Module io 

Enums

FileData

Holds file data — either zero-copy mmap or an owned Vec. Dereferences to &[u8] for transparent use.

Functions

file_size

Get file size without reading it (for byte-count-only optimization).

read_file

Read a file with zero-copy mmap for large files or read() for small files. Opens once with O_NOATIME, uses fstat for metadata to save a syscall.

read_stdin

Read all bytes from stdin into a Vec. Uses a direct read() loop into a pre-allocated buffer instead of read_to_end(), which avoids Vec’s grow-and-probe pattern (extra read() calls and memcpy). On Linux, enlarges the pipe buffer to 4MB first for fewer read() syscalls. Uses the full spare capacity for each read() to minimize syscalls — after the pipe is enlarged to 4MB, each read() returns up to 4MB of data.