ref: f43f12363861625ef9c454a90e5c9fd7a0af9781
dir: /w_wad.c/
//
// Copyright(C) 1993-1996 Id Software, Inc.
// Copyright(C) 2005-2014 Simon Howard
//
// 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 the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// DESCRIPTION:
// Handles WAD file header, directory, lump I/O.
//
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "doomtype.h"
#include "i_system.h"
#include "i_video.h"
#include "m_misc.h"
#include "z_zone.h"
#include "w_wad.h"
typedef PACKED_STRUCT (
{
// Should be "IWAD" or "PWAD".
char identification[4];
int numlumps;
int infotableofs;
}) wadinfo_t;
typedef PACKED_STRUCT (
{
int filepos;
int size;
char name[8];
}) filelump_t;
//
// GLOBALS
//
// Location of each lump on disk.
lumpinfo_t **lumpinfo;
unsigned int numlumps = 0;
// Hash table for fast lookups
static lumpindex_t *lumphash;
// Hash function used for lump names.
unsigned int W_LumpNameHash(const char *s)
{
// This is the djb2 string hash function, modded to work on strings
// that have a maximum length of 8.
unsigned int result = 5381;
unsigned int i;
for (i=0; i < 8 && s[i] != '\0'; ++i)
{
result = ((result << 5) ^ result ) ^ toupper(s[i]);
}
return result;
}
//
// LUMP BASED ROUTINES.
//
//
// W_AddFile
// All files are optional, but at least one file must be
// found (PWAD, if all required lumps are present).
// Files with a .wad extension are wadlink files
// with multiple lumps.
// Other files are single lumps with the base filename
// for the lump name.
wad_file_t *W_AddFile (char *filename)
{
wadinfo_t header;
lumpindex_t i;
wad_file_t *wad_file;
int length;
int startlump;
filelump_t *fileinfo;
filelump_t *filerover;
lumpinfo_t *filelumps;
int numfilelumps;
// If the filename begins with a ~, it indicates that we should use the
// reload hack.
if (filename[0] == '~')
{
I_Error("reload hack not supported.");
}
// Open the file and add to directory
wad_file = W_OpenFile(filename);
if (wad_file == NULL)
{
printf (" couldn't open %s\n", filename);
return NULL;
}
if (strcasecmp(filename+strlen(filename)-3 , "wad" ) )
{
// single lump file
// fraggle: Swap the filepos and size here. The WAD directory
// parsing code expects a little-endian directory, so will swap
// them back. Effectively we're constructing a "fake WAD directory"
// here, as it would appear on disk.
fileinfo = Z_Malloc(sizeof(filelump_t), PU_STATIC, 0);
fileinfo->filepos = LE_LONG(0);
fileinfo->size = LE_LONG(wad_file->length);
// Name the lump after the base of the filename (without the
// extension).
M_ExtractFileBase (filename, fileinfo->name);
numfilelumps = 1;
}
else
{
// WAD file
W_Read(wad_file, 0, &header, sizeof(header));
if (strncmp(header.identification,"IWAD",4))
{
// Homebrew levels?
if (strncmp(header.identification,"PWAD",4))
{
W_CloseFile(wad_file);
I_Error ("Wad file %s doesn't have IWAD "
"or PWAD id\n", filename);
}
// ???modifiedgame = true;
}
header.numlumps = LE_LONG(header.numlumps);
// Vanilla Doom doesn't like WADs with more than 4046 lumps
// https://www.doomworld.com/vb/post/1010985
if (!strncmp(header.identification,"PWAD",4) && header.numlumps > 4046)
{
W_CloseFile(wad_file);
I_Error ("Error: Vanilla limit for lumps in a WAD is 4046, "
"PWAD %s has %d", filename, header.numlumps);
}
header.infotableofs = LE_LONG(header.infotableofs);
length = header.numlumps*sizeof(filelump_t);
fileinfo = Z_Malloc(length, PU_STATIC, 0);
W_Read(wad_file, header.infotableofs, fileinfo, length);
numfilelumps = header.numlumps;
}
// Increase size of numlumps array to accomodate the new file.
filelumps = calloc(numfilelumps, sizeof(lumpinfo_t));
if (filelumps == NULL)
{
W_CloseFile(wad_file);
I_Error("Failed to allocate array for lumps from new file.");
}
startlump = numlumps;
numlumps += numfilelumps;
lumpinfo = I_Realloc(lumpinfo, numlumps * sizeof(lumpinfo_t *));
filerover = fileinfo;
for (i = startlump; i < numlumps; ++i)
{
lumpinfo_t *lump_p = &filelumps[i - startlump];
lump_p->wad_file = wad_file;
lump_p->position = LE_LONG(filerover->filepos);
lump_p->size = LE_LONG(filerover->size);
lump_p->cache = NULL;
strncpy(lump_p->name, filerover->name, 8);
lumpinfo[i] = lump_p;
++filerover;
}
Z_Free(fileinfo);
if (lumphash != NULL)
{
Z_Free(lumphash);
lumphash = NULL;
}
return wad_file;
}
//
// W_NumLumps
//
int W_NumLumps (void)
{
return numlumps;
}
//
// W_CheckNumForName
// Returns -1 if name not found.
