Skip to content

[libc] wcsspn implementation #142034

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 5 commits into from
May 30, 2025
Merged

Conversation

sribee8
Copy link
Contributor

@sribee8 sribee8 commented May 29, 2025

Implemented wcsspn as well as tests for the function.

Implemented wcsspn as well as tests for the function.
@llvmbot llvmbot added the libc label May 29, 2025
@llvmbot
Copy link
Member

llvmbot commented May 29, 2025

@llvm/pr-subscribers-libc

Author: None (sribee8)

Changes

Implemented wcsspn as well as tests for the function.


Full diff: https://github.com/llvm/llvm-project/pull/142034.diff

7 Files Affected:

  • (modified) libc/config/linux/x86_64/entrypoints.txt (+1)
  • (modified) libc/include/wchar.yaml (+7)
  • (modified) libc/src/wchar/CMakeLists.txt (+12)
  • (added) libc/src/wchar/wcsspn.cpp (+35)
  • (added) libc/src/wchar/wcsspn.h (+22)
  • (modified) libc/test/src/wchar/CMakeLists.txt (+10)
  • (added) libc/test/src/wchar/wcsspn_test.cpp (+86)
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index c1ba26008ca9c..2a35988ed24f4 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -366,6 +366,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.wchar.wctob
     libc.src.wchar.wmemset
     libc.src.wchar.wcschr
+    libc.src.wchar.wcsspn
 
