From 32ad14f60b7967e3ec092687b193350771804cf2 Mon Sep 17 00:00:00 2001
From: havoc <havoc@d7cf8633-e32d-0410-b094-e92efae38249>
Date: Sun, 4 Apr 2010 23:14:40 +0000
Subject: [PATCH] change representation of string offsets for allocated strings
and engine buffers to use 0x4000000 as base offset instead of using negative
values, to reduce possibility of && and || operators (which do float compares
to 0 in the vm) breaking on string variables
git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@10066 d7cf8633-e32d-0410-b094-e92efae38249
::stable-branch::merge=d0129de1a042fd4244533d2a25663259588a1f8f
---
prvm_edict.c | 85 +++++++++++++++++++++++++---------------------------
1 file changed, 40 insertions(+), 45 deletions(-)
diff --git a/prvm_edict.c b/prvm_edict.c
index 2e137672..e227d612 100644
--- a/prvm_edict.c
+++ b/prvm_edict.c
@@ -2786,52 +2786,38 @@ unsigned int PRVM_EDICT_NUM_ERROR(unsigned int n, char *filename, int fileline)
}
sizebuf_t vm_tempstringsbuf;
+#define PRVM_KNOWNSTRINGBASE 0x40000000
const char *PRVM_GetString(int num)
{
- if (num >= 0)
+ if (num < 0)
{
- if (num < prog->stringssize)
- return prog->strings + num;
- else
-#if 1
- if (num <= prog->stringssize + vm_tempstringsbuf.maxsize)
- {
- num -= prog->stringssize;
- if (num < vm_tempstringsbuf.cursize)
- return (char *)vm_tempstringsbuf.data + num;
- else
- {
- VM_Warning("PRVM_GetString: Invalid temp-string offset (%i >= %i vm_tempstringsbuf.cursize)\n", num, vm_tempstringsbuf.cursize);
- return "";
- }
- }
+ // invalid
+ VM_Warning("PRVM_GetString: Invalid string offset (%i < 0)\n", num);
+ return "";
+ }
+ else if (num < prog->stringssize)
+ {
+ // constant string from progs.dat
+ return prog->strings + num;
+ }
+ else if (num <= prog->stringssize + vm_tempstringsbuf.maxsize)
+ {
+ // tempstring returned by engine to QC (becomes invalid after returning to engine)
+ num -= prog->stringssize;
+ if (num < vm_tempstringsbuf.cursize)
+ return (char *)vm_tempstringsbuf.data + num;
else
-#endif
{
- VM_Warning("PRVM_GetString: Invalid constant-string offset (%i >= %i prog->stringssize)\n", num, prog->stringssize);
+ VM_Warning("PRVM_GetString: Invalid temp-string offset (%i >= %i vm_tempstringsbuf.cursize)\n", num, vm_tempstringsbuf.cursize);
return "";
}
}
- else
+ else if (num & PRVM_KNOWNSTRINGBASE)
{
- num = -1 - num;
-#if 0
- if (num >= (1<<30))
- {
- // special range reserved for tempstrings
- num -= (1<<30);
- if (num < vm_tempstringsbuf.cursize)
- return (char *)vm_tempstringsbuf.data + num;
- else
- {
- VM_Warning("PRVM_GetString: Invalid temp-string offset (%i >= %i vm_tempstringsbuf.cursize)\n", num, vm_tempstringsbuf.cursize);
- return "";
- }
- }
- else
-#endif
- if (num < prog->numknownstrings)
+ // allocated string
+ num = num - PRVM_KNOWNSTRINGBASE;
+ if (num >= 0 && num < prog->numknownstrings)
{
if (!prog->knownstrings[num])
{
@@ -2846,12 +2832,18 @@ const char *PRVM_GetString(int num)
return "";
}
}
+ else
+ {
+ // invalid string offset
+ VM_Warning("PRVM_GetString: Invalid constant-string offset (%i >= %i prog->stringssize)\n", num, prog->stringssize);
+ return "";
+ }
}
const char *PRVM_ChangeEngineString(int i, const char *s)
{
const char *old;
- i = -1 - i;
+ i = i - PRVM_KNOWNSTRINGBASE;
if(i < 0 || i >= prog->numknownstrings)
PRVM_ERROR("PRVM_ChangeEngineString: s is not an engine string");
old = prog->knownstrings[i];
@@ -2871,13 +2863,11 @@ int PRVM_SetEngineString(const char *s)
if (s >= (char *)vm_tempstringsbuf.data && s < (char *)vm_tempstringsbuf.data + vm_tempstringsbuf.maxsize)
#if 1
return prog->stringssize + (s - (char *)vm_tempstringsbuf.data);
-#else
- return -1 - ((1<<30) + (s - (char *)vm_tempstringsbuf.data));
#endif
// see if it's a known string address
for (i = 0;i < prog->numknownstrings;i++)
if (prog->knownstrings[i] == s)
- return -1 - i;
+ return PRVM_KNOWNSTRINGBASE + i;
// new unknown engine string
if (developer_insane.integer)
Con_DPrintf("new engine string %p = \"%s\"\n", s, s);
@@ -2911,7 +2901,7 @@ int PRVM_SetEngineString(const char *s)
prog->knownstrings_freeable[i] = false;
if(prog->leaktest_active)
prog->knownstrings_origin[i] = NULL;
- return -1 - i;
+ return PRVM_KNOWNSTRINGBASE + i;
}
// temp string handling
@@ -2983,7 +2973,12 @@ int PRVM_AllocString(size_t bufferlength, char **pointer)
if(prog->leaktest_active)
memcpy((char **)prog->knownstrings_origin, oldstrings_origin, prog->numknownstrings * sizeof(char *));
}
- // TODO why not Mem_Free the old ones?
+ if (oldstrings)
+ Mem_Free(oldstrings);
+ if (oldstrings_freeable)
+ Mem_Free((unsigned char *)oldstrings_freeable);
+ if (oldstrings_origin)
+ Mem_Free(oldstrings_origin);
}
prog->numknownstrings++;
}
@@ -2994,7 +2989,7 @@ int PRVM_AllocString(size_t bufferlength, char **pointer)
prog->knownstrings_origin[i] = PRVM_AllocationOrigin();
if (pointer)
*pointer = (char *)(prog->knownstrings[i]);
- return -1 - i;
+ return PRVM_KNOWNSTRINGBASE + i;
}
void PRVM_FreeString(int num)
@@ -3003,9 +2998,9 @@ void PRVM_FreeString(int num)
PRVM_ERROR("PRVM_FreeString: attempt to free a NULL string");
else if (num >= 0 && num < prog->stringssize)
PRVM_ERROR("PRVM_FreeString: attempt to free a constant string");
- else if (num < 0 && num >= -prog->numknownstrings)
+ else if (num >= PRVM_KNOWNSTRINGBASE && num < PRVM_KNOWNSTRINGBASE + prog->numknownstrings)
{
- num = -1 - num;
+ num = num - PRVM_KNOWNSTRINGBASE;
if (!prog->knownstrings[num])
PRVM_ERROR("PRVM_FreeString: attempt to free a non-existent or already freed string");
if (!prog->knownstrings_freeable[num])
--
2.39.5