minidlna support now Samsung TV C550/C650 (thx amir909)

[tomato.git] / release / src / router / ntfs-3g / libntfs-3g / runlist.c

/**
 * runlist.c - Run list handling code. Originated from the Linux-NTFS project.
 *
 * Copyright (c) 2002-2005 Anton Altaparmakov
 * Copyright (c) 2002-2005 Richard Russon
 * Copyright (c) 2002-2008 Szabolcs Szakacsits
 * Copyright (c) 2004 Yura Pakhuchiy
 * Copyright (c) 2007-2010 Jean-Pierre Andre
 *
 * This program/include file is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program/include file is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program (in the main directory of the NTFS-3G
 * distribution in the file COPYING); if not, write to the Free Software
 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef HAVE_STDIO_H
#include <stdio.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif

#include "compat.h"
#include "types.h"
#include "volume.h"
#include "layout.h"
#include "debug.h"
#include "device.h"
#include "logging.h"
#include "misc.h"

/**
 * ntfs_rl_mm - runlist memmove
 * @base:
 * @dst:
 * @src:
 * @size:
 *
 * Description...
 *
 * Returns:
 */
static void ntfs_rl_mm(runlist_element *base, int dst, int src, int size)
{
        if ((dst != src) && (size > 0))
                memmove(base + dst, base + src, size * sizeof(*base));
}

/**
 * ntfs_rl_mc - runlist memory copy
 * @dstbase:
 * @dst:
 * @srcbase:
 * @src:
 * @size:
 *
 * Description...
 *
 * Returns:
 */
static void ntfs_rl_mc(runlist_element *dstbase, int dst,
                       runlist_element *srcbase, int src, int size)
{
        if (size > 0)
                memcpy(dstbase + dst, srcbase + src, size * sizeof(*dstbase));
}

/**
 * ntfs_rl_realloc - Reallocate memory for runlists
 * @rl:         original runlist
 * @old_size:   number of runlist elements in the original runlist @rl
 * @new_size:   number of runlist elements we need space for
 *
 * As the runlists grow, more memory will be required. To prevent large
 * numbers of small reallocations of memory, this function returns a 4kiB block
 * of memory.
 *
 * N.B. If the new allocation doesn't require a different number of 4kiB
 *      blocks in memory, the function will return the original pointer.
 *
 * On success, return a pointer to the newly allocated, or recycled, memory.
 * On error, return NULL with errno set to the error code.
 */
static runlist_element *ntfs_rl_realloc(runlist_element *rl, int old_size, 
                                        int new_size)
{
        old_size = (old_size * sizeof(runlist_element) + 0xfff) & ~0xfff;
        new_size = (new_size * sizeof(runlist_element) + 0xfff) & ~0xfff;
        if (old_size == new_size)
                return rl;
        return realloc(rl, new_size);
}

/*
 *              Extend a runlist by some entry count
 *      The runlist may have to be reallocated
 *
 *      Returns the reallocated runlist
 *              or NULL if reallocation was not possible (with errno set)
 *              the runlist is left unchanged if the reallocation fails
 */

runlist_element *ntfs_rl_extend(ntfs_attr *na, runlist_element *rl,
                        int more_entries)
{
        runlist_element *newrl;
        int last;
        int irl;

        if (na->rl && rl) {
                irl = (int)(rl - na->rl);
                last = irl;
                while (na->rl[last].length)
                        last++;
                newrl = ntfs_rl_realloc(na->rl,last+1,last+more_entries+1);
                if (!newrl) {
                        errno = ENOMEM;
                        rl = (runlist_element*)NULL;
                } else
                        na->rl = newrl;
                        rl = &newrl[irl];
        } else {
                ntfs_log_error("Cannot extend unmapped runlist");
                errno = EIO;
                rl = (runlist_element*)NULL;
        }
        return (rl);
}

/**
 * ntfs_rl_are_mergeable - test if two runlists can be joined together
 * @dst:        original runlist
 * @src:        new runlist to test for mergeability with @dst
 *
 * Test if two runlists can be joined together. For this, their VCNs and LCNs
 * must be adjacent.
 *
 * Return: TRUE   Success, the runlists can be merged.
 *         FALSE  Failure, the runlists cannot be merged.
 */
static BOOL ntfs_rl_are_mergeable(runlist_element *dst, runlist_element *src)
{
        if (!dst || !src) {
                ntfs_log_debug("Eeek. ntfs_rl_are_mergeable() invoked with NULL "
                                "pointer!\n");
                return FALSE;
        }

        /* We can merge unmapped regions even if they are misaligned. */
        if ((dst->lcn == LCN_RL_NOT_MAPPED) && (src->lcn == LCN_RL_NOT_MAPPED))
                return TRUE;
        /* If the runs are misaligned, we cannot merge them. */
        if ((dst->vcn + dst->length) != src->vcn)
                return FALSE;
        /* If both runs are non-sparse and contiguous, we can merge them. */
        if ((dst->lcn >= 0) && (src->lcn >= 0) &&
                ((dst->lcn + dst->length) == src->lcn))
                return TRUE;
        /* If we are merging two holes, we can merge them. */
        if ((dst->lcn == LCN_HOLE) && (src->lcn == LCN_HOLE))
                return TRUE;
        /* Cannot merge. */
        return FALSE;
}

/**
 * __ntfs_rl_merge - merge two runlists without testing if they can be merged
 * @dst:        original, destination runlist
 * @src:        new runlist to merge with @dst
 *
 * Merge the two runlists, writing into the destination runlist @dst. The
 * caller must make sure the runlists can be merged or this will corrupt the
 * destination runlist.
 */
static void __ntfs_rl_merge(runlist_element *dst, runlist_element *src)
{
        dst->length += src->length;
}

/**
 * ntfs_rl_append - append a runlist after a given element
 * @dst:        original runlist to be worked on
 * @dsize:      number of elements in @dst (including end marker)
 * @src:        runlist to be inserted into @dst
 * @ssize:      number of elements in @src (excluding end marker)
 * @loc:        append the new runlist @src after this element in @dst
 *
 * Append the runlist @src after element @loc in @dst.  Merge the right end of
 * the new runlist, if necessary. Adjust the size of the hole before the
 * appended runlist.
 *
 * On success, return a pointer to the new, combined, runlist. Note, both
 * runlists @dst and @src are deallocated before returning so you cannot use
 * the pointers for anything any more. (Strictly speaking the returned runlist
 * may be the same as @dst but this is irrelevant.)
 *
 * On error, return NULL, with errno set to the error code. Both runlists are
 * left unmodified.
 */
static runlist_element *ntfs_rl_append(runlist_element *dst, int dsize,
                                       runlist_element *src, int ssize, int loc)
{
        BOOL right = FALSE;     /* Right end of @src needs merging */
        int marker;             /* End of the inserted runs */

        if (!dst || !src) {
                ntfs_log_debug("Eeek. ntfs_rl_append() invoked with NULL "
                                "pointer!\n");
                errno = EINVAL;
                return NULL;
        }

        /* First, check if the right hand end needs merging. */
        if ((loc + 1) < dsize)
                right = ntfs_rl_are_mergeable(src + ssize - 1, dst + loc + 1);

        /* Space required: @dst size + @src size, less one if we merged. */
        dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - right);
        if (!dst)
                return NULL;
        /*
         * We are guaranteed to succeed from here so can start modifying the
         * original runlists.
         */

        /* First, merge the right hand end, if necessary. */
        if (right)
                __ntfs_rl_merge(src + ssize - 1, dst + loc + 1);

        /* marker - First run after the @src runs that have been inserted */
        marker = loc + ssize + 1;

        /* Move the tail of @dst out of the way, then copy in @src. */
        ntfs_rl_mm(dst, marker, loc + 1 + right, dsize - loc - 1 - right);
        ntfs_rl_mc(dst, loc + 1, src, 0, ssize);

        /* Adjust the size of the preceding hole. */
        dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn;

        /* We may have changed the length of the file, so fix the end marker */
        if (dst[marker].lcn == LCN_ENOENT)
                dst[marker].vcn = dst[marker-1].vcn + dst[marker-1].length;

        return dst;
}

/**
 * ntfs_rl_insert - insert a runlist into another
 * @dst:        original runlist to be worked on
 * @dsize:      number of elements in @dst (including end marker)
 * @src:        new runlist to be inserted
 * @ssize:      number of elements in @src (excluding end marker)
 * @loc:        insert the new runlist @src before this element in @dst
 *
 * Insert the runlist @src before element @loc in the runlist @dst. Merge the
 * left end of the new runlist, if necessary. Adjust the size of the hole
 * after the inserted runlist.
 *
 * On success, return a pointer to the new, combined, runlist. Note, both
 * runlists @dst and @src are deallocated before returning so you cannot use
 * the pointers for anything any more. (Strictly speaking the returned runlist
 * may be the same as @dst but this is irrelevant.)
 *
 * On error, return NULL, with errno set to the error code. Both runlists are
 * left unmodified.
 */
static runlist_element *ntfs_rl_insert(runlist_element *dst, int dsize,
                                       runlist_element *src, int ssize, int loc)
{
        BOOL left = FALSE;      /* Left end of @src needs merging */
        BOOL disc = FALSE;      /* Discontinuity between @dst and @src */
        int marker;             /* End of the inserted runs */

        if (!dst || !src) {
                ntfs_log_debug("Eeek. ntfs_rl_insert() invoked with NULL "
                                "pointer!\n");
                errno = EINVAL;
                return NULL;
        }

