[DPWBS-765] feat(libcxx): provide implementations for functions not provided by Dinkumhtc-11.0.1-alpha2020.06-alpha

2 files changed, 177 insertions, 0 deletions

diff --git a/libcxx/src/CMakeLists.txt b/libcxx/src/CMakeLists.txt
index 898ec027f326..31168f17e798 100644
--- a/libcxx/src/CMakeLists.txt
+++ b/libcxx/src/CMakeLists.txt
@@ -1,3 +1,5 @@
+INCLUDE(CheckCXXSourceCompiles)
+
 set(LIBCXX_LIB_CMAKEFILES_DIR "${CMAKE_CURRENT_BINARY_DIR}${CMAKE_FILES_DIRECTORY}"  PARENT_SCOPE)
 
 # Get sources
@@ -69,6 +71,20 @@ elseif("${CMAKE_SYSTEM_NAME}" STREQUAL "SunOS")
     )
 endif()
 
+check_cxx_source_compiles("
+#include <stdio.h>
+#ifndef _HAS_DINKUM_CLIB
+#error
+#endif
+int main(void) { return 0; }
+" LIBCXX_HAS_DINKUM_CLIB)
+
+if(LIBCXX_HAS_DINKUM_CLIB)
+  list(APPEND LIBCXX_SOURCES
+    support/dinkum/support.cpp
+    )
+endif()
+
 if (LIBCXX_ENABLE_FILESYSTEM)
   list(APPEND LIBCXX_SOURCES
     filesystem/filesystem_common.h
diff --git a/libcxx/src/support/dinkum/support.cpp b/libcxx/src/support/dinkum/support.cpp
new file mode 100644
index 000000000000..25e5d890e062
--- /dev/null
+++ b/libcxx/src/support/dinkum/support.cpp
@@ -0,0 +1,161 @@
+// -*- C++ -*-
+//===----------------------- support/dinkum/support.cpp -------------------===//
+//
+// 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 <cerrno>  // errno
+#include <cstdarg> // va_start, va_end
+#include <cstddef> // size_t
+#include <cstdlib> // malloc
+#include <cstdio>  // vsprintf, vsnprintf
+#include <cstring> // strcpy, wcsncpy
+#include <cwchar>  // mbstate_t
+
+// Like sprintf, but when return value >= 0 it returns
+// a pointer to a malloc'd string in *sptr.
+// If return >= 0, use free to delete *sptr.
+int vasprintf( char **sptr, const char *__restrict format, va_list ap )
+{
+    *sptr = NULL;
+    // Query the count required.
+    int count = vsnprintf( NULL, 0, format, ap );
+    if (count < 0)
+        return count;
+    size_t buffer_size = static_cast<size_t>(count) + 1;
+    char* p = static_cast<char*>(malloc(buffer_size));
+    if ( ! p )
+        return -1;
+    // If we haven't used exactly what was required, something is wrong.
+    // Maybe bug in vsnprintf. Report the error and return.
+    if (vsnprintf(p, buffer_size, format, ap) != count) {
+        free(p);
+        return -1;
+    }
+    // All good. This is returning memory to the caller not freeing it.
+    *sptr = p;
+    return count;
+}
+
+// Returns >= 0: the number of wide characters found in the
+// multi byte sequence src (of src_size_bytes), that fit in the buffer dst
+// (of max_dest_chars elements size). The count returned excludes the
+// null terminator. When dst is NULL, no characters are copied
+// and no "out" parameters are updated.
+// Returns (size_t) -1: an incomplete sequence encountered.
+// Leaves *src pointing the next character to convert or NULL
+// if a null character was converted from *src.
+size_t mbsnrtowcs( wchar_t *__restrict dst, const char **__restrict src,
+                   size_t src_size_bytes, size_t max_dest_chars, mbstate_t *__restrict ps )
+{
+    const size_t terminated_sequence = static_cast<size_t>(0);
+    const size_t incomplete_sequence = static_cast< size_t>(-2);
+
+    size_t dest_converted = 0;
+    size_t source_converted = 0;
+    size_t source_remaining = src_size_bytes;
+    size_t result = 0;
+    bool have_result = false;
+
+    // If dst is null then max_dest_chars should be ignored according to the
+    // standard.  Setting max_dest_chars to a large value has this effect.
+    if (!dst)
+        max_dest_chars = static_cast<size_t>(-1);
+
+    while ( source_remaining ) {
+        if ( dst && dest_converted >= max_dest_chars )
+            break;
+        // Converts one multi byte character.
+        // if result > 0, it's the size in bytes of that character.
+        // othewise if result is zero it indicates the null character has been found.
+        // otherwise it's an error and errno may be set.
+        size_t char_size = mbrtowc( dst ? dst + dest_converted : NULL, *src + source_converted, source_remaining, ps );
+        // Don't do anything to change errno from here on.
+        if ( char_size > 0 ) {
+            source_remaining -= char_size;
+            source_converted += char_size;
+            ++dest_converted;
+            continue;
+        }
+        result = char_size;
+        have_result = true;
+        break;
+    }
+    if ( dst ) {
+        if ( have_result && result == terminated_sequence )
+            *src = NULL;
+        else
+            *src += source_converted;
+    }
+    if ( have_result && result != terminated_sequence && result != incomplete_sequence )
+        return static_cast<size_t>(-1);
+
+    return dest_converted;
+}
+
+// Converts max_source_chars from the wide character buffer pointer to by *src,
+// into the multi byte character sequence buffer stored at dst which must be
+// dst_size_bytes bytes in size.
+// Returns >= 0: the number of bytes in the sequence
+// converted from *src, excluding the null terminator.
+// Returns size_t(-1) if an error occurs, also sets errno.
+// If dst is NULL dst_size_bytes is ignored and no bytes are copied to dst
+// and no "out" parameters are updated.
+size_t wcsnrtombs( char *__restrict dst, const wchar_t **__restrict src,
+                   size_t max_source_chars, size_t dst_size_bytes, mbstate_t *__restrict ps )
+{
+    size_t source_converted = 0;
+    size_t dest_converted = 0;
+    size_t dest_remaining = dst_size_bytes;
+    size_t char_size = 0;
+    const errno_t no_error = ( errno_t) 0;
+    errno_t result = ( errno_t ) 0;
+    bool have_result = false;
+    bool terminator_found = false;
+
+    // If dst is null then dst_size_bytes should be ignored according to the
+    // standard.  Setting dest_remaining to a large value has this effect.
+    if (!dst)
+        dest_remaining = static_cast<size_t>(-1);
+
+    while ( source_converted != max_source_chars ) {
+        if ( ! dest_remaining )
+            break;
+        wchar_t c = (*src)[source_converted];
+        if ( dst )
+            result = wcrtomb_s( &char_size, dst + dest_converted, dest_remaining, c, ps);
+        else
+            result = wcrtomb_s( &char_size, NULL, 0, c, ps);
+        // If result is zero there is no error and char_size contains the
+        // size of the multi-byte-sequence converted.
+        // Otherwise result indicates an errno type error.
+        if ( result == no_error ) {
+            if ( c == L'\0' ) {
+                terminator_found = true;
+                break;
+            }
+            ++source_converted;
+            if ( dst )
+                dest_remaining -= char_size;
+            dest_converted += char_size;
+            continue;
+        }
+        have_result = true;
+        break;
+    }
+    if ( dst ) {
+        if ( terminator_found )
+            *src = NULL;
+        else
+            *src = *src + source_converted;
+    }
+    if ( have_result && result != no_error ) {
+        errno = result;
+        return static_cast<size_t>(-1);
+    }
+
+    return dest_converted;
+}