From 1a6284b177bf695006ff41d80648878dc9e7b686 Mon Sep 17 00:00:00 2001 From: Kamal Ahmad Date: Sat, 10 Aug 2019 22:41:28 +0500 Subject: [PATCH] Reduce allocations in filtering by reusing buffers --- Cargo.lock | 216 +++++++++++++++++++++++++++++++++++++++++++++++++ src/filters.rs | 23 +++--- src/png/mod.rs | 37 +++++---- 3 files changed, 250 insertions(+), 26 deletions(-) diff --git a/Cargo.lock b/Cargo.lock index 8d488d85..d23e5418 100644 --- a/Cargo.lock +++ b/Cargo.lock @@ -80,6 +80,14 @@ dependencies = [ "vec_map 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)", ] +[[package]] +name = "cloudabi" +version = "0.0.3" +source = "registry+https://github.com/rust-lang/crates.io-index" +dependencies = [ + "bitflags 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)", +] + [[package]] name = "cloudflare-zlib" version = "0.2.2" @@ -157,6 +165,11 @@ name = "either" version = "1.5.2" source = "registry+https://github.com/rust-lang/crates.io-index" +[[package]] +name = "fuchsia-cprng" +version = "0.1.1" +source = "registry+https://github.com/rust-lang/crates.io-index" + [[package]] name = "glob" version = "0.2.11" @@ -201,6 +214,15 @@ name = "libc" version = "0.2.58" source = "registry+https://github.com/rust-lang/crates.io-index" +[[package]] +name = "lock_api" +version = "0.1.5" +source = "registry+https://github.com/rust-lang/crates.io-index" +dependencies = [ + "owning_ref 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)", + "scopeguard 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)", +] + [[package]] name = "lzw" version = "0.10.0" @@ -274,6 +296,21 @@ name = "numtoa" version = "0.1.0" source = "registry+https://github.com/rust-lang/crates.io-index" +[[package]] +name = "object-pool" +version = "0.3.1" +dependencies = [ + "parking_lot 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)", +] + +[[package]] +name = "owning_ref" +version = "0.4.0" +source = 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termion 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "6a8fb22f7cde82c8220e5aeacb3258ed7ce996142c77cba193f203515e26c330" "checksum textwrap 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d326610f408c7a4eb6f51c37c330e496b08506c9457c9d34287ecc38809fb060" diff --git a/src/filters.rs b/src/filters.rs index 875c3420..5e18fa47 100644 --- a/src/filters.rs +++ b/src/filters.rs @@ -1,12 +1,12 @@ -pub fn filter_line(filter: u8, bpp: usize, data: &[u8], last_line: &[u8]) -> Vec { - let mut filtered = Vec::with_capacity(data.len()); +pub fn filter_line(filter: u8, bpp: usize, data: &[u8], last_line: &[u8], buf: &mut Vec) { + buf.reserve(data.len()); match filter { 0 => { - filtered.extend_from_slice(data); + buf.extend_from_slice(data); } 1 => { - filtered.extend_from_slice(&data[0..bpp]); - filtered.extend( + buf.extend_from_slice(&data[0..bpp]); + buf.extend( data.iter() .skip(bpp) .zip(data.iter()) @@ -15,9 +15,9 @@ pub fn filter_line(filter: u8, bpp: usize, data: &[u8], last_line: &[u8]) -> Vec } 2 => { if last_line.is_empty() { - filtered.extend_from_slice(data); + buf.extend_from_slice(data); } else { - filtered.extend( + buf.extend( data.iter() .zip(last_line.iter()) .map(|(cur, last)| cur.wrapping_sub(*last)), @@ -27,12 +27,12 @@ pub fn filter_line(filter: u8, bpp: usize, data: &[u8], last_line: &[u8]) -> Vec 