From 26a029d407be480d791972afb5975cf62c9360a6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 19 Apr 2024 02:47:55 +0200 Subject: Adding upstream version 124.0.1. Signed-off-by: Daniel Baumann --- mfbt/MacroArgs.h | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+) create mode 100644 mfbt/MacroArgs.h (limited to 'mfbt/MacroArgs.h') diff --git a/mfbt/MacroArgs.h b/mfbt/MacroArgs.h new file mode 100644 index 0000000000..9afaaef945 --- /dev/null +++ b/mfbt/MacroArgs.h @@ -0,0 +1,97 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +/* + * Implements various macros meant to ease the use of variadic macros. + */ + +#ifndef mozilla_MacroArgs_h +#define mozilla_MacroArgs_h + +// Concatenates pre-processor tokens in a way that can be used with __LINE__. +#define MOZ_CONCAT2(x, y) x##y +#define MOZ_CONCAT(x, y) MOZ_CONCAT2(x, y) + +/* + * MOZ_ARG_COUNT(...) counts the number of variadic arguments. + * You must pass in between 0 and 50 (inclusive) variadic arguments. + * For example: + * + * MOZ_ARG_COUNT() expands to 0 + * MOZ_ARG_COUNT(a) expands to 1 + * MOZ_ARG_COUNT(a, b) expands to 2 + * + * Implementation notes: + * The `##__VA_ARGS__` form is a GCC extension that removes the comma if + * __VA_ARGS__ is empty. It is supported by Clang too. MSVC ignores ##, + * and its default behavior is already to strip the comma when __VA_ARGS__ + * is empty. + * + * So MOZ_MACROARGS_ARG_COUNT_HELPER() expands to + * (_, 50, 49, ...) + * MOZ_MACROARGS_ARG_COUNT_HELPER(a) expands to + * (_, a, 50, 49, ...) + * etc. + */ +#define MOZ_ARG_COUNT(...) \ + MOZ_MACROARGS_ARG_COUNT_HELPER2(MOZ_MACROARGS_ARG_COUNT_HELPER(__VA_ARGS__)) + +#define MOZ_MACROARGS_ARG_COUNT_HELPER(...) \ + (_, ##__VA_ARGS__, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, \ + 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, \ + 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) + +#define MOZ_MACROARGS_ARG_COUNT_HELPER2(aArgs) \ + MOZ_MACROARGS_ARG_COUNT_HELPER3 aArgs + +#define MOZ_MACROARGS_ARG_COUNT_HELPER3( \ + a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, \ + a17, a18, a19, a20, a21, a22, a23, a24, a25, a26, a27, a28, a29, a30, a31, \ + a32, a33, a34, a35, a36, a37, a38, a39, a40, a41, a42, a43, a44, a45, a46, \ + a47, a48, a49, a50, a51, ...) \ + a51 + +/* + * MOZ_PASTE_PREFIX_AND_ARG_COUNT(aPrefix, ...) counts the number of variadic + * arguments and prefixes it with |aPrefix|. For example: + * + * MOZ_PASTE_PREFIX_AND_ARG_COUNT(, foo, 42) expands to 2 + * MOZ_PASTE_PREFIX_AND_ARG_COUNT(A, foo, 42, bar) expands to A3 + * MOZ_PASTE_PREFIX_AND_ARG_COUNT(A) expands to A0 + * MOZ_PASTE_PREFIX_AND_ARG_COUNT() expands to 0, but MSVC warns there + * aren't enough arguments given. + * + * You must pass in between 0 and 50 (inclusive) variadic arguments, past + * |aPrefix|. + */ +#define MOZ_PASTE_PREFIX_AND_ARG_COUNT_GLUE(a, b) a b +#define MOZ_PASTE_PREFIX_AND_ARG_COUNT(aPrefix, ...) \ + MOZ_PASTE_PREFIX_AND_ARG_COUNT_GLUE(MOZ_CONCAT, \ + (aPrefix, MOZ_ARG_COUNT(__VA_ARGS__))) + +/* + * MOZ_ARGS_AFTER_N expands to its arguments excluding the first |N| + * arguments. For example: + * + * MOZ_ARGS_AFTER_2(a, b, c, d) expands to: c, d + */ +#define MOZ_ARGS_AFTER_1(a1, ...) __VA_ARGS__ +#define MOZ_ARGS_AFTER_2(a1, a2, ...) __VA_ARGS__ + +/* + * MOZ_ARG_N expands to its |N|th argument. + */ +#define MOZ_ARG_1(a1, ...) a1 +#define MOZ_ARG_2(a1, a2, ...) a2 +#define MOZ_ARG_3(a1, a2, a3, ...) a3 +#define MOZ_ARG_4(a1, a2, a3, a4, ...) a4 +#define MOZ_ARG_5(a1, a2, a3, a4, a5, ...) a5 +#define MOZ_ARG_6(a1, a2, a3, a4, a5, a6, ...) a6 +#define MOZ_ARG_7(a1, a2, a3, a4, a5, a6, a7, ...) a7 +#define MOZ_ARG_8(a1, a2, a3, a4, a5, a6, a7, a8, ...) a8 +#define MOZ_ARG_9(a1, a2, a3, a4, a5, a6, a7, a8, a9, ...) a9 + +#endif /* mozilla_MacroArgs_h */ -- cgit v1.2.3