[libc] Implement strcasestr

Differential Revision: https://reviews.llvm.org/D142518

diff --git a/libc/config/baremetal/entrypoints.txt b/libc/config/baremetal/entrypoints.txt
index db645c0..5dc233e 100644 (file)
--- a/libc/config/baremetal/entrypoints.txt
+++ b/libc/config/baremetal/entrypoints.txt
@@ -32,6 +32,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.string.stpcpy
     libc.src.string.stpncpy
     libc.src.string.strcasecmp
+    libc.src.string.strcasestr
     libc.src.string.strcat
     libc.src.string.strchr
     libc.src.string.strcmp

diff --git a/libc/config/darwin/arm/entrypoints.txt b/libc/config/darwin/arm/entrypoints.txt
index cf29319..a1ad122 100644 (file)
--- a/libc/config/darwin/arm/entrypoints.txt
+++ b/libc/config/darwin/arm/entrypoints.txt
@@ -32,6 +32,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.string.stpcpy
     libc.src.string.stpncpy
     libc.src.string.strcasecmp
+    libc.src.string.strcasestr
     libc.src.string.strcat
     libc.src.string.strchr
     libc.src.string.strcmp

diff --git a/libc/config/gpu/entrypoints.txt b/libc/config/gpu/entrypoints.txt
index 57b314f..ee39c64 100644 (file)
--- a/libc/config/gpu/entrypoints.txt
+++ b/libc/config/gpu/entrypoints.txt
@@ -31,6 +31,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.string.stpcpy
     libc.src.string.stpncpy
     libc.src.string.strcasecmp
+    libc.src.string.strcasestr
     libc.src.string.strcat
     libc.src.string.strchr
     libc.src.string.strcmp

diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 7223975..b9460ac 100644 (file)
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -41,6 +41,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.string.stpcpy
     libc.src.string.stpncpy
     libc.src.string.strcasecmp
+    libc.src.string.strcasestr
     libc.src.string.strcat
     libc.src.string.strchr
     libc.src.string.strcmp

diff --git a/libc/config/linux/arm/entrypoints.txt b/libc/config/linux/arm/entrypoints.txt
index f4228f1..98d00aa 100644 (file)
--- a/libc/config/linux/arm/entrypoints.txt
+++ b/libc/config/linux/arm/entrypoints.txt
@@ -32,6 +32,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.string.stpcpy
     libc.src.string.stpncpy
     libc.src.string.strcasecmp
+    libc.src.string.strcasestr
     libc.src.string.strcat
     libc.src.string.strchr
     libc.src.string.strcmp

diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 2c1c938..7b12ec7 100644 (file)
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -41,6 +41,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.string.stpcpy
     libc.src.string.stpncpy
     libc.src.string.strcasecmp
+    libc.src.string.strcasestr
     libc.src.string.strcat
     libc.src.string.strchr
     libc.src.string.strcmp

diff --git a/libc/config/windows/entrypoints.txt b/libc/config/windows/entrypoints.txt
index 01c33f9..61cf5a1 100644 (file)
--- a/libc/config/windows/entrypoints.txt
+++ b/libc/config/windows/entrypoints.txt
@@ -32,6 +32,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.string.stpcpy
     libc.src.string.stpncpy
     libc.src.string.strcasecmp
+    libc.src.string.strcasestr
     libc.src.string.strcat
     libc.src.string.strchr
     libc.src.string.strcmp

diff --git a/libc/spec/gnu_ext.td b/libc/spec/gnu_ext.td
index 239790b..f3311e3 100644 (file)
--- a/libc/spec/gnu_ext.td
+++ b/libc/spec/gnu_ext.td
@@ -68,6 +68,11 @@ def GnuExtensions : StandardSpec<"GNUExtensions"> {
             RetValSpec<CharPtr>,
             [ArgSpec<IntType>, ArgSpec<CharPtr>, ArgSpec<SizeTType>]
         >,
+        FunctionSpec<
+            "strcasestr",
+            RetValSpec<CharPtr>,
+            [ArgSpec<ConstCharPtr>, ArgSpec<ConstCharPtr>]
+        >,
       ]
   >;
 

diff --git a/libc/src/string/CMakeLists.txt b/libc/src/string/CMakeLists.txt
index 9c580dc..944889a 100644 (file)
--- a/libc/src/string/CMakeLists.txt
+++ b/libc/src/string/CMakeLists.txt
@@ -128,6 +128,17 @@ add_entrypoint_object(
 )
 
