// Function to create an optimized SVG url
// to use in an background-image through data:image/svg+xml

@function svg-url($svg) {
  /* Add missing namespace */
  @if not str-index($svg,xmlns) {
    $svg: str-replace($svg, '<svg', '<svg xmlns="http://www.w3.org/2000/svg"');
  }
  /*
   * Chunk up string in order to avoid
   * "stack level too deep" error
   */
  $encoded: '';
  $slice: 2000;
  $index: 0;
  $loops: ceil(str-length($svg)/$slice);
  @for $i from 1 through $loops {
    $chunk: str-slice($svg, $index, $index + $slice - 1);
    /* Encode */
    $chunk: str-replace($chunk, '"', '\'');
    $chunk: str-replace($chunk, '%', '%25');
    $chunk: str-replace($chunk, '#', '%23');
    $chunk: str-replace($chunk, '{', '%7B');
    $chunk: str-replace($chunk, '}', '%7D');
    $chunk: str-replace($chunk, '<', '%3C');
    $chunk: str-replace($chunk, '>', '%3E');
    /*
     * The maybe list
     *
     * Keep size and compile time down
     * ... only add on documented fail
     *
     * $chunk: str-replace($chunk, '&', '%26');
     * $chunk: str-replace($chunk, '|', '%7C');
     * $chunk: str-replace($chunk, '[', '%5B');
     * $chunk: str-replace($chunk, ']', '%5D');
     * $chunk: str-replace($chunk, '^', '%5E');
     * $chunk: str-replace($chunk, '`', '%60');
     * $chunk: str-replace($chunk, ';', '%3B');
     * $chunk: str-replace($chunk, '?', '%3F');
     * $chunk: str-replace($chunk, ':', '%3A');
     * $chunk: str-replace($chunk, '@', '%40');
     * $chunk: str-replace($chunk, '=', '%3D');
     */
    $encoded: #{$encoded}#{$chunk};
    $index: $index + $slice;
  }
  @return url("data:image/svg+xml,#{$encoded}");
}


// Helper function to replace characters in a string
@function str-replace($string, $search, $replace: '') {
  $index: str-index($string, $search);
  @return if($index,
    str-slice($string, 1, $index - 1) + $replace +
    str-replace(str-slice($string, $index +
    str-length($search)), $search, $replace),
    $string);
}