Initial import.

tools/vector.c

@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining 
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be 
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "brssl.h"
+
+/*
+ * Prepare a vector buffer for adding 'extra' elements.
+ *   buf      current buffer
+ *   esize    size of a vector element
+ *   ptr      pointer to the 'ptr' vector field
+ *   len      pointer to the 'len' vector field
+ *   extra    number of elements to add
+ *
+ * If the buffer must be enlarged, then this function allocates the new
+ * buffer and releases the old one. The new buffer address is then returned.
+ * If the buffer needs not be enlarged, then the buffer address is returned.
+ *
+ * In case of enlargement, the 'len' field is adjusted accordingly. The
+ * 'ptr' field is not modified.
+ */
+void *
+vector_expand(void *buf,
+	size_t esize, size_t *ptr, size_t *len, size_t extra)
+{
+	size_t nlen;
+	void *nbuf;
+
+	if (*len - *ptr >= extra) {
+		return buf;
+	}
+	nlen = (*len << 1);
+	if (nlen - *ptr < extra) {
+		nlen = extra + *ptr;
+		if (nlen < 8) {
+			nlen = 8;
+		}
+	}
+	nbuf = xmalloc(nlen * esize);
+	if (buf != NULL) {
+		memcpy(nbuf, buf, *len * esize);
+		xfree(buf);
+	}
+	*len = nlen;
+	return nbuf;
+}