diff --git a/Source/CFCalendar.c b/Source/CFCalendar.c
index 3c44716..3c7507c 100644
--- a/Source/CFCalendar.c
+++ b/Source/CFCalendar.c
@@ -795,18 +795,79 @@ CFCalendarGetTimeRangeOfUnit (CFCalendarRef cal, CFCalendarUnit unit,
   return true;
 }
 
+/* The ICU field that represents smallerUnit measured within biggerUnit. */
+static UCalendarDateFields
+CFCalendarCompoundField (CFCalendarUnit smaller, CFCalendarUnit bigger)
+{
+  switch (smaller)
+    {
+      case kCFCalendarUnitDay:
+      case kCFCalendarUnitWeekday:
+        if (bigger == kCFCalendarUnitYear)
+          return UCAL_DAY_OF_YEAR;
+        if (bigger == kCFCalendarUnitWeek)
+          return UCAL_DAY_OF_WEEK;
+        return UCAL_DATE;
+      case kCFCalendarUnitMonth:
+        return UCAL_MONTH;
+      case kCFCalendarUnitWeek:
+        if (bigger == kCFCalendarUnitMonth)
+          return UCAL_WEEK_OF_MONTH;
+        return UCAL_WEEK_OF_YEAR;
+      case kCFCalendarUnitHour:
+        return UCAL_HOUR_OF_DAY;
+      case kCFCalendarUnitMinute:
+        return UCAL_MINUTE;
+      case kCFCalendarUnitSecond:
+        return UCAL_SECOND;
+      default:
+        return (UCalendarDateFields) -1;
+    }
+}
+
 CFRange
 CFCalendarGetRangeOfUnit (CFCalendarRef cal, CFCalendarUnit smallerUnit,
   CFCalendarUnit biggerUnit, CFAbsoluteTime at)
 {
-  return CFRangeMake (kCFNotFound, kCFNotFound);
+  UCalendarDateFields field;
+  UErrorCode err = U_ZERO_ERROR;
+  int32_t min, max;
+
+  field = CFCalendarCompoundField (smallerUnit, biggerUnit);
+  if (field == (UCalendarDateFields) -1)
+    return CFRangeMake (kCFNotFound, kCFNotFound);
+
+  CFCalendarOpenUCalendar (cal);
+  ucal_setMillis (cal->_ucal, ABSOLUTETIME_TO_UDATE (at), &err);
+  min = ucal_getLimit (cal->_ucal, field, UCAL_ACTUAL_MINIMUM, &err);
+  max = ucal_getLimit (cal->_ucal, field, UCAL_ACTUAL_MAXIMUM, &err);
+  if (U_FAILURE (err))
+    return CFRangeMake (kCFNotFound, kCFNotFound);
+
+  /* ICU numbers months from zero. */
+  return CFRangeMake (field == UCAL_MONTH ? min + 1 : min, max - min + 1);
 }
 
 CFIndex
 CFCalendarGetOrdinalityOfUnit (CFCalendarRef cal, CFCalendarUnit smallerUnit,
   CFCalendarUnit biggerUnit, CFAbsoluteTime at)
 {
-  return kCFNotFound;
+  UCalendarDateFields field;
+  UErrorCode err = U_ZERO_ERROR;
+  int32_t value;
+
+  field = CFCalendarCompoundField (smallerUnit, biggerUnit);
+  if (field == (UCalendarDateFields) -1)
+    return kCFNotFound;
+
+  CFCalendarOpenUCalendar (cal);
+  ucal_setMillis (cal->_ucal, ABSOLUTETIME_TO_UDATE (at), &err);
+  value = ucal_get (cal->_ucal, field, &err);
+  if (U_FAILURE (err))
+    return kCFNotFound;
+
+  /* ICU numbers months from zero. */
+  return field == UCAL_MONTH ? value + 1 : value;
 }
 
 static CFRange
diff --git a/Tests/CFCalendar/ordinality.m b/Tests/CFCalendar/ordinality.m
new file mode 100644
index 0000000..1e2ca5a
--- /dev/null
+++ b/Tests/CFCalendar/ordinality.m
@@ -0,0 +1,41 @@
+#include "CoreFoundation/CFCalendar.h"
+#include "CoreFoundation/CFTimeZone.h"
+#include "../CFTesting.h"
+
+/* CFCalendarGetOrdinalityOfUnit and CFCalendarGetRangeOfUnit.  Times are
+   built directly as offsets from the reference date. */
+
+int main (void)
+{
+  double day = 86400.0;
+  CFTimeZoneRef gmt = CFTimeZoneCreateWithTimeIntervalFromGMT (NULL, 0.0);
+  CFCalendarRef cal = CFCalendarCreateWithIdentifier (NULL,
+    kCFGregorianCalendar);
+  CFRange r;
+
+  CFCalendarSetTimeZone (cal, gmt);
+
+  r = CFCalendarGetRangeOfUnit (cal, kCFCalendarUnitDay, kCFCalendarUnitMonth,
+    45 * day);                   /* 2001-02-15 */
+  PASS_CF (r.location == 1 && r.length == 28,
+    "The days of February 2001 range from 1 to 28.");
+
+  r = CFCalendarGetRangeOfUnit (cal, kCFCalendarUnitDay, kCFCalendarUnitMonth,
+    63 * day);                   /* 2001-03-05 */
+  PASS_CF (r.location == 1 && r.length == 31,
+    "The days of March 2001 range from 1 to 31.");
+
+  PASS_CF (CFCalendarGetOrdinalityOfUnit (cal, kCFCalendarUnitDay,
+    kCFCalendarUnitMonth, 45 * day) == 15,
+    "2001-02-15 is the 15th day of the month.");
+  PASS_CF (CFCalendarGetOrdinalityOfUnit (cal, kCFCalendarUnitDay,
+    kCFCalendarUnitYear, 45 * day) == 46,
+    "2001-02-15 is the 46th day of the year.");
+  PASS_CF (CFCalendarGetOrdinalityOfUnit (cal, kCFCalendarUnitMonth,
+    kCFCalendarUnitYear, 45 * day) == 2,
+    "2001-02-15 is in the 2nd month of the year.");
+
+  CFRelease (cal);
+  CFRelease (gmt);
+  return 0;
+}