 add_entrypoint_object(
+  strcasestr
+  SRCS
+    strcasestr.cpp
+  HDRS
+    strcasestr.h
+  DEPENDS
+    .memory_utils.strstr_implementation
+    libc.src.__support.ctype_utils
+)
+
+add_entrypoint_object(
   strcoll
   SRCS
     strcoll.cpp

diff --git a/libc/src/string/strcasestr.cpp b/libc/src/string/strcasestr.cpp
new file mode 100644 (file)
index 0000000..a127242
--- /dev/null
+++ b/libc/src/string/strcasestr.cpp
@@ -0,0 +1,28 @@
+//===-- Implementation of strcasestr --------------------------------------===//
+//
+// 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/string/strcasestr.h"
+
+#include "src/__support/common.h"
+#include "src/__support/ctype_utils.h"
+#include "src/string/memory_utils/strstr_implementations.h"
+
+namespace __llvm_libc {
+
+// TODO: This is a simple brute force implementation. This can be
+// improved upon using well known string matching algorithms.
+LLVM_LIBC_FUNCTION(char *, strcasestr,
+                   (const char *haystack, const char *needle)) {
+  auto case_cmp = [](char a, char b) {
+    return __llvm_libc::internal::tolower(a) -
+           __llvm_libc::internal::tolower(b);
+  };
+  return strstr_implementation(haystack, needle, case_cmp);
+}
+
+} // namespace __llvm_libc

diff --git a/libc/src/string/strcasestr.h b/libc/src/string/strcasestr.h
new file mode 100644 (file)
index 0000000..8c4bc51
--- /dev/null
+++ b/libc/src/string/strcasestr.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for strcasestr --------------------*- 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_STRING_STRCASECMP_H
+#define LLVM_LIBC_SRC_STRING_STRCASECMP_H
+
+namespace __llvm_libc {
+
+char *strcasestr(const char *needle, const char *haystack);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_STRING_STRCASECMP_H

diff --git a/libc/test/src/string/CMakeLists.txt b/libc/test/src/string/CMakeLists.txt
index 99dfabb..4c9ab58 100644 (file)
--- a/libc/test/src/string/CMakeLists.txt
+++ b/libc/test/src/string/CMakeLists.txt
@@ -115,6 +115,16 @@ add_libc_unittest(
 )
 
 add_libc_unittest(
+  strcasestr_test
+  SUITE
+    libc_string_unittests
+  SRCS
+    strcasestr_test.cpp
+  DEPENDS
+    libc.src.string.strcasestr
+)
+
+add_libc_unittest(
   strcoll_test
   SUITE
     libc_string_unittests

diff --git a/libc/test/src/string/strcasestr_test.cpp b/libc/test/src/string/strcasestr_test.cpp
new file mode 100644 (file)
index 0000000..313ad8e
--- /dev/null
+++ b/libc/test/src/string/strcasestr_test.cpp
@@ -0,0 +1,24 @@
+//===-- Unittests for strcasestr ------------------------------------------===//
+//
+// 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/string/strcasestr.h"
+#include "utils/UnitTest/Test.h"
+
+TEST(LlvmLibcStrCaseStrTest, NeedleNotInHaystack) {
+  EXPECT_STREQ(__llvm_libc::strcasestr("abcd", "e"), nullptr);
+  EXPECT_STREQ(__llvm_libc::strcasestr("ABCD", "e"), nullptr);
+  EXPECT_STREQ(__llvm_libc::strcasestr("abcd", "E"), nullptr);
+  EXPECT_STREQ(__llvm_libc::strcasestr("ABCD", "E"), nullptr);
+}
+
+TEST(LlvmLibcStrCaseStrTest, NeedleInMiddle) {
+  EXPECT_STREQ(__llvm_libc::strcasestr("abcdefghi", "def"), "defghi");
+  EXPECT_STREQ(__llvm_libc::strcasestr("ABCDEFGHI", "def"), "DEFGHI");
+  EXPECT_STREQ(__llvm_libc::strcasestr("abcdefghi", "DEF"), "defghi");
+  EXPECT_STREQ(__llvm_libc::strcasestr("ABCDEFGHI", "DEF"), "DEFGHI");
+}