From 460b9883cfa65f72ee9470852d5ec8d5d674fbed Mon Sep 17 00:00:00 2001
From: Andrew <andrew@digerati.co.nz>
Date: Mon, 24 Oct 2022 16:36:58 +1300
Subject: [PATCH] Use libdeflater crc

---
 src/deflate/deflater.rs | 6 ++++++
 src/deflate/mod.rs      | 2 ++
 src/headers.rs          | 4 ++--
 src/lib.rs              | 8 ++------
 src/png/mod.rs          | 3 +--
 5 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/src/deflate/deflater.rs b/src/deflate/deflater.rs
index c6b0d35a..a2f9dacb 100644
--- a/src/deflate/deflater.rs
+++ b/src/deflate/deflater.rs
@@ -36,3 +36,9 @@ pub fn inflate(data: &[u8], out_size: usize) -> PngResult<Vec<u8>> {
     dest.truncate(len);
     Ok(dest)
 }
+
+pub fn crc32(data: &[u8]) -> u32 {
+    let mut crc = Crc::new();
+    crc.update(data);
+    crc.sum()
+}
diff --git a/src/deflate/mod.rs b/src/deflate/mod.rs
index 59ace7ef..d465b715 100644
--- a/src/deflate/mod.rs
+++ b/src/deflate/mod.rs
@@ -13,6 +13,8 @@ pub mod miniz_stream;
 #[cfg(feature = "libdeflater")]
 mod deflater;
 #[cfg(feature = "libdeflater")]
+pub use deflater::crc32;
+#[cfg(feature = "libdeflater")]
 pub use deflater::deflate as libdeflater_deflate;
 #[cfg(feature = "libdeflater")]
 pub use deflater::inflate as libdeflater_inflate;
diff --git a/src/headers.rs b/src/headers.rs
index 1183ca69..1b92d9b3 100644
--- a/src/headers.rs
+++ b/src/headers.rs
@@ -1,7 +1,7 @@
 use crate::colors::{BitDepth, ColorType};
+use crate::deflate::crc32;
 use crate::error::PngError;
 use crate::PngResult;
-use crc::{Crc, CRC_32_ISO_HDLC};
 use indexmap::IndexSet;
 use std::io;
 use std::io::{Cursor, Read};
@@ -130,7 +130,7 @@ pub fn parse_next_header<'a>(
     let header_bytes = byte_data
         .get(header_start..header_start + 4 + length as usize)
         .ok_or(PngError::TruncatedData)?;
-    if !fix_errors && Crc::<u32>::new(&CRC_32_ISO_HDLC).checksum(header_bytes) != crc {
+    if !fix_errors && crc32(header_bytes) != crc {
         return Err(PngError::new(&format!(
             "CRC Mismatch in {} header; May be recoverable by using --fix",
             String::from_utf8_lossy(chunk_name)
diff --git a/src/lib.rs b/src/lib.rs
index af152183..70370445 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -26,12 +26,11 @@ mod rayon;
 
 use crate::atomicmin::AtomicMin;
 use crate::colors::BitDepth;
-use crate::deflate::libdeflater_inflate;
+use crate::deflate::{crc32, libdeflater_inflate};
 use crate::evaluate::Evaluator;
 use crate::png::PngData;
 use crate::png::PngImage;
 use crate::reduction::*;
-use crc::{Crc, CRC_32_ISO_HDLC};
 use image::{DynamicImage, GenericImageView, ImageFormat, Pixel};
 use log::{debug, error, info, warn};
 use rayon::prelude::*;
@@ -966,10 +965,7 @@ fn srgb_rendering_intent(mut iccp: &[u8]) -> Option<u8> {
         }
         b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" => {
             // Known-bad profiles are identified by their CRC
-            match (
-                Crc::<u32>::new(&CRC_32_ISO_HDLC).checksum(&icc_data),
-                icc_data.len(),
-            ) {
+            match (crc32(&icc_data), icc_data.len()) {
                 (0x5d51_29ce, 3024) | (0x182e_a552, 3144) | (0xf29e_526d, 3144) => {
                     Some(rendering_intent)
                 }
diff --git a/src/png/mod.rs b/src/png/mod.rs
index 846269f3..e1d87295 100644
--- a/src/png/mod.rs
+++ b/src/png/mod.rs
@@ -4,7 +4,6 @@ use crate::error::PngError;
 use crate::filters::*;
 use crate::headers::*;
 use crate::interlace::{deinterlace_image, interlace_image};
-use crc::{Crc, CRC_32_ISO_HDLC};
 use indexmap::IndexMap;
 use rgb::ComponentSlice;
 use rgb::RGBA8;
@@ -370,7 +369,7 @@ fn write_png_block(key: &[u8], header: &[u8], output: &mut Vec<u8>) {
     header_data.extend_from_slice(header);
     output.reserve(header_data.len() + 8);
     output.extend_from_slice(&(header_data.len() as u32 - 4).to_be_bytes());
-    let crc = Crc::<u32>::new(&CRC_32_ISO_HDLC).checksum(&header_data);
+    let crc = deflate::crc32(&header_data);
     output.append(&mut header_data);
     output.extend_from_slice(&crc.to_be_bytes());
 }