/*
 * SLB support routines for PhysicsFS.
 *
 * This driver handles SLB archives ("slab files"). This uncompressed format
 * is used in I-War / Independence War and Independence War: Defiance.
 *
 * The format begins with four zero bytes (version?), the file count and the
 * location of the table of contents. Each ToC entry contains a 64-byte buffer
 * containing a zero-terminated filename, the offset of the data, and its size.
 * All the filenames begin with the separator character '\'. 
 *
 * Please see the file LICENSE.txt in the source's root directory.
 *
 * This file written by Aleksi Nurmi, based on the GRP archiver by
 * Ryan C. Gordon.
 */

#define __PHYSICSFS_INTERNAL__
#include "physfs_internal.h"

#if PHYSFS_SUPPORTS_SLB

static int slbLoadEntries(PHYSFS_Io *io, const PHYSFS_uint32 count, void *arc)
{
    PHYSFS_uint32 i;
    for (i = 0; i < count; i++)
    {
        PHYSFS_uint32 location;
        PHYSFS_uint32 size;
        char name[64];
        char backslash;
        char *ptr;

        /* don't include the '\' in the beginning */
        BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, &backslash, 1), 0);
        BAIL_IF(backslash != '\\', PHYSFS_ERR_CORRUPT, 0);

        /* read the rest of the buffer, 63 bytes */
        BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, &name, 63), 0);
        name[63] = '\0'; /* in case the name lacks the null terminator */

        /* convert backslashes */
        for (ptr = name; *ptr; ptr++)
        {
            if (*ptr == '\\')
                *ptr = '/';
        } /* for */

        BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, &location, 4), 0);
        location = PHYSFS_swapULE32(location);

        BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, &size, 4), 0);
        size = PHYSFS_swapULE32(size);

        BAIL_IF_ERRPASS(!UNPK_addEntry(arc, name, 0, location, size), 0);
    } /* for */

    return 1;
} /* slbLoadEntries */


static void *SLB_openArchive(PHYSFS_Io *io, const char *name, int forWriting)
{
    PHYSFS_uint32 version;
    PHYSFS_uint32 count;
    PHYSFS_uint32 tocPos;
    void *unpkarc;

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

    BAIL_IF(forWriting, PHYSFS_ERR_READ_ONLY, NULL);

    BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, &version, sizeof (version)), NULL);
    version = PHYSFS_swapULE32(version);
    BAIL_IF(version != 0, PHYSFS_ERR_UNSUPPORTED, NULL);

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

    /* offset of the table of contents */
    BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, &tocPos, sizeof (tocPos)), NULL);
    tocPos = PHYSFS_swapULE32(tocPos);
    
    /* seek to the table of contents */
    BAIL_IF_ERRPASS(!io->seek(io, tocPos), NULL);

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

    if (!slbLoadEntries(io, count, unpkarc))
    {
        UNPK_closeArchive(unpkarc);
        return NULL;
    } /* if */

    return unpkarc;
} /* SLB_openArchive */


const PHYSFS_Archiver __PHYSFS_Archiver_SLB =
{
    CURRENT_PHYSFS_ARCHIVER_API_VERSION,
    {
        "SLB",
        "I-War / Independence War Slab file",
        "Aleksi Nurmi <aleksi.nurmi@gmail.com>",
        "https://bitbucket.org/ahnurmi/",
        0,  /* supportsSymlinks */
    },
    SLB_openArchive,
    UNPK_enumerateFiles,
    UNPK_openRead,
    UNPK_openWrite,
    UNPK_openAppend,
    UNPK_remove,
    UNPK_mkdir,
    UNPK_stat,
    UNPK_closeArchive
};

#endif  /* defined PHYSFS_SUPPORTS_SLB */

/* end of archiver_slb.c ... */