        /* disc => Discontinuity between the end of @dst and the start of @src.
         *         This means we might need to insert a "notmapped" run.
         */
        if (loc == 0)
                disc = (src[0].vcn > 0);
        else {
                s64 merged_length;

                left = ntfs_rl_are_mergeable(dst + loc - 1, src);

                merged_length = dst[loc - 1].length;
                if (left)
                        merged_length += src->length;

                disc = (src[0].vcn > dst[loc - 1].vcn + merged_length);
        }

        /* Space required: @dst size + @src size, less one if we merged, plus
         * one if there was a discontinuity.
         */
        dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc);
        if (!dst)
                return NULL;
        /*
         * We are guaranteed to succeed from here so can start modifying the
         * original runlist.
         */

        if (left)
                __ntfs_rl_merge(dst + loc - 1, src);

        /*
         * marker - First run after the @src runs that have been inserted
         * Nominally: marker = @loc + @ssize (location + number of runs in @src)
         * If "left", then the first run in @src has been merged with one in @dst.
         * If "disc", then @dst and @src don't meet and we need an extra run to fill the gap.
         */
        marker = loc + ssize - left + disc;

        /* Move the tail of @dst out of the way, then copy in @src. */
        ntfs_rl_mm(dst, marker, loc, dsize - loc);
        ntfs_rl_mc(dst, loc + disc, src, left, ssize - left);

        /* Adjust the VCN of the first run after the insertion ... */
        dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
        /* ... and the length. */
        if (dst[marker].lcn == LCN_HOLE || dst[marker].lcn == LCN_RL_NOT_MAPPED)
                dst[marker].length = dst[marker + 1].vcn - dst[marker].vcn;

        /* Writing beyond the end of the file and there's a discontinuity. */
        if (disc) {
                if (loc > 0) {
                        dst[loc].vcn = dst[loc - 1].vcn + dst[loc - 1].length;
                        dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn;
                } else {
                        dst[loc].vcn = 0;
                        dst[loc].length = dst[loc + 1].vcn;
                }
                dst[loc].lcn = LCN_RL_NOT_MAPPED;
        }
        return dst;
}

/**
 * ntfs_rl_replace - overwrite a runlist element with another runlist
 * @dst:        original runlist to be worked on
 * @dsize:      number of elements in @dst (including end marker)
 * @src:        new runlist to be inserted
 * @ssize:      number of elements in @src (excluding end marker)
 * @loc:        index in runlist @dst to overwrite with @src
 *
 * Replace the runlist element @dst at @loc with @src. Merge the left and
 * right ends of the inserted runlist, if necessary.
 *
 * On success, return a pointer to the new, combined, runlist. Note, both
 * runlists @dst and @src are deallocated before returning so you cannot use
 * the pointers for anything any more. (Strictly speaking the returned runlist
 * may be the same as @dst but this is irrelevant.)
 *
 * On error, return NULL, with errno set to the error code. Both runlists are
 * left unmodified.
 */
static runlist_element *ntfs_rl_replace(runlist_element *dst, int dsize,
                                        runlist_element *src, int ssize, 
                                        int loc)
{
        signed delta;
        BOOL left  = FALSE;     /* Left end of @src needs merging */
        BOOL right = FALSE;     /* Right end of @src needs merging */
        int tail;               /* Start of tail of @dst */
        int marker;             /* End of the inserted runs */

        if (!dst || !src) {
                ntfs_log_debug("Eeek. ntfs_rl_replace() invoked with NULL "
                                "pointer!\n");
                errno = EINVAL;
                return NULL;
        }

        /* First, see if the left and right ends need merging. */
        if ((loc + 1) < dsize)
                right = ntfs_rl_are_mergeable(src + ssize - 1, dst + loc + 1);
        if (loc > 0)
                left = ntfs_rl_are_mergeable(dst + loc - 1, src);

        /* Allocate some space. We'll need less if the left, right, or both
         * ends get merged.  The -1 accounts for the run being replaced.
         */
        delta = ssize - 1 - left - right;
        if (delta > 0) {
                dst = ntfs_rl_realloc(dst, dsize, dsize + delta);
                if (!dst)
                        return NULL;
        }
        /*
         * We are guaranteed to succeed from here so can start modifying the
         * original runlists.
         */

        /* First, merge the left and right ends, if necessary. */
        if (right)
                __ntfs_rl_merge(src + ssize - 1, dst + loc + 1);
        if (left)
                __ntfs_rl_merge(dst + loc - 1, src);

        /*
         * tail - Offset of the tail of @dst
         * Nominally: @tail = @loc + 1 (location, skipping the replaced run)
         * If "right", then one of @dst's runs is already merged into @src.
         */
        tail = loc + right + 1;

        /*
         * marker - First run after the @src runs that have been inserted
         * Nominally: @marker = @loc + @ssize (location + number of runs in @src)
         * If "left", then the first run in @src has been merged with one in @dst.
         */
        marker = loc + ssize - left;

        /* Move the tail of @dst out of the way, then copy in @src. */
        ntfs_rl_mm(dst, marker, tail, dsize - tail);
        ntfs_rl_mc(dst, loc, src, left, ssize - left);

        /* We may have changed the length of the file, so fix the end marker */
        if (((dsize - tail) > 0) && (dst[marker].lcn == LCN_ENOENT))
                dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;

        return dst;
}

/**
 * ntfs_rl_split - insert a runlist into the centre of a hole
 * @dst:        original runlist to be worked on
 * @dsize:      number of elements in @dst (including end marker)
 * @src:        new runlist to be inserted
 * @ssize:      number of elements in @src (excluding end marker)
 * @loc:        index in runlist @dst at which to split and insert @src
 *
 * Split the runlist @dst at @loc into two and insert @new in between the two
 * fragments. No merging of runlists is necessary. Adjust the size of the
 * holes either side.
 *
 * On success, return a pointer to the new, combined, runlist. Note, both
 * runlists @dst and @src are deallocated before returning so you cannot use
 * the pointers for anything any more. (Strictly speaking the returned runlist
 * may be the same as @dst but this is irrelevant.)
 *
 * On error, return NULL, with errno set to the error code. Both runlists are
 * left unmodified.
 */
static runlist_element *ntfs_rl_split(runlist_element *dst, int dsize,
                                      runlist_element *src, int ssize, int loc)
{
        if (!dst || !src) {
                ntfs_log_debug("Eeek. ntfs_rl_split() invoked with NULL pointer!\n");
                errno = EINVAL;
                return NULL;
        }

        /* Space required: @dst size + @src size + one new hole. */
        dst = ntfs_rl_realloc(dst, dsize, dsize + ssize + 1);
        if (!dst)
                return dst;
        /*
         * We are guaranteed to succeed from here so can start modifying the
         * original runlists.
         */

        /* Move the tail of @dst out of the way, then copy in @src. */
        ntfs_rl_mm(dst, loc + 1 + ssize, loc, dsize - loc);
        ntfs_rl_mc(dst, loc + 1, src, 0, ssize);

        /* Adjust the size of the holes either size of @src. */
        dst[loc].length         = dst[loc+1].vcn       - dst[loc].vcn;
        dst[loc+ssize+1].vcn    = dst[loc+ssize].vcn   + dst[loc+ssize].length;
        dst[loc+ssize+1].length = dst[loc+ssize+2].vcn - dst[loc+ssize+1].vcn;

        return dst;
}


/**
 * ntfs_runlists_merge_i - see ntfs_runlists_merge
 */
static runlist_element *ntfs_runlists_merge_i(runlist_element *drl, 
                                              runlist_element *srl)
{
        int di, si;             /* Current index into @[ds]rl. */
        int sstart;             /* First index with lcn > LCN_RL_NOT_MAPPED. */
        int dins;               /* Index into @drl at which to insert @srl. */
        int dend, send;         /* Last index into @[ds]rl. */
        int dfinal, sfinal;     /* The last index into @[ds]rl with
                                   lcn >= LCN_HOLE. */
        int marker = 0;
        VCN marker_vcn = 0;

        ntfs_log_debug("dst:\n");
        ntfs_debug_runlist_dump(drl);
        ntfs_log_debug("src:\n");
        ntfs_debug_runlist_dump(srl);

        /* Check for silly calling... */
        if (!srl)
                return drl;

        /* Check for the case where the first mapping is being done now. */
        if (!drl) {
                drl = srl;
                /* Complete the source runlist if necessary. */
                if (drl[0].vcn) {
                        /* Scan to the end of the source runlist. */
                        for (dend = 0; drl[dend].length; dend++)
                                ;
                        dend++;
                        drl = ntfs_rl_realloc(drl, dend, dend + 1);
                        if (!drl)
                                return drl;
                        /* Insert start element at the front of the runlist. */
                        ntfs_rl_mm(drl, 1, 0, dend);
                        drl[0].vcn = 0;
                        drl[0].lcn = LCN_RL_NOT_MAPPED;
                        drl[0].length = drl[1].vcn;
                }
                goto finished;
        }

        si = di = 0;

        /* Skip any unmapped start element(s) in the source runlist. */
        while (srl[si].length && srl[si].lcn < (LCN)LCN_HOLE)
                si++;

        /* Can't have an entirely unmapped source runlist. */
        if (!srl[si].length) {
                errno = EINVAL;
                ntfs_log_perror("%s: unmapped source runlist", __FUNCTION__);
                return NULL;
        }

        /* Record the starting points. */
        sstart = si;

