/*
** Return true if the filename given is a valid filename for
** a file in a repository.  Valid filenames follow all of the
** following rules:
**
**     *  Does not begin with "/"
**     *  Does not contain any path element named "." or ".."
**     *  Does not contain any of these characters in the path: "\"
**     *  Does not end with "/".
**     *  Does not contain two or more "/" characters in a row.
**     *  Contains at least one character
**
** Invalid UTF8 characters result in a false return if bStrictUtf8 is
** true.  If bStrictUtf8 is false, invalid UTF8 characters are silently
** ignored. See http://en.wikipedia.org/wiki/UTF-8#Invalid_byte_sequences
** and http://en.wikipedia.org/wiki/Unicode (for the noncharacters)
**
** The bStrictUtf8 flag is true for new inputs, but is false when parsing
** legacy manifests, for backwards compatibility.
*/
int file_is_simple_pathname(const char *z, int bStrictUtf8){
  int i;
  unsigned char c = (unsigned char) z[0];
  char maskNonAscii = bStrictUtf8 ? 0x80 : 0x00;
  if( c=='/' || c==0 ) return 0;
  if( c=='.' ){
    if( z[1]=='/' || z[1]==0 ) return 0;
    if( z[1]=='.' && (z[2]=='/' || z[2]==0) ) return 0;
  }
  for(i=0; (c=(unsigned char)z[i])!=0; i++){

    if( c & maskNonAscii ){
      if( (z[++i]&0xc0)!=0x80 ){
        /* Invalid first continuation byte */
        return 0;
      }
      if( c<0xc2 ){
        /* Invalid 1-byte UTF-8 sequence, or 2-byte overlong form. */
        return 0;
      }else if( (c&0xe0)==0xe0 ){
        /* 3-byte or more */
        int unicode;
        if( c&0x10 ){
          /* Unicode characters > U+FFFF are not supported.
           * Windows XP and earlier cannot handle them.
           */
          return 0;
        }

        /* This is a 3-byte UTF-8 character */
        unicode = ((c&0x0f)<<12) + ((z[i]&0x3f)<<6) + (z[i+1]&0x3f);
        if( unicode <= 0x07ff ){
          /* overlong form */
          return 0;
        }else if( unicode>=0xe000 ){
          /* U+E000..U+FFFF */
          if( (unicode<=0xf8ff) || (unicode>=0xfffe) ){
            /* U+E000..U+F8FF are for private use.

             * U+FFFE..U+FFFF are noncharacters. */
            return 0;
          } else if( (unicode>=0xfdd0) && (unicode<=0xfdef) ){
            /* U+FDD0..U+FDEF are noncharacters. */
            return 0;
          }
        }else if( (unicode>=0xd800) && (unicode<=0xdfff) ){

          /* U+D800..U+DFFF are for surrogate pairs. */
          return 0;
        }
        if( (z[++i]&0xc0)!=0x80 ){
          /* Invalid second continuation byte */
          return 0;
        }
      }
    }else if( bStrictUtf8 && (c=='\\') ){
      return 0;

    }
    if( c=='/' ){
      if( z[i+1]=='/' ) return 0;
      if( z[i+1]=='.' ){
        if( z[i+2]=='/' || z[i+2]==0 ) return 0;
        if( z[i+2]=='.' && (z[i+3]=='/' || z[i+3]==0) ) return 0;
      }

#if defined(_WIN32)
  for(i=0; i<n; i++){
    if( z[i]=='\\' ) z[i] = '/';
  }
#endif

  /* Removing trailing "/" characters */
  if( !slash ){
    while( n>1 && z[n-1]=='/' ){ n--; }
  }

  /* Remove duplicate '/' characters.  Except, two // at the beginning
  ** of a pathname is allowed since this is important on windows. */
  for(i=j=1; i<n; i++){
    z[j++] = z[i];

    if( zPath[i]==0 ){
      blob_reset(pOut);
      if( zPwd[i]==0 ){
        blob_append(pOut, ".", 1);
      }else{
        blob_append(pOut, "..", 2);
        for(j=i+1; zPwd[j]; j++){
          if( zPwd[j]=='/' ){
            blob_append(pOut, "/..", 3);
          }
        }
      }
      return;
    }
    if( zPwd[i]==0 && zPath[i]=='/' ){
      memcpy(&tmp, pOut, sizeof(tmp));
      blob_set(pOut, "./");
      blob_append(pOut, &zPath[i+1], -1);
      blob_reset(&tmp);
      return;
    }
    while( zPath[i-1]!='/' ){ i--; }
    blob_set(&tmp, "../");
    for(j=i; zPwd[j]; j++){
      if( zPwd[j]=='/' ){
        blob_append(&tmp, "../", 3);
      }
    }
    blob_append(&tmp, &zPath[i], -1);
    blob_reset(pOut);
    memcpy(pOut, &tmp, sizeof(tmp));
  }