int *aEdit;        /* Array of copy/delete/insert triples */
  int nEdit;         /* Number of integers (3x num of triples) in aEdit[] */
  int nEditAlloc;    /* Space allocated for aEdit[] */
  DLine *aFrom;      /* File on left side of the diff */
  int nFrom;         /* Number of lines in aFrom[] */
  DLine *aTo;        /* File on right side of the diff */
  int nTo;           /* Number of lines in aTo[] */
  int (*same_fn)(const DLine *, const DLine *); /* Function to be used for comparing */
};

/*
** Return an array of DLine objects containing a pointer to the
** start of each line and a hash of that line.  The lower
** bits of the hash store the length of each line.
**

    }
    a[i].n = k;
    s = 0;
    if( diffFlags & DIFF_IGNORE_EOLWS ){
      while( k>0 && fossil_isspace(z[k-1]) ){ k--; }
    }
    if( (diffFlags & DIFF_IGNORE_ALLWS)==DIFF_IGNORE_ALLWS ){
      int numws = 0;
      while( s<k && fossil_isspace(z[s]) ){ s++; }
      for(h=0, x=s; x<k; x++){
        if( fossil_isspace(z[x]) ){
          ++numws;
        }else{
          h = h ^ (h<<2) ^ z[x];
        }
      }
      k -= numws;
    }else{
      for(h=0, x=s; x<k; x++){
        h = h ^ (h<<2) ^ z[x];
      }
    }
    a[i].indent = s;
    a[i].h = h = (h<<LENGTH_MASK_SZ) | (k-s);
    h2 = h % nLine;
    a[i].iNext = a[h2].iHash;
    a[h2].iHash = i+1;
    z += j+1;
  }

  /* Return results */
  *pnLine = nLine;
  return a;
}

/*
** Return true if two DLine elements are identical.
*/
static int same_dline(const DLine *pA, const DLine *pB){
  return pA->h==pB->h && memcmp(pA->z,pB->z, pA->h&LENGTH_MASK)==0;
}

/*
** Return true if two DLine elements are identical, ignoring
** all whitespace. The indent field of pA/pB already points
** to the first non-space character in the string.
*/

static int same_dline_ignore_allws(const DLine *pA, const DLine *pB){
  int a = pA->indent, b = pB->indent;
  if( pA->h==pB->h ){
    while( a<pA->n && b<pB->n ){
      if( pA->z[a++] != pB->z[b++] ) return 0;
      while( a<pA->n && fossil_isspace(pA->z[a])) ++a;
      while( b<pB->n && fossil_isspace(pB->z[b])) ++b;
    }
    return pA->n-a == b<pB->n-b;
  }
  return 0;
}

/*
** Return true if the regular expression *pRe matches any of the
** N dlines
*/
static int re_dline_match(

  int i, j;                  /* Loop counters */
  int k;                     /* Length of a candidate subsequence */
  int iSXb = iS1;            /* Best match so far */
  int iSYb = iS2;            /* Best match so far */

  for(i=iS1; i<iE1-mxLength; i++){
    for(j=iS2; j<iE2-mxLength; j++){
      if( !p->same_fn(&p->aFrom[i], &p->aTo[j]) ) continue;
      if( mxLength && !p->same_fn(&p->aFrom[i+mxLength], &p->aTo[j+mxLength]) ){
        continue;
      }
      k = 1;
      while( i+k<iE1 && j+k<iE2 && p->same_fn(&p->aFrom[i+k],&p->aTo[j+k]) ){
        k++;
      }
      if( k>mxLength ){
        iSXb = i;
        iSYb = j;
        mxLength = k;
      }

