[libc] Changed CharacterConverter returns (#146130)

changed internal CharacterConverter returns to return errno macro when
necessary for consistency.

---------

Co-authored-by: Sriya Pratipati <sriyap@google.com>

libc/src/__support/wchar/CMakeLists.txt

@@ -13,6 +13,7 @@ add_object_library(
   SRCS 
     character_converter.cpp
   DEPENDS
+    libc.hdr.errno_macros
     libc.hdr.types.char8_t
     libc.hdr.types.char32_t
     libc.src.__support.error_or

libc/src/__support/wchar/character_converter.cpp

@@ -6,6 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "hdr/errno_macros.h"
 #include "hdr/types/char32_t.h"
 #include "hdr/types/char8_t.h"
 #include "src/__support/CPP/bit.h"
@@ -76,7 +77,7 @@ int CharacterConverter::push(char8_t utf8_byte) {
     else {
       // bytes_stored and total_bytes will always be 0 here
       state->partial = static_cast<char32_t>(0);
-      return -1;
+      return EILSEQ;
     }
     state->partial = static_cast<char32_t>(utf8_byte);
     state->bytes_stored++;
@@ -93,7 +94,7 @@ int CharacterConverter::push(char8_t utf8_byte) {
   }
   // Invalid byte -> reset the state
   clear();
-  return -1;
+  return EILSEQ;
 }
 
 int CharacterConverter::push(char32_t utf32) {
@@ -115,7 +116,7 @@ int CharacterConverter::push(char32_t utf32) {
   // `utf32` contains a value that is too large to actually represent a valid
   // unicode character
   clear();
-  return -1;
+  return EILSEQ;
 }
 
 ErrorOr<char32_t> CharacterConverter::pop_utf32() {

libc/src/__support/wchar/mbrtowc.cpp

@@ -32,8 +32,8 @@ ErrorOr<size_t> mbrtowc(wchar_t *__restrict pwc, const char *__restrict s,
   for (; i < n && !char_conv.isFull(); ++i) {
     int err = char_conv.push(static_cast<char8_t>(s[i]));
     // Encoding error
-    if (err == -1)
-      return Error(EILSEQ);
+    if (err == EILSEQ)
+      return Error(err);
   }
   auto wc = char_conv.pop_utf32();
   if (wc.has_value()) {

libc/src/__support/wchar/wcrtomb.cpp

@@ -30,12 +30,9 @@ ErrorOr<size_t> wcrtomb(char *__restrict s, wchar_t wc,
   if (!cr.isValidState())
     return Error(EINVAL);
 
-  if (s == nullptr)
-    return Error(EILSEQ);
-
   int status = cr.push(static_cast<char32_t>(wc));
   if (status != 0)
-    return Error(EILSEQ);
+    return Error(status);
 
   size_t count = 0;
   while (!cr.isEmpty()) {

libc/test/src/__support/wchar/utf8_to_32_test.cpp

@@ -6,6 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "hdr/errno_macros.h"
 #include "src/__support/error_or.h"
 #include "src/__support/wchar/character_converter.h"
 #include "src/__support/wchar/mbstate.h"
@@ -87,7 +88,7 @@ TEST(LlvmLibcCharacterConverterUTF8To32Test, InvalidByte) {
   LIBC_NAMESPACE::internal::CharacterConverter char_conv(&state);
   int err = char_conv.push(static_cast<char8_t>(ch));
 
-  ASSERT_EQ(err, -1);
+  ASSERT_EQ(err, EILSEQ);
 }
 
 TEST(LlvmLibcCharacterConverterUTF8To32Test, InvalidMultiByte) {
@@ -100,12 +101,12 @@ TEST(LlvmLibcCharacterConverterUTF8To32Test, InvalidMultiByte) {
 
   LIBC_NAMESPACE::internal::CharacterConverter char_conv(&state);
   int err = char_conv.push(static_cast<char8_t>(ch[0]));
-  ASSERT_EQ(err, -1);
+  ASSERT_EQ(err, EILSEQ);
   err = char_conv.push(static_cast<char8_t>(ch[1]));
   ASSERT_EQ(err, 0);
   // Prev byte was single byte so trying to push another should error.
   err = char_conv.push(static_cast<char8_t>(ch[2]));
-  ASSERT_EQ(err, -1);
+  ASSERT_EQ(err, EILSEQ);
   err = char_conv.push(static_cast<char8_t>(ch[3]));
   ASSERT_EQ(err, 0);
 }
@@ -127,7 +128,7 @@ TEST(LlvmLibcCharacterConverterUTF8To32Test, InvalidLastByte) {
   err = char_conv.push(static_cast<char8_t>(ch[2]));
   ASSERT_EQ(err, 0);
   err = char_conv.push(static_cast<char8_t>(ch[3]));
-  ASSERT_EQ(err, -1);
+  ASSERT_EQ(err, EILSEQ);
 }
 
 TEST(LlvmLibcCharacterConverterUTF8To32Test, ValidTwoByteWithExtraRead) {
@@ -144,7 +145,7 @@ TEST(LlvmLibcCharacterConverterUTF8To32Test, ValidTwoByteWithExtraRead) {
   ASSERT_EQ(err, 0);
   // Should produce an error on 3rd byte
   err = char_conv.push(static_cast<char8_t>(ch[2]));
-  ASSERT_EQ(err, -1);
+  ASSERT_EQ(err, EILSEQ);
 
   // Should produce an error since mbstate was reset
   auto wch = char_conv.pop_utf32();