| //===----------------------------------------------------------------------===// | |
| // | |
| // 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 | |
| // | |
| //===----------------------------------------------------------------------===// | |
| // 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 the number of bytes in the sequence | |
| // converted from *src, excluding the null terminator. | |
| // Returns (size_t) -1 if an error occurs and sets errno. | |
| // If `dst` is NULL, `dst_size_bytes` is ignored and no bytes are copied to `dst`. | |
| _LIBCPP_EXPORTED_FROM_ABI 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) { | |
| const size_t invalid_wchar = static_cast<size_t>(-1); | |
| size_t source_converted; | |
| size_t dest_converted; | |
| size_t result = 0; | |
| // If `dst` is null then `dst_size_bytes` should be ignored according to the | |
| // standard. Setting dst_size_bytes to a large value has this effect. | |
| if (dst == nullptr) | |
| dst_size_bytes = static_cast<size_t>(-1); | |
| for (dest_converted = source_converted = 0; | |
| source_converted < max_source_chars && (!dst || dest_converted < dst_size_bytes); | |
| ++source_converted, dest_converted += result) { | |
| wchar_t c = (*src)[source_converted]; | |
| size_t dest_remaining = dst_size_bytes - dest_converted; | |
| if (dst == nullptr) { | |
| result = wcrtomb(nullptr, c, ps); | |
| } else if (dest_remaining >= static_cast<size_t>(MB_CUR_MAX)) { | |
| // dst has enough space to translate in-place. | |
| result = wcrtomb(dst + dest_converted, c, ps); | |
| } else { | |
| /* | |
| * dst may not have enough space, so use a temporary buffer. | |
| * | |
| * We need to save a copy of the conversion state | |
| * here so we can restore it if the multibyte | |
| * character is too long for the buffer. | |
| */ | |
| char buff[MB_LEN_MAX]; | |
| mbstate_t mbstate_tmp; | |
| if (ps != nullptr) | |
| mbstate_tmp = *ps; | |
| result = wcrtomb(buff, c, ps); | |
| if (result > dest_remaining) { | |
| // Multi-byte sequence for character won't fit. | |
| if (ps != nullptr) | |
| *ps = mbstate_tmp; | |
| if (result != invalid_wchar) | |
| break; | |
| } else { | |
| // The buffer was used, so we need copy the translation to dst. | |
| memcpy(dst, buff, result); | |
| } | |
| } | |
| // result (char_size) contains the size of the multi-byte-sequence converted. | |
| // Otherwise, result (char_size) is (size_t) -1 and wcrtomb() sets the errno. | |
| if (result == invalid_wchar) { | |
| if (dst) | |
| *src = *src + source_converted; | |
| return invalid_wchar; | |
| } | |
| if (c == L'\0') { | |
| if (dst) | |
| *src = nullptr; | |
| return dest_converted; | |
| } | |
| } | |
| if (dst) | |
| *src = *src + source_converted; | |
| return dest_converted; | |
| } | |