util-lib: split out allocation calls into alloc-util.[ch]

src/basic/alloc-util.c

@@ -0,0 +1,81 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "alloc-util.h"
+#include "util.h"
+
+void* memdup(const void *p, size_t l) {
+        void *r;
+
+        assert(p);
+
+        r = malloc(l);
+        if (!r)
+                return NULL;
+
+        memcpy(r, p, l);
+        return r;
+}
+
+void* greedy_realloc(void **p, size_t *allocated, size_t need, size_t size) {
+        size_t a, newalloc;
+        void *q;
+
+        assert(p);
+        assert(allocated);
+
+        if (*allocated >= need)
+                return *p;
+
+        newalloc = MAX(need * 2, 64u / size);
+        a = newalloc * size;
+
+        /* check for overflows */
+        if (a < size * need)
+                return NULL;
+
+        q = realloc(*p, a);
+        if (!q)
+                return NULL;
+
+        *p = q;
+        *allocated = newalloc;
+        return q;
+}
+
+void* greedy_realloc0(void **p, size_t *allocated, size_t need, size_t size) {
+        size_t prev;
+        uint8_t *q;
+
+        assert(p);
+        assert(allocated);
+
+        prev = *allocated;
+
+        q = greedy_realloc(p, allocated, need, size);
+        if (!q)
+                return NULL;
+
+        if (*allocated > prev)
+                memzero(q + prev * size, (*allocated - prev) * size);
+
+        return q;
+}