Function compress

#[export_name = "compress"]
pub unsafe extern "C-unwind" fn compress(
    dest: *mut Bytef,
    destLen: *mut c_ulong,
    source: *const Bytef,
    sourceLen: c_ulong,
) -> c_int

Compresses source into dest, and writes the final deflated size into destLen.

sourceLen is the byte length of the source buffer. Upon entry, destLen is the total size of the destination buffer, which must be at least the value returned by compressBound(sourceLen). Upon exit, destLen is the actual size of the compressed data.

A call to compress is equivalent to compress2 with a level parameter of Z_DEFAULT_COMPRESSION.

Returns

• Z_OK if success
• Z_MEM_ERROR if there was not enough memory
• Z_BUF_ERROR if there was not enough room in the output buffer

Safety

The caller must guarantee that

• The destLen pointer satisfies the requirements of core::ptr::read
• Either
  • dest is NULL
  • dest and *destLen satisfy the requirements of core::slice::from_raw_parts_mut::<MaybeUninit<u8>>
• Either
  • source is NULL
  • source and sourceLen satisfy the requirements of core::slice::from_raw_parts

Example

use libz_rs_sys::{Z_OK, compress};

let source = b"Ferris";

let mut dest = vec![0u8; 100];
let mut dest_len = dest.len() as _;

let err = unsafe {
    compress(
        dest.as_mut_ptr(),
        &mut dest_len,
        source.as_ptr(),
        source.len() as _,
    )
};

assert_eq!(err, Z_OK);
assert_eq!(dest_len, 14);

dest.truncate(dest_len as usize);
assert_eq!(dest, [120, 156, 115, 75, 45, 42, 202, 44, 6, 0, 8, 6, 2, 108]);