1 files changed, 88 insertions, 0 deletions
diff --git a/src/cmd/mk/bufblock.c b/src/cmd/mk/bufblock.c
new file mode 100644
index 00000000..979403bc
--- /dev/null
+++ b/src/cmd/mk/bufblock.c
@@ -0,0 +1,88 @@
+#include	"mk.h"
+
+static Bufblock *freelist;
+#define	QUANTA	4096
+
+Bufblock *
+newbuf(void)
+{
+	Bufblock *p;
+
+	if (freelist) {
+		p = freelist;
+		freelist = freelist->next;
+	} else {
+		p = (Bufblock *) Malloc(sizeof(Bufblock));
+		p->start = Malloc(QUANTA*sizeof(*p->start));
+		p->end = p->start+QUANTA;
+	}
+	p->current = p->start;
+	*p->start = 0;
+	p->next = 0;
+	return p;
+}
+
+void
+freebuf(Bufblock *p)
+{
+	p->next = freelist;
+	freelist = p;
+}
+
+void
+growbuf(Bufblock *p)
+{
+	int n;
+	Bufblock *f;
+	char *cp;
+
+	n = p->end-p->start+QUANTA;
+		/* search the free list for a big buffer */
+	for (f = freelist; f; f = f->next) {
+		if (f->end-f->start >= n) {
+			memcpy(f->start, p->start, p->end-p->start);
+			cp = f->start;
+			f->start = p->start;
+			p->start = cp;
+			cp = f->end;
+			f->end = p->end;
+			p->end = cp;
+			f->current = f->start;
+			break;
+		}
+	}
+	if (!f) {		/* not found - grow it */
+		p->start = Realloc(p->start, n);
+		p->end = p->start+n;
+	}
+	p->current = p->start+n-QUANTA;
+}
+
+void
+bufcpy(Bufblock *buf, char *cp, int n)
+{
+
+	while (n--)
+		insert(buf, *cp++);
+}
+
+void
+insert(Bufblock *buf, int c)
+{
+
+	if (buf->current >= buf->end)
+		growbuf(buf);
+	*buf->current++ = c;
+}
+
+void
+rinsert(Bufblock *buf, Rune r)
+{
+	int n;
+
+	n = runelen(r);
+	if (buf->current+n > buf->end)
+		growbuf(buf);
+	runetochar(buf->current, &r);
+	buf->current += n;
+}