}

  /** Helper to manually escape a 7-bit ascii character */
  private String escapeAscii(char c) {
    Preconditions.checkArgument(c < 128);
    String hex = "0123456789ABCDEF";
    return "%" + hex.charAt((c >> 4) & 0xf) + hex.charAt(c & 0xf);
  }

  }

  /** Helper to manually escape a 7-bit ascii character */
  private String escapeAscii(char c) {
    Preconditions.checkArgument(c < 128);
    String hex = "0123456789ABCDEF";
    return "%" + hex.charAt((c >> 4) & 0xf) + hex.charAt(c & 0xf);
  }

func isHexes(s string) bool {
	if s == "" {
		return false
	}
	if s == "empty" {
		return true
	}
	for _, f := range strings.Split(s, " or ") {
		if f == "" || len(f)%2 != 0 || strings.TrimLeft(f, "0123456789abcdef") != "" {
			return false
		}
	}
	return true
}

// It would be nice if the error messages always began with
// the standard file:line: prefix,
// but that's not where we are today.

   */
  public static BaseEncoding base32Hex() {
    return BASE32_HEX;
  }

  private static final BaseEncoding BASE16 = new Base16Encoding("base16()", "0123456789ABCDEF");

  /**
   * The "base16" encoding specified by <a href="http://tools.ietf.org/html/rfc4648#section-8">RFC
   * 4648 section 8</a>, Base 16 Encoding. (This is the same as the base 16 encoding from <a

				for i := 0; i < b.N; i++ {
					LastIndexAny(x[:k], cs[:j])
				}
			})
		}
	}
}

func BenchmarkTrimASCII(b *testing.B) {
	cs := "0123456789abcdef"
	for k := 1; k <= 4096; k <<= 4 {
		for j := 1; j <= 16; j <<= 1 {
			b.Run(fmt.Sprintf("%d:%d", k, j), func(b *testing.B) {
				x := Repeat([]byte(cs[:j]), k) // Always matches set

    }

    // Test getImageFilename with docMap
    @Test
    public void test_getImageFilename_withDocMap() {
        Map<String, Object> docMap = new HashMap<>();
        docMap.put("_id", "1234567890abcdef");

        String filename = thumbnailManager.getImageFilename(docMap);
        assertNotNull(filename);
        assertTrue(filename.endsWith(".png"));
        assertTrue(filename.contains("/"));
    }