From dc4c2b8d50fa7014bccfc5251c7a90d62926ddb6 Mon Sep 17 00:00:00 2001
From: John Wiegley <johnw@newartisans.com>
Date: Mon, 14 Feb 2005 07:45:09 +0000
Subject: [PATCH] Added the new transaction handler `truncate_entries' which
 can be used to trim a number of entries from the beginning or end of a
 transction stream.  (push_to_transactions_list): Removed unneeded "handler"
 argument.

---
 walk.cc | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 walk.h  | 24 +++++++++++++++++++++---
 2 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/walk.cc b/walk.cc
index da7db316..a402ebf5 100644
--- a/walk.cc
+++ b/walk.cc
@@ -56,6 +56,53 @@ void add_transaction_to(const transaction_t& xact, value_t& value)
     value = xact.amount;
 }
 
+void truncate_entries::flush()
+{
+  if (! xacts.size())
+    return;
+
+  entry_t * last_entry = (*xacts.begin())->entry;
+
+  int l = 0;
+  for (transactions_list::iterator x = xacts.begin();
+       x != xacts.end();
+       x++)
+    if (last_entry != (*x)->entry) {
+      l++;
+      last_entry = (*x)->entry;
+    }
+  l++;
+
+  last_entry = (*xacts.begin())->entry;
+
+  int i = 0;
+  for (transactions_list::iterator x = xacts.begin();
+       x != xacts.end();
+       x++) {
+    if (last_entry != (*x)->entry) {
+      last_entry = (*x)->entry;
+      i++;
+    }
+
+    bool print = false;
+    if (tailwise) {
+      if (count > 0 && l - i <= count)
+	print = true;
+      else if (count < 0 && l - i > - count)
+	print = true;
+    } else {
+      if (count > 0 && i < count)
+	print = true;
+      else if (count < 0 && i >= - count)
+	print = true;
+    }
+
+    if (print)
+      item_handler<transaction_t>::operator()(**x);
+  }
+  item_handler<transaction_t>::flush();
+}
+
 void set_account_value::operator()(transaction_t& xact)
 {
   add_transaction_to(xact, account_xdata(*xact.account).value);
diff --git a/walk.h b/walk.h
index 871a9639..c8e15a88 100644
--- a/walk.h
+++ b/walk.h
@@ -145,6 +145,25 @@ class ignore_transactions : public item_handler<transaction_t>
   virtual void operator()(transaction_t& xact) {}
 };
 
+class truncate_entries : public item_handler<transaction_t>
+{
+  int  count;
+  bool tailwise;
+
+  transactions_list xacts;
+
+ public:
+  truncate_entries(item_handler<transaction_t> * handler,
+		   int _count, bool _tailwise = false)
+    : item_handler<transaction_t>(handler),
+      count(_count), tailwise(_tailwise) {}
+
+  virtual void flush();
+  virtual void operator()(transaction_t& xact) {
+    xacts.push_back(&xact);
+  }
+};
+
 class set_account_value : public item_handler<transaction_t>
 {
  public:
@@ -159,9 +178,8 @@ class push_to_transactions_list : public item_handler<transaction_t>
  public:
   transactions_list& xact_list;
 
-  push_to_transactions_list(transactions_list& _xact_list,
-			    item_handler<transaction_t> * handler = NULL)
-    : item_handler<transaction_t>(handler), xact_list(_xact_list) {}
+  push_to_transactions_list(transactions_list& _xact_list)
+    : xact_list(_xact_list) {}
 
   virtual void operator()(transaction_t& xact) {
     xact_list.push_back(&xact);