From nobody Mon May 6 10:35:12 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1503384812351767.755751855347; Mon, 21 Aug 2017 23:53:32 -0700 (PDT) Received: from localhost ([::1]:46068 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dk345-0002S0-9n for importer@patchew.org; Tue, 22 Aug 2017 02:53:29 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48715) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dk336-00021T-3q for qemu-devel@nongnu.org; Tue, 22 Aug 2017 02:52:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dk333-0007nZ-2O for qemu-devel@nongnu.org; Tue, 22 Aug 2017 02:52:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55486) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dk332-0007n7-S4 for qemu-devel@nongnu.org; Tue, 22 Aug 2017 02:52:24 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B95EF7EA80 for ; Tue, 22 Aug 2017 06:52:22 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-116-60.ams2.redhat.com [10.36.116.60]) by smtp.corp.redhat.com (Postfix) with ESMTPS id ADAD07EBD1; Tue, 22 Aug 2017 06:52:20 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 1B2271138646; Tue, 22 Aug 2017 08:52:19 +0200 (CEST) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com B95EF7EA80 Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=armbru@redhat.com From: Markus Armbruster To: qemu-devel@nongnu.org Date: Tue, 22 Aug 2017 08:52:19 +0200 Message-Id: <1503384739-17207-1-git-send-email-armbru@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Tue, 22 Aug 2017 06:52:23 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH] qobject: Explain how QNum works, and why X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: marcandre.lureau@redhat.com, mreitz@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Suggested-by: Max Reitz Signed-off-by: Markus Armbruster Reviewed-by: Marc-Andr=C3=A9 Lureau Reviewed-by: Max Reitz --- include/qapi/qmp/qnum.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/include/qapi/qmp/qnum.h b/include/qapi/qmp/qnum.h index 09d745c..9182129 100644 --- a/include/qapi/qmp/qnum.h +++ b/include/qapi/qmp/qnum.h @@ -23,6 +23,27 @@ typedef enum { QNUM_DOUBLE } QNumKind; =20 +/* + * QNum encapsulates how our dialect of JSON fills in the blanks left + * by the JSON specification (RFC 7159) regarding numbers. + * + * Conceptually, we treat number as an abstract type with three + * concrete subtypes: floating-point, signed integer, unsigned + * integer. QNum implements this a discriminated union of double, + * int64_t, uint64_t. + * + * The JSON parser picks the subtype as follows. If the number has a + * decimal point or an exponent, it is floating-point. Else if it + * fits into int64_t, it's signed integer. Else if it first into + * uint64_t, it's unsigned integer. Else it's floating-point. + * + * Any number can serve as double: qnum_get_double() converts under + * the hood. + * + * An integer can serve as signed / unsigned integer as long as it is + * in range: qnum_get_try_int() / qnum_get_try_uint() check range and + * convert under the hood. + */ typedef struct QNum { QObject base; QNumKind kind; --=20 2.7.5