From 4750be2da326297830691c54adbab0a5dea14802 Mon Sep 17 00:00:00 2001
From: Jari Vetoniemi <mailroxas@gmail.com>
Date: Fri, 23 Feb 2018 12:54:43 +0200
Subject: wip

---
 src/util/membuf.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 src/util/membuf.c

(limited to 'src/util/membuf.c')

diff --git a/src/util/membuf.c b/src/util/membuf.c
new file mode 100644
index 0000000..0602679
--- /dev/null
+++ b/src/util/membuf.c
@@ -0,0 +1,31 @@
+#include "membuf.h"
+
+#include <stdlib.h>
+#include <assert.h>
+#include <memory.h>
+#include <err.h>
+
+static void
+membuf_bounds_check(const struct membuf *buf, const size_t nmemb)
+{
+   assert(buf);
+
+   if (buf->mem.len < nmemb || buf->written > buf->mem.len - nmemb)
+      errx(EXIT_FAILURE, "%s: %zu bytes exceeds the maximum storage size of %zu bytes", __func__, buf->written + nmemb, buf->mem.len);
+}
+
+void
+membuf_terminate(struct membuf *buf, const void *data, const size_t data_sz)
+{
+   assert(data || !data_sz);
+   membuf_bounds_check(buf, data_sz);
+   memcpy((char*)buf->mem.data + buf->written, data, data_sz);
+}
+
+void
+membuf_append(struct membuf *buf, const void *data, const size_t data_sz)
+{
+   membuf_terminate(buf, data, data_sz);
+   buf->written += data_sz;
+   assert(buf->written <= buf->mem.len);
+}
-- 
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