/*

 * When sorting the grp entries in an archive, we use a modified QuickSort.

 *  When there are less then GRP_QUICKSORT_THRESHOLD entries left to sort,

 *  we switch over to an InsertionSort for the remainder. Tweak to taste.

 */

#define GRP_QUICKSORT_THRESHOLD 4

    char name[13];

    PHYSFS_uint64 startPos;

    PHYSFS_uint64 size;

} GRPentry;

typedef struct

{

    PHYSFS_sint64 last_mod_time;

    PHYSFS_uint32 entryCount;

    GRPentry *entries;

    GRPentry *entry;

    PHYSFS_sint64 curPos;

    GRPinfo *info = ((GRPinfo *) h->opaque);

    free(info->filename);

    free(info->entries);

    free(info);

    GRPentry *entry = finfo->entry;

    PHYSFS_uint64 bytesLeft = entry->size - finfo->curPos;

    PHYSFS_sint64 rc;

    rc = __PHYSFS_platformRead(finfo->handle, buffer, objSize, objCount);

    if (rc > 0)

        finfo->curPos += (rc * objSize);

    return(rc);

    GRPentry *entry = finfo->entry;

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

    return(((GRPfileinfo *) (handle->opaque))->curPos);

    GRPentry *entry = finfo->entry;

    PHYSFS_uint64 newPos = (entry->startPos + offset);

    int rc;

    BAIL_IF_MACRO(newPos > entry->startPos + entry->size, ERR_PAST_EOF, 0);

    rc = __PHYSFS_platformSeek(finfo->handle, newPos);

    if (rc)

        finfo->curPos = offset;

    return(rc);

    return(((GRPfileinfo *) handle->opaque)->entry->size);

    GRPfileinfo *finfo = ((GRPfileinfo *) handle->opaque);

    BAIL_IF_MACRO(!__PHYSFS_platformClose(finfo->handle), NULL, 0);

    free(finfo);

static int grp_open(const char *filename, int forWriting,

                    void **fh, PHYSFS_uint32 *count)

    if (__PHYSFS_platformRead(*fh, count, sizeof (PHYSFS_uint32), 1) != 1)

    *count = PHYSFS_swapULE32(*count);

} /* grp_open */

    PHYSFS_uint32 fileCount;

    int retval = grp_open(filename, forWriting, &fh, &fileCount);

static void grp_entry_swap(GRPentry *a, PHYSFS_uint32 one, PHYSFS_uint32 two)

{

    GRPentry tmp;

    memcpy(&tmp, &a[one], sizeof (GRPentry));

    memcpy(&a[one], &a[two], sizeof (GRPentry));

    memcpy(&a[two], &tmp, sizeof (GRPentry));

} /* grp_entry_swap */

static void grp_quick_sort(GRPentry *a, PHYSFS_uint32 lo, PHYSFS_uint32 hi)

{

    PHYSFS_uint32 i;

    PHYSFS_uint32 j;

    GRPentry *v;

	if ((hi - lo) > GRP_QUICKSORT_THRESHOLD)

	{

		i = (hi + lo) / 2;

		if (strcmp(a[lo].name, a[i].name) > 0) grp_entry_swap(a, lo, i);

		if (strcmp(a[lo].name, a[hi].name) > 0) grp_entry_swap(a, lo, hi);

		if (strcmp(a[i].name, a[hi].name) > 0) grp_entry_swap(a, i, hi);

		j = hi - 1;

		grp_entry_swap(a, i, j);

		i = lo;

		v = &a[j];

		while (1)

		{

			while(strcmp(a[++i].name, v->name) < 0) {}

			while(strcmp(a[--j].name, v->name) > 0) {}

			if (j < i)

                break;

			grp_entry_swap(a, i, j);

		} /* while */

		grp_entry_swap(a, i, hi-1);

		grp_quick_sort(a, lo, j);

		grp_quick_sort(a, i+1, hi);

	} /* if */

} /* grp_quick_sort */

static void grp_insertion_sort(GRPentry *a, PHYSFS_uint32 lo, PHYSFS_uint32 hi)

