From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 5BFD33858D39 for ; Wed, 19 Oct 2022 10:29:12 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 5BFD33858D39 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666175351; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=VIf1j+5LIcsKqg7ac0TzXvMybuDVwVHhIcSZAHAa4a8=; b=S4gjOj7SSm96Zmr4DO6hxhN3T9w7KuJcau0PIg3k4HiMdciwpwfrQoM6B6N1rwr+mTFM9j eVXmLjM0KXp5HbNHz4ONvy0CZ/4q1zY/opMhhNJ13IwyD7UkOEXHNyJWJjUIb0xdSz7X18 +dN4jAOEBh5vpsL67oSavDFVp8vv1PM= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-75-uM_YEaa6O_-vawDjDJEwsg-1; Wed, 19 Oct 2022 06:29:08 -0400 X-MC-Unique: uM_YEaa6O_-vawDjDJEwsg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 7784187B2A4; Wed, 19 Oct 2022 10:29:03 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.2.16.74]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 29DB1414A819; Wed, 19 Oct 2022 10:28:55 +0000 (UTC) From: Florian Weimer To: Pedro Alves Cc: gdb@sourceware.org, "Zaric, Zoran (Zare)" Subject: Re: gmp's c++ interface / mpz_class References: Date: Wed, 19 Oct 2022 12:28:53 +0200 In-Reply-To: (Pedro Alves's message of "Fri, 14 Oct 2022 21:42:10 +0100") Message-ID: <87lepcgl96.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-4.8 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,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 List-Id: * Pedro Alves: > Hmm. Since we don't need infinite precision, it will end up a lot > more efficient to roll our own type, with fixed (or templated) storage > size. Like a simplified version of GCC's wide_int. Not sure yet > whether efficiency really matters in practice, but I suspect it does. > > I'd still be curious about GMP's native C++ interface. I tried to use it recently in a hobby project, but it turned out to be a poor fit because it's not integrated well with C++11 and later features (no move constructors, no rvalue references). The unconditional use of malloc is rather off-putting, too. I'm contemplating to use tagged integers/pointers as the main representation, with heap allocation only on demand, maybe using the the mpn* functions directly, or perhaps copy things out of a long-lasting mpz_t object that's used as a temporary for arithmetic. For 72-bit integers, that seems a bit over the top, though. Thanks, Florian