[libc] implement strings/str{n}casecmp_l (#130407)

ref:
https://pubs.opengroup.org/onlinepubs/9799919799/functions/strcasecmp_l.html

This patch introduces the `strcasecmp_l` function. At present, the
locale parameter is ignored, making it a stub implementation. This is
consistent with how other locale-related functions, such as `islower_l`,
are treated in our codebase as well as in
[musl](https://github.com/bminor/musl/blob/master/src/string/strcasecmp.c)
and
[bionic](https://cs.android.com/android/platform/superproject/main/+/main:bionic/libc/bionic/strings_l.cpp).

---------

Co-authored-by: Michael Jones <[email protected]>

Author: c8ef

libc/config/linux/aarch64/entrypoints.txt

@@ -911,6 +911,10 @@ if(LLVM_LIBC_FULL_BUILD)
     # sched.h entrypoints
     libc.src.sched.__sched_getcpucount
 
+    # strings.h entrypoints
+    libc.src.strings.strcasecmp_l
+    libc.src.strings.strncasecmp_l
+
     # setjmp.h entrypoints
     libc.src.setjmp.longjmp
     libc.src.setjmp.setjmp

libc/config/linux/x86_64/entrypoints.txt

@@ -938,6 +938,10 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.string.strcoll_l
     libc.src.string.strxfrm_l
 
+    # strings.h entrypoints
+    libc.src.strings.strcasecmp_l
+    libc.src.strings.strncasecmp_l
+
     # assert.h entrypoints
     libc.src.assert.__assert_fail
 

libc/include/strings.yaml

@@ -3,6 +3,7 @@ header_template: strings.h.def
 macros: []
 types:
   - type_name: size_t
+  - type_name: locale_t
 enums: []
 objects: []
 functions:
@@ -68,6 +69,14 @@ functions:
     arguments:
       - type: const char *
       - type: const char *
+  - name: strcasecmp_l
+    standards:
+      - BSDExtensions
+    return_type: int
+    arguments:
+      - type: const char *
+      - type: const char *
+      - type: locale_t
   - name: strncasecmp
     standards:
       - BSDExtensions
@@ -76,3 +85,12 @@ functions:
       - type: const char *
       - type: const char *
       - type: size_t
+  - name: strncasecmp_l
+    standards:
+      - BSDExtensions
+    return_type: int
+    arguments:
+      - type: const char *
+      - type: const char *
+      - type: size_t
+      - type: locale_t

libc/src/strings/CMakeLists.txt

@@ -115,6 +115,18 @@ add_entrypoint_object(
     libc.src.string.memory_utils.inline_strcmp
 )
 
+add_entrypoint_object(
+  strcasecmp_l
+  SRCS
+    strcasecmp_l.cpp
+  HDRS
+    strcasecmp_l.h
+  DEPENDS
+    libc.hdr.types.locale_t
+    libc.src.__support.ctype_utils
+    libc.src.string.memory_utils.inline_strcmp
+)
+
 add_entrypoint_object(
   strncasecmp
   SRCS
@@ -125,3 +137,15 @@ add_entrypoint_object(
     libc.src.__support.ctype_utils
     libc.src.string.memory_utils.inline_strcmp
 )
+
+add_entrypoint_object(
+  strncasecmp_l
+  SRCS
+    strncasecmp_l.cpp
+  HDRS
+    strncasecmp_l.h
+  DEPENDS
+    libc.hdr.types.locale_t
+    libc.src.__support.ctype_utils
+    libc.src.string.memory_utils.inline_strcmp
+)

libc/src/strings/strcasecmp_l.cpp

@@ -0,0 +1,27 @@
+//===-- Implementation of strcasecmp_l ------------------------------------===//
+//
+// 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/strings/strcasecmp_l.h"
+
+#include "src/__support/common.h"
+#include "src/__support/ctype_utils.h"
+#include "src/__support/macros/config.h"
+#include "src/string/memory_utils/inline_strcmp.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, strcasecmp_l,
+                   (const char *left, const char *right, locale_t)) {
+  auto case_cmp = [](char a, char b) {
+    return LIBC_NAMESPACE::internal::tolower(a) -
+           LIBC_NAMESPACE::internal::tolower(b);
+  };
+  return inline_strcmp(left, right, case_cmp);
+}
+
+} // namespace LIBC_NAMESPACE_DECL

