[libc-commits] [libc] f773d37 - [libc] Implements strnlen.
via libc-commits
libc-commits at lists.llvm.org
Wed Jul 22 15:28:53 PDT 2020
Author: cgyurgyik
Date: 2020-07-22T18:28:35-04:00
New Revision: f773d37ee1df1d5fd6b75ab83ddfa53dcb4bed84
URL: https://github.com/llvm/llvm-project/commit/f773d37ee1df1d5fd6b75ab83ddfa53dcb4bed84
DIFF: https://github.com/llvm/llvm-project/commit/f773d37ee1df1d5fd6b75ab83ddfa53dcb4bed84.diff
LOG: [libc] Implements strnlen.
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D84247
Added:
libc/src/string/strnlen.cpp
libc/src/string/strnlen.h
libc/test/src/string/strnlen_test.cpp
Modified:
libc/config/linux/aarch64/entrypoints.txt
libc/config/linux/api.td
libc/config/linux/x86_64/entrypoints.txt
libc/spec/posix.td
libc/src/string/CMakeLists.txt
libc/test/src/string/CMakeLists.txt
Removed:
################################################################################
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index cd805d7b8653..4a0aa28c9d2b 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -12,6 +12,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.string.memchr
libc.src.string.strchr
libc.src.string.strstr
+ libc.src.string.strnlen
)
set(TARGET_LIBM_ENTRYPOINTS
diff --git a/libc/config/linux/api.td b/libc/config/linux/api.td
index 22e97b891a75..7fc199eabc6b 100644
--- a/libc/config/linux/api.td
+++ b/libc/config/linux/api.td
@@ -213,6 +213,7 @@ def StringAPI : PublicAPI<"string.h"> {
"strtok",
"strerror",
"strlen",
+ "strnlen"
];
let TypeDeclarations = [
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index e8a1adbb278e..04acfb31da04 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -30,6 +30,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.string.memchr
libc.src.string.strchr
libc.src.string.strstr
+ libc.src.string.strnlen
# sys/mman.h entrypoints
libc.src.sys.mman.mmap
diff --git a/libc/spec/posix.td b/libc/spec/posix.td
index 7085e81a6b80..732b6a6be250 100644
--- a/libc/spec/posix.td
+++ b/libc/spec/posix.td
@@ -11,6 +11,8 @@ def RestrictStructSigactionPtr : RestrictedPtrType<StructSigaction>;
def ConstRestrictStructSigactionPtr : ConstType<RestrictStructSigactionPtr>;
def POSIX : StandardSpec<"POSIX"> {
+ PtrType CharPtr = PtrType<CharType>;
+ ConstType ConstCharPtr = ConstType<CharPtr>;
NamedType OffTType = NamedType<"off_t">;
NamedType SSizeTType = NamedType<"ssize_t">;
@@ -203,11 +205,30 @@ def POSIX : StandardSpec<"POSIX"> {
>,
]
>;
+
+ HeaderSpec String = HeaderSpec<
+ "string.h",
+ [
+ Macro<"NULL">,
+ ],
+ [
+ SizeTType,
+ ],
+ [], // Enumerations
+ [
+ FunctionSpec<
+ "strnlen",
+ RetValSpec<SizeTType>,
+ [ArgSpec<ConstCharPtr>, ArgSpec<SizeTType>]
+ >,
+ ]
+ >;
let Headers = [
Errno,
SysMMan,
Signal,
UniStd,
+ String
];
}
diff --git a/libc/src/string/CMakeLists.txt b/libc/src/string/CMakeLists.txt
index 98693ccc0598..8bd7c1c045cf 100644
--- a/libc/src/string/CMakeLists.txt
+++ b/libc/src/string/CMakeLists.txt
@@ -68,6 +68,16 @@ add_entrypoint_object(
strstr.h
)
+add_entrypoint_object(
+ strnlen
+ SRCS
+ strnlen.cpp
+ HDRS
+ strnlen.h
+ DEPENDS
+ .memchr
+)
+
# Helper to define a function with multiple implementations
# - Computes flags to satisfy required/rejected features and arch,
# - Declares an entry point,
diff --git a/libc/src/string/strnlen.cpp b/libc/src/string/strnlen.cpp
new file mode 100644
index 000000000000..17dd6e171504
--- /dev/null
+++ b/libc/src/string/strnlen.cpp
@@ -0,0 +1,23 @@
+//===-- Implementation of strnlen------------------------------------------===//
+//