        /*
         * Skip forward in @drl until we reach the position where @srl needs to
         * be inserted. If we reach the end of @drl, @srl just needs to be
         * appended to @drl.
         */
        for (; drl[di].length; di++) {
                if (drl[di].vcn + drl[di].length > srl[sstart].vcn)
                        break;
        }
        dins = di;

        /* Sanity check for illegal overlaps. */
        if ((drl[di].vcn == srl[si].vcn) && (drl[di].lcn >= 0) &&
                        (srl[si].lcn >= 0)) {
                errno = ERANGE;
                ntfs_log_perror("Run lists overlap. Cannot merge");
                return NULL;
        }

        /* Scan to the end of both runlists in order to know their sizes. */
        for (send = si; srl[send].length; send++)
                ;
        for (dend = di; drl[dend].length; dend++)
                ;

        if (srl[send].lcn == (LCN)LCN_ENOENT)
                marker_vcn = srl[marker = send].vcn;

        /* Scan to the last element with lcn >= LCN_HOLE. */
        for (sfinal = send; sfinal >= 0 && srl[sfinal].lcn < LCN_HOLE; sfinal--)
                ;
        for (dfinal = dend; dfinal >= 0 && drl[dfinal].lcn < LCN_HOLE; dfinal--)
                ;

        {
        BOOL start;
        BOOL finish;
        int ds = dend + 1;              /* Number of elements in drl & srl */
        int ss = sfinal - sstart + 1;

        start  = ((drl[dins].lcn <  LCN_RL_NOT_MAPPED) ||    /* End of file   */
                  (drl[dins].vcn == srl[sstart].vcn));       /* Start of hole */
        finish = ((drl[dins].lcn >= LCN_RL_NOT_MAPPED) &&    /* End of file   */
                 ((drl[dins].vcn + drl[dins].length) <=      /* End of hole   */
                  (srl[send - 1].vcn + srl[send - 1].length)));

        /* Or we'll lose an end marker */
        if (finish && !drl[dins].length)
                ss++;
        if (marker && (drl[dins].vcn + drl[dins].length > srl[send - 1].vcn))
                finish = FALSE;

        ntfs_log_debug("dfinal = %i, dend = %i\n", dfinal, dend);
        ntfs_log_debug("sstart = %i, sfinal = %i, send = %i\n", sstart, sfinal, send);
        ntfs_log_debug("start = %i, finish = %i\n", start, finish);
        ntfs_log_debug("ds = %i, ss = %i, dins = %i\n", ds, ss, dins);

        if (start) {
                if (finish)
                        drl = ntfs_rl_replace(drl, ds, srl + sstart, ss, dins);
                else
                        drl = ntfs_rl_insert(drl, ds, srl + sstart, ss, dins);
        } else {
                if (finish)
                        drl = ntfs_rl_append(drl, ds, srl + sstart, ss, dins);
                else
                        drl = ntfs_rl_split(drl, ds, srl + sstart, ss, dins);
        }
        if (!drl) {
                ntfs_log_perror("Merge failed");
                return drl;
        }
        free(srl);
        if (marker) {
                ntfs_log_debug("Triggering marker code.\n");
                for (ds = dend; drl[ds].length; ds++)
                        ;
                /* We only need to care if @srl ended after @drl. */
                if (drl[ds].vcn <= marker_vcn) {
                        int slots = 0;

                        if (drl[ds].vcn == marker_vcn) {
                                ntfs_log_debug("Old marker = %lli, replacing with "
                                                "LCN_ENOENT.\n",
                                                (long long)drl[ds].lcn);
                                drl[ds].lcn = (LCN)LCN_ENOENT;
                                goto finished;
                        }
                        /*
                         * We need to create an unmapped runlist element in
                         * @drl or extend an existing one before adding the
                         * ENOENT terminator.
                         */
                        if (drl[ds].lcn == (LCN)LCN_ENOENT) {
                                ds--;
                                slots = 1;
                        }
                        if (drl[ds].lcn != (LCN)LCN_RL_NOT_MAPPED) {
                                /* Add an unmapped runlist element. */
                                if (!slots) {
                                        /* FIXME/TODO: We need to have the
                                         * extra memory already! (AIA)
                                         */
                                        drl = ntfs_rl_realloc(drl, ds, ds + 2);
                                        if (!drl)
                                                goto critical_error;
                                        slots = 2;
                                }
                                ds++;
                                /* Need to set vcn if it isn't set already. */
                                if (slots != 1)
                                        drl[ds].vcn = drl[ds - 1].vcn +
                                                        drl[ds - 1].length;
                                drl[ds].lcn = (LCN)LCN_RL_NOT_MAPPED;
                                /* We now used up a slot. */
                                slots--;
                        }
                        drl[ds].length = marker_vcn - drl[ds].vcn;
                        /* Finally add the ENOENT terminator. */
                        ds++;
                        if (!slots) {
                                /* FIXME/TODO: We need to have the extra
                                 * memory already! (AIA)
                                 */
                                drl = ntfs_rl_realloc(drl, ds, ds + 1);
                                if (!drl)
                                        goto critical_error;
                        }
                        drl[ds].vcn = marker_vcn;
                        drl[ds].lcn = (LCN)LCN_ENOENT;
                        drl[ds].length = (s64)0;
                }
        }
        }

finished:
        /* The merge was completed successfully. */
        ntfs_log_debug("Merged runlist:\n");
        ntfs_debug_runlist_dump(drl);
        return drl;

critical_error:
        /* Critical error! We cannot afford to fail here. */
        ntfs_log_perror("libntfs: Critical error");
        ntfs_log_debug("Forcing segmentation fault!\n");
        marker_vcn = ((runlist*)NULL)->lcn;
        return drl;
}

/**
 * ntfs_runlists_merge - merge two runlists into one
 * @drl:        original runlist to be worked on
 * @srl:        new runlist to be merged into @drl
 *
 * First we sanity check the two runlists @srl and @drl to make sure that they
 * are sensible and can be merged. The runlist @srl must be either after the
 * runlist @drl or completely within a hole (or unmapped region) in @drl.
 *
 * Merging of runlists is necessary in two cases:
 *   1. When attribute lists are used and a further extent is being mapped.
 *   2. When new clusters are allocated to fill a hole or extend a file.
 *
 * There are four possible ways @srl can be merged. It can:
 *      - be inserted at the beginning of a hole,
 *      - split the hole in two and be inserted between the two fragments,
 *      - be appended at the end of a hole, or it can
 *      - replace the whole hole.
 * It can also be appended to the end of the runlist, which is just a variant
 * of the insert case.
 *
 * On success, return a pointer to the new, combined, runlist. Note, both
 * runlists @drl and @srl are deallocated before returning so you cannot use
 * the pointers for anything any more. (Strictly speaking the returned runlist
 * may be the same as @dst but this is irrelevant.)
 *
 * On error, return NULL, with errno set to the error code. Both runlists are
 * left unmodified. The following error codes are defined:
 *      ENOMEM          Not enough memory to allocate runlist array.
 *      EINVAL          Invalid parameters were passed in.
 *      ERANGE          The runlists overlap and cannot be merged.
 */
runlist_element *ntfs_runlists_merge(runlist_element *drl,
                runlist_element *srl)
{
        runlist_element *rl; 
        
        ntfs_log_enter("Entering\n");
        rl = ntfs_runlists_merge_i(drl, srl);
        ntfs_log_leave("\n");
        return rl;
}

/**
 * ntfs_mapping_pairs_decompress - convert mapping pairs array to runlist
 * @vol:        ntfs volume on which the attribute resides
 * @attr:       attribute record whose mapping pairs array to decompress
 * @old_rl:     optional runlist in which to insert @attr's runlist
 *
 * Decompress the attribute @attr's mapping pairs array into a runlist. On
 * success, return the decompressed runlist.
 *
 * If @old_rl is not NULL, decompressed runlist is inserted into the
 * appropriate place in @old_rl and the resultant, combined runlist is
 * returned. The original @old_rl is deallocated.
 *
 * On error, return NULL with errno set to the error code. @old_rl is left
 * unmodified in that case.
 *
 * The following error codes are defined:
 *      ENOMEM          Not enough memory to allocate runlist array.
 *      EIO             Corrupt runlist.
 *      EINVAL          Invalid parameters were passed in.
 *      ERANGE          The two runlists overlap.
 *
 * FIXME: For now we take the conceptionally simplest approach of creating the
 * new runlist disregarding the already existing one and then splicing the
 * two into one, if that is possible (we check for overlap and discard the new
 * runlist if overlap present before returning NULL, with errno = ERANGE).
 */
static runlist_element *ntfs_mapping_pairs_decompress_i(const ntfs_volume *vol,
                const ATTR_RECORD *attr, runlist_element *old_rl)
{
        VCN vcn;                /* Current vcn. */
        LCN lcn;                /* Current lcn. */
        s64 deltaxcn;           /* Change in [vl]cn. */
        runlist_element *rl;    /* The output runlist. */
        const u8 *buf;          /* Current position in mapping pairs array. */
        const u8 *attr_end;     /* End of attribute. */
        int err, rlsize;        /* Size of runlist buffer. */
        u16 rlpos;              /* Current runlist position in units of
                                   runlist_elements. */
        u8 b;                   /* Current byte offset in buf. */

        ntfs_log_trace("Entering for attr 0x%x.\n",
                        (unsigned)le32_to_cpu(attr->type));
        /* Make sure attr exists and is non-resident. */
        if (!attr || !attr->non_resident ||
                        sle64_to_cpu(attr->lowest_vcn) < (VCN)0) {
                errno = EINVAL;
                return NULL;
        }
        /* Start at vcn = lowest_vcn and lcn 0. */
        vcn = sle64_to_cpu(attr->lowest_vcn);
        lcn = 0;
        /* Get start of the mapping pairs array. */
        buf = (const u8*)attr + le16_to_cpu(attr->mapping_pairs_offset);
        attr_end = (const u8*)attr + le32_to_cpu(attr->length);
        if (buf < (const u8*)attr || buf > attr_end) {
                ntfs_log_debug("Corrupt attribute.\n");
                errno = EIO;
                return NULL;
        }
        /* Current position in runlist array. */
        rlpos = 0;
        /* Allocate first 4kiB block and set current runlist size to 4kiB. */
        rlsize = 0x1000;
        rl = ntfs_malloc(rlsize);
        if (!rl)
                return NULL;
        /* Insert unmapped starting element if necessary. */
        if (vcn) {
                rl->vcn = (VCN)0;
                rl->lcn = (LCN)LCN_RL_NOT_MAPPED;
                rl->length = vcn;
                rlpos++;
        }
        while (buf < attr_end && *buf) {
                /*
                 * Allocate more memory if needed, including space for the
                 * not-mapped and terminator elements.
                 */
                if ((int)((rlpos + 3) * sizeof(*old_rl)) > rlsize) {
                        runlist_element *rl2;