  iSYb = iSYp = iS2;
  iEYb = iEYp = iS2;
  mid = (iE1 + iS1)/2;
  for(i=iS1; i<iE1; i++){
    int limit = 0;
    j = p->aTo[p->aFrom[i].h % p->nTo].iHash;
    while( j>0
      && (j-1<iS2 || j>=iE2 || !p->same_fn(&p->aFrom[i], &p->aTo[j-1]))
    ){
      if( limit++ > 10 ){
        j = 0;
        break;
      }
      j = p->aTo[j-1].iNext;
    }
    if( j==0 ) continue;
    assert( i>=iSXb && i>=iSXp );
    if( i<iEXb && j>=iSYb && j<iEYb ) continue;
    if( i<iEXp && j>=iSYp && j<iEYp ) continue;
    iSX = i;
    iSY = j-1;
    pA = &p->aFrom[iSX-1];
    pB = &p->aTo[iSY-1];
    n = minInt(iSX-iS1, iSY-iS2);
    for(k=0; k<n && p->same_fn(pA,pB); k++, pA--, pB--){}
    iSX -= k;
    iSY -= k;
    iEX = i+1;
    iEY = j;
    pA = &p->aFrom[iEX];
    pB = &p->aTo[iEY];
    n = minInt(iE1-iEX, iE2-iEY);
    for(k=0; k<n && p->same_fn(pA,pB); k++, pA++, pB++){}
    iEX += k;
    iEY += k;
    skew = (iSX-iS1) - (iSY-iS2);
    if( skew<0 ) skew = -skew;
    dist = (iSX+iEX)/2 - mid;
    if( dist<0 ) dist = -dist;
    score = (iEX - iSX)*(sqlite3_int64)span - (skew + dist);

*/
static void diff_all(DContext *p){
  int mnE, iS, iE1, iE2;

  /* Carve off the common header and footer */
  iE1 = p->nFrom;
  iE2 = p->nTo;
  while( iE1>0 && iE2>0 && p->same_fn(&p->aFrom[iE1-1], &p->aTo[iE2-1]) ){
    iE1--;
    iE2--;
  }
  mnE = iE1<iE2 ? iE1 : iE2;
  for(iS=0; iS<mnE && p->same_fn(&p->aFrom[iS],&p->aTo[iS]); iS++){}

  /* do the difference */
  if( iS>0 ){
    appendTriple(p, iS, 0, 0);
  }
  diff_step(p, iS, iE1, iS, iE2);
  if( iE1<p->nFrom ){

    lnFrom += cpy;
    lnTo += cpy;

    /* Shift insertions toward the beginning of the file */
    while( cpy>0 && del==0 && ins>0 ){
      DLine *pTop = &p->aFrom[lnFrom-1];  /* Line before start of insert */
      DLine *pBtm = &p->aTo[lnTo+ins-1];  /* Last line inserted */
      if( p->same_fn(pTop, pBtm)==0 ) break;
      if( LENGTH(pTop+1)+LENGTH(pBtm)<=LENGTH(pTop)+LENGTH(pBtm-1) ) break;
      lnFrom--;
      lnTo--;
      p->aEdit[r]--;
      p->aEdit[r+3]++;
      cpy--;
    }

    /* Shift insertions toward the end of the file */
    while( r+3<p->nEdit && p->aEdit[r+3]>0 && del==0 && ins>0 ){
      DLine *pTop = &p->aTo[lnTo];       /* First line inserted */
      DLine *pBtm = &p->aTo[lnTo+ins];   /* First line past end of insert */
      if( p->same_fn(pTop, pBtm)==0 ) break;
      if( LENGTH(pTop)+LENGTH(pBtm-1)<=LENGTH(pTop+1)+LENGTH(pBtm) ) break;
      lnFrom++;
      lnTo++;
      p->aEdit[r]++;
      p->aEdit[r+3]--;
      cpy++;
    }

    /* Shift deletions toward the beginning of the file */
    while( cpy>0 && del>0 && ins==0 ){
      DLine *pTop = &p->aFrom[lnFrom-1];     /* Line before start of delete */
      DLine *pBtm = &p->aFrom[lnFrom+del-1]; /* Last line deleted */
      if( p->same_fn(pTop, pBtm)==0 ) break;
      if( LENGTH(pTop+1)+LENGTH(pBtm)<=LENGTH(pTop)+LENGTH(pBtm-1) ) break;
      lnFrom--;
      lnTo--;
      p->aEdit[r]--;
      p->aEdit[r+3]++;
      cpy--;
    }

    /* Shift deletions toward the end of the file */
    while( r+3<p->nEdit && p->aEdit[r+3]>0 && del>0 && ins==0 ){
      DLine *pTop = &p->aFrom[lnFrom];     /* First line deleted */
      DLine *pBtm = &p->aFrom[lnFrom+del]; /* First line past end of delete */
      if( p->same_fn(pTop, pBtm)==0 ) break;
      if( LENGTH(pTop)+LENGTH(pBtm-1)<=LENGTH(pTop)+LENGTH(pBtm) ) break;
      lnFrom++;
      lnTo++;
      p->aEdit[r]++;
      p->aEdit[r+3]--;
      cpy++;
    }

