From 812a36fbe9a6dd602e835ab7ba938069df4611e2 Mon Sep 17 00:00:00 2001
From: Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
Date: Wed, 4 Oct 2023 14:27:32 +0200
Subject: [PATCH] Use core and alloc a bit more

We still depend mostly on std::io and std::fs, but the rest can be done
without std.
---
 src/arch/ssse3.rs           | 14 +++++---------
 src/arch/wasm.rs            |  2 +-
 src/decoder.rs              |  2 +-
 src/decoder/lossless.rs     |  2 ++
 src/worker/mod.rs           |  2 ++
 src/worker/multithreaded.rs |  8 ++++----
 src/worker/rayon.rs         |  4 +++-
 tests/reftest/mod.rs        |  2 +-
 8 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/src/arch/ssse3.rs b/src/arch/ssse3.rs
index e0bd2e43..d4c86b48 100644
--- a/src/arch/ssse3.rs
+++ b/src/arch/ssse3.rs
@@ -1,7 +1,8 @@
+use core::ptr;
 #[cfg(target_arch = "x86")]
-use std::arch::x86::*;
+use core::arch::x86::*;
 #[cfg(target_arch = "x86_64")]
-use std::arch::x86_64::*;
+use core::arch::x86_64::*;
 
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 #[target_feature(enable = "ssse3")]
@@ -139,11 +140,6 @@ pub unsafe fn dequantize_and_idct_block_8x8(
                 .unwrap()
     );
 
-    #[cfg(target_arch = "x86")]
-    use std::arch::x86::*;
-    #[cfg(target_arch = "x86_64")]
-    use std::arch::x86_64::*;
-
     const SHIFT: i32 = 3;
 
     // Read the DCT coefficients, scale them up and dequantize them.
@@ -183,7 +179,7 @@ pub unsafe fn dequantize_and_idct_block_8x8(
                 _mm_setzero_si128(),
             ),
         );
-        std::ptr::copy_nonoverlapping::<u8>(
+        ptr::copy_nonoverlapping::<u8>(
             buf.as_ptr(),
             output.as_mut_ptr().wrapping_add(output_linestride * i) as *mut _,
             8,
@@ -277,7 +273,7 @@ pub unsafe fn color_convert_line_ycbcr(y: &[u8], cb: &[u8], cr: &[u8], output: &
         let mut data = [0u8; 32];
         _mm_storeu_si128(data.as_mut_ptr() as *mut _, rgb_low);
         _mm_storeu_si128(data.as_mut_ptr().wrapping_add(16) as *mut _, rgb_hi);
-        std::ptr::copy_nonoverlapping::<u8>(
+        ptr::copy_nonoverlapping::<u8>(
             data.as_ptr(),
             output.as_mut_ptr().wrapping_add(24 * i),
             24,
diff --git a/src/arch/wasm.rs b/src/arch/wasm.rs
index 7a94551f..c65538dc 100644
--- a/src/arch/wasm.rs
+++ b/src/arch/wasm.rs
@@ -1,5 +1,5 @@
 #[cfg(target_arch = "wasm32")]
-use std::arch::wasm32::*;
+use core::arch::wasm32::*;
 
 #[cfg(target_arch = "wasm32")]
 #[target_feature(enable = "simd128")]
diff --git a/src/decoder.rs b/src/decoder.rs
index e4fa5f64..0d64f43b 100644
--- a/src/decoder.rs
+++ b/src/decoder.rs
@@ -16,7 +16,7 @@ use alloc::{format, vec};
 use core::cmp;
 use core::mem;
 use core::ops::Range;
-use std::convert::TryInto;
+use core::convert::TryInto;
 use std::io::Read;
 
 pub const MAX_COMPONENTS: usize = 4;
diff --git a/src/decoder/lossless.rs b/src/decoder/lossless.rs
index cd00476f..71939774 100644
--- a/src/decoder/lossless.rs
+++ b/src/decoder/lossless.rs
@@ -1,3 +1,5 @@
+use alloc::{format, vec};
+use alloc::vec::Vec;
 use crate::decoder::{Decoder, MAX_COMPONENTS};
 use crate::error::{Error, Result};
 use crate::huffman::HuffmanDecoder;
diff --git a/src/worker/mod.rs b/src/worker/mod.rs
index abf9488c..cd3fabdd 100644
--- a/src/worker/mod.rs
+++ b/src/worker/mod.rs
@@ -11,7 +11,9 @@ use crate::error::Result;
 use crate::parser::{Component, Dimensions};
 use crate::upsampler::Upsampler;
 
+use alloc::boxed::Box;
 use alloc::sync::Arc;
+use alloc::vec;
 use alloc::vec::Vec;
 use core::cell::RefCell;
 
diff --git a/src/worker/multithreaded.rs b/src/worker/multithreaded.rs
index 8a9f5c6b..be08c4f2 100644
--- a/src/worker/multithreaded.rs
+++ b/src/worker/multithreaded.rs
@@ -4,14 +4,14 @@
 //! and allow scaling to more cores.
 //! However, that would be more complex, so we use this as a starting point.
 
+use alloc::format;
+use alloc::vec::Vec;
+use core::mem;
 use super::immediate::ImmediateWorker;
 use super::{RowData, Worker};
 use crate::decoder::MAX_COMPONENTS;
 use crate::error::Result;
-use std::{
-    mem,
-    sync::mpsc::{self, Receiver, Sender},
-};
+use std::sync::mpsc::{self, Receiver, Sender};
 
 enum WorkerMsg {
     Start(RowData),
diff --git a/src/worker/rayon.rs b/src/worker/rayon.rs
index ec7df258..59712512 100644
--- a/src/worker/rayon.rs
+++ b/src/worker/rayon.rs
@@ -10,7 +10,9 @@ use crate::parser::Component;
 use crate::upsampler::Upsampler;
 use crate::{decoder::MAX_COMPONENTS, parser::Dimensions};
 
-use std::sync::Arc;
+use alloc::sync::Arc;
+use alloc::vec;
+use alloc::vec::Vec;
 
 use super::{RowData, Worker};
 
diff --git a/tests/reftest/mod.rs b/tests/reftest/mod.rs
index 9b2eeab0..6c42f5e0 100644
--- a/tests/reftest/mod.rs
+++ b/tests/reftest/mod.rs
@@ -1,6 +1,6 @@
 use jpeg;
 use png;
-use std::cmp;
+use core::cmp;
 use std::fs::File;
 use std::path::Path;