From patchwork Wed May 1 19:41:22 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Wakely X-Patchwork-Id: 89255 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 987D43858C50 for ; Wed, 1 May 2024 19:45:53 +0000 (GMT) X-Original-To: gcc-patches@gcc.gnu.org Delivered-To: gcc-patches@gcc.gnu.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id EFB3F3858D20 for ; Wed, 1 May 2024 19:45:24 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org EFB3F3858D20 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org EFB3F3858D20 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1714592726; cv=none; b=pfKsJ1gOcizBUctTXJNXKBUW3OIHRlkfaLjLzLiIpiDjfNle9qTHJLhJ55xGQ2NoCvwccqWCNFHfujQOPjFGznh4CfA+OcIalq8RRN07f7+i1Mtv7LZowy7mzMMkJIe0A0eSiYIB18E9BnmRANuep7zpq8PBQpDoI/ITVqnqiwQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1714592726; c=relaxed/simple; bh=MPQ1klDgOHhGyyeCXWe6kUlHWHewbigPsavR3yKL1BI=; h=DKIM-Signature:From:To:Subject:Date:Message-ID:MIME-Version; b=qLZBv2m+I0ZbD3GZPdxXBmGECWuXtNnPdJwAdXTrsvSCUOk0L7dXaTUJ4KflKguLfP5sYcJogz3S+m1Hju//v3qlzLR3kojJ3Fh6kWyC0oD2uiVLSFRHpGd4rw7j/oU2Ixtao5gaqVGdLgzHaELnFwzzg43CsudXAoNxG0SKMNs= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1714592724; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=yEXcO/k3hZWOV0aSELEn3XTC0bblzSVB93B7ah52WeY=; b=HI82/BBdhylajDzMPNTSdXH+lbt0EwvNtnp1GfljXGSpWoBywNeLFbNXHYlyy0/a+d4FjC 8MRszgVevNxgIvMo+KsgRORso+OVvusBVN2bP8akfh0PjtD1DSjgGpHYCfgcfxGsF3+pr4 5KPTgdDvdrIlXEhynnjsVWCD4olqT5s= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-295-l-O28qCHOE-TSTaDfup04Q-1; Wed, 01 May 2024 15:45:22 -0400 X-MC-Unique: l-O28qCHOE-TSTaDfup04Q-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E51E380021A; Wed, 1 May 2024 19:45:21 +0000 (UTC) Received: from localhost (unknown [10.42.28.238]) by smtp.corp.redhat.com (Postfix) with ESMTP id B2E6D1C060D0; Wed, 1 May 2024 19:45:21 +0000 (UTC) From: Jonathan Wakely To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org Subject: [PATCH] libstdc++: Fix handling of incomplete UTF-8 sequences in _Unicode_view Date: Wed, 1 May 2024 20:41:22 +0100 Message-ID: <20240501194521.3292302-1-jwakely@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.7 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-12.3 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: gcc-patches-bounces+patchwork=sourceware.org@gcc.gnu.org Tested x86_64-linux. I'm considering making the increment of __to_incr conditional: if constexpr (!random_access_iterator<_Iter>) ++__to_incr; and then when we call _M_update using _M_curr() - __g._M_orig for the number of characters consumed. I should benchmark that to see if it makes any measurable difference though. -- >8 -- Eddie Nolan reported to me that _Unicode_view was not correctly implementing the substitution of ill-formed subsequences with U+FFFD, due to failing to increment the counter when the iterator reaches the end of the sequence before a multibyte sequence is complete. As a result, the incomplete sequence was not completely consumed, and then the remaining character was treated as another ill-formed sequence, giving two U+FFFD characters instead of one. To avoid similar mistakes in future, this change introduces a lambda that increments