libc/src/strings/strcasecmp_l.h

@@ -0,0 +1,21 @@
+//===-- Implementation header for strcasecmp_l ------------------*- 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_STRINGS_STRCASECMP_L_H
+#define LLVM_LIBC_SRC_STRINGS_STRCASECMP_L_H
+
+#include "hdr/types/locale_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int strcasecmp_l(const char *left, const char *right, locale_t locale);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_STRINGS_STRCASECMP_L_H

libc/src/strings/strncasecmp_l.cpp

@@ -0,0 +1,27 @@
+//===-- Implementation of strncasecmp_l -----------------------------------===//
+//
+// 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/strings/strncasecmp_l.h"
+
+#include "src/__support/common.h"
+#include "src/__support/ctype_utils.h"
+#include "src/__support/macros/config.h"
+#include "src/string/memory_utils/inline_strcmp.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, strncasecmp_l,
+                   (const char *left, const char *right, size_t n, locale_t)) {
+  auto case_cmp = [](char a, char b) {
+    return LIBC_NAMESPACE::internal::tolower(a) -
+           LIBC_NAMESPACE::internal::tolower(b);
+  };
+  return inline_strncmp(left, right, n, case_cmp);
+}
+
+} // namespace LIBC_NAMESPACE_DECL

libc/src/strings/strncasecmp_l.h

@@ -0,0 +1,23 @@
+//===-- Implementation header for strncasecmp_l -----------------*- 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_STRINGS_STRNCASECMP_L_H
+#define LLVM_LIBC_SRC_STRINGS_STRNCASECMP_L_H
+
+#include "hdr/types/locale_t.h"
+#include "src/__support/macros/config.h"
+#include <stddef.h>
+
+namespace LIBC_NAMESPACE_DECL {
+
+int strncasecmp_l(const char *left, const char *right, size_t n,
+                  locale_t locale);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_STRINGS_STRNCASECMP_L_H

libc/test/src/strings/CMakeLists.txt

@@ -74,6 +74,19 @@ add_libc_test(
     libc.src.strings.strcasecmp
 )
 
+add_libc_test(
+  strcasecmp_l_test
+  SUITE
+    libc-strings-tests
+  SRCS
+    strcasecmp_l_test.cpp
+  DEPENDS
+    libc.hdr.locale_macros
+    libc.src.locale.freelocale
+    libc.src.locale.newlocale
+    libc.src.strings.strcasecmp_l
+)
+
 add_libc_test(
   strncasecmp_test
   SUITE
@@ -84,5 +97,18 @@ add_libc_test(
     libc.src.strings.strncasecmp
 )
 
+add_libc_test(
+  strncasecmp_l_test
+  SUITE
+    libc-strings-tests
+  SRCS
+    strncasecmp_l_test.cpp
+  DEPENDS
+    libc.hdr.locale_macros
+    libc.src.locale.freelocale
+    libc.src.locale.newlocale
+    libc.src.strings.strncasecmp_l
+)
+
 add_libc_multi_impl_test(bcmp libc-strings-tests SRCS bcmp_test.cpp)
 add_libc_multi_impl_test(bzero libc-strings-tests SRCS bzero_test.cpp)

libc/test/src/strings/strcasecmp_l_test.cpp

@@ -0,0 +1,21 @@
+//===-- Unittests for strcasecmp_l ----------------------------------------===//
+//
+// 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 "hdr/locale_macros.h"
+#include "src/locale/freelocale.h"
+#include "src/locale/newlocale.h"
+#include "src/strings/strcasecmp_l.h"
+#include "test/UnitTest/Test.h"
+
+TEST(LlvmLibcStrCaseCmpLTest, Case) {
+  locale_t locale = LIBC_NAMESPACE::newlocale(LC_ALL, "C", nullptr);
+  ASSERT_EQ(LIBC_NAMESPACE::strcasecmp_l("hello", "HELLO", locale), 0);
+  ASSERT_LT(LIBC_NAMESPACE::strcasecmp_l("hello1", "hello2", locale), 0);
+  ASSERT_GT(LIBC_NAMESPACE::strcasecmp_l("hello2", "hello1", locale), 0);
+  LIBC_NAMESPACE::freelocale(locale);
+}