Libc-1439.100.3.tar.gz

[apple/libc.git] / stdio / FreeBSD / open_memstream.c

diff --git a/stdio/FreeBSD/open_memstream.c b/stdio/FreeBSD/open_memstream.c
index a2d9bda9c2a0a4bad8fc06261753c6abc6294566..e36f3e62ea407e3b7843cf998bf75f4c7ce7cc3d 100644 (file)
--- a/stdio/FreeBSD/open_memstream.c
+++ b/stdio/FreeBSD/open_memstream.c
@@ -31,12 +31,14 @@ __FBSDID("$FreeBSD$");
 #include <assert.h>
 #include <errno.h>
 #include <limits.h>
+#include <os/overflow.h>
 #ifdef DEBUG
 #include <stdint.h>
 #endif
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/param.h>
 #include <wchar.h>
 
 /* XXX: There is no FPOS_MAX.  This assumes fpos_t is an off_t. */
@@ -60,6 +62,18 @@ memstream_grow(struct memstream *ms, fpos_t newoff)
        else
                newsize = newoff;
        if (newsize > ms->len) {
+               /*
+                * Grow by 1.5x (15 / 10).
+                */
+               ssize_t growsize;
+               bool ovf = os_mul_overflow(ms->len, 15, &growsize);
+               if (ovf) {
+                       growsize = SSIZE_MAX - 1;
+               } else {
+                       growsize /= 10;
+               }
+               newsize = MAX(growsize, newsize);
+
                buf = realloc(*ms->bufp, newsize + 1);
                if (buf != NULL) {
 #ifdef DEBUG
@@ -79,7 +93,6 @@ memstream_grow(struct memstream *ms, fpos_t newoff)
 static void
 memstream_update(struct memstream *ms)
 {
-
        assert(ms->len >= 0 && ms->offset >= 0);
        *ms->sizep = ms->len < ms->offset ? ms->len : ms->offset;
 }