*/
void canonical16(char *z, int n){
  while( *z && n-- ){
    *z = zEncode[zDecode[(*z)&0x7f]&0x1f];
    z++;
  }
}

/*
** Decode hexadecimal into a string and return the new string.  Space to
** hold the string is obtained from fossil_malloc() and should be released
** by the caller.
**
** If the input is not hex, return NULL.
*/
char *decode16_dup(const char *zIn){
  int nIn = (int)strlen(zIn);
  char *zOut;
  if( !validate16(zIn, nIn) ) return 0;
  zOut = fossil_malloc(nIn/2+1);
  decode16((const u8*)zIn, (u8*)zOut, nIn);
  zOut[nIn/2] = 0;
  return zOut;
}


/*
** Decode a string encoded using "quoted-printable".
**
**   (1)  "=" followed by two hex digits becomes a single
**        byte specified by the two digits
**

      ){
        @ <div class='file-change-line'><span>
        @ Changes to %h(zFile)
        @ </span></div>
        if( pCfg ){
          char *zFullFN;
          char *zHexFN;

          zFullFN = file_canonical_name_dup(zLhs);

          zHexFN = mprintf("x%H", zFullFN);



          fossil_free(zFullFN);
          pCfg->zLeftHash = zHexFN;
          text_diff(&lhs, &rhs, cgi_output_blob(), pCfg);
          pCfg->zLeftHash = 0;
          fossil_free(zHexFN);
        }
      }

** if the web server is run on a loopback interface (in other words, was
** started using "fossil ui" or similar) from within an open check-out.
**
** If the "exbase=PATH" query parameter is provided, then the diff shown
** uses the files in PATH as the baseline.  This is the same as using
** the "--from PATH" argument to the "fossil diff" command-line.  In fact,
** when using "fossil ui --from PATH", the --from argument becomes the value
** of the exbase query parameter for the start page.  Note that if PATH
** is a pure hexadecimal string, it is decoded first before being used as
** the pathname.  Real pathnames should contain at least one directory
** separator character.
**
** Other query parameters related to diffs are also accepted.
*/
void ckout_page(void){
  int vid;
  const char *zHome;          /* Home directory */
  int nHome;

  }else{
    style_header("Checkout Status: %h", zCwd);
  }
  render_checkin_context(vid, 0, 0, 0);
  @ <hr>
  zExBase = P("exbase");
  if( zExBase && zExBase[0] ){
    char *zPath = decode16_dup(zExBase);
    char *zCBase = file_canonical_name_dup(zPath?zPath:zExBase);
    if( nHome && strncmp(zCBase, zHome, nHome)==0 && zCBase[nHome]=='/' ){
      @ <p>Using external baseline: ~%h(zCBase+nHome)</p>
    }else{
      @ <p>Using external baseline: %h(zCBase)</p>
    }
    ckout_external_base_diff(vid, zCBase);
    fossil_free(zCBase);
    fossil_free(zPath);
  }else{
    ckout_normal_diff(vid);
  }
  style_finish_page();
}

/*

      fossil_fatal("the argument to --from must be a pathname for"
                   " the \"ui\" command");
    }
    zInitPage = find_option("page", "p", 1);
    if( zInitPage && zInitPage[0]=='/' ) zInitPage++;
    zFossilCmd = find_option("fossilcmd", 0, 1);
    if( zFrom && zInitPage==0 ){
      zInitPage = mprintf("ckout?exbase=%H", zFrom);
    }
  }
  zNotFound = find_option("notfound", 0, 1);
  allowRepoList = find_option("repolist",0,0)!=0;
  if( find_option("nocompress",0,0)!=0 ) g.fNoHttpCompress = 1;
  zAltBase = find_option("baseurl", 0, 1);
  fCreate = find_option("create",0,0)!=0;

#define etROOT       24 /* String value of g.zTop: %R */
#define etJSONSTR    25 /* String encoded as a JSON string literal: %j
                           Use %!j to include double-quotes around it. */
#define etSHELLESC   26 /* Escape a filename for use in a shell command: %$
                           See blob_append_escaped_arg() for details
                           "%$"  -> adds "./" prefix if necessary.
                           "%!$" -> omits the "./" prefix. */
#define etHEX        27 /* Encode a string as hexadecimal */


/*
** An "etByte" is an 8-bit unsigned value.
*/
typedef unsigned char etByte;

** most frequently used conversion types first.
**
** NB: When modifying this table is it vital that you also update the fmtchr[]
** variable to match!!!
*/
static const char aDigits[] = "0123456789ABCDEF0123456789abcdef";
static const char aPrefix[] = "-x0\000X0";
static const char fmtchr[] = "dsgzqQbBWhRtTwFSjcouxXfeEGin%p/$H";
static const et_info fmtinfo[] = {
  {  'd', 10, 1, etRADIX,      0,  0 },
  {  's',  0, 4, etSTRING,     0,  0 },
  {  'g',  0, 1, etGENERIC,    30, 0 },
  {  'z',  0, 6, etDYNSTRING,  0,  0 },
  {  'q',  0, 4, etSQLESCAPE,  0,  0 },
  {  'Q',  0, 4, etSQLESCAPE2, 0,  0 },

  {  'G',  0, 1, etGENERIC,    14, 0 },
  {  'i', 10, 1, etRADIX,      0,  0 },
  {  'n',  0, 0, etSIZE,       0,  0 },
  {  '%',  0, 0, etPERCENT,    0,  0 },
  {  'p', 16, 0, etPOINTER,    0,  1 },
  {  '/',  0, 0, etPATH,       0,  0 },
  {  '$',  0, 0, etSHELLESC,   0,  0 },
  {  'H',  0, 0, etHEX,        0,  0 },
  {  etERROR, 0,0,0,0,0}  /* Must be last */
};
#define etNINFO count(fmtinfo)

/*
** Verify that the fmtchr[] and fmtinfo[] arrays are in agreement.
**

        break;
      }
      case etSHELLESC: {
        char *zArg = va_arg(ap, char*);
        blob_append_escaped_arg(pBlob, zArg, !flag_altform2);
        length = width = 0;
        break;
      }
      case etHEX: {
        char *zArg = va_arg(ap, char*);
        int szArg = (int)strlen(zArg);
        int szBlob = blob_size(pBlob);
        u8 *aBuf = (u8*)&blob_buffer(pBlob)[szBlob];
        blob_resize(pBlob, szBlob+szArg*2+1);
        encode16((const u8*)zArg, aBuf, szArg);
        length = width = 0;
        break;
      }
      case etERROR:
        buf[0] = '%';
        buf[1] = c;
        errorflag = 0;
        idx = 1+(c!=0);
        blob_append(pBlob,"%",idx);