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authorValentin Popov <valentin@popov.link>2024-01-08 00:21:28 +0300
committerValentin Popov <valentin@popov.link>2024-01-08 00:21:28 +0300
commit1b6a04ca5504955c571d1c97504fb45ea0befee4 (patch)
tree7579f518b23313e8a9748a88ab6173d5e030b227 /vendor/image/src/codecs/jpeg/transform.rs
parent5ecd8cf2cba827454317368b68571df0d13d7842 (diff)
downloadfparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.tar.xz
fparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.zip
Initial vendor packages
Signed-off-by: Valentin Popov <valentin@popov.link>
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+/*
+fdct is a Rust translation of jfdctint.c from the
+Independent JPEG Group's libjpeg version 9a
+obtained from http://www.ijg.org/files/jpegsr9a.zip
+It comes with the following conditions of distribution and use:
+
+ In plain English:
+
+ 1. We don't promise that this software works. (But if you find any bugs,
+ please let us know!)
+ 2. You can use this software for whatever you want. You don't have to pay us.
+ 3. You may not pretend that you wrote this software. If you use it in a
+ program, you must acknowledge somewhere in your documentation that
+ you've used the IJG code.
+
+ In legalese:
+
+ The authors make NO WARRANTY or representation, either express or implied,
+ with respect to this software, its quality, accuracy, merchantability, or
+ fitness for a particular purpose. This software is provided "AS IS", and you,
+ its user, assume the entire risk as to its quality and accuracy.
+
+ This software is copyright (C) 1991-2014, Thomas G. Lane, Guido Vollbeding.
+ All Rights Reserved except as specified below.
+
+ Permission is hereby granted to use, copy, modify, and distribute this
+ software (or portions thereof) for any purpose, without fee, subject to these
+ conditions:
+ (1) If any part of the source code for this software is distributed, then this
+ README file must be included, with this copyright and no-warranty notice
+ unaltered; and any additions, deletions, or changes to the original files
+ must be clearly indicated in accompanying documentation.
+ (2) If only executable code is distributed, then the accompanying
+ documentation must state that "this software is based in part on the work of
+ the Independent JPEG Group".
+ (3) Permission for use of this software is granted only if the user accepts
+ full responsibility for any undesirable consequences; the authors accept
+ NO LIABILITY for damages of any kind.
+
+ These conditions apply to any software derived from or based on the IJG code,
+ not just to the unmodified library. If you use our work, you ought to
+ acknowledge us.
+
+ Permission is NOT granted for the use of any IJG author's name or company name
+ in advertising or publicity relating to this software or products derived from
+ it. This software may be referred to only as "the Independent JPEG Group's
+ software".
+
+ We specifically permit and encourage the use of this software as the basis of
+ commercial products, provided that all warranty or liability claims are
+ assumed by the product vendor.
+*/
+
+static CONST_BITS: i32 = 13;
+static PASS1_BITS: i32 = 2;
+
+static FIX_0_298631336: i32 = 2446;
+static FIX_0_390180644: i32 = 3196;
+static FIX_0_541196100: i32 = 4433;
+static FIX_0_765366865: i32 = 6270;
+static FIX_0_899976223: i32 = 7373;
+static FIX_1_175875602: i32 = 9633;
+static FIX_1_501321110: i32 = 12_299;
+static FIX_1_847759065: i32 = 15_137;
+static FIX_1_961570560: i32 = 16_069;
+static FIX_2_053119869: i32 = 16_819;
+static FIX_2_562915447: i32 = 20_995;
+static FIX_3_072711026: i32 = 25_172;
+
+pub(crate) fn fdct(samples: &[u8; 64], coeffs: &mut [i32; 64]) {
+ // Pass 1: process rows.