     # sys/uio.h entrypoints
     libc.src.sys.uio.writev
diff --git a/libc/include/wchar.yaml b/libc/include/wchar.yaml
index 0342c726146b3..94b9ed89c1e45 100644
--- a/libc/include/wchar.yaml
+++ b/libc/include/wchar.yaml
@@ -42,3 +42,10 @@ functions:
     arguments: 
       - type: const wchar_t *
       - type: wchar_t
+  - name: wcsspn
+    standards:
+      - stdc
+    return_type: size_t
+    arguments: 
+      - type: const wchar_t *
+      - type: const wchar_t *
diff --git a/libc/src/wchar/CMakeLists.txt b/libc/src/wchar/CMakeLists.txt
index caec1a3f3266f..dcafd36978e49 100644
--- a/libc/src/wchar/CMakeLists.txt
+++ b/libc/src/wchar/CMakeLists.txt
@@ -56,3 +56,15 @@ add_entrypoint_object(
     libc.hdr.wchar_macros
     libc.src.__support.wctype_utils
 )
+
+add_entrypoint_object(
+  wcsspn
+  SRCS
+    wcsspn.cpp
+  HDRS
+    wcsspn.h
+  DEPENDS
+    libc.hdr.wchar_macros
+    libc.hdr.types.size_t
+    libc.src.__support.wctype_utils
+)
diff --git a/libc/src/wchar/wcsspn.cpp b/libc/src/wchar/wcsspn.cpp
new file mode 100644
index 0000000000000..8bbb7096c0344
--- /dev/null
+++ b/libc/src/wchar/wcsspn.cpp
@@ -0,0 +1,35 @@
+//===-- Implementation of wcsspn ------------------------------------------===//
+//
+// 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/wchar/wcsspn.h"
+
+#include "hdr/types/size_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/__support/CPP/bitset.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(size_t, wcsspn, (const wchar_t *s1, const wchar_t *s2)) {
+  size_t i = 0;
+  int in_s2 = 0;
+  for (; s1[i]; ++i) {
+    for (int n = 0; s2[n] && in_s2 == 0; ++n) {
+      if (s1[i] == s2[n])
+        in_s2 = 1;
+    }
+    if (in_s2 == 0) {
+      return i;
+    }
+    in_s2 = 0;
+  }
+  return i;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/wchar/wcsspn.h b/libc/src/wchar/wcsspn.h
new file mode 100644
index 0000000000000..6dbe65d9a4a98
--- /dev/null
+++ b/libc/src/wchar/wcsspn.h
@@ -0,0 +1,22 @@
+//===-- Implementation header for wcsspn ----------------------------------===//
+//
+// 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_WCHAR_WCSSPN_H
+#define LLVM_LIBC_SRC_WCHAR_WCSSPN_H
+
+#include "hdr/types/size_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+size_t wcsspn(const wchar_t *s1, const wchar_t *s2);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_WCHAR_WCSCHR_H
diff --git a/libc/test/src/wchar/CMakeLists.txt b/libc/test/src/wchar/CMakeLists.txt
index 4c75f070cf400..2b99a94d14a7e 100644
--- a/libc/test/src/wchar/CMakeLists.txt
+++ b/libc/test/src/wchar/CMakeLists.txt
@@ -54,3 +54,13 @@ add_libc_test(
   DEPENDS
     libc.src.wchar.wcschr
 )
+
+add_libc_test(
+  wcsspn_test
+  SUITE
+    libc_wchar_unittests
+  SRCS
+    wcsspn_test.cpp
+  DEPENDS
+    libc.src.wchar.wcsspn
+)
diff --git a/libc/test/src/wchar/wcsspn_test.cpp b/libc/test/src/wchar/wcsspn_test.cpp
new file mode 100644
index 0000000000000..fbcc35f2f63c3
--- /dev/null
+++ b/libc/test/src/wchar/wcsspn_test.cpp
@@ -0,0 +1,86 @@
+//===-- Unittests for wcsspn ----------------------------------------------===//
+//
+// 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/types/size_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/wchar/wcsspn.h"
+#include "test/UnitTest/Test.h"
+
+TEST(LlvmLibcWCSSpnTest, EmptyStringShouldReturnZeroLengthSpan) {
+  // The search should not include the null terminator.
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"", L""), size_t{0});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"_", L""), size_t{0});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"", L"_"), size_t{0});
+}
+
+TEST(LlvmLibcWCSSpnTest, ShouldNotSpanAnythingAfterNullTerminator) {
+  const wchar_t src[4] = {'a', 'b', '\0', 'c'};
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(src, L"ab"), size_t{2});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(src, L"c"), size_t{0});
+
+  // Same goes for the segment to be searched for.
+  const wchar_t segment[4] = {'1', '2', '\0', '3'};
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"123", segment), size_t{2});
+}
+
+TEST(LlvmLibcWCSSpnTest, SpanEachIndividualCharacter) {
+  const wchar_t *src = L"12345";
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(src, L"1"), size_t{1});
+  // Since '1' is not within the segment, the span
+  // size should remain zero.
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(src, L"2"), size_t{0});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(src, L"3"), size_t{0});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(src, L"4"), size_t{0});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(src, L"5"), size_t{0});
+}
+
+TEST(LlvmLibcWCSSpnTest, UnmatchedCharacterShouldNotBeCountedInSpan) {
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"a", L"b"), size_t{0});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"abcdef", L"1"), size_t{0});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"123", L"4"), size_t{0});
+}
+
+TEST(LlvmLibcWCSSpnTest, SequentialCharactersShouldSpan) {
+  const wchar_t *src = L"abcde";
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(src, L"a"), size_t{1});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(src, L"ab"), size_t{2});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(src, L"abc"), size_t{3});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(src, L"abcd"), size_t{4});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(src, L"abcde"), size_t{5});
+  // Same thing for when the roles are reversed.
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"abcde", src), size_t{5});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"abcd", src), size_t{4});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"abc", src), size_t{3});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"ab", src), size_t{2});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"a", src), size_t{1});
+}
+
+TEST(LlvmLibcWCSSpnTest, NonSequentialCharactersShouldNotSpan) {
+  const wchar_t *src = L"123456789";
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(src, L"_1_abc_2_def_3_"), size_t{3});
+  // Only spans 4 since '5' is not within the span.
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(src, L"67__34abc12"), size_t{4});
+}
+
+TEST(LlvmLibcWCSSpnTest, ReverseCharacters) {
+  // Since these are still sequential, this should span.
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"12345", L"54321"), size_t{5});
+  // Does not span any since '1' is not within the span.
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"12345", L"432"), size_t{0});
+  // Only spans 1 since '2' is not within the span.
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"12345", L"51"), size_t{1});
+}
+
+TEST(LlvmLibcWCSSpnTest, DuplicatedCharactersToBeSearchedForShouldStillMatch) {
+  // Only a single character, so only spans 1.
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"a", L"aa"), size_t{1});
+  // This should count once for each 'a' in the source string.
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"aa", L"aa"), size_t{2});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"aaa", L"aa"), size_t{3});
+  EXPECT_EQ(LIBC_NAMESPACE::wcsspn(L"aaaa", L"aa"), size_t{4});
+}

Copy link
Contributor

@michaelrj-google michaelrj-google left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Overall LGTM with some test comments

Copy link
Contributor

@michaelrj-google michaelrj-google left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

LGTM

@michaelrj-google michaelrj-google merged commit d4791f5 into llvm:main May 30, 2025
13 of 15 checks passed
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
Projects
None yet
Development

Successfully merging this pull request may close these issues.

3 participants