new venti library.

src/libventi/mem.c

@@ -0,0 +1,87 @@
+#include <u.h>
+#include <libc.h>
+#include <venti.h>
+
+enum {
+	IdealAlignment = 32,
+	ChunkSize 	= 128*1024,
+};
+
+
+void
+vtfree(void *p)
+{
+	if(p == 0)
+		return;
+	free(p);
+}
+
+void *
+vtmalloc(int size)
+{
+	void *p;
+
+	p = malloc(size);
+	if(p == 0)
+		sysfatal("vtmalloc: out of memory");
+	setmalloctag(p, getcallerpc(&size));
+	return p;
+}
+
+void *
+vtmallocz(int size)
+{
+	void *p = vtmalloc(size);
+	memset(p, 0, size);
+	setmalloctag(p, getcallerpc(&size));
+	return p;
+}
+
+void *
+vtrealloc(void *p, int size)
+{
+	if(p == nil)
+		return vtmalloc(size);
+	p = realloc(p, size);
+	if(p == 0)
+		sysfatal("vtMemRealloc: out of memory");
+	setrealloctag(p, getcallerpc(&size));
+	return p;
+}
+
+void *
+vtbrk(int n)
+{
+	static Lock lk;
+	static uchar *buf;
+	static int nbuf;
+	static int nchunk;
+	int align, pad;
+	void *p;
+
+	if(n >= IdealAlignment)
+		align = IdealAlignment;
+	else if(n > 8)
+		align = 8;
+	else	
+		align = 4;
+
+	lock(&lk);
+	pad = (align - (ulong)buf) & (align-1);
+	if(n + pad > nbuf) {
+		buf = vtmallocz(ChunkSize);
+		nbuf = ChunkSize;
+		pad = (align - (ulong)buf) & (align-1);
+		nchunk++;
+	}
+
+	assert(n + pad <= nbuf);	
+	
+	p = buf + pad;
+	buf += pad + n;
+	nbuf -= pad + n;
+	unlock(&lk);
+
+	return p;
+}
+