core/io: fix reading behaviour with e.g. BufReader

[nihav.git] / nihav-core / src / io / byteio.rs

diff --git a/nihav-core/src/io/byteio.rs b/nihav-core/src/io/byteio.rs
index 7da5e2232a902d5307813b0ae2a1a237fcb76d2b..7b5f220727e3ef21ceff699e7c40b53ebeb65ccf 100644 (file)
--- a/nihav-core/src/io/byteio.rs
+++ b/nihav-core/src/io/byteio.rs
@@ -1,6 +1,5 @@
 //! Bytestream reading/writing functionality.
 pub use std::io::SeekFrom;
-use std::fs::File;
 use std::io::prelude::*;
 use std::ptr;
 
@@ -76,7 +75,7 @@ pub trait ByteIO {
 /// [`MemoryReader`]: ./struct.MemoryReader.html
 #[allow(dead_code)]
 pub struct ByteReader<'a> {
-    io: &'a mut ByteIO,
+    io: &'a mut dyn ByteIO,
 }
 
 /// Bytestream reader from memory.
@@ -85,9 +84,9 @@ pub struct MemoryReader<'a> {
     pos:      usize,
 }
 
-/// Bytestream reader from file.
-pub struct FileReader<'a> {
-    file:     &'a File,
+/// Bytestream reader from anything implementing `std::io::Read` and `std::io::Seek`.
+pub struct FileReader<T: Read+Seek> {
+    file:     Box<T>,
     eof:      bool,
 }
 
@@ -242,7 +241,7 @@ impl<'a> ByteReader<'a> {
     /// # Ok(())
     /// # }
     /// ````
-    pub fn new(io: &'a mut ByteIO) -> Self { ByteReader { io } }
+    pub fn new(io: &'a mut dyn ByteIO) -> Self { ByteReader { io } }
 
     /// Reads data into provided buffer. Partial read is treated as success.
     pub fn read_buf(&mut self, buf: &mut [u8])  -> ByteIOResult<usize> {
@@ -540,15 +539,15 @@ impl<'a> ByteIO for MemoryReader<'a> {
     }
 }
 
-impl<'a> FileReader<'a> {
+impl<T: Read+Seek> FileReader<T> {
 
     /// Constructs a new instance of `FileReader`.
-    pub fn new_read(file: &'a mut File) -> Self {
-        FileReader { file, eof : false }
+    pub fn new_read(file: T) -> Self {
+        FileReader { file: Box::new(file), eof : false }
     }
 }
 
-impl<'a> ByteIO for FileReader<'a> {
+impl<T: Read+Seek> ByteIO for FileReader<T> {
     fn read_byte(&mut self) -> ByteIOResult<u8> {
         let mut byte : [u8; 1] = [0];
         let ret = self.file.read(&mut byte);
@@ -565,18 +564,30 @@ impl<'a> ByteIO for FileReader<'a> {
     }
 
     fn read_buf(&mut self, buf: &mut [u8]) -> ByteIOResult<usize> {
-        let ret = self.file.read(buf);
-        if ret.is_err() { return Err(ByteIOError::ReadError); }
-        let sz = ret.unwrap();
-        if sz < buf.len() { self.eof = true; return Err(ByteIOError::EOF); }
-        Ok(sz)
+        match self.file.read_exact(buf) {
+            Ok(())  => Ok(buf.len()),
+            Err(err) => {
+                if err.kind() == std::io::ErrorKind::UnexpectedEof {
+                    self.eof = true;
+                    Err(ByteIOError::EOF)
+                } else {
+                    Err(ByteIOError::ReadError)
+                }
+            },
+        }
     }
 
     fn read_buf_some(&mut self, buf: &mut [u8]) -> ByteIOResult<usize> {
         let ret = self.file.read(buf);
         if ret.is_err() { return Err(ByteIOError::ReadError); }
         let sz = ret.unwrap();
-        if sz < buf.len() { self.eof = true; }
+        if sz < buf.len() {
+            if let Err(_err) = self.file.read(&mut buf[sz..][..1]) {
+                self.eof = true;
+            } else {
+                return Ok(sz + 1);
+            }
+        }
         Ok(sz)
     }
 
@@ -640,7 +651,7 @@ impl<'a> ByteIO for FileReader<'a> {
 /// [`MemoryWriter`]: ./struct.MemoryWriter.html
 #[allow(dead_code)]
 pub struct ByteWriter<'a> {
-    io: &'a mut ByteIO,
+    io: &'a mut dyn ByteIO,
 }
 
 /// Bytestream writer to memory.
@@ -649,9 +660,9 @@ pub struct MemoryWriter<'a> {
     pos:      usize,
 }
 
-/// Bytestream writer to file.
-pub struct FileWriter {
-    file:     File,
+/// Bytestream writer to anything implementing `std::io::Write` and `std::io::Seek`.
+pub struct FileWriter<T: Write+Seek> {
+    file:     Box<T>,
 }
 
 /// Bytestream writer to memory.
@@ -666,7 +677,7 @@ pub struct GrowableMemoryWriter<'a> {
 
 impl<'a> ByteWriter<'a> {
     /// Constructs a new instance of `ByteWriter`.
-    pub fn new(io: &'a mut ByteIO) -> Self { ByteWriter { io } }
+    pub fn new(io: &'a mut dyn ByteIO) -> Self { ByteWriter { io } }
 
     /// Writes byte array to the output.
     pub fn write_buf(&mut self, buf: &[u8])  -> ByteIOResult<()> {
@@ -919,14 +930,14 @@ impl<'a> ByteIO for GrowableMemoryWriter<'a> {
     }
 }
 
-impl FileWriter {
+impl<T: Write+Seek> FileWriter<T> {
     /// Constructs a new instance of `FileWriter`.
-    pub fn new_write(file: File) -> Self {
-        FileWriter { file }
+    pub fn new_write(file: T) -> Self {
+        FileWriter { file: Box::new(file) }
     }
 }
 
-impl ByteIO for FileWriter {
+impl<T: Write+Seek> ByteIO for FileWriter<T> {
     #[allow(unused_variables)]
     fn read_byte(&mut self) -> ByteIOResult<u8> {
         Err(ByteIOError::NotImplemented)