rio.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include "rio.h"

ssize_t rio_readn(int fd, void *buf, size_t n) {
	size_t nleft = n;
	ssize_t nread;
	char *bufp = buf;

	while(nleft > 0) {
		if((nread = read(fd, bufp, nleft)) < 0) {
			if(errno == EINTR) {
				nread = 0;    // interrupted by sig handler, return and call read() again
			} else {
				return -1;    // errno set by read()
			}
		} else if(nread == 0) {
			break;    // EOF
		}

		nleft -= nread;
		bufp += nread;
	}

	return (n - nleft);
}

ssize_t rio_writen(int fd, void *buf, size_t n) {
	size_t nleft = n;
	ssize_t nwritten;
	char *bufp = buf;

	while(nleft > 0) {
		if((nwritten = write(fd, bufp, nleft)) <= 0) {
			if(errno == EINTR) {    // interrupted by sig handler, return and call wirte() again
				nwritten = 0;
			} else {
				return -1;    // errno set by write()
			}
		}

		nleft -= nwritten;
		bufp += nwritten;
	}

	return n;
}

void rio_readinitb(rio_t *rp, int fd) {
	rp->rio_fd = fd;
	rp->rio_cnt = 0;
	rp->rio_bufptr = rp->rio_buf;
}

ssize_t rio_read(rio_t *rp, char *buf, size_t n) {
	int cnt;

	while(rp->rio_cnt <= 0) {
		rp->rio_cnt = read(rp->rio_fd, rp->rio_buf, sizeof(rp->rio_buf));
		if(rp->rio_cnt < 0) {
			if(errno != EINTR) {
				return -1;
			}
		} else if(rp->rio_cnt == 0) {
			return 0;
		} else {
			rp->rio_bufptr = rp->rio_buf;
		}
	}

	cnt = n;
	if(rp->rio_cnt < (ssize_t)n) {
		cnt = rp->rio_cnt;
	}

	memcpy(buf, rp->rio_bufptr, cnt);
	rp->rio_bufptr += cnt;
	rp->rio_cnt -= cnt;
	
	return cnt;
}

ssize_t rio_readlineb(rio_t *rp, void *buf, size_t maxlen) {
	int n, rc;
	char c, *bufp = buf;

	for(n = 1; n < (int)maxlen; n++) {
		if((rc = rio_read(rp, &c, 1)) == 1) {
			*bufp++ = c;
			if(c == '\n') {
				break;
			}
		} else if(rc == 0) {
			if(n == 1) {
				return 0;
			} else {
				break;
			}
		} else {
			return -1;
		}
	}
	
	*bufp = 0;
	return n;
}

ssize_t rio_readnb(rio_t *rp, void *buf, size_t n) {
	size_t nleft = n;
	ssize_t nread;
	char *bufp = buf;

	while(nleft > 0) {
		if((nread = rio_read(rp, bufp, nleft)) < 0) {
			if(errno == EINTR) {
				nread = 0;
			} else {
				return -1;
			}
		} else if(nread == 0) {
			break;
		}
		nleft -= nread;
		bufp += nread;
	}

	return (n - nleft);
}