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Diffstat (limited to 'vendor/jpeg-decoder/src/idct.rs')
| -rw-r--r-- | vendor/jpeg-decoder/src/idct.rs | 657 |
1 files changed, 657 insertions, 0 deletions
diff --git a/vendor/jpeg-decoder/src/idct.rs b/vendor/jpeg-decoder/src/idct.rs new file mode 100644 index 0000000..ad8dc4c --- /dev/null +++ b/vendor/jpeg-decoder/src/idct.rs @@ -0,0 +1,657 @@ +// Malicious JPEG files can cause operations in the idct to overflow. +// One example is tests/crashtest/images/imagetestsuite/b0b8914cc5f7a6eff409f16d8cc236c5.jpg +// That's why wrapping operators are needed. + +// Note: we have many values that are straight from a reference. +// Do not warn on them or try to automatically change them. +#![allow(clippy::excessive_precision)] +// Note: consistency for unrolled, scaled offset loops +#![allow(clippy::erasing_op)] +#![allow(clippy::identity_op)] +use crate::parser::Dimensions; +use core::{convert::TryFrom, num::Wrapping}; + +pub(crate) fn choose_idct_size(full_size: Dimensions, requested_size: Dimensions) -> usize { + fn scaled(len: u16, scale: usize) -> u16 { + ((len as u32 * scale as u32 - 1) / 8 + 1) as u16 + } + + for &scale in &[1, 2, 4] { + if scaled(full_size.width, scale) >= requested_size.width + || scaled(full_size.height, scale) >= requested_size.height + { + return scale; + } + } + + 8 +} + +#[test] +fn test_choose_idct_size() { + assert_eq!( + choose_idct_size( + Dimensions { + width: 5472, + height: 3648 + }, + Dimensions { + width: 200, + height: 200 + } + ), + 1 + ); + assert_eq!( + choose_idct_size( + Dimensions { + width: 5472, + height: 3648 + }, + Dimensions { + width: 500, + height: 500 + } + ), + 1 + ); + assert_eq!( + choose_idct_size( + Dimensions { + width: 5472, + height: 3648 + }, + Dimensions { + width: 684, + height: 456 + } + ), + 1 + ); + assert_eq!( + choose_idct_size( + Dimensions { + width: 5472, + height: 3648 + }, + Dimensions { + width: 999, + height: 456 + } + ), + 1 + ); + assert_eq!( + choose_idct_size( + Dimensions { + width: 5472, + height: 3648 + }, + Dimensions { + width: 684, + height: 999 + } + ), + 1 + ); + assert_eq!( + choose_idct_size( + Dimensions { + width: 500, + height: 333 + }, + Dimensions { + width: 63, + height: 42 + } + ), + 1 + ); + + assert_eq!( + choose_idct_size( + Dimensions { + width: 5472, + height: 3648 + }, + Dimensions { + width: 685, + height: 999 + } + ), + 2 + ); + assert_eq!( + choose_idct_size( + Dimensions { + width: 5472, + height: 3648 + }, + Dimensions { + width: 1000, + height: 1000 + } + ), + 2 + ); + assert_eq!( + choose_idct_size( + Dimensions { + width: 5472, + height: 3648 + }, + Dimensions { + width: 1400, + height: 1400 + } + ), + 4 + ); + + assert_eq!( + choose_idct_size( + Dimensions { + width: 5472, + height: 3648 + }, + Dimensions { + width: 5472, + height: 3648 + } + ), + 8 + ); + assert_eq!( + choose_idct_size( + Dimensions { + width: 5472, + height: 3648 + }, + Dimensions { + width: 16384, + height: 16384 + } + ), + 8 + ); + assert_eq!( + choose_idct_size( + Dimensions { + width: 1, + height: 1 + }, + Dimensions { + width: 65535, + height: 65535 + } + ), + 8 + ); + assert_eq!