61 lines
1.3 KiB
Rust
61 lines
1.3 KiB
Rust
//! Miscellaneous functions to read fixed-size data from a file.
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use std::fs::File;
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use std::io::Read;
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use std::mem;
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use ::error::NrgError;
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/// Reads a String of size `size` from `fd`.
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pub fn read_sized_string(fd: &File, size: u64) -> Result<String, NrgError> {
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let mut handle = fd.take(size);
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let mut string = String::new();
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try!(handle.read_to_string(&mut string));
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Ok(string)
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}
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/// Reads a 64-bit unsigned integer from `fd`.
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pub fn read_u64(fd: &mut File) -> Result<u64, NrgError> {
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let mut buf = [0u8; 8];
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try!(fd.read_exact(&mut buf));
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let i: u64;
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unsafe {
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i = mem::transmute(buf);
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}
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Ok(u64::from_be(i))
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}
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/// Reads a 32-bit unsigned integer from `fd`.
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pub fn read_u32(fd: &mut File) -> Result<u32, NrgError> {
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let mut buf = [0u8; 4];
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try!(fd.read_exact(&mut buf));
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let i: u32;
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unsafe {
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i = mem::transmute(buf);
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}
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Ok(u32::from_be(i))
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}
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/// Reads a 16-bit unsigned integer from `fd`.
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pub fn read_u16(fd: &mut File) -> Result<u16, NrgError> {
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let mut buf = [0u8; 2];
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try!(fd.read_exact(&mut buf));
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let i: u16;
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unsafe {
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i = mem::transmute(buf);
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}
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Ok(u16::from_be(i))
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}
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/// Reads an unsigned byte from `fd`.
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pub fn read_u8(fd: &mut File) -> Result<u8, NrgError> {
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let mut buf = [0u8; 1];
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try!(fd.read_exact(&mut buf));
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Ok(buf[0])
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}
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