[chocolate-doom] 05/29: Use a new PU_FREE tag to mark free blocks, rather than the 'user' field (avoids using magic numbers to mark allocated blocks with no user)
Jonathan Dowland
jmtd at moszumanska.debian.org
Mon Jan 30 15:06:41 UTC 2017
This is an automated email from the git hooks/post-receive script.
jmtd pushed a commit to annotated tag chocolate-doom-0.0.4
in repository chocolate-doom.
commit d29e73f05afa62a514e1156afa2fb40abae6346e
Author: Simon Howard <fraggle at gmail.com>
Date: Thu Sep 22 12:58:46 2005 +0000
Use a new PU_FREE tag to mark free blocks, rather than the 'user' field
(avoids using magic numbers to mark allocated blocks with no user)
Subversion-branch: /trunk/chocolate-doom
Subversion-revision: 119
---
src/z_zone.c | 191 ++++++++++++++++++++++++++++++-----------------------------
src/z_zone.h | 24 +++++---
2 files changed, 112 insertions(+), 103 deletions(-)
diff --git a/src/z_zone.c b/src/z_zone.c
index 1922a62..3739a28 100644
--- a/src/z_zone.c
+++ b/src/z_zone.c
@@ -1,7 +1,7 @@
// Emacs style mode select -*- C++ -*-
//-----------------------------------------------------------------------------
//
-// $Id: z_zone.c 8 2005-07-23 16:44:57Z fraggle $
+// $Id: z_zone.c 119 2005-09-22 12:58:46Z fraggle $
//
// Copyright(C) 1993-1996 Id Software, Inc.
// Copyright(C) 2005 Simon Howard
@@ -22,6 +22,10 @@
// 02111-1307, USA.
//
// $Log$
+// Revision 1.3 2005/09/22 12:58:46 fraggle
+// Use a new PU_FREE tag to mark free blocks, rather than the 'user' field
+// (avoids using magic numbers to mark allocated blocks with no user)
+//
// Revision 1.2 2005/07/23 16:44:57 fraggle
// Update copyright to GNU GPL
//
@@ -35,7 +39,7 @@
//-----------------------------------------------------------------------------
static const char
-rcsid[] = "$Id: z_zone.c 8 2005-07-23 16:44:57Z fraggle $";
+rcsid[] = "$Id: z_zone.c 119 2005-09-22 12:58:46Z fraggle $";
#include "z_zone.h"
#include "i_system.h"
@@ -92,8 +96,8 @@ void Z_ClearZone (memzone_t* zone)
block->prev = block->next = &zone->blocklist;
- // NULL indicates a free block.
- block->user = NULL;
+ // a free block.
+ block->tag = PU_FREE;
block->size = zone->size - sizeof(memzone_t);
}
@@ -122,8 +126,8 @@ void Z_Init (void)
block->prev = block->next = &mainzone->blocklist;
- // NULL indicates a free block.
- block->user = NULL;
+ // free block
+ block->tag = PU_FREE;
block->size = mainzone->size - sizeof(memzone_t);
}
@@ -142,45 +146,42 @@ void Z_Free (void* ptr)
if (block->id != ZONEID)
I_Error ("Z_Free: freed a pointer without ZONEID");
- if (block->user > (void **)0x100)
+ if (block->tag != PU_FREE && block->user != NULL)
{
- // smaller values are not pointers
- // Note: OS-dependend?
