/*

 * WAD support routines for PhysicsFS.

 *

 * This driver handles DOOM engine archives ("wads"). 

 * This format (but not this driver) was designed by id Software for use

 *  with the DOOM engine.

 * The specs of the format are from the unofficial doom specs v1.666

 * found here: http://www.gamers.org/dhs/helpdocs/dmsp1666.html

 * The format of the archive: (from the specs)

 *

 *  A WAD file has three parts:

 *  (1) a twelve-byte header

 *  (2) one or more "lumps"

 *  (3) a directory or "info table" that contains the names, offsets, and

 *      sizes of all the lumps in the WAD

 *

 *  The header consists of three four-byte parts:

 *    (a) an ASCII string which must be either "IWAD" or "PWAD"

 *    (b) a 4-byte (long) integer which is the number of lumps in the wad

 *    (c) a long integer which is the file offset to the start of

 *    the directory

 *

 *  The directory has one 16-byte entry for every lump. Each entry consists

 *  of three parts:

 *

 *    (a) a long integer, the file offset to the start of the lump

 *    (b) a long integer, the size of the lump in bytes

 *    (c) an 8-byte ASCII string, the name of the lump, padded with zeros.

 *        For example, the "DEMO1" entry in hexadecimal would be

 *        (44 45 4D 4F 31 00 00 00)

 * 

 * Note that there is no way to tell if an opened WAD archive is a

 *  IWAD or PWAD with this archiver.

 * I couldn't think of a way to provide that information, without being too

 *  hacky.

 * I don't think it's really that important though.

 *

 *

 * Please see the file LICENSE.txt in the source's root directory.

 *

 * This file written by Travis Wells, based on the GRP archiver by

 *  Ryan C. Gordon.

 */

#if (defined PHYSFS_SUPPORTS_WAD)

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "physfs.h"

#define __PHYSICSFS_INTERNAL__

#include "physfs_internal.h"

typedef struct

{

    char name[18];

    PHYSFS_uint32 startPos;

    PHYSFS_uint32 size;

} WADentry;

typedef struct

{

    char *filename;

    PHYSFS_sint64 last_mod_time;

    PHYSFS_uint32 entryCount;

    PHYSFS_uint32 entryOffset;

    WADentry *entries;

} WADinfo;

typedef struct

{

    void *handle;

    WADentry *entry;

    PHYSFS_uint32 curPos;

} WADfileinfo;

static void WAD_dirClose(dvoid *opaque)

{

    WADinfo *info = ((WADinfo *) opaque);

    allocator.Free(info->filename);

    allocator.Free(info->entries);

    allocator.Free(info);

} /* WAD_dirClose */

static PHYSFS_sint64 WAD_read(fvoid *opaque, void *buffer,

                              PHYSFS_uint32 objSize, PHYSFS_uint32 objCount)

{

    WADfileinfo *finfo = (WADfileinfo *) opaque;

    WADentry *entry = finfo->entry;

    PHYSFS_uint32 bytesLeft = entry->size - finfo->curPos;

    PHYSFS_uint32 objsLeft = (bytesLeft / objSize);

    PHYSFS_sint64 rc;

    if (objsLeft < objCount)

        objCount = objsLeft;

    rc = __PHYSFS_platformRead(finfo->handle, buffer, objSize, objCount);

    if (rc > 0)

        finfo->curPos += (PHYSFS_uint32) (rc * objSize);

    return rc;

} /* WAD_read */

static PHYSFS_sint64 WAD_write(fvoid *opaque, const void *buffer,

                               PHYSFS_uint32 objSize, PHYSFS_uint32 objCount)

{

    BAIL_MACRO(ERR_NOT_SUPPORTED, -1);

} /* WAD_write */

static int WAD_eof(fvoid *opaque)

{

    WADfileinfo *finfo = (WADfileinfo *) opaque;

    WADentry *entry = finfo->entry;

    return (finfo->curPos >= entry->size);

} /* WAD_eof */

static PHYSFS_sint64 WAD_tell(fvoid *opaque)