3 => { for (i, byte) in data.iter().enumerate() { if last_line.is_empty() { - filtered.push(match i.checked_sub(bpp) { + buf.push(match i.checked_sub(bpp) { Some(x) => byte.wrapping_sub(data[x] >> 1), None => *byte, }); } else { - filtered.push(match i.checked_sub(bpp) { + buf.push(match i.checked_sub(bpp) { Some(x) => byte.wrapping_sub( ((u16::from(data[x]) + u16::from(last_line[i])) >> 1) as u8, ), @@ -44,12 +44,12 @@ pub fn filter_line(filter: u8, bpp: usize, data: &[u8], last_line: &[u8]) -> Vec 4 => { for (i, byte) in data.iter().enumerate() { if last_line.is_empty() { - filtered.push(match i.checked_sub(bpp) { + buf.push(match i.checked_sub(bpp) { Some(x) => byte.wrapping_sub(data[x]), None => *byte, }); } else { - filtered.push(match i.checked_sub(bpp) { + buf.push(match i.checked_sub(bpp) { Some(x) => { byte.wrapping_sub(paeth_predictor(data[x], last_line[i], last_line[x])) } @@ -60,7 +60,6 @@ pub fn filter_line(filter: u8, bpp: usize, data: &[u8], last_line: &[u8]) -> Vec } _ => unreachable!(), } - filtered } pub fn unfilter_line(filter: u8, bpp: usize, data: &[u8], last_line: &[u8]) -> Vec { diff --git a/src/png/mod.rs b/src/png/mod.rs index 2fd5184f..33799f92 100644 --- a/src/png/mod.rs +++ b/src/png/mod.rs @@ -305,11 +305,14 @@ impl PngImage { /// 4: Paeth /// 5: All (heuristically pick the best filter for each line) pub fn filter_image(&self, filter: u8) -> Vec { + //dbg!(self.data.len()); let mut filtered = Vec::with_capacity(self.data.len()); let bpp = ((self.ihdr.bit_depth.as_u8() * self.channels_per_pixel() + 7) / 8) as usize; let mut last_line: &[u8] = &[]; let mut last_pass: Option = None; + let mut f_buf = Vec::new(); for line in self.scan_lines() { + f_buf.clear(); match filter { 0 | 1 | 2 | 3 | 4 => { let filter = if last_pass == line.pass || filter <= 1 { @@ -318,28 +321,34 @@ impl PngImage { 0 }; filtered.push(filter); - filtered.extend_from_slice(&filter_line(filter, bpp, &line.data, last_line)); + filter_line(filter, bpp, &line.data, last_line, &mut f_buf); + filtered.extend_from_slice(&f_buf); } 5 => { // Heuristically guess best filter per line // Uses MSAD algorithm mentioned in libpng reference docs // http://www.libpng.org/pub/png/book/chapter09.html - let mut trials: Vec<(u8, Vec)> = Vec::with_capacity(5); + let mut best_filter = 0; + let mut best_line = Vec::new(); + let mut best_size = std::u64::MAX; + // Avoid vertical filtering on first line of each interlacing pass for filter in if last_pass == line.pass { 0..5 } else { 0..2 } { - trials.push((filter, filter_line(filter, bpp, &line.data, last_line))); + filter_line(filter, bpp, &line.data, last_line, &mut f_buf); + let size = f_buf.iter().fold(0u64, |acc, &x| { + let signed = x as i8; + acc + i16::from(signed).abs() as u64 + }); + if size < best_size { + best_size = size; + best_filter = filter; + std::mem::swap(&mut best_line, &mut f_buf); + } + f_buf.clear() //discard buffer, and start again + } - let (best_filter, best_line) = trials - .iter() - .min_by_key(|(_, line)| { - line.iter().fold(0u64, |acc, &x| { - let signed = x as i8; - acc + i16::from(signed).abs() as u64 - }) - }) - .unwrap(); - filtered.push(*best_filter); - filtered.extend_from_slice(best_line); + filtered.push(best_filter); + filtered.extend_from_slice(&best_line); } _ => unreachable!(), }