( + choose_idct_size( + Dimensions { + width: 5472, + height: 3648 + }, + Dimensions { + width: 16384, + height: 16384 + } + ), + 8 + ); +} + +pub(crate) fn dequantize_and_idct_block( + scale: usize, + coefficients: &[i16; 64], + quantization_table: &[u16; 64], + output_linestride: usize, + output: &mut [u8], +) { + match scale { + 8 => dequantize_and_idct_block_8x8( + coefficients, + quantization_table, + output_linestride, + output, + ), + 4 => dequantize_and_idct_block_4x4( + coefficients, + quantization_table, + output_linestride, + output, + ), + 2 => dequantize_and_idct_block_2x2( + coefficients, + quantization_table, + output_linestride, + output, + ), + 1 => dequantize_and_idct_block_1x1( + coefficients, + quantization_table, + output_linestride, + output, + ), + _ => panic!("Unsupported IDCT scale {}/8", scale), + } +} + +pub fn dequantize_and_idct_block_8x8( + coefficients: &[i16; 64], + quantization_table: &[u16; 64], + output_linestride: usize, + output: &mut [u8], +) { + #[cfg(not(feature = "platform_independent"))] + if let Some(idct) = crate::arch::get_dequantize_and_idct_block_8x8() { + #[allow(unsafe_code)] + unsafe { + return idct(coefficients, quantization_table, output_linestride, output); + } + } + + let output = output.chunks_mut(output_linestride); + dequantize_and_idct_block_8x8_inner(coefficients, quantization_table, output) +} + +// This is based on stb_image's 'stbi__idct_block'. +fn dequantize_and_idct_block_8x8_inner<'a, I>( + coefficients: &[i16; 64], + quantization_table: &[u16; 64], + output: I, +) where + I: IntoIterator<Item = &'a mut [u8]>, + I::IntoIter: ExactSizeIterator<Item = &'a mut [u8]>, +{ + let output = output.into_iter(); + debug_assert!( + output.len() >= 8, + "Output iterator has the wrong length: {}", + output.len() + ); + + let mut temp = [Wrapping(0); 64]; + + // columns + for i in 0..8 { + if coefficients[i + 8] == 0 + && coefficients[i + 16] == 0 + && coefficients[i + 24] == 0 + && coefficients[i + 32] == 0 + && coefficients[i + 40] == 0 + && coefficients[i + 48] == 0 + && coefficients[i + 56] == 0 + { + let dcterm = dequantize(coefficients[i], quantization_table[i]) << 2; + temp[i] = dcterm; + temp[i + 8] = dcterm; + temp[i + 16] = dcterm; + temp[i + 24] = dcterm; + temp[i + 32] = dcterm; + temp[i + 40] = dcterm; + temp[i + 48] = dcterm; + temp[i + 56] = dcterm; + } else { + let s0 = dequantize(coefficients[i], quantization_table[i]); + let s1 = dequantize(coefficients[i + 8], quantization_table[i + 8]); + let s2 = dequantize(coefficients[i + 16], quantization_table[i + 16]); + let s3 = dequantize(coefficients[i + 24], quantization_table[i + 24]); + let s4 = dequantize(coefficients[i + 32], quantization_table[i + 32]); + let s5 = dequantize(coefficients[i + 40], quantization_table[i + 40]); + let s6 = dequantize(coefficients[i + 48], quantization_table[i + 48]); + let s7 = dequantize(coefficients[i + 56], quantization_table[i + 56]); + + let Kernel { + xs: [x0, x1, x2, x3], + ts: [t0, t1, t2, t3], + } = kernel( + [s0, s1, s2, s3, s4, s5, s6, s7], + // constants scaled things up by 1<<12; let's bring them back + // down, but keep 2 extra bits of precision + 512, + ); + + temp[i] = (x0 + t3) >> 10; + temp[i + 56] = (x0 - t3) >> 10; + temp[i + 8] = (x1 + t2) >> 10; + temp[i + 48] = (x1 - t2) >> 10; + temp[i + 16] = (x2 + t1) >> 10; + temp[i + 40] = (x2 - t1) >> 10; + temp[i + 24] = (x3 + t0) >> 10; + temp[i + 32] = (x3 - t0) >> 10; + } + } + + for (chunk, output_chunk) in