{

    return ((WADfileinfo *) opaque)->curPos;

} /* WAD_tell */

static int WAD_seek(fvoid *opaque, PHYSFS_uint64 offset)

{

    WADfileinfo *finfo = (WADfileinfo *) opaque;

    WADentry *entry = finfo->entry;

    int rc;

    BAIL_IF_MACRO(offset < 0, ERR_INVALID_ARGUMENT, 0);

    BAIL_IF_MACRO(offset >= entry->size, ERR_PAST_EOF, 0);

    rc = __PHYSFS_platformSeek(finfo->handle, entry->startPos + offset);

    if (rc)

        finfo->curPos = (PHYSFS_uint32) offset;

    return rc;

} /* WAD_seek */

static PHYSFS_sint64 WAD_fileLength(fvoid *opaque)

{

    WADfileinfo *finfo = (WADfileinfo *) opaque;

    return ((PHYSFS_sint64) finfo->entry->size);

} /* WAD_fileLength */

static int WAD_fileClose(fvoid *opaque)

{

    WADfileinfo *finfo = (WADfileinfo *) opaque;

    BAIL_IF_MACRO(!__PHYSFS_platformClose(finfo->handle), NULL, 0);

    allocator.Free(finfo);

    return 1;

} /* WAD_fileClose */

static int wad_open(const char *filename, int forWriting,

                    void **fh, PHYSFS_uint32 *count,PHYSFS_uint32 *offset)

{

    PHYSFS_uint8 buf[4];

    *fh = NULL;

    BAIL_IF_MACRO(forWriting, ERR_ARC_IS_READ_ONLY, 0);

    *fh = __PHYSFS_platformOpenRead(filename);

    BAIL_IF_MACRO(*fh == NULL, NULL, 0);

    if (__PHYSFS_platformRead(*fh, buf, 4, 1) != 1)

        goto openWad_failed;

    if (memcmp(buf, "IWAD", 4) != 0 && memcmp(buf, "PWAD", 4) != 0)

    {

        __PHYSFS_setError(ERR_UNSUPPORTED_ARCHIVE);

        goto openWad_failed;

    } /* if */

    if (__PHYSFS_platformRead(*fh, count, sizeof (PHYSFS_uint32), 1) != 1)

        goto openWad_failed;

    *count = PHYSFS_swapULE32(*count);

    if (__PHYSFS_platformRead(*fh, offset, sizeof (PHYSFS_uint32), 1) != 1)

        goto openWad_failed;

    *offset = PHYSFS_swapULE32(*offset);

    return 1;

openWad_failed:

    if (*fh != NULL)

        __PHYSFS_platformClose(*fh);

    *count = -1;

    *fh = NULL;

    return 0;

} /* wad_open */

static int WAD_isArchive(const char *filename, int forWriting)

{

    void *fh;

    PHYSFS_uint32 fileCount,offset;

    int retval = wad_open(filename, forWriting, &fh, &fileCount,&offset);

    if (fh != NULL)

        __PHYSFS_platformClose(fh);

    return retval;

} /* WAD_isArchive */

static int wad_entry_cmp(void *_a, PHYSFS_uint32 one, PHYSFS_uint32 two)

{

    if (one != two)

    {

        const WADentry *a = (const WADentry *) _a;

        return strcmp(a[one].name, a[two].name);

    } /* if */

    return 0;

} /* wad_entry_cmp */

static void wad_entry_swap(void *_a, PHYSFS_uint32 one, PHYSFS_uint32 two)

{

    if (one != two)

    {

        WADentry tmp;

        WADentry *first = &(((WADentry *) _a)[one]);

        WADentry *second = &(((WADentry *) _a)[two]);

        memcpy(&tmp, first, sizeof (WADentry));

        memcpy(first, second, sizeof (WADentry));

        memcpy(second, &tmp, sizeof (WADentry));

    } /* if */

} /* wad_entry_swap */

static int wad_load_entries(const char *name, int forWriting, WADinfo *info)

{

    void *fh = NULL;