the iterator and the counter together. This ensures the counter is always incremented when the iterator is incremented, so that we always know how many characters have been consumed. libstdc++-v3/ChangeLog: * include/bits/unicode.h (_Unicode_view::_M_read_utf8): Ensure count of characters consumed is correct when the end of the input is reached unexpectedly. * testsuite/ext/unicode/view.cc: Test incomplete UTF-8 sequences. --- libstdc++-v3/include/bits/unicode.h | 24 ++++++++++------------ libstdc++-v3/testsuite/ext/unicode/view.cc | 7 +++++++ 2 files changed, 18 insertions(+), 13 deletions(-) diff --git a/libstdc++-v3/include/bits/unicode.h b/libstdc++-v3/include/bits/unicode.h index 29813b743dc..46238143fb6 100644 --- a/libstdc++-v3/include/bits/unicode.h +++ b/libstdc++-v3/include/bits/unicode.h @@ -261,9 +261,13 @@ namespace __unicode { _Guard<_Iter> __g{this, _M_curr()}; char32_t __c{}; - uint8_t __u = *_M_curr()++; const uint8_t __lo_bound = 0x80, __hi_bound = 0xBF; + uint8_t __u = *_M_curr()++; uint8_t __to_incr = 1; + auto __incr = [&, this] { + ++__to_incr; + return ++_M_curr(); + }; if (__u <= 0x7F) [[likely]] // 0x00 to 0x7F __c = __u; @@ -281,8 +285,7 @@ namespace __unicode else { __c = (__c << 6) | (__u & 0x3F); - ++_M_curr(); - ++__to_incr; + __incr(); } } else if (__u <= 0xEF) // 0xE0 to 0xEF @@ -295,11 +298,10 @@ namespace __unicode if (__u < __lo_bound_2 || __u > __hi_bound_2) [[unlikely]] __c = _S_error(); - else if (++_M_curr() == _M_last) [[unlikely]] + else if (__incr() == _M_last) [[unlikely]] __c = _S_error(); else { - ++__to_incr; __c = (__c << 6) | (__u & 0x3F); __u = *_M_curr(); @@ -308,8 +310,7 @@ namespace __unicode else { __c = (__c << 6) | (__u & 0x3F); - ++_M_curr(); - ++__to_incr; + __incr(); } } } @@ -323,21 +324,19 @@ namespace __unicode if (__u < __lo_bound_2 || __u > __hi_bound_2) [[unlikely]] __c = _S_error(); - else if (++_M_curr() == _M_last) [[unlikely]] + else if (__incr() == _M_last) [[unlikely]] __c = _S_error(); else { - ++__to_incr; __c = (__c << 6) | (__u & 0x3F); __u = *_M_curr(); if (__u < __lo_bound || __u > __hi_bound) [[unlikely]] __c = _S_error(); - else if (++_M_curr() == _M_last) [[unlikely]] + else if (__incr() == _M_last) [[unlikely]] __c = _S_error(); else { - ++__to_incr; __c = (__c << 6) | (__u & 0x3F); __u = *_M_curr(); @@ -346,8 +345,7 @@ namespace __unicode else { __c = (__c << 6) | (__u & 0x3F); - ++_M_curr(); - ++__to_incr; + __incr(); } } } diff --git a/libstdc++-v3/testsuite/ext/unicode/view.cc b/libstdc++-v3/testsuite/ext/unicode/view.cc index ee23b0b1d8a..6f3c099bd84 100644 --- a/libstdc++-v3/testsuite/ext/unicode/view.cc +++ b/libstdc++-v3/testsuite/ext/unicode/view.cc @@ -55,6 +55,13 @@ test_illformed_utf8() VERIFY( std::ranges::equal(v5, u8"\uFFFD\uFFFD\uFFFD\uFFFD\uFFFD\x41\uFFFD\uFFFD\x42"sv) ); uc::_Utf8_view v6("\xe1\x80\xe2\xf0\x91\x92\xf1\xbf\x41"sv); // Table 3-11 VERIFY( std::ranges::equal(v6, u8"\uFFFD\uFFFD\uFFFD\uFFFD\x41"sv) ); + + uc::_Utf32_view v7("\xe1\x80"sv); + VERIFY( std::ranges::equal(v7, U"\uFFFD"sv) ); + uc::_Utf32_view v8("\xf1\x80"sv); + VERIFY( std::ranges::equal(v8, U"\uFFFD"sv) ); + uc::_Utf32_view v9("\xf1\x80\x80"sv); + VERIFY( std::ranges::equal(v9, U"\uFFFD"sv) ); } constexpr void