fossil: import from plan 9

R=rsc
https://codereview.appspot.com/7988047

1 files changed, 65 insertions, 0 deletions

diff --git a/src/cmd/fossil/walk.c b/src/cmd/fossil/walk.c
new file mode 100644
index 00000000..802af640
--- /dev/null
+++ b/src/cmd/fossil/walk.c
@@ -0,0 +1,65 @@
+/*
+ * Generic traversal routines.
+ */
+
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+static uint
+etype(Entry *e)
+{
+	uint t;
+
+	if(e->flags&VtEntryDir)
+		t = BtDir;
+	else
+		t = BtData;
+	return t+e->depth;
+}
+
+void
+initWalk(WalkPtr *w, Block *b, uint size)
+{
+	memset(w, 0, sizeof *w);
+	switch(b->l.type){
+	case BtData:
+		return;
+
+	case BtDir:
+		w->data = b->data;
+		w->m = size / VtEntrySize;
+		w->isEntry = 1;
+		return;
+
+	default:
+		w->data = b->data;
+		w->m = size / VtScoreSize;
+		w->type = b->l.type;
+		w->tag = b->l.tag;
+		return;
+	}
+}
+
+int
+nextWalk(WalkPtr *w, uchar score[VtScoreSize], uchar *type, u32int *tag, Entry **e)
+{
+	if(w->n >= w->m)
+		return 0;
+
+	if(w->isEntry){
+		*e = &w->e;
+		entryUnpack(&w->e, w->data, w->n);
+		memmove(score, w->e.score, VtScoreSize);
+		*type = etype(&w->e);
+		*tag = w->e.tag;
+	}else{
+		*e = nil;
+		memmove(score, w->data+w->n*VtScoreSize, VtScoreSize);
+		*type = w->type-1;
+		*tag = w->tag;
+	}
+	w->n++;
+	return 1;
+}
+