)|th] index bias.
huff_tables_slow : array[8] array[16] base.u32,
// huff_tables_fast[(tc*4)|th][b] is a u16 that decodes the bit-length
// and symbol when the MSB-first bit-stream starts with b.
// - the high 8 bits hold the bit-length. Zero means no fast path.
// - the low 8 bits hold the symbol.
huff_tables_fast : array[8] array[256] base.u16,
swizzler : base.pixel_swizzler,
util : base.utility,
) + (
bitstream_buffer : array[0x800] base.u8, // 0x800 = 2048.
// Decoding sequential JPEGs only uses the first element of this array,
// since sequential decode_mcu calls decode_idct straight away.
// Decoding progressive JPEGs can use all of it.
mcu_blocks : array[10] array[64] base.u16,
swizzle_immediately_buffer : array[640] base.u8,
swizzle_ycck_scratch_buffer_2k : array[2048] base.u8,
// The dht_temp_etc fields are decode_dht temporary values.
// dht_temp_counts[n] is the number of codes with bit-length (n+1).
dht_temp_counts : array[16] base.u8,
// dht_temp_bit_lengths[i] is the bit-length of the i'th code.
dht_temp_bit_lengths : array[256] base.u8,
// dht_temp_bit_strings[i] is the bit-string of the i'th code.
dht_temp_bit_strings : array[256] base.u16,
dst_palette : array[4 * 256] base.u8,
)
pub func decoder.get_quirk(key: base.u32) base.u64 {
if args.key == base.QUIRK_QUALITY {
if this.use_lower_quality {
return 0xFFFF_FFFF_FFFF_FFFF
}
} else if args.key == QUIRK_REJECT_PROGRESSIVE_JPEGS {
if this.reject_progressive_jpegs {
return 1
}
}
return 0
}
pub func decoder.set_quirk!(key: base.u32, value: base.u64) base.status {
if args.key == base.QUIRK_QUALITY {
this.use_lower_quality = args.value >= 0x8000_0000_0000_0000
return ok
} else if args.key == QUIRK_REJECT_PROGRESSIVE_JPEGS {
this.reject_progressive_jpegs = args.value <> 0
return ok
}
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
}
}
pri func decoder.do_decode_image_config?(dst: nptr base.image_config, src: base.io_reader) {
var c8 : base.u8
var marker : base.u8
var pixfmt : base.u32
if this.call_sequence <> 0x00 {
return base."#bad call sequence"
}
c8 = args.src.read_u8?()
if c8 <> 0xFF {
return "#bad header"
}
c8 = args.src.read_u8?()
if c8 <> 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 {
c8 = args.src.read_u8?()
if c8 == 0xFF {
break
}
// Getting here is invalid according to the JPEG spec, but libjpeg
// treats this as a warning (JWRN_EXTRANEOUS_DATA), not an error.
}
while true {
c8 = args.src.read_u8?()
if c8 <> 0xFF {
marker = c8
break
}
// Section B.1.1.2: "Any marker may optionally be preceded by any
// number of [0xFF] fill bytes".
}
if marker == 0x00 {
// Ignore byte stuffing.
continue
} else if (0xD0 <= marker) and (marker <= 0xD9) {
// RSTn (Restart), SOI and EOI markers have no payload.
if marker <= 0xD7 {
continue
}
} else {
this.payload_length = args.src.read_u16be_as_u32?()
// Payload length includes the 2 bytes for the u16be just read.
if this.payload_length >= 2 {
this.payload_length -= 2
} else if (marker == 0xFE) or // COM.
((0xE0 <= marker) and (marker < 0xF0)) { // APPn.
// Strictly speaking, this is invalid according to Section
// B.1.1.4 "Marker segments". However, libjpeg-turbo allows it
// (for COM and APPn markers; see its jdmarker.c file's
// skip_variable function) so we do too.
continue
} else {
return "#bad marker"
}
}
// Switch on the marker.
if marker < 0xC0 {
return "#unsupported marker"
} else if marker < 0xD0 { // SOFn (Start of Frame) and friends.
if marker <= 0xC2 {
if (marker == 0xC2) and this.reject_progressive_jpegs {
return "#rejected progressive JPEG"
} else if this.sof_marker <> 0 {
return "#bad SOF marker"
} else if (marker == 0xC0) {
// SOF0 (which is 0xC0) means a baseline JPEG. The baseline
// (th <= 1) restriction is specified in table B.5.
if this.seen_dht[2] or this.seen_dht[3] or this.seen_dht[6] or this.seen_dht[7] {
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).
this.decode_dht?(src: args.src)
continue
} 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).
this.decode_appn?(src: args.src, marker: marker)
continue
} else {
if marker == 0xFE { // COM (Comment).
// No-op.
} else {
return "#unsupported marker"
}
}
args.src.skip_u32?(n: this.payload_length)
this.payload_length = 0
}
choose decode_idct = [
// TODO: decode_idct_arm_neon,
decode_idct_x86_avx2]
this.frame_config_io_position = args.src.position()
if args.dst <> nullptr {
pixfmt = base.PIXEL_FORMAT__Y
if this.num_components > 1 {
// TODO: base.PIXEL_FORMAT__YCBCR is probably more correct,
// although possibly less convenient for the caller.
pixfmt = base.PIXEL_FORMAT__BGRX
}
args.dst.set!(
pixfmt: pixfmt,
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 c8 : base.u8
var q : base.u8[..= 3]
var i : base.u32
while this.payload_length > 0 {
this.payload_length -= 1
c8 = args.src.read_u8?()
if (c8 & 0x0F) > 3 {
return "#bad DQT marker"
}
q = c8 & 0x0F
if (c8 >> 4) == 1 {
return "#unsupported precision"
} else if ((c8 >> 4) > 1) or (this.payload_length < 64) {
return "#bad DQT marker"
}
this.payload_length -= 64
i = 0
while i < 64 {
i += 1
this.quant_tables[q][UNZIG[i]] = args.src.read_u8_as_u16?()
}
this.seen_dqt[q] = true
if this.sof_marker == 0 {
i = 0
while i < 64 {
this.saved_quant_tables[q][i] = this.quant_tables[q][i]
i += 1
}
this.saved_seen_dqt[q] = true
}
}
}
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?()
if this.sof_marker == 0 {
this.saved_restart_interval = this.restart_interval
}
}
// APPn tags are listed at https://exiftool.org/TagNames/JPEG.html
pri func decoder.decode_appn?(src: base.io_reader, marker: base.u8) {
var c8 : base.u8
var c32 : base.u32
while.goto_done true {{
if args.marker == 0xE0 { // APP0.
if this.payload_length >= 5 {
this.payload_length -= 5
c32 = args.src.read_u32le?()
if c32 <> 'JFIF'le {
this.payload_length = 0xFFFF & (this.payload_length + 1)
break.goto_done
}
c8 = args.src.read_u8?()
this.is_jfif = (c8 == 0)
}
} else if args.marker == 0xEE { // APP14.
if this.payload_length >= 12 {
this.payload_length -= 12
c32 = args.src.read_u32le?()
if c32 <> 'Adob'le {
this.payload_length = 0xFFFF & (this.payload_length + 8)
break.goto_done
}
c32 = args.src.read_u32le?()
if (0xFF & c32) <> 'e' {
this.payload_length = 0xFFFF & (this.payload_length + 4)
break.goto_done
}
// After the 5 bytes of "Adobe" come 2 bytes of DCTEncodeVersion
// and 4 bytes of flags. The 12th byte is the color transform.
