treewide: Replace <name>_cnt by n_<name>s and <name>_cap by allocated_<name>.

[pspp] / src / math / sort.c

diff --git a/src/math/sort.c b/src/math/sort.c
index 8719d877e096fcc9fc0d0f911d462d7bd0566725..a784960420874dd17d0bff8ba8715d824506614b 100644 (file)
--- a/src/math/sort.c
+++ b/src/math/sort.c
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 1997-9, 2000, 2006, 2009 Free Software Foundation, Inc.
+   Copyright (C) 1997-9, 2000, 2006, 2009, 2011, 2012 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -16,24 +16,21 @@
 
 #include <config.h>
 
-#include "sort.h"
+#include "math/sort.h"
 
 #include <stdio.h>
 
-#include <data/case.h>
-#include <data/casereader.h>
-#include <data/casewriter.h>
-#include <data/casewriter-provider.h>
-#include <data/settings.h>
-#include <data/subcase.h>
-#include <libpspp/array.h>
-#include <libpspp/assertion.h>
-#include <math/merge.h>
+#include "data/case.h"
+#include "data/casereader.h"
+#include "data/casewriter-provider.h"
+#include "data/casewriter.h"
+#include "data/settings.h"
+#include "data/subcase.h"
+#include "libpspp/array.h"
+#include "libpspp/assertion.h"
+#include "math/merge.h"
 
-#include "xalloc.h"
-
-#include "gettext.h"
-#define _(msgid) gettext (msgid)
+#include "gl/xalloc.h"
 
 /* These should only be changed for testing purposes. */
 int min_buffers = 64;
@@ -169,7 +166,9 @@ static struct casewriter_class sort_casewriter_class =
   };
 \f
 /* Reads all the cases from INPUT.  Sorts the cases according to
-   ORDERING.  Returns the sorted cases in a new casereader. */
+   ORDERING.  Returns the sorted cases in a new casereader.
+   INPUT is destroyed by this function.
+ */
 struct casereader *
 sort_execute (struct casereader *input, const struct subcase *ordering)
 {
@@ -181,7 +180,7 @@ sort_execute (struct casereader *input, const struct subcase *ordering)
 
 /* Reads all the cases from INPUT.  Sorts the cases in ascending
    order according to VARIABLE.  Returns the sorted cases in a
-   new casereader. */
+   new casereader.  INPUT is destroyed by this function. */
 struct casereader *
 sort_execute_1var (struct casereader *input, const struct variable *var)
 {
@@ -198,8 +197,9 @@ struct pqueue
   {
     struct subcase ordering;
     struct pqueue_record *records;
-    size_t record_cnt;
-    size_t record_cap;
+    size_t n_records;           /* Current number of records. */
+    size_t allocated_records;   /* Space currently allocated for records. */
+    size_t max_records;         /* Max space we are willing to allocate. */
     casenumber idx;
   };
 
@@ -220,13 +220,14 @@ pqueue_create (const struct subcase *ordering, const struct caseproto *proto)
 
   pq = xmalloc (sizeof *pq);
   subcase_clone (&pq->ordering, ordering);
-  pq->record_cap = settings_get_workspace_cases (proto);
-  if (pq->record_cap > max_buffers)
-    pq->record_cap = max_buffers;
-  else if (pq->record_cap < min_buffers)
-    pq->record_cap = min_buffers;
-  pq->record_cnt = 0;
-  pq->records = xnmalloc (pq->record_cap, sizeof *pq->records);
+  pq->max_records = settings_get_workspace_cases (proto);
+  if (pq->max_records > max_buffers)
+    pq->max_records = max_buffers;
+  else if (pq->max_records < min_buffers)
+    pq->max_records = min_buffers;
+  pq->n_records = 0;
+  pq->allocated_records = 0;
+  pq->records = NULL;
   pq->idx = 0;
 
   return pq;
@@ -252,13 +253,13 @@ pqueue_destroy (struct pqueue *pq)
 static bool
 pqueue_is_full (const struct pqueue *pq)
 {
-  return pq->record_cnt >= pq->record_cap;
+  return pq->n_records >= pq->max_records;
 }
 
 static bool
 pqueue_is_empty (const struct pqueue *pq)
 {
-  return pq->record_cnt == 0;
+  return pq->n_records == 0;
 }
 
 static void
@@ -268,12 +269,23 @@ pqueue_push (struct pqueue *pq, struct ccase *c, casenumber id)
 
   assert (!pqueue_is_full (pq));
 
-  r = &pq->records[pq->record_cnt++];
+  if (pq->n_records >= pq->allocated_records)
+    {
+      pq->allocated_records = pq->allocated_records * 2;
+      if (pq->allocated_records < 16)
+        pq->allocated_records = 16;
+      else if (pq->allocated_records > pq->max_records)
+        pq->allocated_records = pq->max_records;
+      pq->records = xrealloc (pq->records,
+                              pq->allocated_records * sizeof *pq->records);
+    }
+
+  r = &pq->records[pq->n_records++];
   r->id = id;
   r->c = c;
   r->idx = pq->idx++;
 
-  push_heap (pq->records, pq->record_cnt, sizeof *pq->records,
+  push_heap (pq->records, pq->n_records, sizeof *pq->records,
              compare_pqueue_records_minheap, pq);
 }
 
@@ -284,10 +296,10 @@ pqueue_pop (struct pqueue *pq, casenumber *id)
 
   assert (!pqueue_is_empty (pq));
 
-  pop_heap (pq->records, pq->record_cnt--, sizeof *pq->records,
+  pop_heap (pq->records, pq->n_records--, sizeof *pq->records,
             compare_pqueue_records_minheap, pq);
 
-  r = &pq->records[pq->record_cnt];
+  r = &pq->records[pq->n_records];
   *id = r->id;
   return r->c;
 }