/*

 * 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

{

    PHYSFS_Io *io;

    PHYSFS_uint32 entryCount;

    WADentry *entries;

} WADinfo;

typedef struct

{

    PHYSFS_Io *io;

    WADentry *entry;

    PHYSFS_uint32 curPos;

} WADfileinfo;

static inline int readAll(PHYSFS_Io *io, void *buf, const PHYSFS_uint64 len)

{

    return (io->read(io, buf, len) == len);

} /* readAll */

static void WAD_dirClose(dvoid *opaque)

{

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

    info->io->destroy(info->io);

    allocator.Free(info->entries);

    allocator.Free(info);

} /* WAD_dirClose */

static PHYSFS_sint64 WAD_read(PHYSFS_Io *io, void *buffer, PHYSFS_uint64 len)

{

    WADfileinfo *finfo = (WADfileinfo *) io->opaque;

    const WADentry *entry = finfo->entry;

    const PHYSFS_uint64 bytesLeft = (PHYSFS_uint64)(entry->size-finfo->curPos);

    PHYSFS_sint64 rc;

    if (bytesLeft < len)

        len = bytesLeft;

    rc = finfo->io->read(finfo->io, buffer, len);

    if (rc > 0)

        finfo->curPos += (PHYSFS_uint32) rc;

    return rc;

} /* WAD_read */

static PHYSFS_sint64 WAD_write(PHYSFS_Io *io, const void *b, PHYSFS_uint64 len)

{

    BAIL_MACRO(ERR_NOT_SUPPORTED, -1);

} /* WAD_write */

static PHYSFS_sint64 WAD_tell(PHYSFS_Io *io)

{

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

} /* WAD_tell */

static int WAD_seek(PHYSFS_Io *io, PHYSFS_uint64 offset)

{

    WADfileinfo *finfo = (WADfileinfo *) io->opaque;

    const WADentry *entry = finfo->entry;

    int rc;

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

    rc = finfo->io->seek(finfo->io, entry->startPos + offset);

    if (rc)

        finfo->curPos = (PHYSFS_uint32) offset;

    return rc;

} /* WAD_seek */

static PHYSFS_sint64 WAD_length(PHYSFS_Io *io)

{

    const WADfileinfo *finfo = (WADfileinfo *) io->opaque;

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

} /* WAD_length */

static PHYSFS_Io *WAD_duplicate(PHYSFS_Io *_io)

{

    WADfileinfo *origfinfo = (WADfileinfo *) _io->opaque;

    PHYSFS_Io *io = NULL;

    PHYSFS_Io *retval = (PHYSFS_Io *) allocator.Malloc(sizeof (PHYSFS_Io));

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

    GOTO_IF_MACRO(retval == NULL, ERR_OUT_OF_MEMORY, WAD_duplicate_failed);

    GOTO_IF_MACRO(finfo == NULL, ERR_OUT_OF_MEMORY, WAD_duplicate_failed);

    io = origfinfo->io->duplicate(origfinfo->io);

    GOTO_IF_MACRO(io == NULL, NULL, WAD_duplicate_failed);

    finfo->io = io;

    finfo->entry = origfinfo->entry;

    finfo->curPos = 0;

    memcpy(retval, _io, sizeof (PHYSFS_Io));

    retval->opaque = finfo;

    return retval;

WAD_duplicate_failed:

    if (finfo != NULL) allocator.Free(finfo);

    if (retval != NULL) allocator.Free(retval);

    if (io != NULL) io->destroy(io);

    return NULL;

} /* WAD_duplicate */

static int WAD_flush(PHYSFS_Io *io) { return 1;  /* no write support. */ }

static void WAD_destroy(PHYSFS_Io *io)

{

    WADfileinfo *finfo = (WADfileinfo *) io->opaque;

    finfo->io->destroy(finfo->io);

    allocator.Free(finfo);

    allocator.Free(io);

} /* WAD_destroy */

static const PHYSFS_Io WAD_Io =

{

    WAD_read,

    WAD_write,

    WAD_seek,

    WAD_tell,

    WAD_length,

    WAD_duplicate,

    WAD_flush,

    WAD_destroy,

    NULL

};

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

{

    if (one != two)

    {

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

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

    } /* if */

    return 0;

} /* wadEntryCmp */

static void wadEntrySwap(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 */

} /* wadEntrySwap */

static int wad_load_entries(PHYSFS_Io *io, WADinfo *info)

{

    PHYSFS_uint32 fileCount = info->entryCount;

    PHYSFS_uint32 directoryOffset;

    WADentry *entry;

    BAIL_IF_MACRO(!readAll(io, &directoryOffset, 4), NULL, 0);

    directoryOffset = PHYSFS_swapULE32(directoryOffset);

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

    BAIL_IF_MACRO(info->entries == NULL, ERR_OUT_OF_MEMORY, 0);

    BAIL_IF_MACRO(!io->seek(io, directoryOffset), NULL, 0);

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

    {

        BAIL_IF_MACRO(!readAll(io, &entry->startPos, 4), NULL, 0);

        BAIL_IF_MACRO(!readAll(io, &entry->size, 4), NULL, 0);

        BAIL_IF_MACRO(!readAll(io, &entry->name, 8), NULL, 0);

        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_sort(info->entries, info->entryCount, wadEntryCmp, wadEntrySwap);

    return 1;

} /* wad_load_entries */

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

{

    PHYSFS_uint8 buf[4];

    WADinfo *info = NULL;