// Technically, 0=Unknown, 1=YCbCr and 2=YCbCrK. In practice, per
// libjpeg-turbo, treat 0=RGB/CMYK and NonZero=YCbCr/YCbCrK.
//
// https://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/JPEG.html#Adobe
c32 = args.src.read_u32le?()
if (c32 >> 24) == 0 {
this.is_adobe = 1
} else {
this.is_adobe = 2
}
}
}
break.goto_done
}}.goto_done
args.src.skip_u32?(n: this.payload_length)
this.payload_length = 0
}
pri func decoder.decode_sof?(src: base.io_reader) {
var c8 : base.u8
var comp_h : base.u8
var comp_v : base.u8
var i : base.u32
var j : base.u32
var has_h24 : base.bool
var has_h3 : base.bool
var has_v24 : base.bool
var has_v3 : base.bool
var upper_bound : base.u32[..= 0x1_0008]
var wh0 : base.u64[..= 0x1_0010_0040] // 0x1_0008 * 0x1_0008.
var wh1 : base.u64[..= 0x1_0010_0040] // 0x1_0008 * 0x1_0008.
var wh2 : base.u64[..= 0x1_0010_0040] // 0x1_0008 * 0x1_0008.
var wh3 : base.u64[..= 0x1_0010_0040] // 0x1_0008 * 0x1_0008.
var progressive : base.u64[..= 2]
if this.payload_length < 6 {
return "#bad SOF marker"
}
this.payload_length -= 6
c8 = args.src.read_u8?()
if c8 == 8 {
// No-op.
} else if c8 == 12 {
return "#unsupported precision (12 bits)"
} else if c8 == 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"
}
c8 = args.src.read_u8?()
if (c8 == 0) or (c8 > 4) {
return "#bad SOF marker"
} else if c8 == 2 {
return "#unsupported color model"
}
this.num_components = c8 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?()
c8 = args.src.read_u8?()
comp_h = c8 >> 4
comp_v = c8 & 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
if this.max_incl_components_h < this.components_h[i] {
this.max_incl_components_h = this.components_h[i]
}
this.components_v[i] = comp_v
if this.max_incl_components_v < this.components_v[i] {
this.max_incl_components_v = this.components_v[i]
}
c8 = args.src.read_u8?()
if c8 >= 4 {
return "#bad SOF marker"
}
this.components_tq[i] = c8
// 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
}
i += 1
}
if this.num_components == 1 {
// The first (and only) component's H and V factors are effectively
// always 1. Section A.2.2: "When Ns = 1 (where Ns is the number of
// components in a scan), the order of data units [8x8 blocks] within a
// scan shall be left-to-right and top-to-bottom... regardless of the
// values of H1 and V1.".
this.max_incl_components_h = 1
this.max_incl_components_v = 1
this.components_h[0] = 1
this.components_v[0] = 1
} else {
has_h24 = false
has_h3 = false
has_v24 = false
has_v3 = false
i = 0
while i < this.num_components {
assert i < 4 via "a < b: a < c; c <= b"(c: this.num_components)
has_h24 = has_h24 or (this.components_h[i] == 2) or (this.components_h[i] == 4)
has_h3 = has_h3 or (this.components_h[i] == 3)
has_v24 = has_v24 or (this.components_v[i] == 2) or (this.components_v[i] == 4)
has_v3 = has_v3 or (this.components_v[i] == 3)
i += 1
}
if (has_h24 and has_h3) or (has_v24 and has_v3) {
return "#unsupported fractional sampling"
}
// Match the behavior of libjpeg-turbo's jdapimin.c.
if this.num_components == 4 {
this.is_rgb_or_cmyk = this.is_adobe < 2
} else { // this.num_components == 3
if this.is_jfif {
this.is_rgb_or_cmyk = false
} else if this.is_adobe > 0 {
this.is_rgb_or_cmyk = this.is_adobe == 1
} else {
this.is_rgb_or_cmyk =
(this.components_c[0] == 'R') and
(this.components_c[1] == 'G') and
(this.components_c[2] == 'B')
}
}
}
this.width_in_mcus = this.quantize_dimension(
width: this.width, h: 1, max_incl_h: this.max_incl_components_h)
this.height_in_mcus = this.quantize_dimension(
width: this.height, h: 1, max_incl_h: this.max_incl_components_v)
upper_bound = 0x1_0008
this.components_workbuf_widths[0] = upper_bound.min(no_more_than:
8 * this.width_in_mcus * (this.components_h[0] as base.u32))
this.components_workbuf_widths[1] = upper_bound.min(no_more_than:
8 * this.width_in_mcus * (this.components_h[1] as base.u32))
this.components_workbuf_widths[2] = upper_bound.min(no_more_than:
8 * this.width_in_mcus * (this.components_h[2] as base.u32))
this.components_workbuf_widths[3] = upper_bound.min(no_more_than:
8 * this.width_in_mcus * (this.components_h[3] as base.u32))
this.components_workbuf_heights[0] = upper_bound.min(no_more_than:
8 * this.height_in_mcus * (this.components_v[0] as base.u32))
this.components_workbuf_heights[1] = upper_bound.min(no_more_than:
8 * this.height_in_mcus * (this.components_v[1] as base.u32))
this.components_workbuf_heights[2] = upper_bound.min(no_more_than:
8 * this.height_in_mcus * (this.components_v[2] as base.u32))
this.components_workbuf_heights[3] = upper_bound.min(no_more_than:
8 * this.height_in_mcus * (this.components_v[3] as base.u32))
wh0 = (this.components_workbuf_widths[0] as base.u64) * (this.components_workbuf_heights[0] as base.u64)
wh1 = (this.components_workbuf_widths[1] as base.u64) * (this.components_workbuf_heights[1] as base.u64)
wh2 = (this.components_workbuf_widths[2] as base.u64) * (this.components_workbuf_heights[2] as base.u64)
wh3 = (this.components_workbuf_widths[3] as base.u64) * (this.components_workbuf_heights[3] as base.u64)
progressive = 0
if this.sof_marker >= 0xC2 {
// Pre-IDCT block coefficients (mcu_blocks elements) are 2 bytes each.
