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// Copyright 2021 The Wuffs Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------
// This program exercises the Rust PNG decoder at
// https://github.com/image-rs/image-png
// which is the top result for https://crates.io/search?q=png&sort=downloads
//
// Wuffs' C code doesn't depend on Rust per se, but this program gives some
// performance data for specific Rust PNG implementations. The equivalent Wuffs
// benchmarks (on the same test images) are run via:
//
// wuffs bench std/png
//
// To run this program, do "cargo run --release" from the parent directory (the
// directory containing the Cargo.toml file).
extern crate png;
extern crate rustc_version_runtime;
use std::time::Instant;
use std::convert::TryInto;
const ITERSCALE: u64 = 50;
const REPS: u64 = 5;
fn main() {
let version = rustc_version_runtime::version();
print!(
"# Rust {}.{}.{}\n",
version.major, version.minor, version.patch,
);
print!("#\n");
print!("# The output format, including the \"Benchmark\" prefixes, is compatible with the\n");
print!("# https://godoc.org/golang.org/x/perf/cmd/benchstat tool. To install it, first\n");
print!("# install Go, then run \"go install golang.org/x/perf/cmd/benchstat\".\n");
let mut dst0 = vec![0u8; 64 * 1024 * 1024];
let mut dst1 = vec![0u8; 64 * 1024 * 1024];
// The various magic constants below are copied from test/c/std/png.c
for i in 0..(1 + REPS) {
bench(
"19k_8bpp",
&mut dst0[..],
&mut dst1[..],
include_bytes!("../../../test/data/bricks-gray.no-ancillary.png"),
i == 0, // warm_up
160 * 120 * 1, // want_num_bytes = 19_200
50, // iters_unscaled
);
bench(
"40k_24bpp",
&mut dst0[..],
&mut dst1[..],
include_bytes!("../../../test/data/hat.png"),
i == 0, // warm_up
90 * 112 * 4, // want_num_bytes = 40_320
30, // iters_unscaled
);
bench(
"77k_8bpp",
&mut dst0[..],
&mut dst1[..],
include_bytes!("../../../test/data/bricks-dither.png"),
i == 0, // warm_up
160 * 120 * 4, // want_num_bytes = 76_800
30, // iters_unscaled
);
bench(
"552k_32bpp_verify_checksum",
&mut dst0[..],
&mut dst1[..],
include_bytes!("../../../test/data/hibiscus.primitive.png"),
i == 0, // warm_up
312 * 442 * 4, // want_num_bytes = 551_616
4, // iters_unscaled
);
bench(
"4002k_24bpp",
&mut dst0[..],
&mut dst1[..],
include_bytes!("../../../test/data/harvesters.png"),
i == 0, // warm_up
1165 * 859 * 4, // want_num_bytes = 4_002_940
1, // iters_unscaled
);
}
}
fn bench(
name: &str, // Benchmark name.
dst0: &mut [u8], // Destination buffer #0.
dst1: &mut [u8], // Destination buffer #1.
src: &[u8], // Source data.
warm_up: bool, // Whether this is a warm up rep.
want_num_bytes: u64, // Expected num_bytes per iteration.
iters_unscaled: u64, // Base number of iterations.
) {
let iters = iters_unscaled * ITERSCALE;
let mut total_num_bytes = 0u64;
let start = Instant::now();
for _ in 0..iters {
let n = decode(&mut dst0[..], &mut dst1[..], src);
if n != want_num_bytes {
panic!("num_bytes: got {}, want {}", n, want_num_bytes);
}
total_num_bytes += n;
}
let elapsed = start.elapsed();
let elapsed_nanos = (elapsed.as_secs() * 1_000_000_000) + (elapsed.subsec_nanos() as u64);
let kb_per_s: u64 = total_num_bytes * 1_000_000 / elapsed_nanos;
if warm_up {
return;
}
print!(
"Benchmarkrust_png_decode_image_{:16} {:8} {:12} ns/op {:3}.{:03} MB/s\n",
name,
iters,
elapsed_nanos / iters,
kb_per_s / 1_000,
kb_per_s % 1_000
);
}
// decode returns the number of bytes processed.
fn decode(dst0: &mut [u8], dst1: &mut [u8], src: &[u8]) -> u64 {
let decoder = png::Decoder::new(src);
let (info, mut reader) = decoder.read_info().unwrap();
let num_bytes = info.buffer_size() as u64;
reader.next_frame(dst0).unwrap();
if info.color_type == png::ColorType::Grayscale {
// No conversion necessary.
return num_bytes;
} else if info.color_type == png::ColorType::RGB {
// Convert RGB => BGRA.
let new_size = ((num_bytes / 3) * 4) as usize;
rgb_to_bgra(&dst0[..num_bytes as usize], &mut dst1[..new_size]);
return new_size as u64;
} else if info.color_type == png::ColorType::RGBA {
// Convert RGBA => BGRA.
for i in 0..((num_bytes / 4) as usize) {
let d = dst0[(4 * i) + 0];
dst0[(4 * i) + 0] = dst0[(4 * i) + 2];
dst0[(4 * i) + 2] = d;
}
return num_bytes;
}
// Returning 0 should lead to a panic (when want_num_bytes != 0).
0
}
/// Copy `src` (treated as 3-byte chunks) into `dst`
/// (treated as 4-byte chunks), filling out `dst` by adding
/// a `0xff` "alpha value" at the end of each entry.
///
/// # Panics:
///
/// Will panic if
///
/// * The length of `src` is not a multiple of 3.
/// * The length of `dst` is not a multiple of 4.
/// * `src` and `dst` do not have the same length in chunks.
#[inline]
pub fn rgb_to_bgra(src: &[u8], dst: &mut [u8]) {
let nsrc = src.len();
let ndst = dst.len();
assert_eq!(0, nsrc % 3);
assert_eq!(0, ndst % 4);
assert_eq!(nsrc, (ndst / 4) * 3);
for (s, d) in src.chunks_exact(3).zip(dst.chunks_exact_mut(4)) {
let s: &[u8; 3] = s.try_into().unwrap();
let d: &mut [u8; 4] = d.try_into().unwrap();
// R
d[0] = s[2];
// G
d[1] = s[1];
// B
d[2] = s[0];
// A
d[3] = 0xff;
}
}