+ // Results are scaled by sqrt(8) compared to a true DCT
+ // furthermore we scale the results by 2**PASS1_BITS
+ for y in 0usize..8 {
+ let y0 = y * 8;
+
+ // Even part
+ let t0 = i32::from(samples[y0]) + i32::from(samples[y0 + 7]);
+ let t1 = i32::from(samples[y0 + 1]) + i32::from(samples[y0 + 6]);
+ let t2 = i32::from(samples[y0 + 2]) + i32::from(samples[y0 + 5]);
+ let t3 = i32::from(samples[y0 + 3]) + i32::from(samples[y0 + 4]);
+
+ let t10 = t0 + t3;
+ let t12 = t0 - t3;
+ let t11 = t1 + t2;
+ let t13 = t1 - t2;
+
+ let t0 = i32::from(samples[y0]) - i32::from(samples[y0 + 7]);
+ let t1 = i32::from(samples[y0 + 1]) - i32::from(samples[y0 + 6]);
+ let t2 = i32::from(samples[y0 + 2]) - i32::from(samples[y0 + 5]);
+ let t3 = i32::from(samples[y0 + 3]) - i32::from(samples[y0 + 4]);
+
+ // Apply unsigned -> signed conversion
+ coeffs[y0] = (t10 + t11 - 8 * 128) << PASS1_BITS as usize;
+ coeffs[y0 + 4] = (t10 - t11) << PASS1_BITS as usize;
+
+ let mut z1 = (t12 + t13) * FIX_0_541196100;
+ // Add fudge factor here for final descale
+ z1 += 1 << (CONST_BITS - PASS1_BITS - 1) as usize;
+
+ coeffs[y0 + 2] = (z1 + t12 * FIX_0_765366865) >> (CONST_BITS - PASS1_BITS) as usize;
+ coeffs[y0 + 6] = (z1 - t13 * FIX_1_847759065) >> (CONST_BITS - PASS1_BITS) as usize;
+
+ // Odd part
+ let t12 = t0 + t2;
+ let t13 = t1 + t3;
+
+ let mut z1 = (t12 + t13) * FIX_1_175875602;
+ // Add fudge factor here for final descale
+ z1 += 1 << (CONST_BITS - PASS1_BITS - 1) as usize;
+
+ let mut t12 = t12 * (-FIX_0_390180644);
+ let mut t13 = t13 * (-FIX_1_961570560);
+ t12 += z1;
+ t13 += z1;
+
+ let z1 = (t0 + t3) * (-FIX_0_899976223);
+ let mut t0 = t0 * FIX_1_501321110;
+ let mut t3 = t3 * FIX_0_298631336;
+ t0 += z1 + t12;
+ t3 += z1 + t13;
+
+ let z1 = (t1 + t2) * (-FIX_2_562915447);
+ let mut t1 = t1 * FIX_3_072711026;
+ let mut t2 = t2 * FIX_2_053119869;
+ t1 += z1 + t13;
+ t2 += z1 + t12;
+
+ coeffs[y0 + 1] = t0 >> (CONST_BITS - PASS1_BITS) as usize;
+ coeffs[y0 + 3] = t1 >> (CONST_BITS - PASS1_BITS) as usize;
+ coeffs[y0 + 5] = t2 >> (CONST_BITS - PASS1_BITS) as usize;
+ coeffs[y0 + 7] = t3 >> (CONST_BITS - PASS1_BITS) as usize;
+ }
+
+ // Pass 2: process columns
+ // We remove the PASS1_BITS scaling but leave the results scaled up an
+ // overall factor of 8
+ for x in (0usize..8).rev() {
+ // Even part
+ let t0 = coeffs[x] + coeffs[x + 8 * 7];
+ let t1 = coeffs[x + 8] + coeffs[x + 8 * 6];
+ let t2 = coeffs[x + 8 * 2] + coeffs[x + 8 * 5];
+ let t3 = coeffs[x + 8 * 3] + coeffs[x + 8 * 4];
+
+ // Add fudge factor here for final descale
+ let t10 = t0 + t3 + (1 << (PASS1_BITS - 1) as usize);
+ let t12 = t0 - t3;
+ let t11 = t1 + t2;
+ let t13 = t1 - t2;
+
+ let t0 = coeffs[x] - coeffs[x + 8 * 7];
+ let t1 = coeffs[x + 8] - coeffs[x + 8 * 6];
+ let t2 = coeffs[x + 8 * 2] - coeffs[x + 8 * 5];
+ let t3 = coeffs[x + 8 * 3] - coeffs[x + 8 * 4];
+
+ coeffs[x] = (t10 + t11) >> PASS1_BITS as usize;
+ coeffs[x + 8 * 4] = (t10 - t11) >> PASS1_BITS as usize;
+
+ let mut z1 = (t12 + t13) * FIX_0_541196100;
+ // Add fudge factor here for final descale
+ z1 += 1 << (CONST_BITS + PASS1_BITS - 1) as usize;
+
+ coeffs[x + 8 * 2] = (z1 + t12 * FIX_0_765366865) >> (CONST_BITS + PASS1_BITS) as usize;
+ coeffs[x + 8 * 6] = (z1 - t13 * FIX_1_847759065) >> (CONST_BITS + PASS1_BITS) as usize;
+
+ // Odd part
+ let t12 = t0 + t2;
+ let t13 = t1 + t3;
+
+ let mut z1 = (t12 + t13) * FIX_1_175875602;
+ // Add fudge factor here for final descale
+ z1 += 1 << (CONST_BITS - PASS1_BITS - 1) as usize;
+
+ let mut t12 = t12 * (-FIX_0_390180644);
+ let mut t13 = t13 * (-FIX_1_961570560);
+ t12 += z1;
+ t13 += z1;
+
+ let z1 = (t0 + t3) * (-FIX_0_899976223);
+ let mut t0 = t0 * FIX_1_501321110;
+ let mut t3 = t3 * FIX_0_298631336;
+ t0 += z1 + t12;
+ t3 += z1 + t13;
+
+ let z1 = (t1 + t2) * (-FIX_2_562915447);
+ let mut t1 = t1 * FIX_3_072711026;
+ let mut t2 = t2 * FIX_2_053119869;
+ t1 += z1 + t13;
+ t2 += z1 + t12;
+
+ coeffs[x + 8] = t0 >> (CONST_BITS + PASS1_BITS) as usize;
+ coeffs[x + 8 * 3] = t1 >> (CONST_BITS + PASS1_BITS) as usize;
+ coeffs[x + 8 * 5] = t2 >> (CONST_BITS + PASS1_BITS) as usize;
+ coeffs[x + 8 * 7] = t3 >> (CONST_BITS + PASS1_BITS) as usize;
+ }
+}