CryptoPkg/TlsLib: use binary search in the TlsGetCipherMapping() function

Improve the performance of the TlsGetCipherMapping() function by adopting
the binary search from DhcpFindOptionFormat()
[MdeModulePkg/Universal/Network/Dhcp4Dxe/Dhcp4Option.c].

Cc: Jiaxin Wu <jiaxin.wu@intel.com>
Cc: Qin Long <qin.long@intel.com>
Cc: Siyuan Fu <siyuan.fu@intel.com>
Cc: Ting Ye <ting.ye@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=915
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Long Qin <qin.long@intel.com>
Reviewed-by: Jiaxin Wu <jiaxin.wu@intel.com>

1 files changed, 23 insertions, 13 deletions

diff --git a/CryptoPkg/Library/TlsLib/TlsConfig.c b/CryptoPkg/Library/TlsLib/TlsConfig.c
index 507489386b..c1d91a5994 100644
--- a/CryptoPkg/Library/TlsLib/TlsConfig.c
+++ b/CryptoPkg/Library/TlsLib/TlsConfig.c
@@ -30,6 +30,8 @@ typedef struct {
 // The mapping table between IANA/IETF Cipher Suite definitions and

 // OpenSSL-used Cipher Suite name.

 //

+// Keep the table uniquely sorted by the IanaCipher field, in increasing order.

+//

 STATIC CONST TLS_CIPHER_MAPPING TlsCipherMappingTable[] = {

   { 0x0001, "NULL-MD5" },                 /// TLS_RSA_WITH_NULL_MD5

   { 0x0002, "NULL-SHA" },                 /// TLS_RSA_WITH_NULL_SHA

@@ -71,22 +73,30 @@ TlsGetCipherMapping (
   IN     UINT16                   CipherId

   )

 {

-  CONST TLS_CIPHER_MAPPING  *CipherEntry;

-  UINTN                     TableSize;

-  UINTN                     Index;

-

-  CipherEntry = TlsCipherMappingTable;

-  TableSize = sizeof (TlsCipherMappingTable) / sizeof (TLS_CIPHER_MAPPING);

+  INTN                      Left;

+  INTN                      Right;

+  INTN                      Middle;

 

   //

-  // Search Cipher Mapping Table for IANA-OpenSSL Cipher Translation

+  // Binary Search Cipher Mapping Table for IANA-OpenSSL Cipher Translation

   //

-  for (Index = 0; Index < TableSize; Index++, CipherEntry++) {

-    //

-    // Translate IANA cipher suite name to OpenSSL name.

-    //

-    if (CipherEntry->IanaCipher == CipherId) {

-      return CipherEntry;

+  Left  = 0;

+  Right = ARRAY_SIZE (TlsCipherMappingTable) - 1;

+

+  while (Right >= Left) {

+    Middle = (Left + Right) / 2;

+

+    if (CipherId == TlsCipherMappingTable[Middle].IanaCipher) {

+      //

+      // Translate IANA cipher suite ID to OpenSSL name.

+      //

+      return &TlsCipherMappingTable[Middle];

+    }

+

+    if (CipherId < TlsCipherMappingTable[Middle].IanaCipher) {

+      Right = Middle - 1;

+    } else {

+      Left  = Middle + 1;

     }

   }