                        rlsize += 0x1000;
                        rl2 = realloc(rl, rlsize);
                        if (!rl2) {
                                int eo = errno;
                                free(rl);
                                errno = eo;
                                return NULL;
                        }
                        rl = rl2;
                }
                /* Enter the current vcn into the current runlist element. */
                rl[rlpos].vcn = vcn;
                /*
                 * Get the change in vcn, i.e. the run length in clusters.
                 * Doing it this way ensures that we signextend negative values.
                 * A negative run length doesn't make any sense, but hey, I
                 * didn't make up the NTFS specs and Windows NT4 treats the run
                 * length as a signed value so that's how it is...
                 */
                b = *buf & 0xf;
                if (b) {
                        if (buf + b > attr_end)
                                goto io_error;
                        for (deltaxcn = (s8)buf[b--]; b; b--)
                                deltaxcn = (deltaxcn << 8) + buf[b];
                } else { /* The length entry is compulsory. */
                        ntfs_log_debug("Missing length entry in mapping pairs "
                                        "array.\n");
                        deltaxcn = (s64)-1;
                }
                /*
                 * Assume a negative length to indicate data corruption and
                 * hence clean-up and return NULL.
                 */
                if (deltaxcn < 0) {
                        ntfs_log_debug("Invalid length in mapping pairs array.\n");
                        goto err_out;
                }
                /*
                 * Enter the current run length into the current runlist
                 * element.
                 */
                rl[rlpos].length = deltaxcn;
                /* Increment the current vcn by the current run length. */
                vcn += deltaxcn;
                /*
                 * There might be no lcn change at all, as is the case for
                 * sparse clusters on NTFS 3.0+, in which case we set the lcn
                 * to LCN_HOLE.
                 */
                if (!(*buf & 0xf0))
                        rl[rlpos].lcn = (LCN)LCN_HOLE;
                else {
                        /* Get the lcn change which really can be negative. */
                        u8 b2 = *buf & 0xf;
                        b = b2 + ((*buf >> 4) & 0xf);
                        if (buf + b > attr_end)
                                goto io_error;
                        for (deltaxcn = (s8)buf[b--]; b > b2; b--)
                                deltaxcn = (deltaxcn << 8) + buf[b];
                        /* Change the current lcn to it's new value. */
                        lcn += deltaxcn;
#ifdef DEBUG
                        /*
                         * On NTFS 1.2-, apparently can have lcn == -1 to
                         * indicate a hole. But we haven't verified ourselves
                         * whether it is really the lcn or the deltaxcn that is
                         * -1. So if either is found give us a message so we
                         * can investigate it further!
                         */
                        if (vol->major_ver < 3) {
                                if (deltaxcn == (LCN)-1)
                                        ntfs_log_debug("lcn delta == -1\n");
                                if (lcn == (LCN)-1)
                                        ntfs_log_debug("lcn == -1\n");
                        }
#endif
                        /* Check lcn is not below -1. */
                        if (lcn < (LCN)-1) {
                                ntfs_log_debug("Invalid LCN < -1 in mapping pairs "
                                                "array.\n");
                                goto err_out;
                        }
                        /* Enter the current lcn into the runlist element. */
                        rl[rlpos].lcn = lcn;
                }
                /* Get to the next runlist element. */
                rlpos++;
                /* Increment the buffer position to the next mapping pair. */
                buf += (*buf & 0xf) + ((*buf >> 4) & 0xf) + 1;
        }
        if (buf >= attr_end)
                goto io_error;
        /*
         * If there is a highest_vcn specified, it must be equal to the final
         * vcn in the runlist - 1, or something has gone badly wrong.
         */
        deltaxcn = sle64_to_cpu(attr->highest_vcn);
        if (deltaxcn && vcn - 1 != deltaxcn) {
mpa_err:
                ntfs_log_debug("Corrupt mapping pairs array in non-resident "
                                "attribute.\n");
                goto err_out;
        }
        /* Setup not mapped runlist element if this is the base extent. */
        if (!attr->lowest_vcn) {
                VCN max_cluster;

                max_cluster = ((sle64_to_cpu(attr->allocated_size) +
                                vol->cluster_size - 1) >>
                                vol->cluster_size_bits) - 1;
                /*
                 * A highest_vcn of zero means this is a single extent
                 * attribute so simply terminate the runlist with LCN_ENOENT).
                 */
                if (deltaxcn) {
                        /*
                         * If there is a difference between the highest_vcn and
                         * the highest cluster, the runlist is either corrupt
                         * or, more likely, there are more extents following
                         * this one.
                         */
                        if (deltaxcn < max_cluster) {
                                ntfs_log_debug("More extents to follow; deltaxcn = "
                                                "0x%llx, max_cluster = 0x%llx\n",
                                                (long long)deltaxcn,
                                                (long long)max_cluster);
                                rl[rlpos].vcn = vcn;
                                vcn += rl[rlpos].length = max_cluster - deltaxcn;
                                rl[rlpos].lcn = (LCN)LCN_RL_NOT_MAPPED;
                                rlpos++;
                        } else if (deltaxcn > max_cluster) {
                                ntfs_log_debug("Corrupt attribute. deltaxcn = "
                                                "0x%llx, max_cluster = 0x%llx\n",
                                                (long long)deltaxcn,
                                                (long long)max_cluster);
                                goto mpa_err;
                        }
                }
                rl[rlpos].lcn = (LCN)LCN_ENOENT;
        } else /* Not the base extent. There may be more extents to follow. */
                rl[rlpos].lcn = (LCN)LCN_RL_NOT_MAPPED;

        /* Setup terminating runlist element. */
        rl[rlpos].vcn = vcn;
        rl[rlpos].length = (s64)0;
        /* If no existing runlist was specified, we are done. */
        if (!old_rl) {
                ntfs_log_debug("Mapping pairs array successfully decompressed:\n");
                ntfs_debug_runlist_dump(rl);
                return rl;
        }
        /* Now combine the new and old runlists checking for overlaps. */
        old_rl = ntfs_runlists_merge(old_rl, rl);
        if (old_rl)
                return old_rl;
        err = errno;
        free(rl);
        ntfs_log_debug("Failed to merge runlists.\n");
        errno = err;
        return NULL;
io_error:
        ntfs_log_debug("Corrupt attribute.\n");
err_out:
        free(rl);
        errno = EIO;
        return NULL;
}

runlist_element *ntfs_mapping_pairs_decompress(const ntfs_volume *vol,
                const ATTR_RECORD *attr, runlist_element *old_rl)
{
        runlist_element *rle; 
        
        ntfs_log_enter("Entering\n");
        rle = ntfs_mapping_pairs_decompress_i(vol, attr, old_rl);
        ntfs_log_leave("\n");
        return rle;
}

/**
 * ntfs_rl_vcn_to_lcn - convert a vcn into a lcn given a runlist
 * @rl:         runlist to use for conversion
 * @vcn:        vcn to convert
 *
 * Convert the virtual cluster number @vcn of an attribute into a logical
 * cluster number (lcn) of a device using the runlist @rl to map vcns to their
 * corresponding lcns.
 *
 * Since lcns must be >= 0, we use negative return values with special meaning:
 *
 * Return value                 Meaning / Description
 * ==================================================
 *  -1 = LCN_HOLE               Hole / not allocated on disk.
 *  -2 = LCN_RL_NOT_MAPPED      This is part of the runlist which has not been
 *                              inserted into the runlist yet.
 *  -3 = LCN_ENOENT             There is no such vcn in the attribute.
 *  -4 = LCN_EINVAL             Input parameter error.
 */
LCN ntfs_rl_vcn_to_lcn(const runlist_element *rl, const VCN vcn)
{
        int i;

        if (vcn < (VCN)0)
                return (LCN)LCN_EINVAL;
        /*
         * If rl is NULL, assume that we have found an unmapped runlist. The
         * caller can then attempt to map it and fail appropriately if
         * necessary.
         */
        if (!rl)
                return (LCN)LCN_RL_NOT_MAPPED;

