From 4fb8b45111497775727cc85e84d845276f9788df Mon Sep 17 00:00:00 2001
From: Max Kellermann <max.kellermann@gmail.com>
Date: Mon, 4 Jul 2022 18:21:44 +0200
Subject: [PATCH] song/Filter: use std::span instead of ConstBuffer

---
 src/song/Filter.cxx      | 13 +++++++------
 src/song/Filter.hxx      |  4 ++--
 test/ParseSongFilter.cxx |  3 +--
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/src/song/Filter.cxx b/src/song/Filter.cxx
index 04c8bea3b..024004e63 100644
--- a/src/song/Filter.cxx
+++ b/src/song/Filter.cxx
@@ -30,7 +30,6 @@
 #include "tag/ParseName.hxx"
 #include "time/ISO8601.hxx"
 #include "util/CharUtil.hxx"
-#include "util/ConstBuffer.hxx"
 #include "util/RuntimeError.hxx"
 #include "util/StringCompare.hxx"
 #include "util/StringStrip.hxx"
@@ -410,14 +409,15 @@ SongFilter::Parse(const char *tag_string, const char *value, bool fold_case)
 }
 
 void
-SongFilter::Parse(ConstBuffer<const char *> args, bool fold_case)
+SongFilter::Parse(std::span<const char *const> args, bool fold_case)
 {
 	if (args.empty())
 		throw std::runtime_error("Incorrect number of filter arguments");
 
 	do {
 		if (*args.front() == '(') {
-			const char *s = args.shift();
+			const char *s = args.front();
+			args = args.subspan(1);
 			const char *end = s;
 			auto f = ParseExpression(end, fold_case);
 			if (*end != 0)
@@ -427,11 +427,12 @@ SongFilter::Parse(ConstBuffer<const char *> args, bool fold_case)
 			continue;
 		}
 
-		if (args.size < 2)
+		if (args.size() < 2)
 			throw std::runtime_error("Incorrect number of filter arguments");
 
-		const char *tag = args.shift();
-		const char *value = args.shift();
+		const char *tag = args[0];
+		const char *value = args[1];
+		args = args.subspan(2);
 		Parse(tag, value, fold_case);
 	} while (!args.empty());
 }
diff --git a/src/song/Filter.hxx b/src/song/Filter.hxx
index 09738d668..28aa559a4 100644
--- a/src/song/Filter.hxx
+++ b/src/song/Filter.hxx
@@ -23,6 +23,7 @@
 #include "AndSongFilter.hxx"
 
 #include <cstdint>
+#include <span>
 #include <string>
 #include <string_view>
 
@@ -36,7 +37,6 @@
  */
 #define SORT_TAG_PRIO (TAG_NUM_OF_ITEM_TYPES + 4)
 
-template<typename T> struct ConstBuffer;
 enum TagType : uint8_t;
 struct LightSong;
 
@@ -68,7 +68,7 @@ public:
 	/**
 	 * Throws on error.
 	 */
-	void Parse(ConstBuffer<const char *> args, bool fold_case=false);
+	void Parse(std::span<const char *const> args, bool fold_case=false);
 
 	void Optimize() noexcept;
 
diff --git a/test/ParseSongFilter.cxx b/test/ParseSongFilter.cxx
index 9cd314a5f..b68464180 100644
--- a/test/ParseSongFilter.cxx
+++ b/test/ParseSongFilter.cxx
@@ -23,7 +23,6 @@
  */
 
 #include "song/Filter.hxx"
-#include "util/ConstBuffer.hxx"
 #include "util/PrintException.hxx"
 
 #include <stdexcept>
@@ -39,7 +38,7 @@ try {
 	}
 
 	SongFilter filter;
-	filter.Parse(ConstBuffer<const char *>(argv + 1, argc - 1));
+	filter.Parse({argv + 1, std::size_t(argc - 1)});
 	filter.Optimize();
 
 	puts(filter.ToExpression().c_str());