[libc-commits] [libc] [libc] mbrtowc implementation (PR #144760)

[Uzair Nawaz via libc-commits]

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@@ -0,0 +1,170 @@
+//===-- Unittests for mbrtowc ---------------------------------------------===//
+//
+// 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/mbstate_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/__support/libc_errno.h"
+#include "src/string/memset.h"
+#include "src/wchar/mbrtowc.h"
+#include "test/UnitTest/Test.h"
+
+TEST(LlvmLibcMBRToWC, OneByte) {
+  const char *ch = "A";
+  wchar_t dest[2];
+  // Testing if it works with nullptr mbstate_t
+  mbstate_t *mb = nullptr;
+  size_t n = LIBC_NAMESPACE::mbrtowc(dest, ch, 1, mb);
+  ASSERT_EQ(static_cast<char>(*dest), 'A');
+  ASSERT_EQ(static_cast<int>(n), 1);
+
+  // Should fail since we have not read enough
+  n = LIBC_NAMESPACE::mbrtowc(dest, ch, 0, mb);
+  ASSERT_EQ(static_cast<int>(n), -2);
+}
+
+TEST(LlvmLibcMBRToWC, TwoByte) {
+  const char ch[2] = {static_cast<char>(0xC2),
+                      static_cast<char>(0x8E)}; // Ž car symbol
+  wchar_t dest[2];
+  mbstate_t *mb;
+  LIBC_NAMESPACE::memset(&mb, 0, sizeof(mbstate_t));
+  size_t n = LIBC_NAMESPACE::mbrtowc(dest, ch, 2, mb);
+  ASSERT_EQ(static_cast<int>(*dest), 142);
+  ASSERT_EQ(static_cast<int>(n), 2);
+
+  // Should fail since we have not read enough
+  n = LIBC_NAMESPACE::mbrtowc(dest, ch, 1, mb);
+  ASSERT_EQ(static_cast<int>(n), -2);
+  // Should pass after reading one more byte
+  n = LIBC_NAMESPACE::mbrtowc(dest, ch + 1, 1, mb);
+  ASSERT_EQ(static_cast<int>(n), 1);
+  ASSERT_EQ(static_cast<int>(*dest), 142);
+}
+
+TEST(LlvmLibcMBRToWC, ThreeByte) {
+  const char ch[3] = {static_cast<char>(0xE2), static_cast<char>(0x88),
+                      static_cast<char>(0x91)}; // ∑ sigma symbol
+  wchar_t dest[2];
+  mbstate_t *mb;
+  LIBC_NAMESPACE::memset(&mb, 0, sizeof(mbstate_t));
+  size_t n = LIBC_NAMESPACE::mbrtowc(dest, ch, 3, mb);
+  ASSERT_EQ(static_cast<int>(*dest), 8721);
+  ASSERT_EQ(static_cast<int>(n), 3);
+
+  // Should fail since we have not read enough
+  n = LIBC_NAMESPACE::mbrtowc(dest, ch, 1, mb);
+  ASSERT_EQ(static_cast<int>(n), -2);
+  // Should pass after reading two more bytes
+  n = LIBC_NAMESPACE::mbrtowc(dest, ch + 1, 2, mb);
+  ASSERT_EQ(static_cast<int>(n), 2);
+  ASSERT_EQ(static_cast<int>(*dest), 8721);
+}
+
+TEST(LlvmLibcMBRToWC, FourByte) {
+  const char ch[4] = {static_cast<char>(0xF0), static_cast<char>(0x9F),
+                      static_cast<char>(0xA4),
+                      static_cast<char>(0xA1)}; // 🤡 clown emoji
+  wchar_t dest[2];
+  mbstate_t *mb;
+  LIBC_NAMESPACE::memset(&mb, 0, sizeof(mbstate_t));
+  size_t n = LIBC_NAMESPACE::mbrtowc(dest, ch, 4, mb);
+  ASSERT_EQ(static_cast<int>(*dest), 129313);
+  ASSERT_EQ(static_cast<int>(n), 4);
+
+  // Should fail since we have not read enough
+  n = LIBC_NAMESPACE::mbrtowc(dest, ch, 2, mb);
+  ASSERT_EQ(static_cast<int>(n), -2);
+  // Should pass after reading two more bytes
+  n = LIBC_NAMESPACE::mbrtowc(dest, ch + 2, 2, mb);
+  ASSERT_EQ(static_cast<int>(n), 2);
+  ASSERT_EQ(static_cast<int>(*dest), 129313);
+}
+
+TEST(LlvmLibcMBRToWC, InvalidByte) {
+  const char ch[1] = {static_cast<char>(0x80)};
+  wchar_t dest[2];
+  mbstate_t *mb;
+  LIBC_NAMESPACE::memset(&mb, 0, sizeof(mbstate_t));
+  size_t n = LIBC_NAMESPACE::mbrtowc(dest, ch, 1, mb);
+  ASSERT_EQ(static_cast<int>(n), -1);
+  ASSERT_EQ(static_cast<int>(libc_errno), EILSEQ);
+}
+
+TEST(LlvmLibcMBRToWC, InvalidMultiByte) {
+  const char ch[4] = {static_cast<char>(0x80), static_cast<char>(0x00),
+                      static_cast<char>(0x80),
+                      static_cast<char>(0x00)}; // invalid sequence of bytes
+  wchar_t dest[2];
+  mbstate_t *mb;
+  LIBC_NAMESPACE::memset(&mb, 0, sizeof(mbstate_t));
+  // Trying to push all 4 should error
+  size_t n = LIBC_NAMESPACE::mbrtowc(dest, ch, 4, mb);
+  ASSERT_EQ(static_cast<int>(n), -1);
+  ASSERT_EQ(static_cast<int>(libc_errno), EILSEQ);
+  // Trying to push just the first one should error
+  n = LIBC_NAMESPACE::mbrtowc(dest, ch, 1, mb);
+  ASSERT_EQ(static_cast<int>(n), -1);
+  ASSERT_EQ(static_cast<int>(libc_errno), EILSEQ);
+  // Trying to push the second and third should correspond to null wc
+  n = LIBC_NAMESPACE::mbrtowc(dest, ch + 1, 2, mb);
+  ASSERT_EQ(static_cast<int>(n), 0);
----------------
uzairnawaz wrote:

add a check to confirm that dest[0] == L'\0'

https://github.com/llvm/llvm-project/pull/144760