        /* Catch out of lower bounds vcn. */
        if (vcn < rl[0].vcn)
                return (LCN)LCN_ENOENT;

        for (i = 0; rl[i].length; i++) {
                if (vcn < rl[i+1].vcn) {
                        if (rl[i].lcn >= (LCN)0)
                                return rl[i].lcn + (vcn - rl[i].vcn);
                        return rl[i].lcn;
                }
        }
        /*
         * The terminator element is setup to the correct value, i.e. one of
         * LCN_HOLE, LCN_RL_NOT_MAPPED, or LCN_ENOENT.
         */
        if (rl[i].lcn < (LCN)0)
                return rl[i].lcn;
        /* Just in case... We could replace this with BUG() some day. */
        return (LCN)LCN_ENOENT;
}

/**
 * ntfs_rl_pread - gather read from disk
 * @vol:        ntfs volume to read from
 * @rl:         runlist specifying where to read the data from
 * @pos:        byte position within runlist @rl at which to begin the read
 * @count:      number of bytes to read
 * @b:          data buffer into which to read from disk
 *
 * This function will read @count bytes from the volume @vol to the data buffer
 * @b gathering the data as specified by the runlist @rl. The read begins at
 * offset @pos into the runlist @rl.
 *
 * On success, return the number of successfully read bytes. If this number is
 * lower than @count this means that the read reached end of file or that an
 * error was encountered during the read so that the read is partial. 0 means
 * nothing was read (also return 0 when @count is 0).
 *
 * On error and nothing has been read, return -1 with errno set appropriately
 * to the return code of ntfs_pread(), or to EINVAL in case of invalid
 * arguments.
 *
 * NOTE: If we encounter EOF while reading we return EIO because we assume that
 * the run list must point to valid locations within the ntfs volume.
 */
s64 ntfs_rl_pread(const ntfs_volume *vol, const runlist_element *rl,
                const s64 pos, s64 count, void *b)
{
        s64 bytes_read, to_read, ofs, total;
        int err = EIO;

        if (!vol || !rl || pos < 0 || count < 0) {
                errno = EINVAL;
                ntfs_log_perror("Failed to read runlist [vol: %p rl: %p "
                                "pos: %lld count: %lld]", vol, rl,
                                (long long)pos, (long long)count);
                return -1;
        }
        if (!count)
                return count;
        /* Seek in @rl to the run containing @pos. */
        for (ofs = 0; rl->length && (ofs + (rl->length <<
                        vol->cluster_size_bits) <= pos); rl++)
                ofs += (rl->length << vol->cluster_size_bits);
        /* Offset in the run at which to begin reading. */
        ofs = pos - ofs;
        for (total = 0LL; count; rl++, ofs = 0) {
                if (!rl->length)
                        goto rl_err_out;
                if (rl->lcn < (LCN)0) {
                        if (rl->lcn != (LCN)LCN_HOLE)
                                goto rl_err_out;
                        /* It is a hole. Just fill buffer @b with zeroes. */
                        to_read = min(count, (rl->length <<
                                        vol->cluster_size_bits) - ofs);
                        memset(b, 0, to_read);
                        /* Update counters and proceed with next run. */
                        total += to_read;
                        count -= to_read;
                        b = (u8*)b + to_read;
                        continue;
                }
                /* It is a real lcn, read it from the volume. */
                to_read = min(count, (rl->length << vol->cluster_size_bits) -
                                ofs);
retry:
                bytes_read = ntfs_pread(vol->dev, (rl->lcn <<
                                vol->cluster_size_bits) + ofs, to_read, b);
                /* If everything ok, update progress counters and continue. */
                if (bytes_read > 0) {
                        total += bytes_read;
                        count -= bytes_read;
                        b = (u8*)b + bytes_read;
                        continue;
                }
                /* If the syscall was interrupted, try again. */
                if (bytes_read == (s64)-1 && errno == EINTR)
                        goto retry;
                if (bytes_read == (s64)-1)
                        err = errno;
                goto rl_err_out;
        }
        /* Finally, return the number of bytes read. */
        return total;
rl_err_out:
        if (total)
                return total;
        errno = err;
        return -1;
}

/**
 * ntfs_rl_pwrite - scatter write to disk
 * @vol:        ntfs volume to write to
 * @rl:         runlist entry specifying where to write the data to
 * @ofs:        offset in file for runlist element indicated in @rl
 * @pos:        byte position from runlist beginning at which to begin the write
 * @count:      number of bytes to write
 * @b:          data buffer to write to disk
 *
 * This function will write @count bytes from data buffer @b to the volume @vol
 * scattering the data as specified by the runlist @rl. The write begins at
 * offset @pos into the runlist @rl. If a run is sparse then the related buffer
 * data is ignored which means that the caller must ensure they are consistent.
 *
 * On success, return the number of successfully written bytes. If this number
 * is lower than @count this means that the write has been interrupted in
 * flight or that an error was encountered during the write so that the write
 * is partial. 0 means nothing was written (also return 0 when @count is 0).
 *
 * On error and nothing has been written, return -1 with errno set
 * appropriately to the return code of ntfs_pwrite(), or to to EINVAL in case
 * of invalid arguments.
 */
s64 ntfs_rl_pwrite(const ntfs_volume *vol, const runlist_element *rl,
                s64 ofs, const s64 pos, s64 count, void *b)
{
        s64 written, to_write, total = 0;
        int err = EIO;

        if (!vol || !rl || pos < 0 || count < 0) {
                errno = EINVAL;
                ntfs_log_perror("Failed to write runlist [vol: %p rl: %p "
                                "pos: %lld count: %lld]", vol, rl,
                                (long long)pos, (long long)count);
                goto errno_set;
        }
        if (!count)
                goto out;
        /* Seek in @rl to the run containing @pos. */
        while (rl->length && (ofs + (rl->length <<
                        vol->cluster_size_bits) <= pos)) {
                ofs += (rl->length << vol->cluster_size_bits);
                rl++;
        }
        /* Offset in the run at which to begin writing. */
        ofs = pos - ofs;
        for (total = 0LL; count; rl++, ofs = 0) {
                if (!rl->length)
                        goto rl_err_out;
                if (rl->lcn < (LCN)0) {

                        if (rl->lcn != (LCN)LCN_HOLE)
                                goto rl_err_out;
                        
                        to_write = min(count, (rl->length <<
                                               vol->cluster_size_bits) - ofs);
                        
                        total += to_write;
                        count -= to_write;
                        b = (u8*)b + to_write;
                        continue;
                }
                /* It is a real lcn, write it to the volume. */
                to_write = min(count, (rl->length << vol->cluster_size_bits) -
                                ofs);
retry:
                if (!NVolReadOnly(vol))
                        written = ntfs_pwrite(vol->dev, (rl->lcn <<
                                        vol->cluster_size_bits) + ofs,
                                        to_write, b);
                else
                        written = to_write;
                /* If everything ok, update progress counters and continue. */
                if (written > 0) {
                        total += written;
                        count -= written;
                        b = (u8*)b + written;
                        continue;
                }
                /* If the syscall was interrupted, try again. */
                if (written == (s64)-1 && errno == EINTR)
                        goto retry;
                if (written == (s64)-1)
                        err = errno;
                goto rl_err_out;
        }
out:
        return total;
rl_err_out:
        if (total)
                goto out;
        errno = err;
errno_set:
        total = -1;
        goto out;
}

/**
 * ntfs_get_nr_significant_bytes - get number of bytes needed to store a number
 * @n:          number for which to get the number of bytes for
 *
 * Return the number of bytes required to store @n unambiguously as
 * a signed number.
 *
 * This is used in the context of the mapping pairs array to determine how
 * many bytes will be needed in the array to store a given logical cluster
 * number (lcn) or a specific run length.
 *
 * Return the number of bytes written. This function cannot fail.
 */
int ntfs_get_nr_significant_bytes(const s64 n)
{
        u64 l;
        int i;

        l = (n < 0 ? ~n : n);
        i = 1;
        if (l >= 128) {
                l >>= 7;
                do {
                        i++;
                        l >>= 8;
                } while (l);
        }
        return i;
}

/**
 * ntfs_get_size_for_mapping_pairs - get bytes needed for mapping pairs array
 * @vol:        ntfs volume (needed for the ntfs version)
 * @rl:         runlist for which to determine the size of the mapping pairs
 * @start_vcn:  vcn at which to start the mapping pairs array
 *
 * Walk the runlist @rl and calculate the size in bytes of the mapping pairs
 * array corresponding to the runlist @rl, starting at vcn @start_vcn.  This
 * for example allows us to allocate a buffer of the right size when building
 * the mapping pairs array.
 *
 * If @rl is NULL, just return 1 (for the single terminator byte).
 *
 * Return the calculated size in bytes on success.  On error, return -1 with
 * errno set to the error code.  The following error codes are defined:
 *      EINVAL  - Run list contains unmapped elements. Make sure to only pass
 *                fully mapped runlists to this function.
 *              - @start_vcn is invalid.
 *      EIO     - The runlist is corrupt.
 */
int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol,
                const runlist_element *rl, const VCN start_vcn, int max_size)
{
        LCN prev_lcn;
        int rls;

        if (start_vcn < 0) {
                ntfs_log_trace("start_vcn %lld (should be >= 0)\n",
                                (long long) start_vcn);
                errno = EINVAL;
                goto errno_set;
        }
        if (!rl) {
                if (start_vcn) {
                        ntfs_log_trace("rl NULL, start_vcn %lld (should be > 0)\n",
                                        (long long) start_vcn);
                        errno = EINVAL;
                        goto errno_set;
                }
                rls = 1;
                goto out;
        }
        /* Skip to runlist element containing @start_vcn. */
        while (rl->length && start_vcn >= rl[1].vcn)
                rl++;
        if ((!rl->length && start_vcn > rl->vcn) || start_vcn < rl->vcn) {
                errno = EINVAL;
                goto errno_set;
        }
        prev_lcn = 0;
        /* Always need the terminating zero byte. */
        rls = 1;
        /* Do the first partial run if present. */
        if (start_vcn > rl->vcn) {
                s64 delta;

