/*
 * QPAK support routines for PhysicsFS.
 *
 *  This archiver handles the archive format utilized by Quake 1 and 2.
 *  Quake3-based games use the PkZip/Info-Zip format (which our
 *  physfs_archiver_zip.c handles).
 *
 *  ========================================================================
 *
 *  This format info (in more detail) comes from:
 *     https://web.archive.org/web/20040209101748/http://debian.fmi.uni-sofia.bg/~sergei/cgsr/docs/pak.txt
 *
 *  Quake PAK Format
 *
 *  Header
 *   (4 bytes)  signature = 'PACK'
 *   (4 bytes)  directory offset
 *   (4 bytes)  directory length
 *
 *  Directory
 *   (56 bytes) file name
 *   (4 bytes)  file position
 *   (4 bytes)  file length
 *
 *  ========================================================================
 *
 * Please see the file LICENSE.txt in the source's root directory.
 *
 *  This file written by Ryan C. Gordon.
 */

#define __PHYSICSFS_INTERNAL__
#include "physfs_internal.h"

#if PHYSFS_SUPPORTS_QPAK

#define QPAK_SIG 0x4B434150   /* "PACK" in ASCII. */

static int qpakLoadEntries(PHYSFS_Io *io, const PHYSFS_uint32 count, void *arc)
{
    PHYSFS_uint32 i;
    for (i = 0; i < count; i++)
    {
        PHYSFS_uint32 size;
        PHYSFS_uint32 pos;
        char name[56];
        BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, name, 56), 0);
        BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, &pos, 4), 0);
        BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, &size, 4), 0);
        size = PHYSFS_swapULE32(size);
        pos = PHYSFS_swapULE32(pos);
        BAIL_IF_ERRPASS(!UNPK_addEntry(arc, name, 0, -1, -1, pos, size), 0);
    } /* for */

    return 1;
} /* qpakLoadEntries */


static void *QPAK_openArchive(PHYSFS_Io *io, const char *name,
                              int forWriting, int *claimed)
{
    PHYSFS_uint32 val = 0;
    PHYSFS_uint32 pos = 0;
    PHYSFS_uint32 count = 0;
    void *unpkarc;

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

    BAIL_IF(forWriting, PHYSFS_ERR_READ_ONLY, NULL);

    BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, &val, 4), NULL);
    if (PHYSFS_swapULE32(val) != QPAK_SIG)
        BAIL(PHYSFS_ERR_UNSUPPORTED, NULL);

    *claimed = 1;

    BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, &val, 4), NULL);
    pos = PHYSFS_swapULE32(val);  /* directory table offset. */

    BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, &val, 4), NULL);
    count = PHYSFS_swapULE32(val);

    /* corrupted archive? */
    BAIL_IF((count % 64) != 0, PHYSFS_ERR_CORRUPT, NULL);
    count /= 64;

    BAIL_IF_ERRPASS(!io->seek(io, pos), NULL);

    unpkarc = UNPK_openArchive(io);
    BAIL_IF_ERRPASS(!unpkarc, NULL);

    if (!qpakLoadEntries(io, count, unpkarc))
    {
        UNPK_abandonArchive(unpkarc);
        return NULL;
    } /* if */

    return unpkarc;
} /* QPAK_openArchive */


const PHYSFS_Archiver __PHYSFS_Archiver_QPAK =
{
    CURRENT_PHYSFS_ARCHIVER_API_VERSION,
    {
        "PAK",
        "Quake I/II format",
        "Ryan C. Gordon <icculus@icculus.org>",
        "https://icculus.org/physfs/",
        0,  /* supportsSymlinks */
    },
    QPAK_openArchive,
    UNPK_enumerate,
    UNPK_openRead,
    UNPK_openWrite,
    UNPK_openAppend,
    UNPK_remove,
    UNPK_mkdir,
    UNPK_stat,
    UNPK_closeArchive
};

#endif  /* defined PHYSFS_SUPPORTS_QPAK */

/* end of physfs_archiver_qpak.c ... */