progressive = 2
i = 0
while i < 4 {
j = 0
while j < 10,
inv i < 4,
{
this.block_smoothing_lowest_scan_al[i][j] = 16
j += 1
}
i += 1
}
}
this.components_workbuf_offsets[0] = 0
this.components_workbuf_offsets[1] = this.components_workbuf_offsets[0] + wh0
this.components_workbuf_offsets[2] = this.components_workbuf_offsets[1] + wh1
this.components_workbuf_offsets[3] = this.components_workbuf_offsets[2] + wh2
this.components_workbuf_offsets[4] = this.components_workbuf_offsets[3] + wh3
this.components_workbuf_offsets[5] = this.components_workbuf_offsets[4] + (wh0 * progressive)
this.components_workbuf_offsets[6] = this.components_workbuf_offsets[5] + (wh1 * progressive)
this.components_workbuf_offsets[7] = this.components_workbuf_offsets[6] + (wh2 * progressive)
this.components_workbuf_offsets[8] = this.components_workbuf_offsets[7] + (wh3 * progressive)
}
pri func decoder.quantize_dimension(width: base.u32[..= 0xFFFF], h: base.u8[..= 4], max_incl_h: base.u8[..= 4]) base.u32[..= 0x2000] {
var ratio : base.u32
ratio = 0
if args.h > 0 {
ratio = (args.max_incl_h / args.h) as base.u32
}
if ratio == 1 {
return (args.width + 0x07) / 0x08
} else if ratio == 2 {
return (args.width + 0x0F) / 0x10
} else if ratio == 3 {
return (args.width + 0x17) / 0x18
}
return (args.width + 0x1F) / 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
}
}
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 ddf_status : base.status
var swizzle_status : base.status
var scan_count : base.u32
while true {
scan_count = this.scan_count
ddf_status =? this.do_decode_frame?(dst: args.dst, src: args.src, blend: args.blend, workbuf: args.workbuf, opts: args.opts)
if (ddf_status == base."$short read") and args.src.is_closed() {
ddf_status = "#truncated input"
}
if (not this.swizzle_immediately) and
(ddf_status.is_error() or (scan_count < this.scan_count)) {
if this.sof_marker >= 0xC2 {
this.apply_progressive_idct!(workbuf: args.workbuf)
}
if this.num_components == 1 {
swizzle_status = this.swizzle_gray!(
dst: args.dst,
workbuf: args.workbuf,
x0: 0,
x1: 0xFFFF_FFFF,
y0: 0,
y1: 0xFFFF_FFFF,
stride: this.components_workbuf_widths[0] as base.u64)
} else {
swizzle_status = this.swizzle_colorful!(
dst: args.dst,
workbuf: args.workbuf,
x0: 0,
x1: 0xFFFF_FFFF,
y0: 0,
y1: 0xFFFF_FFFF)
}
if ddf_status.is_error() {
return ddf_status
} else if swizzle_status.is_error() {
return swizzle_status
}
}
yield? ddf_status
}
}
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 pixfmt : base.u32
var status : base.status
var c8 : base.u8
var marker : 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"
}
pixfmt = base.PIXEL_FORMAT__Y
if this.num_components > 1 {
pixfmt = base.PIXEL_FORMAT__BGRX
}
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: pixfmt),
src_palette: this.util.empty_slice_u8(),
blend: args.blend)
if not status.is_ok() {
return status
}
// For progressive JPEGs, zero-initialize the saved pre-IDCT blocks. For
// sequential JPEGs, this is a no-op, other than checking that args.workbuf
// is long enough and setting this.swizzle_immediately.
this.swizzle_immediately = false
if this.components_workbuf_offsets[8] > args.workbuf.length() {
if this.sof_marker >= 0xC2 {
return base."#bad workbuf length"
}
this.swizzle_immediately = this.use_lower_quality
this.swizzle_immediately_status = ok
} else if this.components_workbuf_offsets[4] < this.components_workbuf_offsets[8] {
args.workbuf[this.components_workbuf_offsets[4] .. this.components_workbuf_offsets[8]].bulk_memset!(byte_value: 0)
}
// For both sequential and progressive JPEGs, biased-zero-initialize the
// samples, in case the scans are incomplete (in terms of covering all
// components) or the input is truncated. 0x80 is the same post-IDCT bias
// as per BIAS_AND_CLAMP. For YCbCr, (0x80, 0x80, 0x80) is a medium gray
// but (0x00, 0x00, 0x00) is a dark green.
if this.components_workbuf_offsets[4] <= args.workbuf.length() {
args.workbuf[.. this.components_workbuf_offsets[4]].bulk_memset!(byte_value: 0x80)
}
// Process chunks (markers and their payloads).
while true {
// Read the marker (a two-byte 0xFF 0x?? sequence).
while true {
c8 = args.src.read_u8?()
if c8 == 0xFF {
break
}
// Getting here is invalid according to the JPEG spec, but libjpeg
// treats this as a warning (JWRN_EXTRANEOUS_DATA), not an error.
}
while true {
c8 = args.src.read_u8?()
if c8 <> 0xFF {
marker = c8
break
}
// Section B.1.1.2: "Any marker may optionally be preceded by any
// number of [0xFF] fill bytes".
}
if marker == 0x00 {
// Ignore byte stuffing.
continue
} else if (0xD0 <= marker) and (marker <= 0xD9) {
// RSTn (Restart), SOI and EOI markers have no payload.
if marker <= 0xD7 {
continue
}
} else {
this.payload_length = args.src.read_u16be_as_u32?()
// Payload length includes the 2 bytes for the u16be just read.
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 == 0xC4 { // DHT (Define Huffman Table).
this.decode_dht?(src: args.src)
continue
} else if marker == 0xC8 { // JPG (JPEG extension).
return "#unsupported marker"
}
return "#bad SOF marker"
} else if marker < 0xE0 {
if marker < 0xD9 {
// RSTn markers are already handled above. We have 0xD8 (SOI:
// Start Of Image), which is invalid here.
return "#bad marker"
} else if marker == 0xD9 { // EOI (End Of Image).
break
} else if marker == 0xDA { // SOS (Start Of Scan).
this.decode_sos?(dst: args.dst, src: args.src, workbuf: args.workbuf)
continue
} 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
}
this.call_sequence = 0x60
}
pri func decoder.decode_dht?(src: base.io_reader) {
var c8 : base.u8
var tc : base.u8[..= 1]
var th : base.u8[..= 3]
var tc4_th : base.u8[..= 7]
var working_total_count : base.u32[..= 0xFFFF]
var total_count : base.u32[..= 256]
var i : base.u32
var failed : base.bool
while this.payload_length > 0 {
if this.payload_length < 17 {
return "#bad DHT marker"
}
this.payload_length -= 17
c8 = args.src.read_u8?()
if ((c8 >> 4) > 1) or ((c8 & 0x0F) > 3) {
return "#bad DHT marker"
}
tc = c8 >> 4
th = c8 & 0x0F
tc4_th = ((tc * 4) | th) as base.u8
// SOF0 (which is 0xC0) means a baseline JPEG. The baseline (th <= 1)
// restriction is specified in table B.5.
if (this.sof_marker == 0xC0) and ((tc4_th & 3) > 1) {
return "#bad DHT marker"
}
// Read dht_temp_counts.
i = 0
while i < 16 {
this.dht_temp_counts[i] = args.src.read_u8?()
i += 1
}
working_total_count = 0
i = 0
while i < 16 {
working_total_count =
(working_total_count + (this.dht_temp_counts[i] as base.u32)) & 0xFFFF
i += 1
}
if (working_total_count <= 0) or (256 < working_total_count) {
return "#bad DHT marker"
}
total_count = working_total_count
// Read huff_tables_symbols[tc4_th].
if this.payload_length < total_count {
return "#bad DHT marker"
}
this.payload_length -= total_count
i = 0
while i < total_count {
assert i < 256 via "a < b: a < c; c <= b"(c: total_count)
this.huff_tables_symbols[tc4_th][i] = args.src.read_u8?()
i += 1
}
while i < 256 {
this.huff_tables_symbols[tc4_th][i] = 0
i += 1
}
// For tc == 0 (DC, not AC tables), the symbols must not exceed 15 (for
// lossy JPEG) or 16 (for lossless JPEG). We only support lossy.