                /* We know rl->length != 0 already. */
                if (rl->length < 0 || rl->lcn < LCN_HOLE)
                        goto err_out;
                delta = start_vcn - rl->vcn;
                /* Header byte + length. */
                rls += 1 + ntfs_get_nr_significant_bytes(rl->length - delta);
                /*
                 * If the logical cluster number (lcn) denotes a hole and we
                 * are on NTFS 3.0+, we don't store it at all, i.e. we need
                 * zero space. On earlier NTFS versions we just store the lcn.
                 * Note: this assumes that on NTFS 1.2-, holes are stored with
                 * an lcn of -1 and not a delta_lcn of -1 (unless both are -1).
                 */
                if (rl->lcn >= 0 || vol->major_ver < 3) {
                        prev_lcn = rl->lcn;
                        if (rl->lcn >= 0)
                                prev_lcn += delta;
                        /* Change in lcn. */
                        rls += ntfs_get_nr_significant_bytes(prev_lcn);
                }
                /* Go to next runlist element. */
                rl++;
        }
        /* Do the full runs. */
        for (; rl->length && (rls <= max_size); rl++) {
                if (rl->length < 0 || rl->lcn < LCN_HOLE)
                        goto err_out;
                /* Header byte + length. */
                rls += 1 + ntfs_get_nr_significant_bytes(rl->length);
                /*
                 * If the logical cluster number (lcn) denotes a hole and we
                 * are on NTFS 3.0+, we don't store it at all, i.e. we need
                 * zero space. On earlier NTFS versions we just store the lcn.
                 * Note: this assumes that on NTFS 1.2-, holes are stored with
                 * an lcn of -1 and not a delta_lcn of -1 (unless both are -1).
                 */
                if (rl->lcn >= 0 || vol->major_ver < 3) {
                        /* Change in lcn. */
                        rls += ntfs_get_nr_significant_bytes(rl->lcn -
                                        prev_lcn);
                        prev_lcn = rl->lcn;
                }
        }
out:    
        return rls;
err_out:
        if (rl->lcn == LCN_RL_NOT_MAPPED)
                errno = EINVAL;
        else
                errno = EIO;
errno_set:      
        rls = -1;
        goto out;
}

/**
 * ntfs_write_significant_bytes - write the significant bytes of a number
 * @dst:        destination buffer to write to
 * @dst_max:    pointer to last byte of destination buffer for bounds checking
 * @n:          number whose significant bytes to write
 *
 * Store in @dst, the minimum bytes of the number @n which are required to
 * identify @n unambiguously as a signed number, taking care not to exceed
 * @dest_max, the maximum position within @dst to which we are allowed to
 * write.
 *
 * This is used when building the mapping pairs array of a runlist to compress
 * a given logical cluster number (lcn) or a specific run length to the minimum
 * size possible.
 *
 * Return the number of bytes written on success. On error, i.e. the
 * destination buffer @dst is too small, return -1 with errno set ENOSPC.
 */
int ntfs_write_significant_bytes(u8 *dst, const u8 *dst_max, const s64 n)
{
        s64 l = n;
        int i;

        i = 0;
        if (dst > dst_max)
                goto err_out;
        *dst++ = l;
        i++;
        while ((l > 0x7f) || (l < -0x80)) {
                if (dst > dst_max)
                        goto err_out;
                l >>= 8;
                *dst++ = l;
                i++;
        }
        return i;
err_out:
        errno = ENOSPC;
        return -1;
}

/**
 * ntfs_mapping_pairs_build - build the mapping pairs array from a runlist
 * @vol:        ntfs volume (needed for the ntfs version)
 * @dst:        destination buffer to which to write the mapping pairs array
 * @dst_len:    size of destination buffer @dst in bytes
 * @rl:         runlist for which to build the mapping pairs array
 * @start_vcn:  vcn at which to start the mapping pairs array
 * @stop_vcn:   first vcn outside destination buffer on success or ENOSPC error
 *
 * Create the mapping pairs array from the runlist @rl, starting at vcn
 * @start_vcn and save the array in @dst.  @dst_len is the size of @dst in
 * bytes and it should be at least equal to the value obtained by calling
 * ntfs_get_size_for_mapping_pairs().
 *
 * If @rl is NULL, just write a single terminator byte to @dst.
 *
 * On success or ENOSPC error, if @stop_vcn is not NULL, *@stop_vcn is set to
 * the first vcn outside the destination buffer. Note that on error @dst has
 * been filled with all the mapping pairs that will fit, thus it can be treated
 * as partial success, in that a new attribute extent needs to be created or the
 * next extent has to be used and the mapping pairs build has to be continued
 * with @start_vcn set to *@stop_vcn.
 *
 * Return 0 on success.  On error, return -1 with errno set to the error code.
 * The following error codes are defined:
 *      EINVAL  - Run list contains unmapped elements. Make sure to only pass
 *                fully mapped runlists to this function.
 *              - @start_vcn is invalid.
 *      EIO     - The runlist is corrupt.
 *      ENOSPC  - The destination buffer is too small.
 */
int ntfs_mapping_pairs_build(const ntfs_volume *vol, u8 *dst,
                const int dst_len, const runlist_element *rl,
                const VCN start_vcn, runlist_element const **stop_rl)
{
        LCN prev_lcn;
        u8 *dst_max, *dst_next;
        s8 len_len, lcn_len;
        int ret = 0;

        if (start_vcn < 0)
                goto val_err;
        if (!rl) {
                if (start_vcn)
                        goto val_err;
                if (stop_rl)
                        *stop_rl = rl;
                if (dst_len < 1)
                        goto nospc_err;
                goto ok;
        }
        /* Skip to runlist element containing @start_vcn. */
        while (rl->length && start_vcn >= rl[1].vcn)
                rl++;
        if ((!rl->length && start_vcn > rl->vcn) || start_vcn < rl->vcn)
                goto val_err;
        /*
         * @dst_max is used for bounds checking in
         * ntfs_write_significant_bytes().
         */
        dst_max = dst + dst_len - 1;
        prev_lcn = 0;
        /* Do the first partial run if present. */
        if (start_vcn > rl->vcn) {
                s64 delta;

                /* We know rl->length != 0 already. */
                if (rl->length < 0 || rl->lcn < LCN_HOLE)
                        goto err_out;
                delta = start_vcn - rl->vcn;
                /* Write length. */
                len_len = ntfs_write_significant_bytes(dst + 1, dst_max,
                                rl->length - delta);
                if (len_len < 0)
                        goto size_err;
                /*
                 * If the logical cluster number (lcn) denotes a hole and we
                 * are on NTFS 3.0+, we don't store it at all, i.e. we need
                 * zero space. On earlier NTFS versions we just write the lcn
                 * change.  FIXME: Do we need to write the lcn change or just
                 * the lcn in that case?  Not sure as I have never seen this
                 * case on NT4. - We assume that we just need to write the lcn
                 * change until someone tells us otherwise... (AIA)
                 */
                if (rl->lcn >= 0 || vol->major_ver < 3) {
                        prev_lcn = rl->lcn;
                        if (rl->lcn >= 0)
                                prev_lcn += delta;
                        /* Write change in lcn. */
                        lcn_len = ntfs_write_significant_bytes(dst + 1 +
                                        len_len, dst_max, prev_lcn);
                        if (lcn_len < 0)
                                goto size_err;
                } else
                        lcn_len = 0;
                dst_next = dst + len_len + lcn_len + 1;
                if (dst_next > dst_max)
                        goto size_err;
                /* Update header byte. */
                *dst = lcn_len << 4 | len_len;
                /* Position at next mapping pairs array element. */
                dst = dst_next;
                /* Go to next runlist element. */
                rl++;
        }
        /* Do the full runs. */
        for (; rl->length; rl++) {
                if (rl->length < 0 || rl->lcn < LCN_HOLE)
                        goto err_out;
                /* Write length. */
                len_len = ntfs_write_significant_bytes(dst + 1, dst_max,
                                rl->length);
                if (len_len < 0)
                        goto size_err;
                /*
                 * If the logical cluster number (lcn) denotes a hole and we
                 * are on NTFS 3.0+, we don't store it at all, i.e. we need
                 * zero space. On earlier NTFS versions we just write the lcn
                 * change. FIXME: Do we need to write the lcn change or just
                 * the lcn in that case? Not sure as I have never seen this
                 * case on NT4. - We assume that we just need to write the lcn
                 * change until someone tells us otherwise... (AIA)
                 */
                if (rl->lcn >= 0 || vol->major_ver < 3) {
                        /* Write change in lcn. */
                        lcn_len = ntfs_write_significant_bytes(dst + 1 +
                                        len_len, dst_max, rl->lcn - prev_lcn);
                        if (lcn_len < 0)
                                goto size_err;
                        prev_lcn = rl->lcn;
                } else
                        lcn_len = 0;
                dst_next = dst + len_len + lcn_len + 1;
                if (dst_next > dst_max)
                        goto size_err;
                /* Update header byte. */
                *dst = lcn_len << 4 | len_len;
                /* Position at next mapping pairs array element. */
                dst += 1 + len_len + lcn_len;
        }
        /* Set stop vcn. */
        if (stop_rl)
                *stop_rl = rl;
ok:     
        /* Add terminator byte. */
        *dst = 0;
out:
        return ret;
size_err:
        /* Set stop vcn. */
        if (stop_rl)
                *stop_rl = rl;
        /* Add terminator byte. */
        *dst = 0;
nospc_err:
        errno = ENOSPC;
        goto errno_set;
val_err:
        errno = EINVAL;
        goto errno_set;
err_out:
        if (rl->lcn == LCN_RL_NOT_MAPPED)
                errno = EINVAL;
        else
                errno = EIO;
errno_set:
        ret = -1;
        goto out;
}

