#define DIFF_WIDTH_MASK    0x00ff0000  /* side-by-side column width */
#define DIFF_IGNORE_EOLWS  0x01000000  /* Ignore end-of-line whitespace */
#define DIFF_SIDEBYSIDE    0x02000000  /* Generate a side-by-side diff */
#define DIFF_NEWFILE       0x04000000  /* Missing files are as empty files */
#define DIFF_INLINE        0x08000000  /* Inline (not side-by-side) diff */
#define DIFF_HTML          0x10000000  /* Render for HTML */
#define DIFF_LINENO        0x20000000  /* Show line numbers in context diff */
#define DIFF_NOOPT         0x40000000  /* Suppress optimizations for debug */
#define DIFF_INVERT        0x80000000  /* Invert the diff for debug */

#endif /* INTERFACE */

/*
** Maximum length of a line in a text file.  (8192)
*/
#define LENGTH_MASK_SZ  13

  /* an array of DLine elements services two purposes.  The fields
  ** above are one per line of input text.  But each entry is also
  ** a bucket in a hash table, as follows: */
  unsigned int iHash;   /* 1+(first entry in the hash chain) */
};

/*
** Length of a dline
*/
#define LENGTH(X)   ((X)->h & LENGTH_MASK)

/*
** A context for running a raw diff.
**
** The aEdit[] array describes the raw diff.  Each triple of integers in
** aEdit[] means:
**
**   (1) COPY:   Number of lines aFrom and aTo have in common

  expandEdit(p, p->nEdit+3);
  if( p->aEdit ){
    p->aEdit[p->nEdit++] = 0;
    p->aEdit[p->nEdit++] = 0;
    p->aEdit[p->nEdit++] = 0;
  }
}

/*
** Attempt to shift insertion or deletion blocks so that they begin and
** end on lines that are pure whitespace.  In other words, try to transform
** this:
**
**      int func1(int x){
**         return x*10;
**     +}
**     +
**     +int func2(int x){
**     +   return x*20;
**      }
**
**      int func3(int x){
**         return x/5;
**      }
**
** Into one of these:
**
**      int func1(int x){              int func1(int x){
**         return x*10;                   return x*10;
**      }                              }
**     +
**     +int func2(int x){             +int func2(int x){
**     +   return x*20;               +   return x*20;
**     +}                             +}
**                                    +
**      int func3(int x){              int func3(int x){
**         return x/5;                    return x/5;
**      }                              }
*/
static void diff_optimize(DContext *p){
  int r;       /* Index of current triple */
  int lnFrom;  /* Line number in p->aFrom */
  int lnTo;    /* Line number in p->aTo */
  int cpy, del, ins;

  lnFrom = lnTo = 0;
  for(r=0; r<p->nEdit; r += 3){
    cpy = p->aEdit[r];
    del = p->aEdit[r+1];
    ins = p->aEdit[r+2];
    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( same_dline(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( 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( same_dline(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( same_dline(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( 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( same_dline(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++;
    }

    lnFrom += del;
    lnTo += ins;
  }
}

/*
** Extract the number of lines of context from diffFlags.  Supply an
** appropriate default if no context width is specified.
*/
int diff_context_lines(int diffFlags){
  int n = diffFlags & DIFF_CONTEXT_MASK;

  Blob *pOut,      /* Write diff here if not NULL */
  int diffFlags    /* DIFF_* flags defined above */
){
  int ignoreEolWs; /* Ignore whitespace at the end of lines */
  int nContext;    /* Amount of context to display */	
  DContext c;

  if( diffFlags & DIFF_INVERT ){
    Blob *pTemp = pA_Blob;
    pA_Blob = pB_Blob;
    pB_Blob = pTemp;
  }
  nContext = diff_context_lines(diffFlags);
  ignoreEolWs = (diffFlags & DIFF_IGNORE_EOLWS)!=0;

  /* Prepare the input files */
  memset(&c, 0, sizeof(c));
  c.aFrom = break_into_lines(blob_str(pA_Blob), blob_size(pA_Blob),
                             &c.nFrom, ignoreEolWs);
  c.aTo = break_into_lines(blob_str(pB_Blob), blob_size(pB_Blob),
                           &c.nTo, ignoreEolWs);
  if( c.aFrom==0 || c.aTo==0 ){
    free(c.aFrom);
    free(c.aTo);
    if( pOut ){
      blob_appendf(pOut, "cannot compute difference between binary files\n");
    }
    return 0;
  }

  /* Compute the difference */
  diff_all(&c);
  if( (diffFlags & DIFF_NOOPT)==0 ) diff_optimize(&c);

  if( pOut ){
    /* Compute a context or side-by-side diff into pOut */
    int escHtml = (diffFlags & DIFF_HTML)!=0;
    if( diffFlags & DIFF_SIDEBYSIDE ){
      int width = diff_width(diffFlags);
      sbsDiff(&c, pOut, nContext, width, escHtml);

    */
    free(c.aFrom);
    free(c.aTo);
    return c.aEdit;
  }
}























/*
** Process diff-related command-line options and return an appropriate
** "diffFlags" integer.  
**
**   --side-by-side|-y      Side-by-side diff.     DIFF_SIDEBYSIDE
**   --context|-c N         N lines of context.    DIFF_CONTEXT_MASK
**   --width|-W N           N character lines.     DIFF_WIDTH_MASK

  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;
  return diffFlags;
}

/*
** COMMAND: test-rawdiff
*/
void test_rawdiff_cmd(void){
  Blob a, b;
  int r;
  int i;
  int *R;
  int diffFlags = diff_options();
  if( g.argc<4 ) usage("FILE1 FILE2 ...");
  blob_read_from_file(&a, g.argv[2]);
  for(i=3; i<g.argc; i++){
    if( i>3 ) fossil_print("-------------------------------\n");
    blob_read_from_file(&b, g.argv[i]);
    R = text_diff(&a, &b, 0, diffFlags);
    for(r=0; R[r] || R[r+1] || R[r+2]; r += 3){
      fossil_print(" copy %4d  delete %4d  insert %4d\n", R[r], R[r+1], R[r+2]);
    }
    /* free(R); */
    blob_reset(&b);
  }
}

/*
** COMMAND: test-udiff
**
** Print the difference between two files.  The usual diff options apply.
*/
void test_udiff_cmd(void){

      diffFlags = DIFF_INLINE | DIFF_IGNORE_EOLWS;
    }

    /* "dc" query parameter determines lines of context */
    x = atoi(PD("dc","7"));
    if( x<0 || x>DIFF_CONTEXT_MASK ) x = DIFF_CONTEXT_MASK;
    diffFlags += x;

    /* The "noopt" parameter disables diff optimization */
    if( PD("noopt",0)!=0 ) diffFlags |= DIFF_NOOPT;
  }
  return diffFlags;
}


/*
** WEBPAGE: vinfo