-
- // clear the user's mark
- *block->user = 0;
+ // clear the user's mark
+ *block->user = 0;
}
// mark as free
- block->user = NULL;
- block->tag = 0;
+ block->tag = PU_FREE;
+ block->user = NULL;
block->id = 0;
other = block->prev;
- if (!other->user)
+ if (other->tag == PU_FREE)
{
- // merge with previous free block
- other->size += block->size;
- other->next = block->next;
- other->next->prev = other;
+ // merge with previous free block
+ other->size += block->size;
+ other->next = block->next;
+ other->next->prev = other;
- if (block == mainzone->rover)
- mainzone->rover = other;
+ if (block == mainzone->rover)
+ mainzone->rover = other;
- block = other;
+ block = other;
}
other = block->next;
- if (!other->user)
+ if (other->tag == PU_FREE)
{
- // merge the next free block onto the end
- block->size += other->size;
- block->next = other->next;
- block->next->prev = block;
+ // merge the next free block onto the end
+ block->size += other->size;
+ block->next = other->next;
+ block->next->prev = block;
- if (other == mainzone->rover)
- mainzone->rover = block;
+ if (other == mainzone->rover)
+ mainzone->rover = block;
}
}
@@ -204,6 +205,7 @@ Z_Malloc
memblock_t* rover;
memblock_t* newblock;
memblock_t* base;
+ void *result;
size = (size + 3) & ~3;
@@ -219,42 +221,46 @@ Z_Malloc
// back up over them
base = mainzone->rover;
- if (!base->prev->user)
- base = base->prev;
+ if (base->prev->tag == PU_FREE)
+ base = base->prev;
rover = base;
start = base->prev;
do
{
- if (rover == start)
- {
- // scanned all the way around the list
- I_Error ("Z_Malloc: failed on allocation of %i bytes", size);
- }
+ if (rover == start)
+ {
+ // scanned all the way around the list
+ Z_FileDumpHeap(stdout);
+ I_Error ("Z_Malloc: failed on allocation of %i bytes", size);
+ }
- if (rover->user)
- {
- if (rover->tag < PU_PURGELEVEL)
- {
- // hit a block that can't be purged,
- // so move base past it
- base = rover = rover->next;
- }
- else
- {
- // free the rover block (adding the size to base)
-
- // the rover can be the base block
- base = base->prev;
- Z_Free ((byte *)rover+sizeof(memblock_t));
- base = base->next;
- rover = base->next;
- }
- }
- else
- rover = rover->next;
- } while (base->user || base->size < size);
+ if (rover->tag != PU_FREE)
+ {
+ if (rover->tag < PU_PURGELEVEL)
+ {
+ // hit a block that can't be purged,
+ // so move base past it
+ base = rover = rover->next;
+ }
+ else
+ {
+ // free the rover block (adding the size to base)
+
+ // the rover can be the base block
+ base = base->prev;
+ Z_Free ((byte *)rover+sizeof(memblock_t));
+ base = base->next;
+ rover = base->next;
+ }
+ }
+ else
+ {
+ rover = rover->next;
+ }
+
+ } while (base->tag != PU_FREE || base->size < size);
// found a block big enough
@@ -262,43 +268,39 @@ Z_Malloc
if (extra > MINFRAGMENT)
{
- // there will be a free fragment after the allocated block
- newblock = (memblock_t *) ((byte *)base + size );
- newblock->size = extra;
+ // there will be a free fragment after the allocated block
+ newblock = (memblock_t *) ((byte *)base + size );
+ newblock->size = extra;
- // NULL indicates free block.
- newblock->user = NULL;
- newblock->tag = 0;
- newblock->prev = base;
- newblock->next = base->next;
- newblock->next->prev = newblock;
-
- base->next = newblock;
- base->size = size;
+ newblock->tag = PU_FREE;
+ newblock->user = NULL;
+ newblock->prev = base;
+ newblock->next = base->next;
+ newblock->next->prev = newblock;
+
+ base->next = newblock;
+ base->size = size;
}
- if (user)
- {
- // mark as an in use block
- base->user = user;
- *(void **)user = (void *) ((byte *)base + sizeof(memblock_t));
- }
- else
- {
- if (tag >= PU_PURGELEVEL)
+ if (user == NULL && tag >= PU_PURGELEVEL)
I_Error ("Z_Malloc: an owner is required for purgable blocks");
- // mark as in use, but unowned
- base->user = (void *)2;
- }
+ base->user = user;
base->tag = tag;
+ result = (void *) ((byte *)base + sizeof(memblock_t));
+
+ if (base->user)
+ {
+ *base->user = result;
+ }
+
// next allocation will start looking here
mainzone->rover = base->next;
base->id = ZONEID;
- return (void *) ((byte *)base + sizeof(memblock_t));
+ return result;
}
@@ -322,7 +324,7 @@ Z_FreeTags
next = block->next;
// free block?