/**
 * ntfs_rl_truncate - truncate a runlist starting at a specified vcn
 * @arl:        address of runlist to truncate
 * @start_vcn:  first vcn which should be cut off
 *
 * Truncate the runlist *@arl starting at vcn @start_vcn as well as the memory
 * buffer holding the runlist.
 *
 * Return 0 on success and -1 on error with errno set to the error code.
 *
 * NOTE: @arl is the address of the runlist. We need the address so we can
 * modify the pointer to the runlist with the new, reallocated memory buffer.
 */
int ntfs_rl_truncate(runlist **arl, const VCN start_vcn)
{
        runlist *rl;
        BOOL is_end = FALSE;

        if (!arl || !*arl) {
                errno = EINVAL;
                if (!arl)
                        ntfs_log_perror("rl_truncate error: arl: %p", arl);
                else
                        ntfs_log_perror("rl_truncate error:"
                                " arl: %p *arl: %p", arl, *arl);
                return -1;
        }
        
        rl = *arl;
        
        if (start_vcn < rl->vcn) {
                errno = EINVAL;
                ntfs_log_perror("Start_vcn lies outside front of runlist");
                return -1;
        }
        
        /* Find the starting vcn in the run list. */
        while (rl->length) {
                if (start_vcn < rl[1].vcn)
                        break;
                rl++;
        }
        
        if (!rl->length) {
                errno = EIO;
                ntfs_log_trace("Truncating already truncated runlist?\n");
                return -1;
        }
        
        /* Truncate the run. */
        rl->length = start_vcn - rl->vcn;
        
        /*
         * If a run was partially truncated, make the following runlist
         * element a terminator instead of the truncated runlist
         * element itself.
         */
        if (rl->length) {
                ++rl;
                if (!rl->length)
                        is_end = TRUE;
                rl->vcn = start_vcn;
                rl->length = 0;
        }
        rl->lcn = (LCN)LCN_ENOENT;
        /**
         * Reallocate memory if necessary.
         * FIXME: Below code is broken, because runlist allocations must be 
         * a multiply of 4096. The code caused crashes and corruptions.
         */
/*      
         if (!is_end) {
                size_t new_size = (rl - *arl + 1) * sizeof(runlist_element);
                rl = realloc(*arl, new_size);
                if (rl)
                        *arl = rl;
        }
*/
        return 0;
}

/**
 * ntfs_rl_sparse - check whether runlist have sparse regions or not.
 * @rl:         runlist to check
 *
 * Return 1 if have, 0 if not, -1 on error with errno set to the error code.
 */
int ntfs_rl_sparse(runlist *rl)
{
        runlist *rlc;

        if (!rl) {
                errno = EINVAL;
                ntfs_log_perror("%s: ", __FUNCTION__);
                return -1;
        }

        for (rlc = rl; rlc->length; rlc++)
                if (rlc->lcn < 0) {
                        if (rlc->lcn != LCN_HOLE) {
                                errno = EINVAL;
                                ntfs_log_perror("%s: bad runlist", __FUNCTION__);
                                return -1;
                        }
                        return 1;
                }
        return 0;
}

/**
 * ntfs_rl_get_compressed_size - calculate length of non sparse regions
 * @vol:        ntfs volume (need for cluster size)
 * @rl:         runlist to calculate for
 *
 * Return compressed size or -1 on error with errno set to the error code.
 */
s64 ntfs_rl_get_compressed_size(ntfs_volume *vol, runlist *rl)
{
        runlist *rlc;
        s64 ret = 0;

        if (!rl) {
                errno = EINVAL;
                ntfs_log_perror("%s: ", __FUNCTION__);
                return -1;
        }

        for (rlc = rl; rlc->length; rlc++) {
                if (rlc->lcn < 0) {
                        if (rlc->lcn != LCN_HOLE) {
                                errno = EINVAL;
                                ntfs_log_perror("%s: bad runlist", __FUNCTION__);
                                return -1;
                        }
                } else
                        ret += rlc->length;
        }
        return ret << vol->cluster_size_bits;
}


#ifdef NTFS_TEST
/**
 * test_rl_helper
 */
#define MKRL(R,V,L,S)                           \
        (R)->vcn = V;                           \
        (R)->lcn = L;                           \
        (R)->length = S;
/*
}
*/
/**
 * test_rl_dump_runlist - Runlist test: Display the contents of a runlist
 * @rl:
 *
 * Description...
 *
 * Returns:
 */
static void test_rl_dump_runlist(const runlist_element *rl)
{
        int abbr = 0;   /* abbreviate long lists */
        int len = 0;
        int i;
        const char *lcn_str[5] = { "HOLE", "NOTMAP", "ENOENT", "XXXX" };

        if (!rl) {
                printf("    Run list not present.\n");
                return;
        }

        if (abbr)
                for (len = 0; rl[len].length; len++) ;

        printf("     VCN      LCN      len\n");
        for (i = 0; ; i++, rl++) {
                LCN lcn = rl->lcn;

                if ((abbr) && (len > 20)) {
                        if (i == 4)
                                printf("     ...\n");
                        if ((i > 3) && (i < (len - 3)))
                                continue;
                }

                if (lcn < (LCN)0) {
                        int ind = -lcn - 1;

                        if (ind > -LCN_ENOENT - 1)
                                ind = 3;
                        printf("%8lld %8s %8lld\n",
                                rl->vcn, lcn_str[ind], rl->length);
                } else
                        printf("%8lld %8lld %8lld\n",
                                rl->vcn, rl->lcn, rl->length);
                if (!rl->length)
                        break;
        }
        if ((abbr) && (len > 20))
                printf("    (%d entries)\n", len+1);
        printf("\n");
}

/**
 * test_rl_runlists_merge - Runlist test: Merge two runlists
 * @drl:
 * @srl:
 *
 * Description...
 *
 * Returns:
 */
static runlist_element * test_rl_runlists_merge(runlist_element *drl, runlist_element *srl)
{
        runlist_element *res = NULL;

        printf("dst:\n");
        test_rl_dump_runlist(drl);
        printf("src:\n");
        test_rl_dump_runlist(srl);

        res = ntfs_runlists_merge(drl, srl);

        printf("res:\n");
        test_rl_dump_runlist(res);

        return res;
}

/**
 * test_rl_read_buffer - Runlist test: Read a file containing a runlist
 * @file:
 * @buf:
 * @bufsize:
 *
 * Description...
 *
 * Returns:
 */
static int test_rl_read_buffer(const char *file, u8 *buf, int bufsize)
{
        FILE *fptr;

        fptr = fopen(file, "r");
        if (!fptr) {
                printf("open %s\n", file);
                return 0;
        }

        if (fread(buf, bufsize, 1, fptr) == 99) {
                printf("read %s\n", file);
                return 0;
        }

        fclose(fptr);
        return 1;
}

/**
 * test_rl_pure_src - Runlist test: Complicate the simple tests a little
 * @contig:
 * @multi:
 * @vcn:
 * @len:
 *
 * Description...
 *
 * Returns:
 */
static runlist_element * test_rl_pure_src(BOOL contig, BOOL multi, int vcn, int len)
{
        runlist_element *result;
        int fudge;

        if (contig)
                fudge = 0;
        else
                fudge = 999;

        result = ntfs_malloc(4096);
        if (!result)
                return NULL;
        
        if (multi) {
                MKRL(result+0, vcn + (0*len/4), fudge + vcn + 1000 + (0*len/4), len / 4)
                MKRL(result+1, vcn + (1*len/4), fudge + vcn + 1000 + (1*len/4), len / 4)
                MKRL(result+2, vcn + (2*len/4), fudge + vcn + 1000 + (2*len/4), len / 4)
                MKRL(result+3, vcn + (3*len/4), fudge + vcn + 1000 + (3*len/4), len / 4)
                MKRL(result+4, vcn + (4*len/4), LCN_RL_NOT_MAPPED,              0)
        } else {
                MKRL(result+0, vcn,       fudge + vcn + 1000, len)
                MKRL(result+1, vcn + len, LCN_RL_NOT_MAPPED,  0)
        }
        return result;
}