+// 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/strnlen.h"
+
+#include "src/__support/common.h"
+#include "src/string/memchr.h"
+#include <stddef.h>
+
+namespace __llvm_libc {
+
+size_t LLVM_LIBC_ENTRYPOINT(strnlen)(const char *src, size_t n) {
+ const char *temp =
+ reinterpret_cast<char *>(__llvm_libc::memchr(src, '\0', n));
+ return temp ? temp - src : n;
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/string/strnlen.h b/libc/src/string/strnlen.h
new file mode 100644
index 000000000000..2d2ee9703d83
--- /dev/null
+++ b/libc/src/string/strnlen.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for strnlen ------------------------*- 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_STRNLEN_H
+#define LLVM_LIBC_SRC_STRING_STRNLEN_H
+
+#include <stddef.h>
+
+namespace __llvm_libc {
+
+size_t strnlen(const char *src, size_t n);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_STRING_STRNLEN_H
diff --git a/libc/test/src/string/CMakeLists.txt b/libc/test/src/string/CMakeLists.txt
index 81ae08d7249a..be43cc912b5a 100644
--- a/libc/test/src/string/CMakeLists.txt
+++ b/libc/test/src/string/CMakeLists.txt
@@ -72,6 +72,16 @@ add_libc_unittest(
libc.src.string.strstr
)
+add_libc_unittest(
+ strnlen_test
+ SUITE
+ libc_string_unittests
+ SRCS
+ strnlen_test.cpp
+ DEPENDS
+ libc.src.string.strnlen
+)
+
# Tests all implementations that can run on the host.
function(add_libc_multi_impl_test name)
get_property(fq_implementations GLOBAL PROPERTY ${name}_implementations)
diff --git a/libc/test/src/string/strnlen_test.cpp b/libc/test/src/string/strnlen_test.cpp
new file mode 100644
index 000000000000..9d8616bc8bd7
--- /dev/null
+++ b/libc/test/src/string/strnlen_test.cpp
@@ -0,0 +1,46 @@
+//===-- Unittests for strnlen----------------------------------------------===//
+//
+// 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/strnlen.h"
+#include "utils/UnitTest/Test.h"
+#include <stddef.h>
+
+TEST(StrNLenTest, EmptyString) {
+ const char *empty = "";
+ ASSERT_EQ(static_cast<size_t>(0), __llvm_libc::strnlen(empty, 0));
+ // If N is greater than string length, this should still return 0.
+ ASSERT_EQ(static_cast<size_t>(0), __llvm_libc::strnlen(empty, 1));
+}
+
+TEST(StrNLenTest, OneCharacterString) {
+ const char *single = "X";
+ ASSERT_EQ(static_cast<size_t>(1), __llvm_libc::strnlen(single, 1));
+ // If N is zero, this should return 0.
+ ASSERT_EQ(static_cast<size_t>(0), __llvm_libc::strnlen(single, 0));
+ // If N is greater than string length, this should still return 1.
+ ASSERT_EQ(static_cast<size_t>(1), __llvm_libc::strnlen(single, 2));
+}
+
+TEST(StrNLenTest, ManyCharacterString) {
+ const char *many = "123456789";
+ ASSERT_EQ(static_cast<size_t>(9), __llvm_libc::strnlen(many, 9));
+ // If N is smaller than the string length, it should return N.
+ ASSERT_EQ(static_cast<size_t>(3), __llvm_libc::strnlen(many, 3));
+ // If N is zero, this should return 0.
+ ASSERT_EQ(static_cast<size_t>(0), __llvm_libc::strnlen(many, 0));
+ // If N is greater than the string length, this should still return 9.
+ ASSERT_EQ(static_cast<size_t>(9), __llvm_libc::strnlen(many, 42));
+}
+
+TEST(StrNLenTest, CharactersAfterNullTerminatorShouldNotBeIncluded) {
+ const char str[5] = {'a', 'b', 'c', '\0', 'd'};
+ ASSERT_EQ(static_cast<size_t>(3), __llvm_libc::strnlen(str, 3));
+ // This should only read up to the null terminator.
+ ASSERT_EQ(static_cast<size_t>(3), __llvm_libc::strnlen(str, 4));
+ ASSERT_EQ(static_cast<size_t>(3), __llvm_libc::strnlen(str, 5));
+}
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