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use std::cmp::min;
use crate::traits::{TWrite, TRead};
pub struct Stream {
data: Vec<u8>,
position: usize,
}
#[derive(Copy, Clone)]
#[derive(Eq, PartialEq)]
pub enum StreamError {
EOF,
ZeroLength,
}
impl Stream {
pub fn new() -> Stream {
Stream {
data: Vec::new(),
position: 0,
}
}
pub fn with_capacity(capacity: usize) -> Stream {
Stream {
data: Vec::with_capacity(capacity),
position: 0,
}
}
pub fn truncate_readied(&mut self) {
if self.position == self.data.len() {
self.position = 0;
self.data.clear();
return;
}
if self.position > 0 {
let size = self.available();
self.data.copy_within(self.position.., 0);
self.data.resize(size, 0);
self.position = 0;
}
}
pub fn truncate_capacity(&mut self) {
self.data.shrink_to_fit();
}
}
impl TWrite for Stream {
fn write_byte(&mut self, byte: u8) {
self.data.push(byte);
}
fn write(&mut self, buffer: &[u8]) -> usize {
self.data.extend_from_slice(buffer);
buffer.len()
}
}
impl TRead for Stream {
fn peek_byte(&self) -> Result<u8, StreamError> {
if self.data.is_empty() {
return Err(StreamError::EOF);
}
if self.position == self.data.len() {
return Err(StreamError::EOF);
}
let byte = self.data[self.position];
Ok(byte)
}
fn peek(&self, buffer: &mut [u8]) -> Result<usize, StreamError> {
if self.data.is_empty() {
return Err(StreamError::EOF);
}
let size = min(buffer.len(), self.available());
if size == 0 {
return Err(StreamError::ZeroLength);
}
let slice = &mut buffer[..size];
slice.copy_from_slice(&self.data[..size]);
Ok(size)
}
fn read_byte(&mut self) -> Result<u8, StreamError> {
if self.data.is_empty() {
return Err(StreamError::EOF);
}
if self.position == self.data.len() {
return Err(StreamError::EOF);
}
let byte = self.data[self.position];
self.position += 1;
Ok(byte)
}
fn read(&mut self, buffer: &mut [u8]) -> Result<usize, StreamError> {
if self.data.is_empty() {
return Err(StreamError::EOF);
}
if self.position == self.data.len() {
return Err(StreamError::EOF);
}
let size = min(buffer.len(), self.available());
if size == 0 {
return Err(StreamError::ZeroLength);
}
buffer[..size].copy_from_slice(&self.data[self.position..(self.position + size)]);
self.position += size;
Ok(size)
}
fn skip(&mut self, count: usize) -> usize {
let count = min(count, self.available());
self.position += count;
count
}
fn skip_all(&mut self) -> usize {
let count = self.available();
self.position += count;
count
}
fn view(&self) -> &[u8] {
&self.data[self.position..]
}
fn available(&self) -> usize {
self.data.len() - self.position
}
}