From 667edcd9d0a835c7f562d107d861a4ab88ff86ba Mon Sep 17 00:00:00 2001 From: Max Kellermann Date: Fri, 18 Mar 2016 14:03:00 +0100 Subject: [PATCH] util/IterableSplitString: cheaper variant of SplitString() --- Makefile.am | 1 + src/output/plugins/JackOutputPlugin.cxx | 6 +- src/util/IterableSplitString.hxx | 123 ++++++++++++++++++++++++ src/util/SplitString.cxx | 25 ++--- 4 files changed, 135 insertions(+), 20 deletions(-) create mode 100644 src/util/IterableSplitString.hxx diff --git a/Makefile.am b/Makefile.am index 9be7e6c2e..845fc8f7b 100644 --- a/Makefile.am +++ b/Makefile.am @@ -415,6 +415,7 @@ libutil_a_SOURCES = \ src/util/WStringAPI.hxx \ src/util/DivideString.cxx src/util/DivideString.hxx \ src/util/SplitString.cxx src/util/SplitString.hxx \ + src/util/IterableSplitString.hxx \ src/util/FormatString.cxx src/util/FormatString.hxx \ src/util/Tokenizer.cxx src/util/Tokenizer.hxx \ src/util/TextFile.hxx \ diff --git a/src/output/plugins/JackOutputPlugin.cxx b/src/output/plugins/JackOutputPlugin.cxx index 26d3d838b..7d05e7a73 100644 --- a/src/output/plugins/JackOutputPlugin.cxx +++ b/src/output/plugins/JackOutputPlugin.cxx @@ -23,7 +23,7 @@ #include "../Wrapper.hxx" #include "config/ConfigError.hxx" #include "util/ConstBuffer.hxx" -#include "util/SplitString.hxx" +#include "util/IterableSplitString.hxx" #include "util/Error.hxx" #include "util/Domain.hxx" #include "Log.hxx" @@ -355,14 +355,14 @@ static unsigned parse_port_list(const char *source, std::string dest[], Error &error) { unsigned n = 0; - for (auto &&i : SplitString(source, ',')) { + for (auto i : IterableSplitString(source, ',')) { if (n >= MAX_PORTS) { error.Set(config_domain, "too many port names"); return 0; } - dest[n++] = std::move(i); + dest[n++] = std::string(i.data, i.size); } if (n == 0) { diff --git a/src/util/IterableSplitString.hxx b/src/util/IterableSplitString.hxx new file mode 100644 index 000000000..c89e3edb9 --- /dev/null +++ b/src/util/IterableSplitString.hxx @@ -0,0 +1,123 @@ +/* + * Copyright (C) 2013-2016 Max Kellermann + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * - Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * - Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the + * distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED + * OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef ITERABLE_SPLIT_STRING_HXX +#define ITERABLE_SPLIT_STRING_HXX + +#include "StringView.hxx" + +#include + +/** + * Split a string at a certain separator character into sub strings + * and allow iterating over the segments. + * + * Two consecutive separator characters result in an empty string. + * + * An empty input string returns one empty string. + */ +class IterableSplitString { + StringView s; + + char separator; + +public: + constexpr IterableSplitString(StringView _s, char _separator) + :s(_s), separator(_separator) {} + + class Iterator final { + friend class IterableSplitString; + + StringView current, rest; + + char separator; + + Iterator(StringView _s, char _separator) + :rest(_s), separator(_separator) { + Next(); + } + + constexpr Iterator(std::nullptr_t n) + :current(n), rest(n), separator(0) {} + + void Next() { + if (rest.IsNull()) + current = nullptr; + else { + const char *i = rest.Find(separator); + if (i == nullptr) { + current = rest; + rest.data = nullptr; + } else { + current.data = rest.data; + current.size = i - current.data; + rest.size -= current.size + 1; + rest.data = i + 1; + } + } + } + + public: + typedef std::forward_iterator_tag iterator_category; + + Iterator &operator++() { + Next(); + return *this; + } + + constexpr bool operator==(Iterator other) const { + return current.data == other.current.data; + } + + constexpr bool operator!=(Iterator other) const { + return !(*this == other); + } + + constexpr StringView operator*() const { + return current; + } + + constexpr const StringView *operator->() const { + return ¤t; + } + }; + + typedef Iterator iterator; + typedef Iterator const_iterator; + + const_iterator begin() const { + return {s, separator}; + } + + constexpr const_iterator end() const { + return {nullptr}; + } +}; + +#endif diff --git a/src/util/SplitString.cxx b/src/util/SplitString.cxx index f67351d22..a04aeb564 100644 --- a/src/util/SplitString.cxx +++ b/src/util/SplitString.cxx @@ -28,6 +28,7 @@ */ #include "SplitString.hxx" +#include "IterableSplitString.hxx" #include "StringUtil.hxx" #include @@ -44,26 +45,16 @@ SplitString(const char *s, char separator, bool strip) auto i = list.before_begin(); - while (true) { - const char *next = strchr(s, separator); - if (next == nullptr) - break; + for (auto value : IterableSplitString(s, separator)) { + const char *begin = value.begin(), *end = value.end(); - const char *end = next++; - if (strip) - end = StripRight(s, end); + if (strip) { + begin = StripLeft(begin, end); + end = StripRight(begin, end); + } - i = list.emplace_after(i, s, end); - - s = next; - if (strip) - s = StripLeft(s); + i = list.emplace_after(i, begin, end); } - const char *end = s + strlen(s); - if (strip) - end = StripRight(s, end); - - list.emplace_after(i, s, end); return list; }