  }
  ignoreWs = (diffFlags & DIFF_IGNORE_ALLWS)!=0;
  blob_to_utf8_no_bom(pA_Blob, 0);
  blob_to_utf8_no_bom(pB_Blob, 0);

  /* Prepare the input files */
  memset(&c, 0, sizeof(c));
  if( (diffFlags & DIFF_IGNORE_ALLWS)==DIFF_IGNORE_ALLWS ){
    c.same_fn = same_dline_ignore_allws;
  }else{
    c.same_fn = same_dline;
  }
  c.aFrom = break_into_lines(blob_str(pA_Blob), blob_size(pA_Blob),
                             &c.nFrom, diffFlags);
  c.aTo = break_into_lines(blob_str(pB_Blob), blob_size(pB_Blob),
                           &c.nTo, diffFlags);
  if( c.aFrom==0 || c.aTo==0 ){
    fossil_free(c.aFrom);
    fossil_free(c.aTo);

**
**   --brief                    Show filenames only    DIFF_BRIEF
**   -c|--context N             N lines of context.    DIFF_CONTEXT_MASK
**   --html                     Format for HTML        DIFF_HTML
**   --invert                   Invert the diff        DIFF_INVERT
**   -n|--linenum               Show line numbers      DIFF_LINENO
**   --noopt                    Disable optimization   DIFF_NOOPT
**   --strip-trailing-cr        Strip trailing CR      DIFF_STRIP_EOLCR
**   --unified                  Unified diff.          ~DIFF_SIDEBYSIDE
**   -w|--ignore-all-space      Ignore all whitespaces DIFF_IGNORE_ALLWS
**   -W|--width N               N character lines.     DIFF_WIDTH_MASK
**   -y|--side-by-side          Side-by-side diff.     DIFF_SIDEBYSIDE
**   -Z|--ignore-trailing-space Ignore eol-whitespaces DIFF_IGNORE_EOLWS
*/
u64 diff_options(void){
  u64 diffFlags = 0;
  const char *z;
  int f;
  if( find_option("ignore-trailing-space","Z",0)!=0 ){
    diffFlags = DIFF_IGNORE_EOLWS;
  }
  if( find_option("ignore-all-space","w",0)!=0 ){
    diffFlags = DIFF_IGNORE_ALLWS; /* stronger than DIFF_IGNORE_EOLWS */
  }
  if( find_option("strip-trailing-cr",0,0)!=0 ){
    diffFlags |= DIFF_STRIP_EOLCR;
  }
  if( find_option("side-by-side","y",0)!=0 ) diffFlags |= DIFF_SIDEBYSIDE;
  if( find_option("unified",0,0)!=0 ) diffFlags &= ~DIFF_SIDEBYSIDE;
  if( (z = find_option("context","c",1))!=0 && (f = atoi(z))>=0 ){
    if( f > DIFF_CONTEXT_MASK ) f = DIFF_CONTEXT_MASK;
    diffFlags |= f + DIFF_CONTEXT_EX;
  }
  if( (z = find_option("width","W",1))!=0 && (f = atoi(z))>0 ){
    f *= DIFF_CONTEXT_MASK+1;
    if( f > DIFF_WIDTH_MASK ) f = DIFF_CONTEXT_MASK;
    diffFlags |= f;
  }
  if( find_option("html",0,0)!=0 ) diffFlags |= DIFF_HTML;


  if( find_option("linenum","n",0)!=0 ) diffFlags |= DIFF_LINENO;
  if( find_option("noopt",0,0)!=0 ) diffFlags |= DIFF_NOOPT;
  if( find_option("invert",0,0)!=0 ) diffFlags |= DIFF_INVERT;
  if( find_option("brief",0,0)!=0 ) diffFlags |= DIFF_BRIEF;
  return diffFlags;
}

