danvics/oxipng
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Optimize reading in files

Browse source
This commit is contained in:
Josh Holmer 2020-10-22 09:51:25 -04:00
parent bd0c4061bd
commit b446a8a92e
1 changed files with 8 additions and 9 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

17
src/png/mod.rs
View file

@ -10,7 +10,7 @@ use indexmap::IndexMap;
use rgb::ComponentSlice;
use rgb::RGBA8;
use std::fs::File;
use std::io::{Read, Seek, SeekFrom};
use std::io::{BufReader, Read};
use std::iter::Iterator;
use std::path::Path;
use std::sync::Arc;
@ -62,25 +62,24 @@ impl PngData {
}
pub fn read_file(filepath: &Path) -> Result<Vec<u8>, PngError> {
let mut file = match File::open(filepath) {
let file = match File::open(filepath) {
Ok(f) => f,
Err(_) => return Err(PngError::new("Failed to open file for reading")),
};
let file_len = file.metadata().map(|m| m.len() as usize).unwrap_or(0);
let mut reader = BufReader::new(file);
// Check file for PNG header
let mut header = [0; 8];
if file.read_exact(&mut header).is_err() {
if reader.read_exact(&mut header).is_err() {
return Err(PngError::new("Not a PNG file: too small"));
}
if !file_header_is_valid(&header) {
return Err(PngError::new("Invalid PNG header detected"));
}
if file.seek(SeekFrom::Start(0)).is_err() {
return Err(PngError::new("Failed to read from file"));
}
// Read raw png data into memory
let mut byte_data: Vec<u8> =
Vec::with_capacity(file.metadata().map(|m| m.len() as usize).unwrap_or(0));
match file.read_to_end(&mut byte_data) {
let mut byte_data: Vec<u8> = Vec::with_capacity(file_len);
byte_data.extend_from_slice(&header);
match reader.read_to_end(&mut byte_data) {
Ok(_) => (),
Err(_) => return Err(PngError::new("Failed to read from file")),
}