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authorSimon Howard2010-04-23 20:46:29 +0000
committerSimon Howard2010-04-23 20:46:29 +0000
commit4070ecd92c45dadc80e048e1bc929bced925c232 (patch)
tree05816467343b1496ce07249212a83e85a242bcc2 /src/p_setup.c
parent13d87ff8f1f839a9b10178e00cfbe58aca1c6124 (diff)
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Add REJECT buffer overflow emulation, based on code from PrBoom+ (thanks
entryway). Fixes YDFEAR25.LMP. Subversion-branch: /trunk/chocolate-doom Subversion-revision: 1914
Diffstat (limited to 'src/p_setup.c')
-rw-r--r--src/p_setup.c85
1 files changed, 78 insertions, 7 deletions
diff --git a/src/p_setup.c b/src/p_setup.c
index 2a3a8f85..385759f8 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -76,6 +76,7 @@ line_t* lines;
int numsides;
side_t* sides;
+static int totallines;
// BLOCKMAP
// Created from axis aligned bounding box
@@ -534,7 +535,6 @@ void P_GroupLines (void)
line_t** linebuffer;
int i;
int j;
- int total;
line_t* li;
sector_t* sector;
subsector_t* ss;
@@ -552,21 +552,21 @@ void P_GroupLines (void)
// count number of lines in each sector
li = lines;
- total = 0;
+ totallines = 0;
for (i=0 ; i<numlines ; i++, li++)
{
- total++;
+ totallines++;
li->frontsector->linecount++;
if (li->backsector && li->backsector != li->frontsector)
{
li->backsector->linecount++;
- total++;
+ totallines++;
}
}
// build line tables for each sector
- linebuffer = Z_Malloc (total*sizeof(line_t *), PU_LEVEL, 0);
+ linebuffer = Z_Malloc (totallines*sizeof(line_t *), PU_LEVEL, 0);
for (i=0; i<numsectors; ++i)
{
@@ -643,6 +643,77 @@ void P_GroupLines (void)
}
+// Pad the REJECT lump with extra data when the lump is too small,
+// to simulate a REJECT buffer overflow in Vanilla Doom.
+
+static void PadRejectArray(byte *array, unsigned int len)
+{
+ unsigned int i;
+ unsigned int byte_num;
+ byte *dest;
+
+ // Values to pad the REJECT array with:
+
+ unsigned int rejectpad[4] =
+ {
+ ((totallines * 4 + 3) & ~3) + 24, // Size
+ 0, // Part of z_zone block header
+ 50, // PU_LEVEL
+ 0x1d4a11 // DOOM_CONST_ZONEID
+ };
+
+ // Copy values from rejectpad into the destination array.
+
+ dest = array;
+
+ for (i=0; i<len && i<sizeof(rejectpad); ++i)
+ {
+ byte_num = i % 4;
+ *dest = (rejectpad[i / 4] >> (byte_num * 8)) & 0xff;
+ ++dest;
+ }
+
+ // We only have a limited pad size. Print a warning if the
+ // REJECT lump is too small.
+
+ if (len > sizeof(rejectpad))
+ {
+ fprintf(stderr, "PadRejectArray: REJECT lump too short to pad! (%i > %i)\n",
+ len, sizeof(rejectpad));
+
+ // Pad remaining space with 0xff.
+
+ memset(array + sizeof(rejectpad), 0x00, len - sizeof(rejectpad));
+ }
+}
+
+static void P_LoadReject(int lumpnum)
+{
+ int minlength;
+ int lumplen;
+
+ // Calculate the size that the REJECT lump *should* be.
+
+ minlength = (numsectors * numsectors + 7) / 8;
+
+ // If the lump meets the minimum length, it can be loaded directly.
+ // Otherwise, we need to allocate a buffer of the correct size
+ // and pad it with appropriate data.
+
+ lumplen = W_LumpLength(lumpnum);
+
+ if (lumplen >= minlength)
+ {
+ rejectmatrix = W_CacheLumpNum(lumpnum, PU_LEVEL);
+ }
+ else
+ {
+ rejectmatrix = Z_Malloc(minlength, PU_LEVEL, &rejectmatrix);
+ W_ReadLump(lumpnum, rejectmatrix);
+
+ PadRejectArray(rejectmatrix + lumplen, minlength - lumplen);
+ }
+}
//
// P_SetupLevel
@@ -719,9 +790,9 @@ P_SetupLevel
P_LoadSubsectors (lumpnum+ML_SSECTORS);
P_LoadNodes (lumpnum+ML_NODES);
P_LoadSegs (lumpnum+ML_SEGS);
-
- rejectmatrix = W_CacheLumpNum (lumpnum+ML_REJECT,PU_LEVEL);
+
P_GroupLines ();
+ P_LoadReject (lumpnum+ML_REJECT);
bodyqueslot = 0;
deathmatch_p = deathmatchstarts;