[libc] add isascii and toascii implementations

[michaelrj]

Summary

adding both at once since these are trivial functions.

[michaelrj]

add the functions to the spec in the correct places,
and add them to the entrypoints list for aarch64

libc/config/linux/aarch64/entrypoints.txt

 set(TARGET_LIBC_ENTRYPOINTS
     # ctype.h entrypoints
     libc.src.ctype.isalnum
     libc.src.ctype.isalpha
+    libc.src.ctype.isascii
     libc.src.ctype.isblank
     libc.src.ctype.iscntrl
     libc.src.ctype.isdigit
     libc.src.ctype.isgraph
     libc.src.ctype.islower
     libc.src.ctype.isprint
     libc.src.ctype.ispunct
     libc.src.ctype.isspace
     libc.src.ctype.isupper
     libc.src.ctype.isxdigit
+    libc.src.ctype.toascii
     libc.src.ctype.tolower
     libc.src.ctype.toupper
     
     # errno.h entrypoints
     libc.src.errno.__errno_location
 
     # stdlib.h entrypoints
     libc.src.stdlib.abs

libc/config/linux/x86_64/entrypoints.txt

 set(TARGET_LIBC_ENTRYPOINTS
     # assert.h entrypoints
     libc.src.assert.__assert_fail
     
     # ctype.h entrypoints
     libc.src.ctype.isalnum
     libc.src.ctype.isalpha
+    libc.src.ctype.isascii
     libc.src.ctype.isblank
     libc.src.ctype.iscntrl
     libc.src.ctype.isdigit
     libc.src.ctype.isgraph
     libc.src.ctype.islower
     libc.src.ctype.isprint
     libc.src.ctype.ispunct
     libc.src.ctype.isspace
     libc.src.ctype.isupper
     libc.src.ctype.isxdigit
+    libc.src.ctype.toascii
     libc.src.ctype.tolower
     libc.src.ctype.toupper
 
     # errno.h entrypoints
     libc.src.errno.__errno_location
 
     # fenv.h entrypoints
     libc.src.fenv.feclearexcept

libc/spec/gnu_ext.td

 def GnuExtensions : StandardSpec<"GNUExtensions"> {
+  HeaderSpec CType = HeaderSpec<
+    "ctype.h",
+    [], // Macros
+    [], // Types
+    [], // Enumerations
+    [
+        FunctionSpec<
+            "toascii",
+            RetValSpec<IntType>,
+            [ArgSpec<IntType>]
+        >,
+    ]
+  >;
+
   HeaderSpec Math = HeaderSpec<
       "math.h",
       [], // Macros
       [], // Types
       [], // Enumerations
       [
         FunctionSpec<
             "sincosf",
HeaderSpec String = HeaderSpec<
         FunctionSpec<
             "memrchr",
             RetValSpec<VoidPtr>,
             [ArgSpec<VoidPtr>, ArgSpec<IntType>, ArgSpec<SizeTType>]
         >,
       ]
   >;
 
+
   let Headers = [
-    Math, String,
+    CType,
+    Math, 
+    String,
   ];
 }

libc/spec/posix.td

[
             RetValSpec<CharPtr>,
             [ArgSpec<RestrictedCharPtr>,
              ArgSpec<ConstRestrictedCharPtr>,
              ArgSpec<CharRestrictedDoublePtr>]
         >,
     ]
   >;
 
+  HeaderSpec CType = HeaderSpec<
+    "ctype.h",
+    [], // Macros
+    [], // Types
+    [], // Enumerations
+    [
+        FunctionSpec<
+            "isascii",
+            RetValSpec<IntType>,
+            [ArgSpec<IntType>]
+        >,
+    ]
+  >;
+
   let Headers = [
+    CType,
     Errno,
     SysMMan,
     Signal,
     UniStd,
     String
   ];
 }

libc/src/ctype/CMakeLists.txt

SRCS
     isalpha.cpp
   HDRS
     isalpha.h
   DEPENDS
     .ctype_utils
 )
 
 add_entrypoint_object(
+  isascii
+  SRCS
+    isascii.cpp
+  HDRS
+    isascii.h
+)
+
+add_entrypoint_object(
   isblank
   SRCS
     isblank.cpp
   HDRS
     isblank.h
 )
 
