curl/ares/ares__read_line.c

66 строки
2.0 KiB
C

/* Copyright 1998 by the Massachusetts Institute of Technology.
*
* Permission to use, copy, modify, and distribute this
* software and its documentation for any purpose and without
* fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright
* notice and this permission notice appear in supporting
* documentation, and that the name of M.I.T. not be used in
* advertising or publicity pertaining to distribution of the
* software without specific, written prior permission.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is"
* without express or implied warranty.
*/
#include "setup.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "ares.h"
#include "ares_private.h"
/* This is an internal function. Its contract is to read a line from
* a file into a dynamically allocated buffer, zeroing the trailing
* newline if there is one. The calling routine may call
* ares__read_line multiple times with the same buf and bufsize
* pointers; *buf will be reallocated and *bufsize adjusted as
* appropriate. The initial value of *buf should be NULL. After the
* calling routine is done reading lines, it should free *buf.
*/
int ares__read_line(FILE *fp, char **buf, int *bufsize)
{
char *newbuf;
size_t offset = 0;
size_t len;
if (*buf == NULL)
{
*buf = malloc(128);
if (!*buf)
return ARES_ENOMEM;
*bufsize = 128;
}
while (1)
{
if (!fgets(*buf + offset, *bufsize - (int)offset, fp))
return (offset != 0) ? 0 : (ferror(fp)) ? ARES_EFILE : ARES_EOF;
len = offset + strlen(*buf + offset);
if ((*buf)[len - 1] == '\n')
{
(*buf)[len - 1] = 0;
break;
}
offset = len;
/* Allocate more space. */
newbuf = realloc(*buf, *bufsize * 2);
if (!newbuf)
return ARES_ENOMEM;
*buf = newbuf;
*bufsize *= 2;
}
return ARES_SUCCESS;
}