From 60e92986f739a025a6534972b8e1cf9498ce3fd2 Mon Sep 17 00:00:00 2001
From: Nathan Binkert <binkertn@umich.edu>
Date: Fri, 25 Nov 2005 11:22:41 -0500
Subject: [PATCH] Add the capability to iterate through the packets in a
 pktfifo, and to remove elements in the middle of the fifo.  These elements do
 not free space, they are just marked removed.  Space is only freed from the
 front of the fifo.

dev/etherpkt.cc:
    serialize the current slack
dev/etherpkt.hh:
    add "slack" to the ethernet packet.  It is to be used by any fifo that
    the packet is currently in to account for extra space that the packet
    may be occupying due to the fifo organization.

--HG--
extra : convert_revision : 8e7c541ba316a9a76495c54cc5f707f8fc65b6d5
---
 dev/etherpkt.cc |  2 ++
 dev/etherpkt.hh | 24 ++++++++++++++++++++----
 dev/pktfifo.hh  | 38 ++++++++++++++++++++++++++++++++++----
 3 files changed, 56 insertions(+), 8 deletions(-)

diff --git a/dev/etherpkt.cc b/dev/etherpkt.cc
index 5dee7dc0d..44dbd7c18 100644
--- a/dev/etherpkt.cc
+++ b/dev/etherpkt.cc
@@ -38,6 +38,7 @@ void
 PacketData::serialize(const string &base, ostream &os)
 {
     paramOut(os, base + ".length", length);
+    paramOut(os, base + ".slack", slack);
     arrayParamOut(os, base + ".data", data, length);
 }
 
@@ -46,6 +47,7 @@ PacketData::unserialize(const string &base, Checkpoint *cp,
                         const string &section)
 {
     paramIn(cp, section, base + ".length", length);
+    paramIn(cp, section, base + ".slack", slack);
     if (length)
         arrayParamIn(cp, section, base + ".data", data, length);
 }
diff --git a/dev/etherpkt.hh b/dev/etherpkt.hh
index 82d22bfad..cb9022d72 100644
--- a/dev/etherpkt.hh
+++ b/dev/etherpkt.hh
@@ -47,14 +47,30 @@ class Checkpoint;
 class PacketData : public RefCounted
 {
   public:
+    /*
+     * Pointer to packet data will be deleted
+     */
     uint8_t *data;
+
+    /*
+     * Length of the current packet
+     */
     int length;
 
+    /*
+     * Extra space taken up by the packet in whatever data structure
+     * it is in.
+     *
+     * NOTE: This can only be use by *one* data structure at a time!
+     */
+    int slack;
+
   public:
-    PacketData() : data(NULL), length(0) { }
-    explicit PacketData(size_t size) : data(new uint8_t[size]), length(0) { }
-    PacketData(std::auto_ptr<uint8_t> d, int l)
-        : data(d.release()), length(l) { }
+    PacketData() : data(NULL), length(0), slack(0) { }
+    explicit PacketData(size_t size)
+        : data(new uint8_t[size]), length(0), slack(0) { }
+    PacketData(std::auto_ptr<uint8_t> d, int l, int s = 0)
+        : data(d.release()), length(l), slack(s) { }
     ~PacketData() { if (data) delete [] data; }
 
   public:
diff --git a/dev/pktfifo.hh b/dev/pktfifo.hh
index a8b626618..61e4ead1b 100644
--- a/dev/pktfifo.hh
+++ b/dev/pktfifo.hh
@@ -39,6 +39,10 @@
 class Checkpoint;
 class PacketFifo
 {
+  public:
+    typedef std::list<PacketPtr> fifo_list;
+    typedef fifo_list::iterator iterator;
+
   protected:
     std::list<PacketPtr> fifo;
     int _maxsize;
@@ -64,9 +68,16 @@ class PacketFifo
         return _reserved;
     }
 
+    iterator begin() { return fifo.begin(); }
+    iterator end() { return fifo.end(); }
+
+    PacketPtr front() { return fifo.front(); }
+
     bool push(PacketPtr ptr)
     {
+        assert(ptr->length);
         assert(_reserved <= ptr->length);
+        assert(ptr->slack == 0);
         if (avail() < ptr->length - _reserved)
             return false;
 
@@ -76,25 +87,44 @@ class PacketFifo
         return true;
     }
 
-    PacketPtr front() { return fifo.front(); }
-
     void pop()
     {
         if (empty())
             return;
 
-        _size -= fifo.front()->length;
-        fifo.front() = NULL;
+        PacketPtr &packet = fifo.front();
+        _size -= packet->length;
+        _size -= packet->slack;
+        packet->slack = 0;
+        packet = NULL;
         fifo.pop_front();
     }
 
     void clear()
     {
+        for (iterator i = begin(); i != end(); ++i)
+            (*i)->slack = 0;
         fifo.clear();
         _size = 0;
         _reserved = 0;
     }
 
+    void remove(iterator i)
+    {
+        PacketPtr &packet = *i;
+        if (i != fifo.begin()) {
+            --i;
+            (*i)->slack += packet->length;
+        } else {
+            _size -= packet->length;
+            _size -= packet->slack;
+        }
+
+        packet->slack = 0;
+        packet = NULL;
+        fifo.erase(i);
+    }
+
 /**
  * Serialization stuff
  */
-- 
2.30.2