 add_entrypoint_object(
SRCS
     tolower.cpp
   HDRS
     tolower.h
   DEPENDS
     .ctype_utils
 )
 
 add_entrypoint_object(
+  toascii
+  SRCS
+    toascii.cpp
+  HDRS
+    toascii.h
+)
+
+add_entrypoint_object(
   toupper
   SRCS
     toupper.cpp
   HDRS
     toupper.h
   DEPENDS
     .ctype_utils
 )

libc/src/ctype/isascii.h

+//===-- Implementation header for isascii -------------------------*-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_ISASCII_H
+#define LLVM_LIBC_SRC_CTYPE_ISASCII_H
+
+namespace __llvm_libc {
+
+int isascii(int c);
+
+} // namespace __llvm_libc
+
+#endif //  LLVM_LIBC_SRC_CTYPE_ISASCII_H

libc/src/ctype/isascii.cpp

+//===-- Implementation of isascii------------------------------------------===//
+//
+// 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/isascii.h"
+
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, isascii, (int c)) { return (c & (~0x7f)) == 0; }
+
+} // namespace __llvm_libc

libc/src/ctype/toascii.h

+//===-- Implementation header for toascii -------------------------*-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_TOASCII_H
+#define LLVM_LIBC_SRC_CTYPE_TOASCII_H
+
+namespace __llvm_libc {
+
+int toascii(int c);
+
+} // namespace __llvm_libc
+
+#endif //  LLVM_LIBC_SRC_CTYPE_TOASCII_H

libc/src/ctype/toascii.cpp

+//===-- Implementation of toascii------------------------------------------===//
+//
+// 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/toascii.h"
+
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, toascii, (int c)) { return (c & 0x7f); }
+
+} // namespace __llvm_libc

libc/test/src/ctype/CMakeLists.txt

SUITE
     libc_ctype_unittests
   SRCS
     isalpha_test.cpp
   DEPENDS
     libc.src.ctype.isalpha
 )
 
 add_libc_unittest(
+  isascii
+  SUITE
+    libc_ctype_unittests
+  SRCS
+    isascii_test.cpp
+  DEPENDS
+    libc.src.ctype.isascii
+)
+
+add_libc_unittest(
   isblank
   SUITE
     libc_ctype_unittests
   SRCS
     isblank_test.cpp
   DEPENDS
     libc.src.ctype.isblank
 )
SUITE
     libc_ctype_unittests
   SRCS
     isxdigit_test.cpp
   DEPENDS
     libc.src.ctype.isxdigit
 )
 
 add_libc_unittest(
+  toascii
+  SUITE
+    libc_ctype_unittests
+  SRCS
+    toascii_test.cpp
+  DEPENDS
+    libc.src.ctype.toascii
+)
+
+add_libc_unittest(
   tolower
   SUITE
     libc_ctype_unittests
   SRCS
     tolower_test.cpp
   DEPENDS
     libc.src.ctype.tolower
 )

libc/test/src/ctype/isascii_test.cpp

+//===-- Unittests for isascii----------------------------------------------===//
+//
+// 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/isascii.h"
+
+#include "utils/UnitTest/Test.h"
+
+TEST(IsAscii, DefaultLocale) {
+  // Loops through all characters, verifying that ascii characters
+  //    (which are all 7 bit unsigned integers)
+  // return a non-zero integer and everything else returns zero.
+  for (int ch = 0; ch < 255; ++ch) {
+    if (ch <= 0x7f)
+      EXPECT_NE(__llvm_libc::isascii(ch), 0);
+    else
+      EXPECT_EQ(__llvm_libc::isascii(ch), 0);
+  }
+}

libc/test/src/ctype/toascii_test.cpp

+//===-- Unittests for toascii----------------------------------------------===//
+//
+// 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/toascii.h"
+
+#include "utils/UnitTest/Test.h"
+
+TEST(ToAscii, DefaultLocale) {
+  // Loops through all characters, verifying that ascii characters
+  //    (which are all 7 bit unsigned integers)
+  // return themself, and that all other characters return themself
+  // mod 128 (which is equivalent to & 0x7f)
+  for (int ch = 0; ch < 255; ++ch) {
+    if (ch <= 0x7f)
+      EXPECT_EQ(__llvm_libc::toascii(ch), ch);
+    else
+      EXPECT_EQ(__llvm_libc::toascii(ch), ch & 0x7f);
+  }
+}