if (tc4_th & 4) == 0 {
i = 0
while i < total_count {
assert i < 256 via "a < b: a < c; c <= b"(c: total_count)
if this.huff_tables_symbols[tc4_th][i] > 15 {
return "#bad DHT marker"
}
i += 1
}
}
failed = this.calculate_huff_tables!(tc4_th: tc4_th, total_count: total_count)
if failed {
return "#bad DHT marker"
}
this.seen_dht[tc4_th] = true
}
}
pri func decoder.calculate_huff_tables!(tc4_th: base.u8[..= 7], total_count: base.u32[..= 256]) base.bool {
var i : base.u32
var j : base.u8
var k : base.u8
var bit_length_minus_one : base.u32[..= 15]
var bit_length : base.u8[..= 16]
var bit_string : base.u32
var slow : base.u32
var prefix : base.u8
var fast : base.u16
var reps : base.u32
// Calculate dht_temp_bit_lengths.
i = 0
k = 0
bit_length_minus_one = 0
while i < args.total_count {
assert i < 256 via "a < b: a < c; c <= b"(c: args.total_count)
while k >= this.dht_temp_counts[bit_length_minus_one],
inv i < 256,
post k < this.dht_temp_counts[bit_length_minus_one],
{
k = 0
bit_length_minus_one = (bit_length_minus_one + 1) & 15
}
assert k < 255 via "a < b: a < c; c <= b"(c: this.dht_temp_counts[bit_length_minus_one])
k += 1
this.dht_temp_bit_lengths[i] = (bit_length_minus_one + 1) as base.u8
i += 1
}
// Calculate dht_temp_bit_strings.
bit_length = 0
bit_string = 0
i = 0
while i < args.total_count {
assert i < 256 via "a < b: a < c; c <= b"(c: args.total_count)
while bit_length < this.dht_temp_bit_lengths[i],
inv i < 256,
{
if bit_length >= 16 {
return true
}
bit_length += 1
bit_string ~mod<<= 1
}
this.dht_temp_bit_strings[i] = (bit_string & 0xFFFF) as base.u16
bit_string ~mod+= 1
// Check the bit_string just assigned to dht_temp_bit_strings[i].
// Section C: "the codes shall be generated such that the
// all-1-bits code word of any length is reserved".
if (bit_string >> bit_length) > 0 {
return true
}
i += 1
}
// Calculate huff_tables_slow[args.tc4_th].
k = 0
bit_length_minus_one = 0
while true {
if this.dht_temp_counts[bit_length_minus_one] == 0 {
this.huff_tables_slow[args.tc4_th][bit_length_minus_one] = 0
} else {
slow = 0xFF & ((k as base.u32) ~mod-
(this.dht_temp_bit_strings[k] as base.u32))
k ~mod+= this.dht_temp_counts[bit_length_minus_one]
this.huff_tables_slow[args.tc4_th][bit_length_minus_one] = slow |
(((this.dht_temp_bit_strings[k ~mod- 1] as base.u32) + 1) << 8)
}
bit_length_minus_one = (bit_length_minus_one + 1) & 15
if bit_length_minus_one == 0 {
break
}
}
// Calculate huff_tables_fast[args.tc4_th].
i = 0
while i < 256 {
this.huff_tables_fast[args.tc4_th][i] = 0xFFFF
i += 1
}
j = 0
bit_length_minus_one = 0
while bit_length_minus_one < 8 {
k = 0
while k < this.dht_temp_counts[bit_length_minus_one],
inv bit_length_minus_one < 8,
{
assert k < 255 via "a < b: a < c; c <= b"(c: this.dht_temp_counts[bit_length_minus_one])
prefix = (((this.dht_temp_bit_strings[j] as base.u32) <<
(7 - bit_length_minus_one)) & 0xFF) as base.u8
fast = ((((bit_length_minus_one + 1) as base.u32) << 8) |
(this.huff_tables_symbols[args.tc4_th][j] as base.u32)) as base.u16
reps = (1 as base.u32) << (7 - bit_length_minus_one)
while reps > 0,
inv bit_length_minus_one < 8,
inv k < 255,
{
this.huff_tables_fast[args.tc4_th][prefix] = fast
prefix ~mod+= 1
reps -= 1
}
k += 1
j ~mod+= 1
}
bit_length_minus_one += 1
}
return false
}
pri func decoder.decode_sos?(dst: ptr base.pixel_buffer, src: base.io_reader, workbuf: slice base.u8) {
var my : base.u32
var mx : base.u32
var decode_mcu_result : base.u32
var bitstream_length : base.u32
if this.scan_count >= 32 {
return "#unsupported scan count"
} else if (this.scan_count > 0) and (not this.expect_multiple_scans) {
return "#bad scan count"
}
this.prepare_scan?(src: args.src)
// Reset.
this.next_restart_marker = 0
this.mcu_previous_dc_values[0] = 0
this.mcu_previous_dc_values[1] = 0
this.mcu_previous_dc_values[2] = 0
this.mcu_previous_dc_values[3] = 0
this.restarts_remaining = this.restart_interval
this.eob_run = 0
this.bitstream_bits = 0
this.bitstream_n_bits = 0
this.bitstream_ri = 0
this.bitstream_wi = 0
this.bitstream_padding = 12345
this.fill_bitstream!(src: args.src)
my = 0
while my < this.scan_height_in_mcus {
assert my < 0x2000 via "a < b: a < c; c <= b"(c: this.scan_height_in_mcus)
mx = 0
while mx < this.scan_width_in_mcus,
inv my < 0x2000,
{
assert mx < 0x2000 via "a < b: a < c; c <= b"(c: this.scan_width_in_mcus)
this.mcu_current_block = 0
this.mcu_zig_index = this.scan_ss as base.u32
if this.sof_marker >= 0xC2 {
this.load_mcu_blocks!(mx: mx, my: my, workbuf: args.workbuf)
}
while.decode_mcu true,
inv my < 0x2000,
inv mx < 0x2000,
{
decode_mcu_result = this.decode_mcu!(dst: args.dst, workbuf: args.workbuf, mx: mx, my: my)
if decode_mcu_result == 0 {
break.decode_mcu
} else if decode_mcu_result == 1 {
// No-op.
} else if decode_mcu_result == 2 {
return "#internal error: inconsistent decoder state"
} else {
return this.swizzle_immediately_status
}
while.fill_bitstream true,
inv my < 0x2000,
inv mx < 0x2000,
{
bitstream_length = this.bitstream_wi ~mod- this.bitstream_ri
this.fill_bitstream!(src: args.src)
if bitstream_length < (this.bitstream_wi ~mod- this.bitstream_ri) {
break.fill_bitstream
} else if this.bitstream_padding == 0 {
return "#short SOS bitstream"
} else if args.src.is_closed() and (not this.bitstream_is_closed) {
if this.bitstream_wi < (0x800 / 2) {
assert this.bitstream_wi <= (this.bitstream_wi + 264) via "a <= (a + b): 0 <= b"()
this.bitstream_buffer[this.bitstream_wi .. (this.bitstream_wi + 264)].bulk_memset!(byte_value: 0)
this.bitstream_wi += 264
this.bitstream_is_closed = true
}
break.fill_bitstream
}
yield? base."$short read"
}.fill_bitstream
}.decode_mcu
if this.sof_marker >= 0xC2 {
this.save_mcu_blocks!(mx: mx, my: my, workbuf: args.workbuf)
}
// Check for a restart.
if this.restarts_remaining > 0 {
this.restarts_remaining -= 1
if this.restarts_remaining == 0 {
this.skip_past_the_next_restart_marker?(src: args.src)
// Reset.
