[libc] Add tolower, toupper implementation.

Reviewed By: sivachandra

Differential Revision: https://reviews.llvm.org/D85326

Author: cgyurgyik

libc/config/linux/aarch64/entrypoints.txt

@@ -12,6 +12,8 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.ctype.isspace
     libc.src.ctype.isupper
     libc.src.ctype.isxdigit
+    libc.src.ctype.tolower
+    libc.src.ctype.toupper
 
     # errno.h entrypoints
     libc.src.errno.__errno_location

libc/config/linux/api.td

@@ -100,6 +100,8 @@ def CTypeAPI : PublicAPI<"ctype.h"> {
     "isspace",
     "isupper",
     "isxdigit",
+    "tolower",
+    "toupper",
   ];
 }
 

libc/config/linux/x86_64/entrypoints.txt

@@ -15,6 +15,8 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.ctype.isspace
     libc.src.ctype.isupper
     libc.src.ctype.isxdigit
+    libc.src.ctype.tolower
+    libc.src.ctype.toupper
 
     # errno.h entrypoints
     libc.src.errno.__errno_location

libc/spec/stdc.td

@@ -106,6 +106,16 @@ def StdC : StandardSpec<"stdc"> {
               RetValSpec<IntType>,
               [ArgSpec<IntType>]
           >,
+          FunctionSpec<
+              "tolower",
+              RetValSpec<IntType>,
+              [ArgSpec<IntType>]
+          >,
+          FunctionSpec<
+              "toupper",
+              RetValSpec<IntType>,
+              [ArgSpec<IntType>]
+          >,
       ]
   >;
 

libc/src/ctype/CMakeLists.txt

@@ -66,6 +66,8 @@ add_entrypoint_object(
     islower.cpp
   HDRS
     islower.h
+  DEPENDS
+    .ctype_utils
 )
 
 add_entrypoint_object(
@@ -100,6 +102,8 @@ add_entrypoint_object(
     isupper.cpp
   HDRS
     isupper.h
+  DEPENDS
+    .ctype_utils
 )
 
 add_entrypoint_object(
@@ -111,3 +115,23 @@ add_entrypoint_object(
   DEPENDS
     .ctype_utils
 )
+
+add_entrypoint_object(
+  tolower
+  SRCS
+    tolower.cpp
+  HDRS
+    tolower.h
+  DEPENDS
+    .ctype_utils
+)
+
+add_entrypoint_object(
+  toupper
+  SRCS
+    toupper.cpp
+  HDRS
+    toupper.h
+  DEPENDS
+    .ctype_utils
+)

libc/src/ctype/ctype_utils.h

@@ -18,14 +18,18 @@ namespace internal {
 // of a function call by inlining them.
 // ------------------------------------------------------
 
-static inline int isdigit(unsigned ch) { return (ch - '0') < 10; }
-
 static inline int isalpha(unsigned ch) { return (ch | 32) - 'a' < 26; }
 
+static inline int isdigit(unsigned ch) { return (ch - '0') < 10; }
+
 static inline int isalnum(unsigned ch) { return isalpha(ch) || isdigit(ch); }
 
 static inline int isgraph(unsigned ch) { return 0x20 < ch && ch < 0x7f; }
 
+static inline int islower(unsigned ch) { return (ch - 'a') < 26; }
+
+static inline int isupper(unsigned ch) { return (ch - 'A') < 26; }
+
 } // namespace internal
 } // namespace __llvm_libc
 

libc/src/ctype/islower.cpp

@@ -7,16 +7,14 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/ctype/islower.h"
+#include "src/ctype/ctype_utils.h"
 
 #include "src/__support/common.h"
 
 namespace __llvm_libc {
 
 // TODO: Currently restricted to default locale.
 // These should be extended using locale information.
-int LLVM_LIBC_ENTRYPOINT(islower)(int c) {
-  const unsigned ch = c;
-  return (ch - 'a') < 26;
-}
+int LLVM_LIBC_ENTRYPOINT(islower)(int c) { return internal::islower(c); }
 
 } // namespace __llvm_libc

libc/src/ctype/isupper.cpp

@@ -7,16 +7,14 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/ctype/isupper.h"
+#include "src/ctype/ctype_utils.h"
 
 #include "src/__support/common.h"
 
 namespace __llvm_libc {
 
 // TODO: Currently restricted to default locale.
 // These should be extended using locale information.
-int LLVM_LIBC_ENTRYPOINT(isupper)(int c) {
-  const unsigned ch = c;
-  return (ch - 'A') < 26;
-}
+int LLVM_LIBC_ENTRYPOINT(isupper)(int c) { return internal::isupper(c); }
 
 } // namespace __llvm_libc

libc/src/ctype/tolower.cpp

@@ -0,0 +1,24 @@
+//===-- Implementation of tolower------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/ctype/tolower.h"
+#include "src/ctype/ctype_utils.h"
+
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+// TODO: Currently restricted to default locale.
+// These should be extended using locale information.
+int LLVM_LIBC_ENTRYPOINT(tolower)(int c) {
+  if (internal::isupper(c))
+    return c + 'a' - 'A';
+  return c;
+}
+
+} // namespace __llvm_libc

libc/src/ctype/tolower.h

@@ -0,0 +1,18 @@
+//===-- Implementation header for tolower -------------------------*-C++-*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_CTYPE_TOLOWER_H
+#define LLVM_LIBC_SRC_CTYPE_TOLOWER_H
+
+namespace __llvm_libc {
+
+int tolower(int c);
+
+} // namespace __llvm_libc
+
+#endif //  LLVM_LIBC_SRC_CTYPE_TOLOWER_H