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alter snappy methods to do vec resizing themselves

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This commit is contained in:
Robert Habermeier 2016-06-16 12:57:57 +02:00
parent 7ca5c115d8
commit 53db9921d6
1 changed files with 27 additions and 25 deletions
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52
util/src/snappy.rs
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@ -94,66 +94,68 @@ pub fn decompressed_len(compressed: &[u8]) -> Result<usize, Error> {
/// Compress a buffer using snappy.
pub fn compress(input: &[u8]) -> Vec<u8> {
let mut buf_size = max_compressed_len(input.len());
let mut output = vec![0; buf_size as usize];
buf_size = compress_into(input, &mut output).expect("snappy compression failed with large enough buffer.");
output.truncate(buf_size);
output
let mut buf = Vec::new();
compress_into(input, &mut buf).expect("snappy compression failed");
buf
}
/// Compress a buffer using snappy, writing the result into
/// the given output buffer. Will error iff the buffer is too small.
/// the given output buffer, growing it if necessary.
/// Otherwise, returns the length of the compressed data.
pub fn compress_into(input: &[u8], output: &mut [u8]) -> Result<usize, Error> {
let mut len = output.len() as size_t;
pub fn compress_into(input: &[u8], output: &mut Vec<u8>) -> Result<usize, Error> {
let mut len = max_compressed_len(input.len());
if output.len() < len {
output.resize(len, 0);
}
let status = unsafe {
snappy_compress(
input.as_ptr() as *const c_char,
input.len() as size_t,
output.as_mut_ptr() as *mut c_char,
&mut len,
&mut len as &mut size_t,
)
};
match status {
SNAPPY_OK => Ok(len as usize),
SNAPPY_OK => Ok(len),
SNAPPY_INVALID_INPUT => Err(Error::InvalidInput), // should never happen, but can't hurt!
SNAPPY_BUFFER_TOO_SMALL => Err(Error::BufferTooSmall),
SNAPPY_BUFFER_TOO_SMALL => panic!("buffer cannot be too small, the capacity was just ensured."),
_ => panic!("snappy returned unspecified status"),
}
}
/// Decompress a buffer using snappy. Will return an error if the buffer is not snappy-compressed.
pub fn decompress(input: &[u8]) -> Result<Vec<u8>, Error> {
decompressed_len(input).and_then(|mut buf_size| {
let mut output = vec![0; buf_size];
buf_size = try!(decompress_into(input, &mut output));
output.truncate(buf_size);
Ok(output)
})
let mut v = Vec::new();
decompress_into(input, &mut v).map(|_| v)
}
/// Decompress a buffer using snappy, writing the result into
/// the given output buffer. Will error if the input buffer is not snappy-compressed
/// or the output buffer is too small.
/// the given output buffer, growing it if necessary.
/// Will error if the input buffer is not snappy-compressed.
/// Otherwise, returns the length of the decompressed data.
pub fn decompress_into(input: &[u8], output: &mut [u8]) -> Result<usize, Error> {
let mut len = output.len() as size_t;
pub fn decompress_into(input: &[u8], output: &mut Vec<u8>) -> Result<usize, Error> {
let mut len = try!(decompressed_len(input));
if output.len() < len {
output.resize(len, 0);
}
let status = unsafe {
snappy_uncompress(
input.as_ptr() as *const c_char,
input.len() as size_t,
output.as_mut_ptr() as *mut c_char,
&mut len,
&mut len as &mut size_t,
)
};
match status {
SNAPPY_OK => Ok(len as usize),
SNAPPY_INVALID_INPUT => Err(Error::InvalidInput),
SNAPPY_BUFFER_TOO_SMALL => Err(Error::BufferTooSmall),
SNAPPY_BUFFER_TOO_SMALL => panic!("buffer cannot be too small, size was just set to large enough."),
_ => panic!("snappy returned unspecified status"),
}
}