this.mcu_previous_dc_values[0] = 0
this.mcu_previous_dc_values[1] = 0
this.mcu_previous_dc_values[2] = 0
this.mcu_previous_dc_values[3] = 0
this.restarts_remaining = this.restart_interval
this.eob_run = 0
this.bitstream_bits = 0
this.bitstream_n_bits = 0
this.bitstream_ri = 0
this.bitstream_wi = 0
this.bitstream_padding = 12345
}
}
mx += 1
}
my += 1
}
this.scan_count ~sat+= 1
}
pri func decoder.prepare_scan?(src: base.io_reader) {
var c8 : base.u8
var i : base.u32
var j : base.u32
var j_max_incl : base.u32[..= 9]
var failed : base.bool
if (this.payload_length < 6) or (this.payload_length > 12) {
return "#bad SOS marker"
}
c8 = args.src.read_u8?()
if (c8 < 1) or (c8 > 4) {
return "#bad SOS marker"
}
this.scan_num_components = c8 as base.u32
if (this.scan_num_components > this.num_components) or
(this.payload_length <> (4 + (2 * this.scan_num_components))) {
return "#bad SOS marker"
}
this.payload_length = 0
i = 0
while i < this.scan_num_components {
assert i < 4 via "a < b: a < c; c <= b"(c: this.scan_num_components)
c8 = args.src.read_u8?()
j = 0
while true,
inv i < 4,
{
if j >= this.num_components {
return "#bad SOS marker"
}
assert j < 4 via "a < b: a < c; c <= b"(c: this.num_components)
if c8 == this.components_c[j] {
if not this.seen_dqt[this.components_tq[j]] {
return "#missing Quantization table"
}
this.scan_comps_cselector[i] = j as base.u8
break
}
j += 1
}
// Section B.2.3: "the value of C_sj shall be different from the values
// of C_s1 to C_sj–1".
j = 0
while j < i,
inv i < 4,
{
assert j < 4 via "a < b: a < c; c < b"(c: i)
if this.scan_comps_cselector[i] == this.scan_comps_cselector[j] {
return "#bad SOS marker"
}
j += 1
}
c8 = args.src.read_u8?()
if ((c8 >> 4) > 3) or ((c8 & 0x0F) > 3) {
return "#bad SOS marker"
}
this.scan_comps_td[i] = c8 >> 4
this.scan_comps_ta[i] = c8 & 0x0F
// SOF0 (which is 0xC0) means a baseline JPEG. The baseline (tx <= 1)
// restriction is specified in table B.5.
if this.sof_marker == 0xC0 {
if (this.scan_comps_td[i] > 1) or (this.scan_comps_ta[i] > 1) {
return "#bad SOS marker"
}
}
i += 1
}
if this.scan_count == 0 {
this.expect_multiple_scans =
(this.sof_marker >= 0xC2) or
(this.scan_num_components < this.num_components)
}
if this.sof_marker < 0xC2 {
// At this point, for sequential (not progressive) JPEGs, we should
// check that (Ss, Se, Ah, Al) is (0, 63, 0, 0) but libjpeg treats
// otherwise as a warning (JWRN_NOT_SEQUENTIAL), not an error.
args.src.skip_u32?(n: 3)
this.scan_ss = 0
this.scan_se = 63
this.scan_ah = 0
this.scan_al = 0
} else {
c8 = args.src.read_u8?()
if c8 > 63 {
return "#bad SOS marker"
}
this.scan_ss = c8
c8 = args.src.read_u8?()
if (c8 > 63) or (c8 < this.scan_ss) {
return "#bad SOS marker"
}
this.scan_se = c8
c8 = args.src.read_u8?()
if ((c8 >> 4) > 14) or ((c8 & 0x0F) > 13) {
return "#bad SOS marker"
}
this.scan_ah = c8 >> 4
this.scan_al = c8 & 0x0F
if this.scan_ah > 0 {
if (this.scan_ah - 1) <> this.scan_al {
return "#bad SOS marker"
}
}
if this.scan_ss == 0 {
// Progressive DC scans can have only one spectral element.
if this.scan_se <> 0 {
return "#bad SOS marker"
} else if this.scan_ah == 0 {
choose decode_mcu = [decode_mcu_progressive_dc_high_bits]
} else {
choose decode_mcu = [decode_mcu_progressive_dc_low_bit]
}
} else {
// Progressive AC scans can have only one component.
if this.scan_num_components <> 1 {
return "#bad SOS marker"
} else if this.scan_ah == 0 {
choose decode_mcu = [decode_mcu_progressive_ac_high_bits]
} else {
choose decode_mcu = [decode_mcu_progressive_ac_low_bit]
}
}
}
i = 0
while i < this.scan_num_components {
assert i < 4 via "a < b: a < c; c <= b"(c: this.scan_num_components)
if (this.scan_ss == 0) and (not this.seen_dht[0 | this.scan_comps_td[i]]) {
this.use_default_huffman_table?(tc4_th: 0 | this.scan_comps_td[i])
}
if (this.scan_se <> 0) and (not this.seen_dht[4 | this.scan_comps_ta[i]]) {
this.use_default_huffman_table?(tc4_th: 4 | this.scan_comps_ta[i])
}
j = this.scan_ss as base.u32
j_max_incl = (this.scan_se.min(no_more_than: 9)) as base.u32
while j <= j_max_incl,
inv i < 4,
{
assert j <= 9 via "a <= b: a <= c; c <= b"(c: j_max_incl)
this.block_smoothing_lowest_scan_al[this.scan_comps_cselector[i]][j] = this.scan_al
j += 1
}
i += 1
}
if this.scan_num_components == 1 {
this.calculate_single_component_scan_fields!()
} else {
failed = this.calculate_multiple_component_scan_fields!()
if failed {
return "#bad SOS marker"
}
}
}
pri func decoder.use_default_huffman_table?(tc4_th: base.u8[..= 7]) {
var data : roslice base.u8
var r : base.io_reader
var status : base.status
if args.tc4_th == 0 {
data = DEFAULT_HUFF_TABLE_DC_LUMA[..]
} else if args.tc4_th == 1 {
data = DEFAULT_HUFF_TABLE_DC_CHROMA[..]
} else if args.tc4_th == 4 {
data = DEFAULT_HUFF_TABLE_AC_LUMA[..]
} else if args.tc4_th == 5 {
data = DEFAULT_HUFF_TABLE_AC_CHROMA[..]