temp.chunks_exact(8).zip(output) { + let chunk = <&[_; 8]>::try_from(chunk).unwrap(); + + // constants scaled things up by 1<<12, plus we had 1<<2 from first + // loop, plus horizontal and vertical each scale by sqrt(8) so together + // we've got an extra 1<<3, so 1<<17 total we need to remove. + // so we want to round that, which means adding 0.5 * 1<<17, + // aka 65536. Also, we'll end up with -128 to 127 that we want + // to encode as 0..255 by adding 128, so we'll add that before the shift + const X_SCALE: i32 = 65536 + (128 << 17); + + // eliminate downstream bounds checks + let output_chunk = &mut output_chunk[..8]; + + // TODO When the minimum rust version supports it + // let [s0, rest @ ..] = chunk; + let (s0, rest) = chunk.split_first().unwrap(); + if *rest == [Wrapping(0); 7] { + let dcterm = stbi_clamp((stbi_fsh(*s0) + Wrapping(X_SCALE)) >> 17); + output_chunk[0] = dcterm; + output_chunk[1] = dcterm; + output_chunk[2] = dcterm; + output_chunk[3] = dcterm; + output_chunk[4] = dcterm; + output_chunk[5] = dcterm; + output_chunk[6] = dcterm; + output_chunk[7] = dcterm; + } else { + let Kernel { + xs: [x0, x1, x2, x3], + ts: [t0, t1, t2, t3], + } = kernel(*chunk, X_SCALE); + + output_chunk[0] = stbi_clamp((x0 + t3) >> 17); + output_chunk[7] = stbi_clamp((x0 - t3) >> 17); + output_chunk[1] = stbi_clamp((x1 + t2) >> 17); + output_chunk[6] = stbi_clamp((x1 - t2) >> 17); + output_chunk[2] = stbi_clamp((x2 + t1) >> 17); + output_chunk[5] = stbi_clamp((x2 - t1) >> 17); + output_chunk[3] = stbi_clamp((x3 + t0) >> 17); + output_chunk[4] = stbi_clamp((x3 - t0) >> 17); + } + } +} + +struct Kernel { + xs: [Wrapping<i32>; 4], + ts: [Wrapping<i32>; 4], +} + +#[inline] +fn kernel_x([s0, s2, s4, s6]: [Wrapping<i32>; 4], x_scale: i32) -> [Wrapping<i32>; 4] { + // Even `chunk` indicies + let (t2, t3); + { + let p2 = s2; + let p3 = s6; + + let p1 = (p2 + p3) * stbi_f2f(0.5411961); + t2 = p1 + p3 * stbi_f2f(-1.847759065); + t3 = p1 + p2 * stbi_f2f(0.765366865); + } + + let (t0, t1); + { + let p2 = s0; + let p3 = s4; + + t0 = stbi_fsh(p2 + p3); + t1 = stbi_fsh(p2 - p3); + } + + let x0 = t0 + t3; + let x3 = t0 - t3; + let x1 = t1 + t2; + let x2 = t1 - t2; + + let x_scale = Wrapping(x_scale); + + [x0 + x_scale, x1 + x_scale, x2 + x_scale, x3 + x_scale] +} + +#[inline] +fn kernel_t([s1, s3, s5, s7]: [Wrapping<i32>; 4]) -> [Wrapping<i32>; 4] { + // Odd `chunk` indicies + let mut t0 = s7; + let mut t1 = s5; + let mut t2 = s3; + let mut t3 = s1; + + let p3 = t0 + t2; + let p4 = t1 + t3; + let p1 = t0 + t3; + let p2 = t1 + t2; + let p5 = (p3 + p4) * stbi_f2f(1.175875602); + + t0 *= stbi_f2f(0.298631336); + t1 *= stbi_f2f(2.053119869); + t2 *= stbi_f2f(3.072711026); + t3 *= stbi_f2f(1.501321110); + + let p1 = p5 + p1 * stbi_f2f(-0.899976223); + let p2 = p5 + p2 * stbi_f2f(-2.562915447); + let p3 = p3 * stbi_f2f(-1.961570560); + let p4 = p4 * stbi_f2f(-0.390180644); + + t3 += p1 + p4; + t2 += p2 + p3; + t1 += p2 + p4; + t0 += p1 + p3; + + [t0, t1, t2, t3] +} + +#[inline] +fn kernel([s0, s1, s2, s3, s4, s5, s6, s7]: [Wrapping<i32>; 8], x_scale: i32) -> Kernel { + Kernel { + xs: kernel_x([s0, s2, s4, s6], x_scale), + ts: kernel_t([s1, s3, s5, s7]), + } +} + +#[inline(always)] +fn dequantize(c: i16, q: u16) -> Wrapping<i32> { + Wrapping(i32::from(c) * i32::from(q)) +} + +// 4x4 and 2x2 IDCT based on Rakesh Dugad and Narendra Ahuja: "A Fast Scheme for Image Size Change in the Compressed Domain" (2001). +// http://sylvana.net/jpegcrop/jidctred/ +fn dequantize_and_idct_block_4x4( + coefficients: &[i16; 64], + quantization_table: &[u16; 64], + output_linestride: usize, + output: &mut [u8], +) { + debug_assert_eq!