//
lumpindex_t W_CheckNumForName(char* name)
{
lumpindex_t i;
// Do we have a hash table yet?
if (lumphash != NULL)
{
int hash;
// We do! Excellent.
hash = W_LumpNameHash(name) % numlumps;
for (i = lumphash[hash]; i != -1; i = lumpinfo[i]->next)
{
if (!strncasecmp(lumpinfo[i]->name, name, 8))
{
return i;
}
}
}
else
{
// We don't have a hash table generate yet. Linear search :-(
//
// scan backwards so patch lump files take precedence
for (i = numlumps - 1; i >= 0; --i)
{
if (!strncasecmp(lumpinfo[i]->name, name, 8))
{
return i;
}
}
}
// TFB. Not found.
return -1;
}
//
// W_GetNumForName
// Calls W_CheckNumForName, but bombs out if not found.
//
lumpindex_t W_GetNumForName(char* name)
{
lumpindex_t i;
i = W_CheckNumForName (name);
if (i < 0)
{
I_Error ("W_GetNumForName: %s not found!", name);
}
return i;
}
//
// W_LumpLength
// Returns the buffer size needed to load the given lump.
//
int W_LumpLength(lumpindex_t lump)
{
if (lump >= numlumps)
{
I_Error ("W_LumpLength: %i >= numlumps", lump);
}
return lumpinfo[lump]->size;
}
//
// W_ReadLump
// Loads the lump into the given buffer,
// which must be >= W_LumpLength().
//
void W_ReadLump(lumpindex_t lump, void *dest)
{
int c;
lumpinfo_t *l;
if (lump >= numlumps)
{
I_Error ("W_ReadLump: %i >= numlumps", lump);
}
l = lumpinfo[lump];
// V_BeginRead(l->size);
c = W_Read(l->wad_file, l->position, dest, l->size);
if (c < l->size)
{
I_Error("W_ReadLump: only read %i of %i on lump %i",
c, l->size, lump);
}
}
//
// W_CacheLumpNum
//
// Load a lump into memory and return a pointer to a buffer containing
// the lump data.
//
// 'tag' is the type of zone memory buffer to allocate for the lump
// (usually PU_STATIC or PU_CACHE). If the lump is loaded as
// PU_STATIC, it should be released back using W_ReleaseLumpNum
// when no longer needed (do not use Z_ChangeTag).
//
void *W_CacheLumpNum(lumpindex_t lumpnum, int tag)
{
byte *result;
lumpinfo_t *lump;
if ((unsigned)lumpnum >= numlumps)
{
I_Error ("W_CacheLumpNum: %i >= numlumps", lumpnum);
}
lump = lumpinfo[lumpnum];
// Get the pointer to return. If the lump is in a memory-mapped
// file, we can just return a pointer to within the memory-mapped
// region. If the lump is in an ordinary file, we may already
// have it cached; otherwise, load it into memory.
if (lump->wad_file->mapped != NULL)
{
// Memory mapped file, return from the mmapped region.
result = lump->wad_file->mapped + lump->position;
}
else if (lump->cache != NULL)
{
// Already cached, so just switch the zone tag.
result = lump->cache;
Z_ChangeTag(lump->cache, tag);
}
else
{
// Not yet loaded, so load it now
lump->cache = Z_Malloc(W_LumpLength(lumpnum), tag, &lump->cache);
W_ReadLump (lumpnum, lump->cache);
result = lump->cache;
}
return result;
}
//
// W_CacheLumpName
//
void *W_CacheLumpName(char *name, int tag)
{
return W_CacheLumpNum(W_GetNumForName(name), tag);
}
//
// Release a lump back to the cache, so that it can be reused later
// without having to read from disk again, or alternatively, discarded
// if we run out of memory.
//
// Back in Vanilla Doom, this was just done using Z_ChangeTag
// directly, but now that we have WAD mmap, things are a bit more
// complicated ...
//
void W_ReleaseLumpNum(lumpindex_t lumpnum)
{
lumpinfo_t *lump;
if ((unsigned)lumpnum >= numlumps)
{
I_Error ("W_ReleaseLumpNum: %i >= numlumps", lumpnum);
}
lump = lumpinfo[lumpnum];
if (lump->wad_file->mapped != NULL)
{
// Memory-mapped file, so nothing needs to be done here.
}
else
{
Z_ChangeTag(lump->cache, PU_CACHE);
}
}
void W_ReleaseLumpName(char *name)
{
W_ReleaseLumpNum(W_GetNumForName(name));
}
// Generate a hash table for fast lookups
void W_GenerateHashTable(void)
{
lumpindex_t i;
// Free the old hash table, if there is one:
if (lumphash != NULL)
{
Z_Free(lumphash);
}
// Generate hash table
if (numlumps > 0)
{
lumphash = Z_Malloc(sizeof(lumpindex_t) * numlumps, PU_STATIC, NULL);
for (i = 0; i < numlumps; ++i)
{
lumphash[i] = -1;
}
for (i = 0; i < numlumps; ++i)
{
unsigned int hash;
hash = W_LumpNameHash(lumpinfo[i]->name) % numlumps;
// Hook into the hash table
lumpinfo[i]->next = lumphash[hash];
lumphash[hash] = i;
}
}
// All done!
}