line_buffer API =============== The line_buffer library provides a convenient interface for mostly-line-oriented input. Each line is not permitted to exceed 10000 bytes. The provided functions are not thread-safe or async-signal-safe, and like `fgets()`, they generally do not function correctly if interrupted by a signal without SA_RESTART set. Calling sequence ---------------- The calling program: - specifies a file to read with `buffer_init` - processes input with `buffer_read_line`, `buffer_read_string`, `buffer_skip_bytes`, and `buffer_copy_bytes` - closes the file with `buffer_deinit`, perhaps to start over and read another file. Before exiting, the caller can use `buffer_reset` to deallocate resources for the benefit of profiling tools. Functions --------- `buffer_init`:: Open the named file for input. If filename is NULL, start reading from stdin. On failure, returns -1 (with errno indicating the nature of the failure). `buffer_deinit`:: Stop reading from the current file (closing it unless it was stdin). Returns nonzero if `fclose` fails or the error indicator was set. `buffer_read_line`:: Read a line and strip off the trailing newline. On failure or end of file, returns NULL. `buffer_read_string`:: Read `len` characters of input or up to the end of the file, whichever comes first. Returns NULL on error. Returns whatever characters were read (possibly "") for end of file. `buffer_copy_bytes`:: Read `len` bytes of input and dump them to the standard output stream. Returns early for error or end of file. `buffer_skip_bytes`:: Discards `len` bytes from the input stream (stopping early if necessary because of an error or eof). `buffer_reset`:: Deallocates non-static buffers.