    PHYSFS_uint32 val = 0;

    assert(io != NULL);  /* shouldn't ever happen. */

    BAIL_IF_MACRO(forWriting, ERR_ARC_IS_READ_ONLY, 0);

    BAIL_IF_MACRO(!readAll(io, buf, sizeof (buf)), NULL, NULL);

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

        GOTO_MACRO(ERR_NOT_AN_ARCHIVE, WAD_openArchive_failed);

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

    GOTO_IF_MACRO(info == NULL, ERR_OUT_OF_MEMORY, WAD_openArchive_failed);

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

    info->io = io;

    GOTO_IF_MACRO(!readAll(io,&val,sizeof(val)), NULL, WAD_openArchive_failed);

    info->entryCount = PHYSFS_swapULE32(val);

    GOTO_IF_MACRO(!wad_load_entries(io, info), NULL, WAD_openArchive_failed);

    return info;

WAD_openArchive_failed:

    if (info != NULL)

    {

        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)

{

    /* no directories in WAD files. */

    if (*dname == '\0')

    {

        WADinfo *info = (WADinfo *) opaque;

        WADentry *entry = info->entries;

        PHYSFS_uint32 max = info->entryCount;

        PHYSFS_uint32 i;

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

            cb(callbackdata, origdir, entry->name);

    } /* if */

} /* WAD_enumerateFiles */

static WADentry *wad_find_entry(const WADinfo *info, const char *name)

{

    char *ptr = strchr(name, '.');

    WADentry *a = info->entries;

    PHYSFS_sint32 lo = 0;

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

    PHYSFS_sint32 middle;

    int rc;

    /*

     * Rule out filenames to avoid unneeded processing...no dirs,

     *   big filenames, or extensions.

     */

    BAIL_IF_MACRO(ptr != NULL, ERR_NO_SUCH_FILE, NULL);

    BAIL_IF_MACRO(strlen(name) > 8, ERR_NO_SUCH_FILE, NULL);

    BAIL_IF_MACRO(strchr(name, '/') != NULL, ERR_NO_SUCH_FILE, NULL);

    while (lo <= hi)

    {

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

        rc = __PHYSFS_stricmpASCII(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 PHYSFS_Io *WAD_openRead(dvoid *opaque, const char *fnm, int *fileExists)

{

    PHYSFS_Io *retval = NULL;

    WADinfo *info = (WADinfo *) opaque;

    WADfileinfo *finfo;

    WADentry *entry;

    entry = wad_find_entry(info, fnm);

    *fileExists = (entry != NULL);

    GOTO_IF_MACRO(entry == NULL, NULL, WAD_openRead_failed);

    retval = (PHYSFS_Io *) allocator.Malloc(sizeof (PHYSFS_Io));

    GOTO_IF_MACRO(retval == NULL, ERR_OUT_OF_MEMORY, WAD_openRead_failed);

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

    GOTO_IF_MACRO(finfo == NULL, ERR_OUT_OF_MEMORY, WAD_openRead_failed);

    finfo->io = info->io->duplicate(info->io);

    GOTO_IF_MACRO(finfo->io == NULL, NULL, WAD_openRead_failed);

    if (!finfo->io->seek(finfo->io, entry->startPos))

        GOTO_MACRO(NULL, WAD_openRead_failed);

    finfo->curPos = 0;

    finfo->entry = entry;

    memcpy(retval, &WAD_Io, sizeof (*retval));

    retval->opaque = finfo;

    return retval;

WAD_openRead_failed:

    if (finfo != NULL)

    {

        if (finfo->io != NULL)

            finfo->io->destroy(finfo->io);

        allocator.Free(finfo);

    } /* if */

    if (retval != NULL)

        allocator.Free(retval);

    return NULL;

} /* WAD_openRead */

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

{

    BAIL_MACRO(ERR_NOT_SUPPORTED, NULL);

} /* WAD_openWrite */

static PHYSFS_Io *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 */

static int WAD_stat(dvoid *opaque, const char *filename, int *exists,

                    PHYSFS_Stat *stat)

{

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

    const WADentry *entry = wad_find_entry(info, filename);

    *exists = (entry != 0);

    if (!entry)

        return 0;

    stat->filesize = entry->size;

    stat->filetype = PHYSFS_FILETYPE_REGULAR;

    stat->modtime = -1;

    stat->createtime = -1;

    stat->accesstime = -1;

    stat->readonly = 1;

    return 1;

} /* WAD_stat */

const PHYSFS_ArchiveInfo __PHYSFS_ArchiveInfo_WAD =

{

    "WAD",

    WAD_ARCHIVE_DESCRIPTION,

    "Travis Wells <traviswells@mchsi.com>",

    "http://www.3dmm2.com/doom/",

};

const PHYSFS_Archiver __PHYSFS_Archiver_WAD =

{

    &__PHYSFS_ArchiveInfo_WAD,

    WAD_openArchive,        /* openArchive() method    */

    WAD_enumerateFiles,     /* enumerateFiles() method */

    WAD_openRead,           /* openRead() method       */

    WAD_openWrite,          /* openWrite() method      */

    WAD_openAppend,         /* openAppend() method     */

    WAD_remove,             /* remove() method         */

    WAD_mkdir,              /* mkdir() method          */

    WAD_dirClose,           /* dirClose() method       */

    WAD_stat                /* stat() method           */

};

#endif  /* defined PHYSFS_SUPPORTS_WAD */

/* end of wad.c ... */