compute cost basis correctly

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@1584 57a11ea4-9604-0410-9ed3-97b8803252fd

src/engine/Account.c

@@ -34,6 +34,7 @@
 #include "GroupP.h"
 #include "date.h"
 #include "messages.h"
+#include "Queue.h"
 #include "Transaction.h"
 #include "TransactionP.h"
 #include "util.h"
@@ -203,7 +204,7 @@ void
 xaccAccountCommitEdit (Account *acc)
 {
    if (!acc) return;
-   acc->changed = 1;
+   acc->changed |= ACC_INVALIDATE_ALL;
    acc->open = 0;
 }
 
@@ -263,7 +264,7 @@ disable for now till we figure out what the right thing is.
 */
 
   /* mark the account as having changed */
-  acc -> changed = TRUE;
+  acc -> changed |= ACC_INVALIDATE_ALL;
 
   /* if this split belongs to another acount, remove it from 
    * there first.  We don't want to ever leave the system
@@ -357,7 +358,7 @@ xaccAccountRemoveSplit ( Account *acc, Split *split )
   CHECK (acc);
 
   /* mark the account as having changed */
-  acc -> changed = TRUE;
+  acc -> changed |= ACC_INVALIDATE_ALL;
   
   for( i=0,j=0; j<acc->numSplits; i++,j++ ) {
     acc->splits[i] = acc->splits[j];
@@ -416,7 +417,8 @@ xaccAccountRecomputeBalance( Account * acc )
   Split *split, *last_split = NULL;
   
   if( NULL == acc ) return;
-  if (FALSE == acc->changed) return;
+  if (0x0 == (ACC_INVALID_BALN & acc->changed)) return;
+  acc->changed &= ~ACC_INVALID_BALN;
 
   split = acc->splits[0];
   while (split) {
@@ -453,7 +455,8 @@ xaccAccountRecomputeBalance( Account * acc )
       split -> cleared_balance = dcleared_balance;
       split -> reconciled_balance = dreconciled_balance;
     }
-    split -> cost_basis = dbalance;
+    /* invalidate the cost basis; this has to be computed with other routine */
+    split -> cost_basis = 0.0;
 
     last_split = split;
     i++;
@@ -479,6 +482,46 @@ xaccAccountRecomputeBalance( Account * acc )
   return;
 }
 
+/********************************************************************\
+\********************************************************************/
+
+void
+xaccAccountRecomputeCostBasis( Account * acc )
+{
+  int  i = 0; 
+  double  amt = 0.0;
+  Split *split = NULL;
+  Queue *q;
+  
+  if( NULL == acc ) return;
+  if (0x0 == (ACC_INVALID_COSTB & acc->changed)) return;
+  acc->changed &= ~ACC_INVALID_COSTB;
+
+  /* create the FIFO queue */
+  q = xaccMallocQueue ();
+
+  /* loop over all splits in this account */
+  split = acc->splits[0];
+  while (split) {
+
+    /* positive amounts are a purchase, negative are a sale. 
+     * Use FIFO accounting: purchase to head, sale from tail. */
+    amt = split->damount;
+    if (0.0 < amt) {
+       xaccQueuePushHead (q, split);
+    } else 
+    if (0.0 > amt) {
+       xaccQueuePopTailShares (q, amt);
+    }
+    split->cost_basis = xaccQueueGetValue (q);
+
+    i++;
+    split = acc->splits[i];
+  }
+
+  xaccFreeQueue (q);
+}
+
 /********************************************************************\
  * xaccCheckDateOrder                                               *
  *   check this split to see if the date is in correct order        *

src/engine/AccountP.h

@@ -18,7 +18,7 @@
 /********************************************************************\
  * Account.h -- the Account data structure                          *
  * Copyright (C) 1997 Robin D. Clark                                *
- * Copyright (C) 1997, 1998 Linas Vepstas                           *
+ * Copyright (C) 1997, 1998, 1999 Linas Vepstas                     *
  *                                                                  *
  * This program is free software; you can redistribute it and/or    *
  * modify it under the terms of the GNU General Public License as   *
@@ -129,8 +129,9 @@ struct _account {
   int numSplits;                /* length of splits array below   */
   Split **splits;               /* ptr to array of ptrs to splits */
 
-  /* the "changed" flag helps the gui keep track of 
+  /* The "changed" flag is used to invalidate cached values in this structure.
-   * changes to this account */
+   * currently, the balances and the cost basis are cached.
+   */
   short changed;
 
   /* the "open" flag indicates if the account has been 
@@ -138,6 +139,11 @@ struct _account {
   short open;
 };
 
+/* bitfields for the changed flag */
+#define ACC_INVALID_BALN      0x1
+#define ACC_INVALID_COSTB     0x2
+#define ACC_INVALIDATE_ALL    0x3
+
 /* bitflields for the open flag */
 #define ACC_BEGIN_EDIT        0x1
 #define ACC_DEFER_REBALANCE   0x2
@@ -160,6 +166,12 @@ void         xaccAccountRemoveSplit (Account *, Split *);
 void         xaccAccountRecomputeBalance (Account *);
 void         xaccAccountRecomputeBalances (Account **);
 
+/*
+ * recomputes the cost basis 
+ */
+void         xaccAccountRecomputeCostBasis (Account *);
+
+
 /** GLOBALS *********************************************************/
 
 extern int next_free_unique_account_id;

src/engine/Transaction.c

@@ -203,7 +203,7 @@ xaccConfigGetForceDoubleEntry (void)
 
 #define MARK_SPLIT(split) {			\
    Account *acc = (Account *) ((split)->acc);	\
-   if (acc) acc->changed = 1;			\
+   if (acc) acc->changed |= ACC_INVALIDATE_ALL;	\
 }
 
 static void
@@ -308,6 +308,7 @@ double xaccSplitGetShareBalance (Split *s)
 double xaccSplitGetCostBasis (Split *s) 
 {
    if (!s) return 0.0;
+   xaccAccountRecomputeCostBasis (s->acc);
    return s->cost_basis;
 }