[PATCH v2 04/10] DynamicTablesPkg: Add HexFromAscii() to AcpiHelperLib

["PierreGondois" <pierre.gondois@arm.com>]

From: Pierre Gondois <Pierre.Gondois@arm.com>

Add HexFromAscii(), converting an hexadecimal ascii char
to an integer.

Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
---

Notes:
    v2:
    -Document returned error code. [Sami]

 .../Include/Library/AcpiHelperLib.h           | 15 +++++++++
 .../Library/Common/AcpiHelperLib/AcpiHelper.c | 31 +++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/DynamicTablesPkg/Include/Library/AcpiHelperLib.h b/DynamicTablesPkg/Include/Library/AcpiHelperLib.h
index 53ab19b1d139..094392a1a6d0 100644
--- a/DynamicTablesPkg/Include/Library/AcpiHelperLib.h
+++ b/DynamicTablesPkg/Include/Library/AcpiHelperLib.h
@@ -34,6 +34,21 @@ AsciiFromHex (
   IN  UINT8   Hex
   );
 
+/** Convert an ASCII char representing an hexadecimal number
+    to its integer value.
+
+ @param [in]  Char  Char to convert.
+                    Must be between '0'-'9' or 'A'-'F' or 'a'-'f'.
+
+ @return The corresponding integer (between 0-16).
+         -1 if error.
+**/
+UINT8
+EFIAPI
+HexFromAscii (
+  IN  CHAR8   Char
+  );
+
 /** Check if a HID is a valid PNP ID.
 
   @param     [in] Hid     The Hid to validate.
diff --git a/DynamicTablesPkg/Library/Common/AcpiHelperLib/AcpiHelper.c b/DynamicTablesPkg/Library/Common/AcpiHelperLib/AcpiHelper.c
index 434b472cbb14..0b566f0502ac 100644
--- a/DynamicTablesPkg/Library/Common/AcpiHelperLib/AcpiHelper.c
+++ b/DynamicTablesPkg/Library/Common/AcpiHelperLib/AcpiHelper.c
@@ -38,6 +38,37 @@ AsciiFromHex (
   return (UINT8)-1;
 }
 
+/** Convert an ASCII char representing an hexadecimal number
+    to its integer value.
+
+ @param [in]  Char  Char to convert.
+                    Must be between '0'-'9' or 'A'-'F' or 'a'-'f'.
+
+ @return The corresponding integer (between 0-16).
+         -1 if error.
+**/
+UINT8
+EFIAPI
+HexFromAscii (
+  IN  CHAR8   Char
+  )
+{
+  if ((Char >= '0') && (Char <= '9')) {
+    return (UINT8)(Char - '0');
+  }
+
+  if ((Char >= 'A') && (Char <= 'F')) {
+    return (UINT8)(Char - 'A' + 10);
+  }
+
+  if ((Char >= 'a') && (Char <= 'f')) {
+    return (UINT8)(Char - 'a' + 10);
+  }
+
+  ASSERT (FALSE);
+  return (UINT8)-1;
+}
+
 /** Check if a HID is a valid PNP ID.
 
   @param     [in] Hid     The Hid to validate.
-- 
2.17.1