(coefficients.len(), 64); + let mut temp = [Wrapping(0i32); 4 * 4]; + + const CONST_BITS: usize = 12; + const PASS1_BITS: usize = 2; + const FINAL_BITS: usize = CONST_BITS + PASS1_BITS + 3; + + // columns + for i in 0..4 { + let s0 = Wrapping(coefficients[i + 8 * 0] as i32 * quantization_table[i + 8 * 0] as i32); + let s1 = Wrapping(coefficients[i + 8 * 1] as i32 * quantization_table[i + 8 * 1] as i32); + let s2 = Wrapping(coefficients[i + 8 * 2] as i32 * quantization_table[i + 8 * 2] as i32); + let s3 = Wrapping(coefficients[i + 8 * 3] as i32 * quantization_table[i + 8 * 3] as i32); + + let x0 = (s0 + s2) << PASS1_BITS; + let x2 = (s0 - s2) << PASS1_BITS; + + let p1 = (s1 + s3) * stbi_f2f(0.541196100); + let t0 = (p1 + s3 * stbi_f2f(-1.847759065) + Wrapping(512)) >> (CONST_BITS - PASS1_BITS); + let t2 = (p1 + s1 * stbi_f2f(0.765366865) + Wrapping(512)) >> (CONST_BITS - PASS1_BITS); + + temp[i + 4 * 0] = x0 + t2; + temp[i + 4 * 3] = x0 - t2; + temp[i + 4 * 1] = x2 + t0; + temp[i + 4 * 2] = x2 - t0; + } + + for i in 0..4 { + let s0 = temp[i * 4 + 0]; + let s1 = temp[i * 4 + 1]; + let s2 = temp[i * 4 + 2]; + let s3 = temp[i * 4 + 3]; + + let x0 = (s0 + s2) << CONST_BITS; + let x2 = (s0 - s2) << CONST_BITS; + + let p1 = (s1 + s3) * stbi_f2f(0.541196100); + let t0 = p1 + s3 * stbi_f2f(-1.847759065); + let t2 = p1 + s1 * stbi_f2f(0.765366865); + + // constants scaled things up by 1<<12, plus we had 1<<2 from first + // loop, plus horizontal and vertical each scale by sqrt(8) so together + // we've got an extra 1<<3, so 1<<17 total we need to remove. + // so we want to round that, which means adding 0.5 * 1<<17, + // aka 65536. Also, we'll end up with -128 to 127 that we want + // to encode as 0..255 by adding 128, so we'll add that before the shift + let x0 = x0 + Wrapping(1 << (FINAL_BITS - 1)) + Wrapping(128 << FINAL_BITS); + let x2 = x2 + Wrapping(1 << (FINAL_BITS - 1)) + Wrapping(128 << FINAL_BITS); + + let output = &mut output[i * output_linestride..][..4]; + output[0] = stbi_clamp((x0 + t2) >> FINAL_BITS); + output[3] = stbi_clamp((x0 - t2) >> FINAL_BITS); + output[1] = stbi_clamp((x2 + t0) >> FINAL_BITS); + output[2] = stbi_clamp((x2 - t0) >> FINAL_BITS); + } +} + +fn dequantize_and_idct_block_2x2( + coefficients: &[i16; 64], + quantization_table: &[u16; 64], + output_linestride: usize, + output: &mut [u8], +) { + debug_assert_eq!(coefficients.len(), 64); + + const SCALE_BITS: usize = 3; + + // Column 0 + let s00 = Wrapping(coefficients[8 * 0] as i32 * quantization_table[8 * 0] as i32); + let s10 = Wrapping(coefficients[8 * 1] as i32 * quantization_table[8 * 1] as i32); + + let x0 = s00 + s10; + let x2 = s00 - s10; + + // Column 1 + let s01 = Wrapping(coefficients[8 * 0 + 1] as i32 * quantization_table[8 * 0 + 1] as i32); + let s11 = Wrapping(coefficients[8 * 1 + 1] as i32 * quantization_table[8 * 1 + 1] as i32); + + let x1 = s01 + s11; + let x3 = s01 - s11; + + let x0 = x0 + Wrapping(1 << (SCALE_BITS - 1)) + Wrapping(128 << SCALE_BITS); + let x2 = x2 + Wrapping(1 << (SCALE_BITS - 1)) + Wrapping(128 << SCALE_BITS); + + // Row 0 + output[0] = stbi_clamp((x0 + x1) >> SCALE_BITS); + output[1] = stbi_clamp((x0 - x1) >> SCALE_BITS); + + // Row 1 + output[output_linestride + 0] = stbi_clamp((x2 + x3) >> SCALE_BITS); + output[output_linestride + 1] = stbi_clamp((x2 - x3) >> SCALE_BITS); +} + +fn dequantize_and_idct_block_1x1( + coefficients: &[i16; 64], + quantization_table: &[u16; 64], + _output_linestride: usize, + output: &mut [u8], +) { + debug_assert_eq!(coefficients.len(), 64); + + let s0 = (Wrapping(coefficients[0] as i32 * quantization_table[0] as i32) + Wrapping(128 * 8)) / Wrapping(8); + output[0] = stbi_clamp(s0); +} + +// take a -128..127 value and stbi__clamp it and convert to 0..255 +fn stbi_clamp(x: Wrapping<i32>) -> u8 { + x.0.max(0).min(255) as u8 +} + +fn stbi_f2f(x: f32) -> Wrapping<i32> { + Wrapping((x * 4096.0 + 0.5) as i32) +} + +fn stbi_fsh(x: Wrapping<i32>) -> Wrapping<i32> { + x << 12 +} + +#[test] +fn test_dequantize_and_idct_block_8x8() { + #[cfg_attr(rustfmt, rustfmt_skip)] + let coefficients: [i16; 8 * 8] = [ + -14, -39, 58, -2, 3, 3, 0, 1, + 11, 27, 4, -3, 3, 0, 1, 0, + -6, -13, -9, -1, -2, -1, 0, 0, + -4, 0, -1, -2, 0, 0, 0, 0, + 3, 0, 0, 0, 0, 0, 0, 0, + -3, -2, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0 + ]; + + #[cfg_attr(rustfmt, rustfmt_skip)] + let quantization_table: [u16; 8 * 8] = [ + 8, 6, 5, 8, 12, 20, 26, 31, + 6, 6, 7, 10, 13, 29, 30, 28, + 7, 7, 8, 12, 20, 29, 35, 28, + 7, 9, 11, 15, 26, 44, 40, 31, + 9, 11, 19, 28, 34, 55, 52, 39, + 12, 18, 28, 32, 41, 52, 57, 46, + 25, 32, 39, 44, 52, 61, 60, 51, + 36, 46, 48, 49, 56, 50, 52, 50 + ]; + let output_linestride: usize = 8; + let mut output = [0u8; 8 * 8]; + dequantize_and_idct_block_8x8( + &coefficients, + &quantization_table, + output_linestride, + &mut output, + ); + #[cfg_attr(rustfmt, rustfmt_skip)] + let expected_output = [ + 118, 92, 110, 83, 77, 93, 144, 198, + 172, 116, 114, 87, 78, 93, 146, 191, + 194, 107, 91, 76, 71, 93, 160, 198, + 196, 100, 80, 74, 67, 92, 174, 209, + 182, 104, 88, 81, 68, 89, 178, 206, + 105, 64, 59, 59, 63, 94, 183, 201, + 35, 27, 28, 37, 72, 121, 203, 204, + 37, 45, 41, 47, 98, 154, 223, 208 + ]; + for i in 0..64 { + assert!((output[i] as i16 - expected_output[i] as i16).abs() <= 1); + } +} + +#[test] +fn test_dequantize_and_idct_block_8x8_all_zero() { + let mut output = [0u8; 8 * 8]; + dequantize_and_idct_block_8x8(&[0; 8 * 8], &[666; 8 * 8], 8, &mut output); + assert_eq!(&output[..], &[128; 8 * 8][..]); +} + +#[test] +fn test_dequantize_and_idct_block_8x8_saturated() { + // Arch-specific IDCT implementations need not handle i16::MAX values. + #[cfg(not(feature = "platform_independent"))] + if crate::arch::get_dequantize_and_idct_block_8x8().is_some() { + return; + } + let mut output = [0u8; 8 * 8]; + dequantize_and_idct_block_8x8(&[i16::MAX; 8 * 8], &[u16::MAX; 8 * 8], 8, &mut output); + #[cfg_attr(rustfmt, rustfmt_skip)] + let expected = [ + 0, 0, 0, 255, 255, 0, 0, 255, + 0, 0, 215, 0, 0, 255, 255, 0, + 255, 255, 255, 255, 255, 0, 0, 255, + 0, 0, 255, 0, 255, 0, 255, 255, + 0, 0, 255, 255, 0, 255, 0, 0, + 255, 255, 0, 255, 255, 255, 170, 0, + 0, 255, 0, 0, 0, 0, 0, 255, + 255, 255, 0, 255, 0, 255, 0, 0 + ]; + assert_eq!(&output[..], &expected[..]); +} |