    PHYSFS_uint32 fileCount;

    PHYSFS_uint32 directoryOffset;

    WADentry *entry;

    char lastDirectory[9];

    lastDirectory[8] = 0; /* Make sure lastDirectory stays null-terminated. */

    BAIL_IF_MACRO(!wad_open(name, forWriting, &fh, &fileCount,&directoryOffset), NULL, 0);

    info->entryCount = fileCount;

    info->entries = (WADentry *) allocator.Malloc(sizeof(WADentry)*fileCount);

    if (info->entries == NULL)

    {

        __PHYSFS_platformClose(fh);

        BAIL_MACRO(ERR_OUT_OF_MEMORY, 0);

    } /* if */

    __PHYSFS_platformSeek(fh,directoryOffset);

    for (entry = info->entries; fileCount > 0; fileCount--, entry++)

    {

        if (__PHYSFS_platformRead(fh, &entry->startPos, 4, 1) != 1)

        {

            __PHYSFS_platformClose(fh);

            return 0;

        } /* if */

        if (__PHYSFS_platformRead(fh, &entry->size, 4, 1) != 1)

        {

            __PHYSFS_platformClose(fh);

            return 0;

        } /* if */

        if (__PHYSFS_platformRead(fh, &entry->name, 8, 1) != 1)

        {

            __PHYSFS_platformClose(fh);

            return 0;

        } /* if */

        entry->name[8] = '\0'; /* name might not be null-terminated in file. */

        entry->size = PHYSFS_swapULE32(entry->size);

        entry->startPos = PHYSFS_swapULE32(entry->startPos);

    } /* for */

    __PHYSFS_platformClose(fh);

    __PHYSFS_sort(info->entries, info->entryCount,

                  wad_entry_cmp, wad_entry_swap);

    return 1;

} /* wad_load_entries */

static void *WAD_openArchive(const char *name, int forWriting)

{

    PHYSFS_sint64 modtime = __PHYSFS_platformGetLastModTime(name);

    WADinfo *info = (WADinfo *) allocator.Malloc(sizeof (WADinfo));

    BAIL_IF_MACRO(info == NULL, ERR_OUT_OF_MEMORY, NULL);

    memset(info, '\0', sizeof (WADinfo));

    info->filename = (char *) allocator.Malloc(strlen(name) + 1);

    GOTO_IF_MACRO(!info->filename, ERR_OUT_OF_MEMORY, WAD_openArchive_failed);

    if (!wad_load_entries(name, forWriting, info))

        goto WAD_openArchive_failed;

    strcpy(info->filename, name);

    info->last_mod_time = modtime;

    return info;

WAD_openArchive_failed:

    if (info != NULL)

    {

        if (info->filename != NULL)

            allocator.Free(info->filename);

        if (info->entries != NULL)

            allocator.Free(info->entries);

        allocator.Free(info);

    } /* if */

    return NULL;

} /* WAD_openArchive */

static void WAD_enumerateFiles(dvoid *opaque, const char *dname,

                               int omitSymLinks, PHYSFS_EnumFilesCallback cb,

                               const char *origdir, void *callbackdata)

{

    WADinfo *info = ((WADinfo *) opaque);

    WADentry *entry = info->entries;

    PHYSFS_uint32 max = info->entryCount;

    PHYSFS_uint32 i;

    const char *name;

    char *sep;

    if (*dname == '\0')  /* root directory enumeration? */

    {

        for (i = 0; i < max; i++, entry++)

        {

            name = entry->name;

            if (strchr(name, '/') == NULL)

                cb(callbackdata, origdir, name);

        } /* for */

    } /* if */

    else

    {

        for (i = 0; i < max; i++, entry++)

        {

            name = entry->name;

            sep = strchr(name, '/');

            if (sep != NULL)

            {

                if (strncmp(dname, name, (sep - name)) == 0)

                    cb(callbackdata, origdir, sep + 1);

            } /* if */

        } /* for */

    } /* else */

} /* WAD_enumerateFiles */

{

    WADentry *a = info->entries;

