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-rw-r--r--ares__read_line.c64
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+/* 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.
+ */
+
+static const char rcsid[] = "$Id$";
+
+#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;
+ int offset = 0, len;
+
+ if (*buf == NULL)
+ {
+ *buf = malloc(128);
+ if (!*buf)
+ return ARES_ENOMEM;
+ *bufsize = 128;
+ }
+
+ while (1)
+ {
+ if (!fgets(*buf + offset, *bufsize - 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;
+ return ARES_SUCCESS;
+ }
+ offset = len;
+
+ /* Allocate more space. */
+ newbuf = realloc(*buf, *bufsize * 2);
+ if (!newbuf)
+ return ARES_ENOMEM;
+ *buf = newbuf;
+ *bufsize *= 2;
+ }
+}