/*

 * GRP support routines for PhysicsFS.

 *

 * This driver handles BUILD engine archives ("groupfiles"). This format

 *  (but not this driver) was put together by Ken Silverman.

 *

 * The format is simple enough. In Ken's words:

 *

 *    What's the .GRP file format?

 *

 *     The ".grp" file format is just a collection of a lot of files stored

 *     into 1 big one. I tried to make the format as simple as possible: The

 *     first 12 bytes contains my name, "KenSilverman". The next 4 bytes is

 *     the number of files that were compacted into the group file. Then for

 *     each file, there is a 16 byte structure, where the first 12 bytes are

 *     the filename, and the last 4 bytes are the file's size. The rest of

 *     the group file is just the raw data packed one after the other in the

 *     same order as the list of files.

 *

 * (That info is from http://www.advsys.net/ken/build.htm ...)

 *

 * 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_GRP

static UNPKentry *grpLoadEntries(PHYSFS_Io *io, PHYSFS_uint32 fileCount)

{

    PHYSFS_uint32 location = 16;  /* sizeof sig. */

    UNPKentry *entries = NULL;

    UNPKentry *entry = NULL;

    char *ptr = NULL;

    entries = (UNPKentry *) allocator.Malloc(sizeof (UNPKentry) * fileCount);

    BAIL_IF_MACRO(entries == NULL, PHYSFS_ERR_OUT_OF_MEMORY, NULL);

    location += (16 * fileCount);

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

    {

        GOTO_IF_MACRO(!__PHYSFS_readAll(io, &entry->name, 12), ERRPASS, failed);

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

        entry->name[12] = '\0';  /* name isn't null-terminated in file. */

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

            *ptr = '\0';  /* trim extra spaces. */

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

        entry->startPos = location;

        location += entry->size;

    } /* for */

    return entries;

failed:

    allocator.Free(entries);

    return NULL;

} /* grpLoadEntries */

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

{

    PHYSFS_uint8 buf[12];

    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, sizeof (buf)), ERRPASS, NULL);

    if (memcmp(buf, "KenSilverman", sizeof (buf)) != 0)

        BAIL_MACRO(PHYSFS_ERR_UNSUPPORTED, NULL);

    BAIL_IF_MACRO(!__PHYSFS_readAll(io, &count, sizeof(count)), ERRPASS, NULL);

    count = PHYSFS_swapULE32(count);

    entries = grpLoadEntries(io, count);

    BAIL_IF_MACRO(!entries, ERRPASS, NULL);

    return UNPK_openArchive(io, entries, count);

} /* GRP_openArchive */

const PHYSFS_Archiver __PHYSFS_Archiver_GRP =

{

    CURRENT_PHYSFS_ARCHIVER_API_VERSION,

    {

        "GRP",

        "Build engine Groupfile format",

        "Ryan C. Gordon <icculus@icculus.org>",

        "https://icculus.org/physfs/",

        0,  /* supportsSymlinks */

    },

    GRP_openArchive,

    UNPK_enumerateFiles,

    UNPK_openRead,

    UNPK_openWrite,

    UNPK_openAppend,

    UNPK_remove,

    UNPK_mkdir,

    UNPK_stat,

    UNPK_closeArchive

};

#endif  /* defined PHYSFS_SUPPORTS_GRP */

/* end of archiver_grp.c ... */