    PHYSFS_sint32 lo = 0;

    PHYSFS_sint32 hi = (PHYSFS_sint32) (info->entryCount - 1);

    PHYSFS_sint32 middle;

    int rc;

    while (lo <= hi)

    {

        middle = lo + ((hi - lo) / 2);

        rc = strcmp(name, a[middle].name);

        if (rc == 0)  /* found it! */

            return &a[middle];

        else if (rc > 0)

            lo = middle + 1;

        else

            hi = middle - 1;

    } /* while */

    BAIL_MACRO(ERR_NO_SUCH_FILE, NULL);

} /* wad_find_entry */

static int WAD_exists(dvoid *opaque, const char *name)

{

    return (wad_find_entry((WADinfo *) opaque, name) != NULL);

} /* WAD_exists */

static int WAD_isDirectory(dvoid *opaque, const char *name, int *fileExists)

{

    WADentry *entry = wad_find_entry(((WADinfo *) opaque), name);

    if (entry != NULL)

    {

        char *n;

        *fileExists = 1;

        /* Can't be a directory if it's a subdirectory. */

        if (strchr(entry->name, '/') != NULL)

            return 0;

        /* Check if it matches "MAP??" or "E?M?" ... */

        n = entry->name;

        if ((n[0] == 'E' && n[2] == 'M') ||

            (n[0] == 'M' && n[1] == 'A' && n[2] == 'P' && n[6] == 0))

        {

            return 1;

        } /* if */

        return 0;

    } /* if */

    else

    {

        *fileExists = 0;

        return 0;

    } /* else */

} /* WAD_isDirectory */

static int WAD_isSymLink(dvoid *opaque, const char *name, int *fileExists)

{

    *fileExists = WAD_exists(opaque, name);

    return 0;  /* never symlinks in a wad. */

} /* WAD_isSymLink */

static PHYSFS_sint64 WAD_getLastModTime(dvoid *opaque,

                                        const char *name,

                                        int *fileExists)

{

    WADinfo *info = ((WADinfo *) opaque);

    PHYSFS_sint64 retval = -1;

    *fileExists = (wad_find_entry(info, name) != NULL);

    if (*fileExists)  /* use time of WAD itself in the physical filesystem. */

        retval = info->last_mod_time;

    return retval;

} /* WAD_getLastModTime */

static fvoid *WAD_openRead(dvoid *opaque, const char *fnm, int *fileExists)

{

    WADinfo *info = ((WADinfo *) opaque);

    WADfileinfo *finfo;

    WADentry *entry;

    entry = wad_find_entry(info, fnm);

    *fileExists = (entry != NULL);

    BAIL_IF_MACRO(entry == NULL, NULL, NULL);

    finfo = (WADfileinfo *) allocator.Malloc(sizeof (WADfileinfo));

    BAIL_IF_MACRO(finfo == NULL, ERR_OUT_OF_MEMORY, NULL);

    finfo->handle = __PHYSFS_platformOpenRead(info->filename);

    if ( (finfo->handle == NULL) ||

         (!__PHYSFS_platformSeek(finfo->handle, entry->startPos)) )

    {

        allocator.Free(finfo);

        return NULL;

    } /* if */

    finfo->curPos = 0;

    finfo->entry = entry;

    return finfo;

} /* WAD_openRead */

static fvoid *WAD_openWrite(dvoid *opaque, const char *name)

{

    BAIL_MACRO(ERR_NOT_SUPPORTED, NULL);

} /* WAD_openWrite */

static fvoid *WAD_openAppend(dvoid *opaque, const char *name)

{

    BAIL_MACRO(ERR_NOT_SUPPORTED, NULL);

} /* WAD_openAppend */

static int WAD_remove(dvoid *opaque, const char *name)

{

    BAIL_MACRO(ERR_NOT_SUPPORTED, 0);

} /* WAD_remove */

static int WAD_mkdir(dvoid *opaque, const char *name)

{

    BAIL_MACRO(ERR_NOT_SUPPORTED, 0);

} /* WAD_mkdir */