1 files changed, 75 insertions, 0 deletions

diff --git a/tools/perf/util/pstack.c b/tools/perf/util/pstack.c
new file mode 100644
index 000000000000..13d36faf64eb
--- /dev/null
+++ b/tools/perf/util/pstack.c
@@ -0,0 +1,75 @@
+/*
+ * Simple pointer stack
+ *
+ * (c) 2010 Arnaldo Carvalho de Melo <acme@redhat.com>
+ */
+
+#include "util.h"
+#include "pstack.h"
+#include <linux/kernel.h>
+#include <stdlib.h>
+
+struct pstack {
+        unsigned short  top;
+        unsigned short  max_nr_entries;
+        void            *entries[0];
+};
+
+struct pstack *pstack__new(unsigned short max_nr_entries)
+{
+        struct pstack *self = zalloc((sizeof(*self) +
+                                     max_nr_entries * sizeof(void *)));
+        if (self != NULL)
+                self->max_nr_entries = max_nr_entries;
+        return self;
+}
+
+void pstack__delete(struct pstack *self)
+{
+        free(self);
+}
+
+bool pstack__empty(const struct pstack *self)
+{
+        return self->top == 0;
+}
+
+void pstack__remove(struct pstack *self, void *key)
+{
+        unsigned short i = self->top, last_index = self->top - 1;
+
+        while (i-- != 0) {
+                if (self->entries[i] == key) {
+                        if (i < last_index)
+                                memmove(self->entries + i,
+                                        self->entries + i + 1,
+                                        (last_index - i) * sizeof(void *));
+                        --self->top;
+                        return;
+                }
+        }
+        pr_err("%s: %p not on the pstack!\n", __func__, key);
+}
+
+void pstack__push(struct pstack *self, void *key)
+{
+        if (self->top == self->max_nr_entries) {
+                pr_err("%s: top=%d, overflow!\n", __func__, self->top);
+                return;
+        }
+        self->entries[self->top++] = key;
+}
+
+void *pstack__pop(struct pstack *self)
+{
+        void *ret;
+
+        if (self->top == 0) {
+                pr_err("%s: underflow!\n", __func__);
+                return NULL;
+        }
+
+        ret = self->entries[--self->top];
+        self->entries[self->top] = NULL;
+        return ret;
+}