} else {
return "#missing Huffman table"
}
io_bind (io: r, data: data, history_position: 0) {
this.payload_length = (data.length() & 0xFFFF) as base.u32
status =? this.decode_dht?(src: r)
}
return status
}
pri func decoder.calculate_single_component_scan_fields!() {
var csel : base.u8[..= 3]
this.scan_comps_bx_offset[0] = 0
this.scan_comps_by_offset[0] = 0
this.mcu_num_blocks = 1
this.mcu_blocks_sselector[0] = 0
csel = this.scan_comps_cselector[0]
this.mcu_blocks_offset[0] = this.components_workbuf_offsets[csel]
this.mcu_blocks_mx_mul[0] = 8
this.mcu_blocks_my_mul[0] = 8 * this.components_workbuf_widths[csel]
this.mcu_blocks_dc_hselector[0] = 0 | this.scan_comps_td[0]
this.mcu_blocks_ac_hselector[0] = 4 | this.scan_comps_ta[0]
this.scan_width_in_mcus = this.quantize_dimension(
width: this.width, h: this.components_h[csel], max_incl_h: this.max_incl_components_h)
this.scan_height_in_mcus = this.quantize_dimension(
width: this.height, h: this.components_v[csel], max_incl_h: this.max_incl_components_v)
}
pri func decoder.calculate_multiple_component_scan_fields!() base.bool {
var i : base.u32
var h : base.u32[..= 4]
var v : base.u32[..= 4]
var hv : base.u32[..= 16]
var total_hv : base.u32
var b : base.u32
var bx_offset : base.u32
var by_offset : base.u32
var sibo : base.u32
var ssel : base.u8[..= 3]
var csel : base.u8[..= 3]
total_hv = 0
i = 0
b = 0
bx_offset = 0
by_offset = 0
while i < this.scan_num_components {
assert i < 4 via "a < b: a < c; c <= b"(c: this.scan_num_components)
h = this.components_h[this.scan_comps_cselector[i]] as base.u32
v = this.components_v[this.scan_comps_cselector[i]] as base.u32
hv = ((this.components_h[this.scan_comps_cselector[i]] as base.u32) *
(this.components_v[this.scan_comps_cselector[i]] as base.u32))
this.swizzle_immediately_c_offsets[i] = 64 ~mod* total_hv
total_hv ~mod+= hv
while hv > 0,
inv i < 4,
{
this.scan_comps_bx_offset[b & 15] = (bx_offset & 3) as base.u8
this.scan_comps_by_offset[b & 15] = (by_offset & 3) as base.u8
this.mcu_blocks_sselector[b & 15] = i as base.u8
b ~mod+= 1
bx_offset ~mod+= 1
if bx_offset == h {
bx_offset = 0
by_offset ~mod+= 1
if by_offset == v {
by_offset = 0
}
}
hv -= 1
}
i += 1
}
if total_hv > 10 {
return true
}
this.mcu_num_blocks = total_hv
this.swizzle_immediately_c_offsets[this.scan_num_components] = 64 ~mod* total_hv
b = 0
while b < this.mcu_num_blocks {
assert b < 10 via "a < b: a < c; c <= b"(c: this.mcu_num_blocks)
ssel = this.mcu_blocks_sselector[b]
csel = this.scan_comps_cselector[ssel]
this.mcu_blocks_offset[b] = this.components_workbuf_offsets[csel] +
(8 * (this.scan_comps_bx_offset[b] as base.u64)) +
(8 * (this.scan_comps_by_offset[b] as base.u64) * (this.components_workbuf_widths[csel] as base.u64))
this.mcu_blocks_mx_mul[b] = 8 * (this.components_h[csel] as base.u32)
this.mcu_blocks_my_mul[b] = 8 * (this.components_v[csel] as base.u32) * this.components_workbuf_widths[csel]
this.mcu_blocks_dc_hselector[b] = 0 | this.scan_comps_td[ssel]
this.mcu_blocks_ac_hselector[b] = 4 | this.scan_comps_ta[ssel]
sibo = this.swizzle_immediately_c_offsets[csel] ~mod+ (
(8 * (this.scan_comps_bx_offset[b] as base.u32)) +
(64 * (this.scan_comps_by_offset[b] as base.u32) * (this.components_h[csel] as base.u32)))
this.swizzle_immediately_b_offsets[b] = sibo.min(no_more_than: 576)
b += 1
}
this.scan_width_in_mcus = this.width_in_mcus
this.scan_height_in_mcus = this.height_in_mcus
return false
}
pri func decoder.fill_bitstream!(src: base.io_reader) {
var wi : base.u32[..= 0x800]
var c8 : base.u8
var new_wi : base.u32[..= 0x800]
// Compact unread bytes to the start of the buffer.
if this.bitstream_ri <= 0 {
// No-op.
} else if this.bitstream_ri >= this.bitstream_wi {
this.bitstream_ri = 0
this.bitstream_wi = 0
} else {
assert this.bitstream_wi > this.bitstream_ri via "a > b: b < a"()
wi = this.bitstream_wi - this.bitstream_ri
this.bitstream_buffer[..].copy_from_slice!(s: this.bitstream_buffer[this.bitstream_ri .. this.bitstream_wi])
this.bitstream_ri = 0
this.bitstream_wi = wi
}
wi = this.bitstream_wi
while (wi < 0x800) and (args.src.length() > 0) {
c8 = args.src.peek_u8()
if c8 < 0xFF {
this.bitstream_buffer[wi] = c8
wi += 1
args.src.skip_u32_fast!(actual: 1, worst_case: 1)
continue
} else if args.src.length() <= 1 {
break
} else if (args.src.peek_u16le() >> 8) > 0 {
break
} else {
this.bitstream_buffer[wi] = 0xFF
wi += 1
args.src.skip_u32_fast!(actual: 2, worst_case: 2)
}
}
// If we hit a "\xFF\x??" marker then pad the bitstream. In this method
// invocation, insert up to 264 bytes of implicit zeroes. Repeated calls to
// this method can insert even more.
if args.src.length() > 1 {
if (args.src.peek_u8() >= 0xFF) and ((args.src.peek_u16le() >> 8) > 0) {
new_wi = wi.min(no_more_than: 0x800 - 264) + 264
new_wi = new_wi.min(no_more_than: wi + this.bitstream_padding)
if wi < new_wi {
assert new_wi > wi via "a > b: b < a"()
this.bitstream_padding ~sat-= new_wi - wi
this.bitstream_buffer[wi .. new_wi].bulk_memset!(byte_value: 0)
wi = new_wi
}
}
}
this.bitstream_wi = wi
}
pri func decoder.load_mcu_blocks_for_single_component!(mx: base.u32[..= 0x2000], my: base.u32[..= 0x2000], workbuf: slice base.u8, csel: base.u32[..= 3]),
choosy,
{
var stride16 : base.u64[..= 0x10_0080]
var offset : base.u64
stride16 = (this.components_workbuf_widths[args.csel] * 16) as base.u64
offset = this.components_workbuf_offsets[args.csel | 4] +
((args.mx as base.u64) * 128) +
((args.my as base.u64) * stride16)
if offset <= args.workbuf.length() {
this.mcu_blocks[.. 1].bulk_load_host_endian!(src: args.workbuf[offset ..])
}
}
pri func decoder.load_mcu_blocks!(mx: base.u32[..= 0x2000], my: base.u32[..= 0x2000], workbuf: slice base.u8) {
var b : base.u32
var csel : base.u8[..= 3]
var h : base.u64[..= 4]
var v : base.u64[..= 4]
var stride16 : base.u64[..= 0x10_0080]
var offset : base.u64
h = 1
v = 1
b = 0
while b < this.mcu_num_blocks {
assert b < 10 via "a < b: a < c; c <= b"(c: this.mcu_num_blocks)
csel = this.scan_comps_cselector[this.mcu_blocks_sselector[b]]
if this.scan_num_components > 1 {
h = this.components_h[csel] as base.u64
v = this.components_v[csel] as base.u64
}
stride16 = (this.components_workbuf_widths[csel] * 16) as base.u64
offset = this.components_workbuf_offsets[csel | 4] +
(((h * (args.mx as base.u64)) + (this.scan_comps_bx_offset[b] as base.u64)) * 128) +
(((v * (args.my as base.u64)) + (this.scan_comps_by_offset[b] as base.u64)) * stride16)
if offset <= args.workbuf.length() {
assert b <= (b + 1) via "a <= (a + b): 0 <= b"()
this.mcu_blocks[b .. (b + 1)].bulk_load_host_endian!(src: args.workbuf[offset ..])
