From e300f8c076063b85d545e517972717758828d56e Mon Sep 17 00:00:00 2001
From: Brian Norris <banorris@uci.edu>
Date: Thu, 3 Jan 2013 11:59:13 -0800
Subject: [PATCH] snapshot-interface: change hand-coded stack to vector

The logic, etc., is much simpler when using C++ vectors and constructors
here.
---
 snapshot-interface.cc | 36 ++++++++++++++++--------------------
 1 file changed, 16 insertions(+), 20 deletions(-)

diff --git a/snapshot-interface.cc b/snapshot-interface.cc
index c33b8d4..06dae19 100644
--- a/snapshot-interface.cc
+++ b/snapshot-interface.cc
@@ -2,6 +2,7 @@
 #include <unistd.h>
 #include <cstring>
 #include <inttypes.h>
+#include <vector>
 
 #include "snapshot-interface.h"
 #include "snapshot.h"
@@ -15,9 +16,10 @@
 #define MAPFILE "/proc/self/maps"
 
 struct stackEntry {
-	struct stackEntry *next;
+	stackEntry(snapshot_id id, int idx) : snapshotid(id), index(idx) { }
 	snapshot_id snapshotid;
 	int index;
+	MEMALLOC
 };
 
 class SnapshotStack {
@@ -29,7 +31,7 @@ class SnapshotStack {
 
 	MEMALLOC
  private:
-	struct stackEntry *stack;
+	std::vector<struct stackEntry, ModelAlloc<struct stackEntry> > stack;
 };
 
 static SnapshotStack *snapshotObject;
@@ -125,10 +127,9 @@ static void SnapshotGlobalSegments()
 }
 #endif
 
-SnapshotStack::SnapshotStack()
+SnapshotStack::SnapshotStack() : stack()
 {
 	SnapshotGlobalSegments();
-	stack = NULL;
 }
 
 SnapshotStack::~SnapshotStack()
@@ -143,29 +144,24 @@ SnapshotStack::~SnapshotStack()
  */
 int SnapshotStack::backTrackBeforeStep(int seqindex)
 {
-	while (true) {
-		if (stack->index <= seqindex) {
-			//have right entry
-			snapshot_roll_back(stack->snapshotid);
-			return stack->index;
-		}
-		struct stackEntry *tmp = stack;
-		stack = stack->next;
-		model_free(tmp);
-	}
+	int i;
+	for (i = (int)stack.size() - 1; i >= 0; i++)
+		if (stack[i].index <= seqindex)
+			break;
+		else
+			stack.pop_back();
+
+	ASSERT(i >= 0);
+	snapshot_roll_back(stack[i].snapshotid);
+	return stack[i].index;
 }
 
 /** This method takes a snapshot at the given sequence number. */
 void SnapshotStack::snapshotStep(int seqindex)
 {
-	struct stackEntry *tmp = (struct stackEntry *)model_malloc(sizeof(struct stackEntry));
-	tmp->next = stack;
-	tmp->index = seqindex;
-	tmp->snapshotid = take_snapshot();
-	stack = tmp;
+	stack.push_back(stackEntry(seqindex, take_snapshot()));
 }
 
-
 void snapshot_stack_init()
 {
 	snapshotObject = new SnapshotStack();
-- 
2.34.1