/*

 * HOG support routines for PhysicsFS.

 *

 * This driver handles Descent I/II HOG archives.

 *

 * The format is very simple:

 *

 *   The file always starts with the 3-byte signature "DHF" (Descent

 *   HOG file). After that the files of a HOG are just attached after

 *   another, divided by a 17 bytes header, which specifies the name

 *   and length (in bytes) of the forthcoming file! So you just read

 *   the header with its information of how big the following file is,

 *   and then skip exact that number of bytes to get to the next file

 *   in that HOG.

 *

 *    char sig[3] = {'D', 'H', 'F'}; // "DHF"=Descent HOG File

 *

 *    struct {

 *     char file_name[13]; // Filename, padded to 13 bytes with 0s

 *     int file_size; // filesize in bytes

 *     char data[file_size]; // The file data

 *    } FILE_STRUCT; // Repeated until the end of the file.

 *

 * (That info is from http://www.descent2.com/ddn/specs/hog/)

 *

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

 *

 *  This file written by Bradley Bell.

 *  Based on grp.c by Ryan C. Gordon.

 */

#define __PHYSICSFS_INTERNAL__

#include "physfs_internal.h"

#if PHYSFS_SUPPORTS_HOG

static UNPKentry *hogLoadEntries(PHYSFS_Io *io, PHYSFS_uint32 *_entCount)

{

    const PHYSFS_uint64 iolen = io->length(io);

    PHYSFS_uint32 entCount = 0;

    void *ptr = NULL;

    UNPKentry *entries = NULL;

    UNPKentry *entry = NULL;

    PHYSFS_uint32 size = 0;

    PHYSFS_uint32 pos = 3;

    while (pos < iolen)

    {

        entCount++;

        ptr = allocator.Realloc(ptr, sizeof (UNPKentry) * entCount);

        GOTO_IF_MACRO(ptr == NULL, PHYSFS_ERR_OUT_OF_MEMORY, failed);

        entries = (UNPKentry *) ptr;

        entry = &entries[entCount-1];

        GOTO_IF_MACRO(!__PHYSFS_readAll(io, &entry->name, 13), ERRPASS, failed);

        pos += 13;

        GOTO_IF_MACRO(!__PHYSFS_readAll(io, &size, 4), ERRPASS, failed);

        pos += 4;

        entry->size = PHYSFS_swapULE32(size);

        entry->startPos = pos;

        pos += size;

        /* skip over entry */

        GOTO_IF_MACRO(!io->seek(io, pos), ERRPASS, failed);

    } /* while */

    *_entCount = entCount;

    return entries;

failed:

    allocator.Free(entries);

    return NULL;

} /* hogLoadEntries */

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

{

    PHYSFS_uint8 buf[3];

    PHYSFS_uint32 count = 0;

    UNPKentry *entries = NULL;

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

    BAIL_IF_MACRO(forWriting, PHYSFS_ERR_READ_ONLY, NULL);

    BAIL_IF_MACRO(!__PHYSFS_readAll(io, buf, 3), ERRPASS, NULL);

    BAIL_IF_MACRO(memcmp(buf, "DHF", 3) != 0, PHYSFS_ERR_UNSUPPORTED, NULL);

    entries = hogLoadEntries(io, &count);

    BAIL_IF_MACRO(!entries, ERRPASS, NULL);

    return UNPK_openArchive(io, entries, count);

} /* HOG_openArchive */

const PHYSFS_Archiver __PHYSFS_Archiver_HOG =

{

    {

        "HOG",

        "Descent I/II HOG file format",

        "Bradley Bell <btb@icculus.org>",

    },

};

#endif  /* defined PHYSFS_SUPPORTS_HOG */