}
b += 1
}
}
pri func decoder.save_mcu_blocks!(mx: base.u32[..= 0x2000], my: base.u32[..= 0x2000], workbuf: slice base.u8) {
var b : base.u32
var csel : base.u8[..= 3]
var h : base.u64[..= 4]
var v : base.u64[..= 4]
var stride16 : base.u64[..= 0x10_0080]
var offset : base.u64
h = 1
v = 1
b = 0
while b < this.mcu_num_blocks {
assert b < 10 via "a < b: a < c; c <= b"(c: this.mcu_num_blocks)
csel = this.scan_comps_cselector[this.mcu_blocks_sselector[b]]
if this.scan_num_components > 1 {
h = this.components_h[csel] as base.u64
v = this.components_v[csel] as base.u64
}
stride16 = (this.components_workbuf_widths[csel] * 16) as base.u64
offset = this.components_workbuf_offsets[csel | 4] +
(((h * (args.mx as base.u64)) + (this.scan_comps_bx_offset[b] as base.u64)) * 128) +
(((v * (args.my as base.u64)) + (this.scan_comps_by_offset[b] as base.u64)) * stride16)
if offset <= args.workbuf.length() {
assert b <= (b + 1) via "a <= (a + b): 0 <= b"()
this.mcu_blocks[b .. (b + 1)].bulk_save_host_endian!(dst: args.workbuf[offset ..])
}
b += 1
}
}
pri func decoder.skip_past_the_next_restart_marker?(src: base.io_reader) {
var c8 : base.u8
while true {
if args.src.length() < 2 {
yield? base."$short read"
continue
} else if args.src.peek_u8() < 0xFF {
args.src.skip_u32_fast!(actual: 1, worst_case: 1)
continue
}
c8 = (args.src.peek_u16le() >> 8) as base.u8
if c8 < 0xC0 {
// Either a reserved marker or "\xFF\x00" byte stuffing. Consume it
// and continue.
args.src.skip_u32_fast!(actual: 2, worst_case: 2)
continue
} else if (c8 < 0xD0) or (0xD7 < c8) {
// Not an RSTn (Restart) marker. Leave it and break.
break
}
c8 &= 7
if (this.next_restart_marker == ((c8 + 1) & 7)) or
(this.next_restart_marker == ((c8 + 2) & 7)) {
// A leading RSTn marker. Leave it and break.
break
} else if (this.next_restart_marker == ((c8 + 7) & 7)) or
(this.next_restart_marker == ((c8 + 6) & 7)) {
// A lagging RSTn marker. Consume it and continue.
args.src.skip_u32_fast!(actual: 2, worst_case: 2)
continue
} else {
// The RSTn marker is either the expected one or far away from the
// expected one (neither leading or lagging). Consume it and break.
args.src.skip_u32_fast!(actual: 2, worst_case: 2)
break
}
}
this.next_restart_marker = (this.next_restart_marker ~mod+ 1) & 7
}
pri func decoder.apply_progressive_idct!(workbuf: slice base.u8) {
var csel : base.u32
var block_smoothing_applicable : base.bool
var scan_width_in_mcus : base.u32[..= 0x2000]
var scan_height_in_mcus : base.u32[..= 0x2000]
var mcu_blocks_mx_mul_0 : base.u32[..= 0x00_0020]
var mcu_blocks_my_mul_0 : base.u32[..= 0x20_0100]
var my : base.u32
var mx : base.u32
var stride : base.u64[..= 0x1_0008]
var offset : base.u64
// Copies mcu_blocks[0], which load_mcu_blocks_for_single_component might
// overwrite, as decode_mcu may be suspended (due to a "$short read").
var stashed_mcu_blocks_0 : array[128] base.u8
this.mcu_blocks[.. 1].bulk_save_host_endian!(dst: stashed_mcu_blocks_0[..])
block_smoothing_applicable = true
csel = 0
while csel < this.num_components {
assert csel < 4 via "a < b: a < c; c <= b"(c: this.num_components)
if (this.block_smoothing_lowest_scan_al[csel][0] >= 16) or
this.top_left_quants_has_zero(q: this.components_tq[csel] as base.u32) {
block_smoothing_applicable = false
}
csel += 1
}
csel = 0
while csel < this.num_components {
assert csel < 4 via "a < b: a < c; c <= b"(c: this.num_components)
// Fake a single-component scan.
scan_width_in_mcus = this.quantize_dimension(
width: this.width, h: this.components_h[csel], max_incl_h: this.max_incl_components_h)
scan_height_in_mcus = this.quantize_dimension(
width: this.height, h: this.components_v[csel], max_incl_h: this.max_incl_components_v)
mcu_blocks_mx_mul_0 = 8
mcu_blocks_my_mul_0 = 8 * this.components_workbuf_widths[csel]
// For partially loaded progressive JPEGs, apply what libjpeg-turbo
// calls "block smoothing".
if block_smoothing_applicable and (0 <> (
this.block_smoothing_lowest_scan_al[csel][1] |
this.block_smoothing_lowest_scan_al[csel][2] |
this.block_smoothing_lowest_scan_al[csel][3] |
this.block_smoothing_lowest_scan_al[csel][4] |
this.block_smoothing_lowest_scan_al[csel][5] |
this.block_smoothing_lowest_scan_al[csel][6] |
this.block_smoothing_lowest_scan_al[csel][8] |
this.block_smoothing_lowest_scan_al[csel][8] |
this.block_smoothing_lowest_scan_al[csel][9])) {
choose load_mcu_blocks_for_single_component = [load_mcu_blocks_for_single_component_smooth]
this.block_smoothing_mx_max_incl = scan_width_in_mcus ~sat- 1
this.block_smoothing_my_max_incl = scan_height_in_mcus ~sat- 1
} else {
choose load_mcu_blocks_for_single_component = [load_mcu_blocks_for_single_component]
}
// Apply IDCT to the MCU blocks in the csel'th component.
my = 0
while my < scan_height_in_mcus,
inv csel < 4,
{
assert my < 0x2000 via "a < b: a < c; c <= b"(c: scan_height_in_mcus)
mx = 0
while mx < scan_width_in_mcus,
inv csel < 4,
inv my < 0x2000,
{
assert mx < 0x2000 via "a < b: a < c; c <= b"(c: scan_width_in_mcus)
this.load_mcu_blocks_for_single_component!(mx: mx, my: my, workbuf: args.workbuf, csel: csel)
stride = this.components_workbuf_widths[csel] as base.u64
offset = this.components_workbuf_offsets[csel] +
((mcu_blocks_mx_mul_0 as base.u64) * (mx as base.u64)) +
((mcu_blocks_my_mul_0 as base.u64) * (my as base.u64))
if offset <= args.workbuf.length() {
this.decode_idct!(
dst_buffer: args.workbuf[offset ..],
dst_stride: stride,
q: this.components_tq[csel] as base.u32)
}
mx += 1
}
my += 1
}
csel += 1
}
this.mcu_blocks[.. 1].bulk_load_host_endian!(src: stashed_mcu_blocks_0[..])