{

    PHYSFS_uint32 i;

    PHYSFS_uint32 j;

    GRPentry tmp;

    for (i = lo + 1; i <= hi; i++)

    {

        memcpy(&tmp, &a[i], sizeof (GRPentry));

        j = i;

        while ((j > lo) && (strcmp(a[j - 1].name, tmp.name) > 0))

        {

            memcpy(&a[j], &a[j - 1], sizeof (GRPentry));

            j--;

        } /* while */

        memcpy(&a[j], &tmp, sizeof (GRPentry));

    } /* for */

} /* grp_insertion_sort */

static void grp_sort_entries(GRPentry *entries, PHYSFS_uint32 max)

{

    /*

     * Fast Quicksort algorithm inspired by code from here:

     *   http://www.cs.ubc.ca/spider/harrison/Java/sorting-demo.html

     */

    if (max <= GRP_QUICKSORT_THRESHOLD)

        grp_quick_sort(entries, 0, max - 1);

	grp_insertion_sort(entries, 0, max - 1);

} /* grp_sort_entries */

static int grp_load_entries(const char *name, int forWriting, GRPinfo *info)

    PHYSFS_uint32 fileCount;

    PHYSFS_uint32 location = 32;  /* sizeof sig + sizeof 1st file header. */

    GRPentry *entry;

    char *ptr;

    BAIL_IF_MACRO(!grp_open(name, forWriting, &fh, &fileCount), NULL, 0);

    info->entryCount = fileCount;

    info->entries = (GRPentry *) malloc(sizeof (GRPentry) * fileCount);

    if (info->entries == NULL)

    {

        __PHYSFS_platformClose(fh);

        BAIL_MACRO(ERR_OUT_OF_MEMORY, 0);

    } /* if */

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

    {

        if (__PHYSFS_platformRead(fh, &entry->name, 12, 1) != 1)

        {

            __PHYSFS_platformClose(fh);

            return(0);

        } /* if */

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

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

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

        if (__PHYSFS_platformRead(fh, &entry->size, 4, 1) != 1)

        {

            __PHYSFS_platformClose(fh);

            return(0);

        } /* if */

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

        entry->startPos = location;

        location += entry->size + 16;

    } /* for */

    __PHYSFS_platformClose(fh);

    grp_sort_entries(info->entries, info->entryCount);

    return(1);

} /* grp_load_entries */

static DirHandle *GRP_openArchive(const char *name, int forWriting)

{

    GRPinfo *info;

    PHYSFS_sint64 modtime = __PHYSFS_platformGetLastModTime(name);

    info = retval->opaque = malloc(sizeof (GRPinfo));

    if (info == NULL)

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

    info->filename = (char *) malloc(strlen(name) + 1);

    if (info->filename == NULL)

    if (!grp_load_entries(name, forWriting, info))

    strcpy(info->filename, name);

    info->last_mod_time = modtime;

            if (info->filename != NULL)

                free(info->filename);

            if (info->entries != NULL)

                free(info->entries);

            free(info);

    GRPinfo *info = ((GRPinfo *) h->opaque);

    GRPentry *entry = info->entries;

    LinkedStringList *retval = NULL, *p = NULL;

    PHYSFS_uint32 max = info->entryCount;

    /* no directories in GRP files. */

    BAIL_IF_MACRO(*dirname != '\0', ERR_NOT_A_DIR, NULL);

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

        retval = __PHYSFS_addToLinkedStringList(retval, &p, entry->name, -1);

static GRPentry *grp_find_entry(GRPinfo *info, const char *name)

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

    GRPentry *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 > 3 chars.

     */

    BAIL_IF_MACRO((ptr) && (strlen(ptr) > 4), ERR_NO_SUCH_FILE, NULL);

    BAIL_IF_MACRO(strlen(name) > 12, 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 = strcmp(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);

} /* grp_find_entry */

    return(grp_find_entry(((GRPinfo *) h->opaque), name) != NULL);