From 91c31ff04a7a72b4b0e476972ad3c76e03a106a2 Mon Sep 17 00:00:00 2001
From: Meenakshi Aggarwal <meenakshi.aggarwal@nxp.com>
Date: Mon, 4 Jun 2018 22:01:44 +0530
Subject: [PATCH] EmbeddedPkg/TimeBaseLib: Add function to get Week day.

This patch add function EfiTimeToWday() which returns
day of the week.
It is needed by our upcoming patches in edk2-platforms.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Vabhav Sharma <vabhav.sharma@nxp.com>
Signed-off-by: Meenakshi Aggarwal <meenakshi.aggarwal@nxp.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
---
 EmbeddedPkg/Include/Library/TimeBaseLib.h     |  8 ++++
 EmbeddedPkg/Library/TimeBaseLib/TimeBaseLib.c | 38 +++++++++++++++++--
 2 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/EmbeddedPkg/Include/Library/TimeBaseLib.h b/EmbeddedPkg/Include/Library/TimeBaseLib.h
index fe3618e975..dd0b99f2b6 100644
--- a/EmbeddedPkg/Include/Library/TimeBaseLib.h
+++ b/EmbeddedPkg/Include/Library/TimeBaseLib.h
@@ -65,4 +65,12 @@ EfiTimeToEpoch (
   IN  EFI_TIME  *Time
   );
 
+/**
+  returns Day of the week [0-6] 0=Sunday
+ **/
+UINTN
+EfiTimeToWday (
+  IN  EFI_TIME  *Time
+  );
+
 #endif
diff --git a/EmbeddedPkg/Library/TimeBaseLib/TimeBaseLib.c b/EmbeddedPkg/Library/TimeBaseLib/TimeBaseLib.c
index 0c0d940301..5f2bf65fcd 100644
--- a/EmbeddedPkg/Library/TimeBaseLib/TimeBaseLib.c
+++ b/EmbeddedPkg/Library/TimeBaseLib/TimeBaseLib.c
@@ -77,11 +77,11 @@ EpochToEfiTime (
 }
 
 /**
-  Converts EFI_TIME to Epoch seconds (elapsed since 1970 JANUARY 01, 00:00:00 UTC)
+  Calculate Epoch days
  **/
 UINTN
 EFIAPI
-EfiTimeToEpoch (
+EfiGetEpochDays (
   IN  EFI_TIME  *Time
   )
 {
@@ -90,7 +90,6 @@ EfiTimeToEpoch (
   UINTN m;
   UINTN JulianDate;  // Absolute Julian Date representation of the supplied Time
   UINTN EpochDays;   // Number of days elapsed since EPOCH_JULIAN_DAY
-  UINTN EpochSeconds;
 
   a = (14 - Time->Month) / 12 ;
   y = Time->Year + 4800 - a;
@@ -101,11 +100,44 @@ EfiTimeToEpoch (
   ASSERT (JulianDate >= EPOCH_JULIAN_DATE);
   EpochDays = JulianDate - EPOCH_JULIAN_DATE;
 
+  return EpochDays;
+}
+/**
+  Converts EFI_TIME to Epoch seconds (elapsed since 1970 JANUARY 01, 00:00:00 UTC)
+ **/
+UINTN
+EFIAPI
+EfiTimeToEpoch (
+  IN  EFI_TIME  *Time
+  )
+{
+  UINTN EpochDays;   // Number of days elapsed since EPOCH_JULIAN_DAY
+  UINTN EpochSeconds;
+
+  EpochDays = EfiGetEpochDays (Time);
+
   EpochSeconds = (EpochDays * SEC_PER_DAY) + ((UINTN)Time->Hour * SEC_PER_HOUR) + (Time->Minute * SEC_PER_MIN) + Time->Second;
 
   return EpochSeconds;
 }
 
+/**
+  returns Day of the week [0-6] 0=Sunday
+ **/
+UINTN
+EfiTimeToWday (
+  IN  EFI_TIME  *Time
+  )
+{
+  UINTN EpochDays;   // Number of days elapsed since EPOCH_JULIAN_DAY
+
+  EpochDays = EfiGetEpochDays (Time);
+
+  // 4=1/1/1970 was a Thursday
+
+  return (EpochDays + 4) % 7;
+}
+
 BOOLEAN
 EFIAPI
 IsLeapYear (
-- 
2.39.2