/**
 * test_rl_pure_test - Runlist test: Perform tests using simple runlists
 * @test:
 * @contig:
 * @multi:
 * @vcn:
 * @len:
 * @file:
 * @size:
 *
 * Description...
 *
 * Returns:
 */
static void test_rl_pure_test(int test, BOOL contig, BOOL multi, int vcn, int len, runlist_element *file, int size)
{
        runlist_element *src;
        runlist_element *dst;
        runlist_element *res;

        src = test_rl_pure_src(contig, multi, vcn, len);
        dst = ntfs_malloc(4096);
        if (!src || !dst) {
                printf("Test %2d ---------- FAILED! (no free memory?)\n", test);
                return;
        }

        memcpy(dst, file, size);

        printf("Test %2d ----------\n", test);
        res = test_rl_runlists_merge(dst, src);

        free(res);
}

/**
 * test_rl_pure - Runlist test: Create tests using simple runlists
 * @contig:
 * @multi:
 *
 * Description...
 *
 * Returns:
 */
static void test_rl_pure(char *contig, char *multi)
{
                /* VCN,  LCN, len */
        static runlist_element file1[] = {
                {    0,   -1, 100 },    /* HOLE */
                {  100, 1100, 100 },    /* DATA */
                {  200,   -1, 100 },    /* HOLE */
                {  300, 1300, 100 },    /* DATA */
                {  400,   -1, 100 },    /* HOLE */
                {  500,   -3,   0 }     /* NOENT */
        };
        static runlist_element file2[] = {
                {    0, 1000, 100 },    /* DATA */
                {  100,   -1, 100 },    /* HOLE */
                {  200,   -3,   0 }     /* NOENT */
        };
        static runlist_element file3[] = {
                {    0, 1000, 100 },    /* DATA */
                {  100,   -3,   0 }     /* NOENT */
        };
        static runlist_element file4[] = {
                {    0,   -3,   0 }     /* NOENT */
        };
        static runlist_element file5[] = {
                {    0,   -2, 100 },    /* NOTMAP */
                {  100, 1100, 100 },    /* DATA */
                {  200,   -2, 100 },    /* NOTMAP */
                {  300, 1300, 100 },    /* DATA */
                {  400,   -2, 100 },    /* NOTMAP */
                {  500,   -3,   0 }     /* NOENT */
        };
        static runlist_element file6[] = {
                {    0, 1000, 100 },    /* DATA */
                {  100,   -2, 100 },    /* NOTMAP */
                {  200,   -3,   0 }     /* NOENT */
        };
        BOOL c, m;

        if (strcmp(contig, "contig") == 0)
                c = TRUE;
        else if (strcmp(contig, "noncontig") == 0)
                c = FALSE;
        else {
                printf("rl pure [contig|noncontig] [single|multi]\n");
                return;
        }
        if (strcmp(multi, "multi") == 0)
                m = TRUE;
        else if (strcmp(multi, "single") == 0)
                m = FALSE;
        else {
                printf("rl pure [contig|noncontig] [single|multi]\n");
                return;
        }

        test_rl_pure_test(1,  c, m,   0,  40, file1, sizeof(file1));
        test_rl_pure_test(2,  c, m,  40,  40, file1, sizeof(file1));
        test_rl_pure_test(3,  c, m,  60,  40, file1, sizeof(file1));
        test_rl_pure_test(4,  c, m,   0, 100, file1, sizeof(file1));
        test_rl_pure_test(5,  c, m, 200,  40, file1, sizeof(file1));
        test_rl_pure_test(6,  c, m, 240,  40, file1, sizeof(file1));
        test_rl_pure_test(7,  c, m, 260,  40, file1, sizeof(file1));
        test_rl_pure_test(8,  c, m, 200, 100, file1, sizeof(file1));
        test_rl_pure_test(9,  c, m, 400,  40, file1, sizeof(file1));
        test_rl_pure_test(10, c, m, 440,  40, file1, sizeof(file1));
        test_rl_pure_test(11, c, m, 460,  40, file1, sizeof(file1));
        test_rl_pure_test(12, c, m, 400, 100, file1, sizeof(file1));
        test_rl_pure_test(13, c, m, 160, 100, file2, sizeof(file2));
        test_rl_pure_test(14, c, m, 100, 140, file2, sizeof(file2));
        test_rl_pure_test(15, c, m, 200,  40, file2, sizeof(file2));
        test_rl_pure_test(16, c, m, 240,  40, file2, sizeof(file2));
        test_rl_pure_test(17, c, m, 100,  40, file3, sizeof(file3));
        test_rl_pure_test(18, c, m, 140,  40, file3, sizeof(file3));
        test_rl_pure_test(19, c, m,   0,  40, file4, sizeof(file4));
        test_rl_pure_test(20, c, m,  40,  40, file4, sizeof(file4));
        test_rl_pure_test(21, c, m,   0,  40, file5, sizeof(file5));
        test_rl_pure_test(22, c, m,  40,  40, file5, sizeof(file5));
        test_rl_pure_test(23, c, m,  60,  40, file5, sizeof(file5));
        test_rl_pure_test(24, c, m,   0, 100, file5, sizeof(file5));
        test_rl_pure_test(25, c, m, 200,  40, file5, sizeof(file5));
        test_rl_pure_test(26, c, m, 240,  40, file5, sizeof(file5));
        test_rl_pure_test(27, c, m, 260,  40, file5, sizeof(file5));
        test_rl_pure_test(28, c, m, 200, 100, file5, sizeof(file5));
        test_rl_pure_test(29, c, m, 400,  40, file5, sizeof(file5));
        test_rl_pure_test(30, c, m, 440,  40, file5, sizeof(file5));
        test_rl_pure_test(31, c, m, 460,  40, file5, sizeof(file5));
        test_rl_pure_test(32, c, m, 400, 100, file5, sizeof(file5));
        test_rl_pure_test(33, c, m, 160, 100, file6, sizeof(file6));
        test_rl_pure_test(34, c, m, 100, 140, file6, sizeof(file6));
}

/**
 * test_rl_zero - Runlist test: Merge a zero-length runlist
 *
 * Description...
 *
 * Returns:
 */
static void test_rl_zero(void)
{
        runlist_element *jim = NULL;
        runlist_element *bob = NULL;

        bob = calloc(3, sizeof(runlist_element));
        if (!bob)
                return;

        MKRL(bob+0, 10, 99, 5)
        MKRL(bob+1, 15, LCN_RL_NOT_MAPPED, 0)

        jim = test_rl_runlists_merge(jim, bob);
        if (!jim)
                return;

        free(jim);
}

/**
 * test_rl_frag_combine - Runlist test: Perform tests using fragmented files
 * @vol:
 * @attr1:
 * @attr2:
 * @attr3:
 *
 * Description...
 *
 * Returns:
 */
static void test_rl_frag_combine(ntfs_volume *vol, ATTR_RECORD *attr1, ATTR_RECORD *attr2, ATTR_RECORD *attr3)
{
        runlist_element *run1;
        runlist_element *run2;
        runlist_element *run3;

        run1 = ntfs_mapping_pairs_decompress(vol, attr1, NULL);
        if (!run1)
                return;

        run2 = ntfs_mapping_pairs_decompress(vol, attr2, NULL);
        if (!run2)
                return;

        run1 = test_rl_runlists_merge(run1, run2);

        run3 = ntfs_mapping_pairs_decompress(vol, attr3, NULL);
        if (!run3)
                return;

        run1 = test_rl_runlists_merge(run1, run3);

        free(run1);
}

/**
 * test_rl_frag - Runlist test: Create tests using very fragmented files
 * @test:
 *
 * Description...
 *
 * Returns:
 */
static void test_rl_frag(char *test)
{
        ntfs_volume vol;
        ATTR_RECORD *attr1 = ntfs_malloc(1024);
        ATTR_RECORD *attr2 = ntfs_malloc(1024);
        ATTR_RECORD *attr3 = ntfs_malloc(1024);

        if (!attr1 || !attr2 || !attr3)
                goto out;

        vol.sb = NULL;
        vol.sector_size_bits = 9;
        vol.cluster_size = 2048;
        vol.cluster_size_bits = 11;
        vol.major_ver = 3;

        if (!test_rl_read_buffer("runlist-data/attr1.bin", (u8*) attr1, 1024))
                goto out;
        if (!test_rl_read_buffer("runlist-data/attr2.bin", (u8*) attr2, 1024))
                goto out;
        if (!test_rl_read_buffer("runlist-data/attr3.bin", (u8*) attr3, 1024))
                goto out;

        if      (strcmp(test, "123") == 0)  test_rl_frag_combine(&vol, attr1, attr2, attr3);
        else if (strcmp(test, "132") == 0)  test_rl_frag_combine(&vol, attr1, attr3, attr2);
        else if (strcmp(test, "213") == 0)  test_rl_frag_combine(&vol, attr2, attr1, attr3);
        else if (strcmp(test, "231") == 0)  test_rl_frag_combine(&vol, attr2, attr3, attr1);
        else if (strcmp(test, "312") == 0)  test_rl_frag_combine(&vol, attr3, attr1, attr2);
        else if (strcmp(test, "321") == 0)  test_rl_frag_combine(&vol, attr3, attr2, attr1);
        else
                printf("Frag: No such test '%s'\n", test);

out:
        free(attr1);
        free(attr2);
        free(attr3);
}

/**
 * test_rl_main - Runlist test: Program start (main)
 * @argc:
 * @argv:
 *
 * Description...
 *
 * Returns:
 */
int test_rl_main(int argc, char *argv[])
{
        if      ((argc == 2) && (strcmp(argv[1], "zero") == 0)) test_rl_zero();
        else if ((argc == 3) && (strcmp(argv[1], "frag") == 0)) test_rl_frag(argv[2]);
        else if ((argc == 4) && (strcmp(argv[1], "pure") == 0)) test_rl_pure(argv[2], argv[3]);
        else
                printf("rl [zero|frag|pure] {args}\n");

        return 0;
}

#endif