From: Robert Spalek <robert@ucw.cz>
Date: Mon, 28 Jun 2004 09:30:52 +0000 (+0000)
Subject: added a simple source-code for resizable buffers, I am going to need it at
X-Git-Tag: holmes-import~997
X-Git-Url: http://mj.ucw.cz/gitweb/?a=commitdiff_plain;h=a489a95c5c0852fc68a0b091c42acc56c73e576b;p=libucw.git

added a simple source-code for resizable buffers, I am going to need it at
3 places, so let us separate it
---

diff --git a/lib/gbuf.h b/lib/gbuf.h
new file mode 100644
index 00000000..c56cb795
--- /dev/null
+++ b/lib/gbuf.h
@@ -0,0 +1,58 @@
+/*
+ *	A simple growing buffer
+ *
+ *	(c) 2004, Robert Spalek <robert@ucw.cz>
+ *
+ *	Define the following macros:
+ *
+ *	GBUF_TYPE	data type of records stored in the buffer
+ *	GBUF_PREFIX(x)	add a name prefix to all global symbols
+ */
+
+#define	BUF_T	GBUF_PREFIX(t)
+
+typedef struct
+{
+  uns len;
+  GBUF_TYPE *ptr;
+}
+BUF_T;
+
+static inline void
+GBUF_PREFIX(init)(BUF_T *b)
+{
+  b->ptr = NULL;
+  b->len = 0;
+}
+
+static inline void
+GBUF_PREFIX(done)(BUF_T *b)
+{
+  if (b->ptr)
+    xfree(b->ptr);
+  b->ptr = NULL;
+  b->len = 0;
+}
+
+static inline void
+GBUF_PREFIX(realloc)(BUF_T *b, uns len)
+{
+  b->len = len;
+  if (b->ptr)
+    b->ptr = xrealloc(b->ptr, len * sizeof(GBUF_TYPE));
+  else
+    b->ptr = xmalloc(len * sizeof(GBUF_TYPE));
+}
+
+static inline void
+GBUF_PREFIX(grow)(BUF_T *b, uns len)
+{
+  if (len <= b->len)
+    return;
+  if (len < 2*b->len)			// to ensure logarithmic cost
+    len = 2*b->len;
+  GBUF_PREFIX(realloc)(b, len);
+}
+
+#undef	GBUF_TYPE
+#undef	GBUF_PREFIX