/*
 * io.h - stream I/O for D compiler
 * CSE 413 au07
 *
 * This module centralizes file I/O details for the rest of the compiler.
 * Function io_setup should be called at the beginning of execution to
 * open streams and perform any other setup needed.  After that, use getline
 * to read from the input stream one line at a time, and putline to write to
 * the output stream.  Lines from the input stream are automatically copied
 * to the output stream by default.  See methods set_echo and set_echo_prefix
 * to control how this is done.
 */

#ifndef IO_H
#define IO_H

/* 
 * Initialize I/O routines.  Parameters argc and argv should be those passed
 * to method main.
 * If there are no parameters, input is read from stdin and output written
 * to stdout.
 * If there is one parameter, it is taken as the name of the input file, and
 * stdin is redirected to that file.  In this case, stdout is redirected to
 * a new file whose name is the input file name without it's final extension
 * (following a trailing "."), and with the extension ".s".
 * If there are two parameters, they are taken as the name of the input and
 * output files respectively, and stdin and stdout are redirected accordingly.
 * If either the input or output file cannot be opened, execution of the
 * program is terminated with a call to exit().
 */
void io_init(int argc, char* argv[]);

/*
 * Read the next line of input into s.  Return a pointer to s if the read
 * succeeds, or NULL if there is no more input. (e.g., same as gets).
 * Copy the input line to output if a line is read and echoing is enabled.
 * pre: s has enough space for the entire next line.
 */
char* getline(char* s);

/*
 * Write s to output and advance to the next line.
 */
void putline(char* s);

/*
 * Write s to output without advancing to a new line.
 */
void putstr(char* s);

/*
 * Turn echoing of input on or off as specified (default is on).
 * Return the previous echo setting.
 */
int set_echo(int on_off);

/*
 * Set the echo prefix to the given string.  Default is "; ".
 * pre: prefix is not too long (see constant in io.c)
 */
void set_echo_prefix(char* new_prefix);


#endif /* ifndef IO_H */