- if (!block->user)
+ if (block->tag == PU_FREE)
continue;
if (block->tag >= lowtag && block->tag <= hightag)
@@ -367,7 +369,7 @@ Z_DumpHeap
if ( block->next->prev != block)
printf ("ERROR: next block doesn't have proper back link\n");
- if (!block->user && !block->next->user)
+ if (block->tag == PU_FREE && block->next->tag == PU_FREE)
printf ("ERROR: two consecutive free blocks\n");
}
}
@@ -399,7 +401,7 @@ void Z_FileDumpHeap (FILE* f)
if ( block->next->prev != block)
fprintf (f,"ERROR: next block doesn't have proper back link\n");
- if (!block->user && !block->next->user)
+ if (block->tag == PU_FREE && block->next->tag == PU_FREE)
fprintf (f,"ERROR: two consecutive free blocks\n");
}
}
@@ -427,7 +429,7 @@ void Z_CheckHeap (void)
if ( block->next->prev != block)
I_Error ("Z_CheckHeap: next block doesn't have proper back link\n");
- if (!block->user && !block->next->user)
+ if (block->tag == PU_FREE && block->next->tag == PU_FREE)
I_Error ("Z_CheckHeap: two consecutive free blocks\n");
}
}
@@ -448,10 +450,10 @@ Z_ChangeTag2
block = (memblock_t *) ( (byte *)ptr - sizeof(memblock_t));
if (block->id != ZONEID)
- I_Error ("Z_ChangeTag: freed a pointer without ZONEID");
+ I_Error ("Z_ChangeTag: freed a pointer without ZONEID");
- if (tag >= PU_PURGELEVEL && (unsigned)block->user < 0x100)
- I_Error ("Z_ChangeTag: an owner is required for purgable blocks");
+ if (tag >= PU_PURGELEVEL && block->user == NULL)
+ I_Error ("Z_ChangeTag: an owner is required for purgable blocks");
block->tag = tag;
}
@@ -469,12 +471,13 @@ int Z_FreeMemory (void)
free = 0;
for (block = mainzone->blocklist.next ;
- block != &mainzone->blocklist;
- block = block->next)
+ block != &mainzone->blocklist;
+ block = block->next)
{
- if (!block->user || block->tag >= PU_PURGELEVEL)
- free += block->size;
+ if (block->tag == PU_FREE || block->tag >= PU_PURGELEVEL)
+ free += block->size;
}
+
return free;
}
diff --git a/src/z_zone.h b/src/z_zone.h
index 03b008e..ec58b28 100644
--- a/src/z_zone.h
+++ b/src/z_zone.h
@@ -1,7 +1,7 @@
// Emacs style mode select -*- C++ -*-
//-----------------------------------------------------------------------------
//
-// $Id: z_zone.h 8 2005-07-23 16:44:57Z fraggle $
+// $Id: z_zone.h 119 2005-09-22 12:58:46Z fraggle $
//
// Copyright(C) 1993-1996 Id Software, Inc.
// Copyright(C) 2005 Simon Howard
@@ -40,12 +40,14 @@
// ZONE MEMORY
// PU - purge tags.
// Tags < 100 are not overwritten until freed.
-#define PU_STATIC 1 // static entire execution time
-#define PU_SOUND 2 // static while playing
-#define PU_MUSIC 3 // static while playing
-#define PU_DAVE 4 // anything else Dave wants static
-#define PU_LEVEL 50 // static until level exited
-#define PU_LEVSPEC 51 // a special thinker in a level
+#define PU_STATIC 1 /* static entire execution time */
+#define PU_SOUND 2 /* static while playing */
+#define PU_MUSIC 3 /* static while playing */
+#define PU_DAVE 4 /* anything else Dave wants static */
+#define PU_FREE 5 /* a free block */
+#define PU_LEVEL 50 /* static until level exited */
+#define PU_LEVSPEC 51 /* a special thinker in a level */
+
// Tags >= 100 are purgable whenever needed.
#define PU_PURGELEVEL 100
#define PU_CACHE 101
@@ -65,8 +67,8 @@ int Z_FreeMemory (void);
typedef struct memblock_s
{
int size; // including the header and possibly tiny fragments
- void** user; // NULL if a free block
- int tag; // purgelevel
+ void** user;
+ int tag; // PU_FREE if this is free
int id; // should be ZONEID
struct memblock_s* next;
struct memblock_s* prev;
@@ -89,6 +91,10 @@ typedef struct memblock_s
//-----------------------------------------------------------------------------
//
// $Log$
+// Revision 1.3 2005/09/22 12:58:46 fraggle
+// Use a new PU_FREE tag to mark free blocks, rather than the 'user' field
+// (avoids using magic numbers to mark allocated blocks with no user)
+//
// Revision 1.2 2005/07/23 16:44:57 fraggle
// Update copyright to GNU GPL
//
--
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