** to be annotated.  The annotator takes control of the input Blob and
** will release it when it is finished with it.
*/
static int annotation_start(Annotator *p, Blob *pInput, u64 diffFlags){
  int i;

  memset(p, 0, sizeof(*p));
  if( (diffFlags & DIFF_IGNORE_ALLWS)==DIFF_IGNORE_ALLWS ){
    p->c.same_fn = same_dline_ignore_allws;
  }else{
    p->c.same_fn = same_dline;
  }
  p->c.aTo = break_into_lines(blob_str(pInput), blob_size(pInput),&p->c.nTo,
                              diffFlags);
  if( p->c.aTo==0 ){
    return 1;
  }
  p->aOrig = fossil_malloc( sizeof(p->aOrig[0])*p->c.nTo );
  for(i=0; i<p->c.nTo; i++){

** and omits the username.  The "blame" and "praise" commands show the user
** who made each checkin and omits the line number.
**
** Options:
**   --filevers                 Show file version numbers rather than check-in versions
**   -l|--log                   List all versions analyzed
**   -n|--limit N               Only look backwards in time by N versions
**   -w|--ignore-all-space      Ignore white space when comparing lines
**   -Z|--ignore-trailing-space Ignore whitespace at line end

**
** See also: info, finfo, timeline
*/
void annotate_cmd(void){
  int fnid;         /* Filename ID */
  int fid;          /* File instance ID */
  int mid;          /* Manifest where file was checked in */

  int bBlame = 0;   /* True for BLAME output.  False for ANNOTATE. */

  bBlame = g.argv[1][0]!='a';
  zLimit = find_option("limit","n",1);
  if( zLimit==0 || zLimit[0]==0 ) zLimit = "-1";
  iLimit = atoi(zLimit);
  showLog = find_option("log","l",0)!=0;
  if( find_option("ignore-trailing-space","Z",0)!=0 ){
    annFlags = DIFF_IGNORE_EOLWS;
  }
  if( find_option("ignore-all-space","w",0)!=0 ){
    annFlags = DIFF_IGNORE_ALLWS; /* stronger than DIFF_IGNORE_EOLWS */
  }
  fileVers = find_option("filevers",0,0)!=0;
  db_must_be_within_tree();
  if( g.argc<3 ) {
    usage("FILENAME");
  }
  file_tree_name(g.argv[2], &treename, 1);
  zFilename = blob_str(&treename);

**   --branch BRANCH            Show diff of all changes on BRANCH
**   --brief                    Show filenames only
**   --context|-c N             Use N lines of context
**   --diff-binary BOOL         Include binary files when using external commands
**   --from|-r VERSION          select VERSION as source for the diff
**   --internal|-i              use internal diff logic
**   --side-by-side|-y          side-by-side diff
**   --strip-trailing-cr        Strip trailing CR
**   --tk                       Launch a Tcl/Tk GUI for display
**   --to VERSION               select VERSION as target for the diff
**   --unified                  unified diff
**   -v|--verbose               output complete text of added or deleted files
**   -w|--ignore-all-space      Ignore white space when comparing lines

**   -W|--width <num>           Width of lines in side-by-side diff
**   -Z|--ignore-trailing-space Ignore changes to end-of-line whitespace
*/
void diff_cmd(void){
  int isGDiff;               /* True for gdiff.  False for normal diff */
  int isInternDiff;          /* True for internal diff */
  int verboseFlag;           /* True if -v or --verbose flag is used */
  const char *zFrom;         /* Source version number */

  *  The [/help/info | info command] now shows leaf status of the checkout.
  *  Add support for tunneling https through a http proxy (Ticket [e854101c4f]).
  *  Add option --empty to the "[/help?cmd=open | fossil open]" command.
  *  Enhanced [/help?cmd=/fileage|the fileage page] to support a glob parameter.
  *  Add -w|--ignore-all-space and -Z|--ignore-trailing-space options to
     [/help?cmd=annotate|fossil annotate], [/help?cmd=blame|fossil blame],
     [/help?cmd=diff|fossil (g)diff], [/help?cmd=stash|fossil stash diff].
  *  Add --strip-trailing-cr option to [/help?cmd=diff|fossil (g)diff] and
     [/help?cmd=stash|fossil stash diff].
  *  Add button "Ignore Whitespace" to /annotate, /blame, /ci, /fdiff
     and /vdiff UI pages.

<h2>Changes For Version 1.28 (2014-01-27)</h2>
  *  Enhance [/help?cmd=/reports | /reports] to support event type filtering.
  *  When cloning a repository, the user name passed via the URL (if any)
     is now used as the default local admin user's name.