/*
 * textio: read/write routines for text. These can be used in programs
 * where read and write are used instead of the (preferred) stdio routines
 * for manipulating text files, by doing something like
 *  #define read _text_read
 * Written by Eric R. Smith and placed in the public domain.
 */

#include <stdio.h>
#include <unistd.h>

int
_text_read(fd, buf, nbytes)
	int fd;
	char *buf;
	int nbytes;
{
	char *to, *from;
	int  r;

_again:
	r = read(fd, buf, nbytes);
	if (r <= 0)
		return r;
	nbytes = r;
	to = from = buf;
	while (r-- > 0) {
		if (*from == '\r') {
			from++; nbytes--;
		}
		else
			*to++ = *from++;
	}
	if (nbytes == 0)
		goto _again;
	return nbytes;
}

int
_text_write(fd, from, nbytes)
	int fd;
	char *from;
	int nbytes;
{
	char buf[BUFSIZ+2], *to, c;
	int  w, r, bytes_written;

	bytes_written = 0;
	while (bytes_written < nbytes) {
		w = 0;
		to = buf;
		while (w < BUFSIZ && bytes_written < nbytes) {
			if ((c = *from++) == '\n') {
				*to++ = '\r'; *to++ = c;
				w += 2;
			}
			else {
				*to++ = c;
				w++;
			}
			bytes_written++;
		}
		if ((r = write(fd, buf, w)) != w)
			return (r < 0) ? r : bytes_written - (w-r);
	}
	return bytes_written;
}