From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by sourceware.org (Postfix) with ESMTPS id A2FF63858D37 for ; Tue, 23 May 2023 07:19:09 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org A2FF63858D37 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=suse.de Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id C4E3221AD0 for ; Tue, 23 May 2023 07:19:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1684826348; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=6DzTpyxvRmc7W4ivsVIrEyC4trdyeHnDgVO4WaWVzFo=; b=x2NPJrJbVsKcBmCjq/VrLoQA1/TThNaaYAu/4Xr6TSGZiJAsQfhZw1DBBZUmvrsy3CPvta SYhJ6lzzyk8H6YwekAv7U4H4vd9lPGpNXIax2Fad3hTcn/MG+2U2Eo/Nrj8x5sm89yfqdD /Mm0TrXDDaZBdLGGdhpPBl8ofOPVNw0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1684826348; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=6DzTpyxvRmc7W4ivsVIrEyC4trdyeHnDgVO4WaWVzFo=; b=2IWkBBs0nSpljLTr2vgBfI46TlMN1AJQPV2rgVtDo1ImA/tgIihitzP219dId94yLXYcWo +wO1mzr15kJHHbAg== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id AEF9313588 for ; Tue, 23 May 2023 07:19:08 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id DwOiKexobGT3GwAAMHmgww (envelope-from ) for ; Tue, 23 May 2023 07:19:08 +0000 From: Tom de Vries To: gdb-patches@sourceware.org Subject: [PATCH] [gdb] Add template functions assign_set/return_if_changed Date: Tue, 23 May 2023 09:19:12 +0200 Message-Id: <20230523071912.2197-1-tdevries@suse.de> X-Mailer: git-send-email 2.35.3 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-12.4 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,SPF_HELO_NONE,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE 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: Add template function assign_set_if_changed in gdb/utils.h: ... template void assign_set_if_changed (T &lval, T val, bool &changed) { if (lval == val) return; lval = val; changed = true; } ... This allows us to rewrite code like this: ... if (tui_border_attrs != entry->value) { tui_border_attrs = entry->value; need_redraw = true; } ... into this: ... assign_set_if_changed (tui_border_attrs, entry->value, need_redraw); ... The name is a composition of its functionality: - it assigns val to lval, and - is sets changed to true if the assignment changed lval. I've initially considered using assign_return_if_changed for the rewrite: ... template bool assign_return_if_changed (T &lval, T val) { if (lval == val) return false; lval = val; changed = true; } ... but liked the resulting bitwise operator on the boolean a bit less: ... need_redraw |= assign_return_if_changed (tui_border_attrs, entry->value); ... I've included it anyway, it may be the preferred choice in other cases. Tested on x86_64-linux. --- gdb/utils.c | 39 +++++++++++++++++++++++++++++++++++++++ gdb/utils.h | 27 +++++++++++++++++++++++++++ 2 files changed, 66 insertions(+) diff --git a/gdb/utils.c b/gdb/utils.c index f18228d1086..46bfd9a5bbb 100644 --- a/gdb/utils.c +++ b/gdb/utils.c @@ -3631,6 +3631,43 @@ copy_bitwise (gdb_byte *dest, ULONGEST dest_offset, } } +#if GDB_SELF_TEST +static void +test_assign_set_return_if_changed () +{ + bool changed; + int a; + + for (bool initial : { false, true }) + { + changed = initial; + a = 1; + assign_set_if_changed (a, 1, changed); + SELF_CHECK (a == 1); + SELF_CHECK (changed == initial); + } + + for (bool initial : { false, true }) + { + changed = initial; + a = 1; + assign_set_if_changed (a, 2, changed); + SELF_CHECK (a == 2); + SELF_CHECK (changed == true); + } + + a = 1; + changed = assign_return_if_changed (a, 1); + SELF_CHECK (a == 1); + SELF_CHECK (changed == false); + + a = 1; + assign_set_if_changed (a, 2, changed); + SELF_CHECK (a == 2); + SELF_CHECK (changed == true); +} +#endif + void _initialize_utils (); void _initialize_utils () @@ -3695,5 +3732,7 @@ When set, debugging messages will be marked with seconds and microseconds."), selftests::register_test ("strncmp_iw_with_mode", strncmp_iw_with_mode_tests); selftests::register_test ("pager", test_pager); + selftests::register_test ("assign_set_return_if_changed", + test_assign_set_return_if_changed); #endif } diff --git a/gdb/utils.h b/gdb/utils.h index 00b123e6117..d78d54911bf 100644 --- a/gdb/utils.h +++ b/gdb/utils.h @@ -337,4 +337,31 @@ extern void copy_bitwise (gdb_byte *dest, ULONGEST dest_offset, extern int readline_hidden_cols; +/* Assign VAL to LVAL, and set CHANGED to true if the assignment changed + LVAL. */ + +template +void +assign_set_if_changed (T &lval, T val, bool &changed) +{ + if (lval == val) + return; + + lval = val; + changed = true; +} + +/* Assign VAL to LVAL, and return true if the assignment changed LVAL. */ + +template +bool +assign_return_if_changed (T &lval, T val) +{ + if (lval == val) + return false; + + lval = val; + return true; +} + #endif /* UTILS_H */ base-commit: e1eecd81cc6a40b3547a7c5d456919275a0b4a27 -- 2.35.3