}
pri func decoder.swizzle_gray!(dst: ptr base.pixel_buffer, workbuf: slice base.u8, x0: base.u32, x1: base.u32, y0: base.u32, y1: base.u32, stride: base.u64) 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 x0 : base.u64
var x1 : base.u64
var tab : table base.u8
var dst : slice base.u8
var y : base.u32
var y1 : base.u32[..= 0xFFFF]
// 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
x0 = (dst_bytes_per_pixel * args.x0.min(no_more_than: this.width)) as base.u64
x1 = (dst_bytes_per_pixel * args.x1.min(no_more_than: this.width)) as base.u64
tab = args.dst.plane(p: 0)
y = args.y0
y1 = args.y1.min(no_more_than: this.height)
while y < y1 {
assert y < 0xFFFF via "a < b: a < c; c <= b"(c: y1)
dst = tab.row_u32(y: y)
if x1 < dst.length() {
dst = dst[.. x1]
}
if x0 < dst.length() {
dst = dst[x0 ..]
} else {
dst = this.util.empty_slice_u8()
}
this.swizzler.swizzle_interleaved_from_slice!(
dst: dst,
dst_palette: args.dst.palette_or_else(fallback: this.dst_palette[..]),
src: args.workbuf)
if args.stride <= args.workbuf.length() {
args.workbuf = args.workbuf[args.stride ..]
} else {
args.workbuf = this.util.empty_slice_u8()
}
y += 1
}
return ok
}
pri func decoder.swizzle_colorful!(dst: ptr base.pixel_buffer, workbuf: slice base.u8, x0: base.u32, x1: base.u32, y0: base.u32, y1: base.u32) base.status {
var i : base.u64
var j : base.u64
var src0 : slice base.u8
var src1 : slice base.u8
var src2 : slice base.u8
var src3 : slice base.u8
var width0 : base.u32[..= 0x1_0008]
var width1 : base.u32[..= 0x1_0008]
var width2 : base.u32[..= 0x1_0008]
var width3 : base.u32[..= 0x1_0008]
var height0 : base.u32[..= 0x1_0008]
var height1 : base.u32[..= 0x1_0008]
var height2 : base.u32[..= 0x1_0008]
var height3 : base.u32[..= 0x1_0008]
var status : base.status
if this.swizzle_immediately {
i = this.swizzle_immediately_c_offsets[0] as base.u64
j = this.swizzle_immediately_c_offsets[1] as base.u64
if (i <= j) and (j <= 640) {
src0 = this.swizzle_immediately_buffer[i .. j]
width0 = 8 * (this.components_h[0] as base.u32)
height0 = 8 * (this.components_v[0] as base.u32)
}
i = this.swizzle_immediately_c_offsets[1] as base.u64
j = this.swizzle_immediately_c_offsets[2] as base.u64
if (i <= j) and (j <= 640) {
src1 = this.swizzle_immediately_buffer[i .. j]
width1 = 8 * (this.components_h[1] as base.u32)
height1 = 8 * (this.components_v[1] as base.u32)
}
i = this.swizzle_immediately_c_offsets[2] as base.u64
j = this.swizzle_immediately_c_offsets[3] as base.u64
if (i <= j) and (j <= 640) {
src2 = this.swizzle_immediately_buffer[i .. j]
width2 = 8 * (this.components_h[2] as base.u32)
height2 = 8 * (this.components_v[2] as base.u32)
}
i = this.swizzle_immediately_c_offsets[3] as base.u64
j = this.swizzle_immediately_c_offsets[4] as base.u64
if (i <= j) and (j <= 640) {
src3 = this.swizzle_immediately_buffer[i .. j]
width3 = 8 * (this.components_h[3] as base.u32)
height3 = 8 * (this.components_v[3] as base.u32)
}
} else {
if (this.components_workbuf_offsets[0] <= this.components_workbuf_offsets[1]) and
(this.components_workbuf_offsets[1] <= args.workbuf.length()) {
src0 = args.workbuf[this.components_workbuf_offsets[0] .. this.components_workbuf_offsets[1]]
width0 = this.components_workbuf_widths[0]
height0 = this.components_workbuf_heights[0]
}
if (this.components_workbuf_offsets[1] <= this.components_workbuf_offsets[2]) and
(this.components_workbuf_offsets[2] <= args.workbuf.length()) {
src1 = args.workbuf[this.components_workbuf_offsets[1] .. this.components_workbuf_offsets[2]]
width1 = this.components_workbuf_widths[1]
height1 = this.components_workbuf_heights[1]
}
if (this.components_workbuf_offsets[2] <= this.components_workbuf_offsets[3]) and
(this.components_workbuf_offsets[3] <= args.workbuf.length()) {
src2 = args.workbuf[this.components_workbuf_offsets[2] .. this.components_workbuf_offsets[3]]
width2 = this.components_workbuf_widths[2]
height2 = this.components_workbuf_heights[2]
}
if (this.components_workbuf_offsets[3] <= this.components_workbuf_offsets[4]) and
(this.components_workbuf_offsets[4] <= args.workbuf.length()) {
src3 = args.workbuf[this.components_workbuf_offsets[3] .. this.components_workbuf_offsets[4]]
width3 = this.components_workbuf_widths[3]
height3 = this.components_workbuf_heights[3]
}
}
status = this.swizzler.swizzle_ycck!(
dst: args.dst,
dst_palette: args.dst.palette_or_else(fallback: this.dst_palette[..]),
x_min_incl: args.x0 & 0xFFFF,
x_max_excl: args.x1.min(no_more_than: this.width),
y_min_incl: args.y0 & 0xFFFF,
y_max_excl: args.y1.min(no_more_than: this.height),
src0: src0,
src1: src1,
src2: src2,
src3: src3,
width0: width0,
width1: width1,
width2: width2,
width3: width3,
height0: height0,
height1: height1,
height2: height2,
height3: height3,
stride0: width0,
stride1: width1,
stride2: width2,
stride3: width3,
h0: this.components_h[0],
h1: this.components_h[1],
h2: this.components_h[2],
h3: this.components_h[3],
v0: this.components_v[0],
v1: this.components_v[1],
v2: this.components_v[2],
v3: this.components_v[3],
is_rgb_or_cmyk: this.is_rgb_or_cmyk,
triangle_filter_for_2to1: not this.use_lower_quality,
scratch_buffer_2k: this.swizzle_ycck_scratch_buffer_2k[..])
return status
}
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 {
var i : base.u32
var j : base.u32
if this.call_sequence < 0x20 {
return base."#bad call sequence"
}
if args.index <> 0 {
return base."#bad argument"
}
this.call_sequence = 0x28
this.bitstream_is_closed = false
this.expect_multiple_scans = false
this.frame_config_io_position = args.io_position
this.scan_count = 0
this.restart_interval = this.saved_restart_interval
i = 0
while i < 4 {
this.seen_dqt[i] = this.saved_seen_dqt[i]
j = 0
while j < 64,
inv i < 4,
{
this.quant_tables[i][j] = this.saved_quant_tables[i][j]
j += 1
}
i += 1
}
i = 0
while i < 4 {
j = 0
while j < 10,
inv i < 4,
{
this.block_smoothing_lowest_scan_al[i][j] = 16
j += 1
}
i += 1
}
i = 0
while i < 8 {
this.seen_dht[i] = false
i += 1
}
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 {
if this.use_lower_quality and (this.sof_marker < 0xC2) {
return this.util.make_range_ii_u64(
min_incl: 0,
max_incl: this.components_workbuf_offsets[8])
}
return this.util.make_range_ii_u64(
min_incl: this.components_workbuf_offsets[8],
max_incl: this.components_workbuf_offsets[8])
}