From 8ea9b8932145942ed44289351fe27d08e4ee78b0 Mon Sep 17 00:00:00 2001
From: Max Kellermann <max.kellermann@gmail.com>
Date: Mon, 13 Mar 2023 12:45:01 +0100
Subject: [PATCH] pcm/Normalizer: use std::span

---
 src/filter/plugins/NormalizeFilterPlugin.cxx | 2 +-
 src/pcm/Normalizer.cxx                       | 8 ++++----
 src/pcm/Normalizer.hxx                       | 3 ++-
 test/run_normalize.cxx                       | 9 ++++-----
 4 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/filter/plugins/NormalizeFilterPlugin.cxx b/src/filter/plugins/NormalizeFilterPlugin.cxx
index 74b9d52e9..868787a09 100644
--- a/src/filter/plugins/NormalizeFilterPlugin.cxx
+++ b/src/filter/plugins/NormalizeFilterPlugin.cxx
@@ -54,7 +54,7 @@ NormalizeFilter::FilterPCM(std::span<const std::byte> src)
 	auto *dest = (int16_t *)buffer.Get(src.size());
 	memcpy(dest, src.data(), src.size());
 
-	normalizer.ProcessS16(dest, src.size() / 2);
+	normalizer.ProcessS16({dest, src.size() / 2});
 	return { (const std::byte *)dest, src.size() };
 }
 
diff --git a/src/pcm/Normalizer.cxx b/src/pcm/Normalizer.cxx
index ab9c67e04..cb15ca27b 100644
--- a/src/pcm/Normalizer.cxx
+++ b/src/pcm/Normalizer.cxx
@@ -8,7 +8,7 @@
 #include "Traits.hxx"
 
 void
-PcmNormalizer::ProcessS16(int16_t *audio, std::size_t count) noexcept
+PcmNormalizer::ProcessS16(const std::span<int16_t> audio) noexcept
 {
 	constexpr SampleFormat format = SampleFormat::S16;
 	using Traits = SampleTraits<format>;
@@ -16,7 +16,7 @@ PcmNormalizer::ProcessS16(int16_t *audio, std::size_t count) noexcept
         const int slot = (pos + 1) % bufsz;
 
         int peakVal = 1, peakPos = 0;
-	for (std::size_t i = 0; i < count; i++) {
+	for (std::size_t i = 0; i < audio.size(); i++) {
 		int val = audio[i];
                 if (val < 0)
                         val = -val;
@@ -52,7 +52,7 @@ PcmNormalizer::ProcessS16(int16_t *audio, std::size_t count) noexcept
 		newGain = 1 << 10;
 
         //! Make sure the adjusted gain won't cause clipping
-        std::size_t ramp = count;
+        std::size_t ramp = audio.size();
         if ((peakVal*newGain >> 10) > Traits::MAX)
         {
                 newGain = (Traits::MAX << 10)/peakVal;
@@ -69,7 +69,7 @@ PcmNormalizer::ProcessS16(int16_t *audio, std::size_t count) noexcept
                 curGain = 1 << 10;
 	const int delta = (newGain - curGain) / (int)ramp;
 
-	for (std::size_t i = 0; i < count; i++) {
+	for (std::size_t i = 0; i < audio.size(); i++) {
 		//! Amplify the sample
 		audio[i] = PcmClamp<format>(audio[i] * curGain >> 10);
 
diff --git a/src/pcm/Normalizer.hxx b/src/pcm/Normalizer.hxx
index 507df73be..0c826343d 100644
--- a/src/pcm/Normalizer.hxx
+++ b/src/pcm/Normalizer.hxx
@@ -6,6 +6,7 @@
 
 #include <cstddef>
 #include <cstdint>
+#include <span>
 
 class PcmNormalizer {
 	///! Target level (on a scale of 0-32767)
@@ -40,7 +41,7 @@ public:
 	}
 
 	//! Process 16-bit signed data
-	void ProcessS16(int16_t *data, std::size_t count) noexcept;
+	void ProcessS16(std::span<int16_t> audio) noexcept;
 };
 
 //! TODO: Compressor_Process_int32, Compressor_Process_float, others as needed
diff --git a/test/run_normalize.cxx b/test/run_normalize.cxx
index 682c5600f..ac8bfd140 100644
--- a/test/run_normalize.cxx
+++ b/test/run_normalize.cxx
@@ -11,6 +11,7 @@
 #include "pcm/AudioParser.hxx"
 #include "pcm/AudioFormat.hxx"
 #include "util/PrintException.hxx"
+#include "util/SpanCast.hxx"
 
 #include <stdexcept>
 
@@ -22,9 +23,6 @@
 
 int main(int argc, char **argv)
 try {
-	static char buffer[4096];
-	ssize_t nbytes;
-
 	if (argc > 2) {
 		fprintf(stderr, "Usage: run_normalize [FORMAT] <IN >OUT\n");
 		return 1;
@@ -36,9 +34,10 @@ try {
 
 	PcmNormalizer normalizer;
 
+	static std::byte buffer[4096];
+	ssize_t nbytes;
 	while ((nbytes = read(0, buffer, sizeof(buffer))) > 0) {
-		normalizer.ProcessS16((int16_t *)buffer, nbytes / 2);
-
+		normalizer.ProcessS16(FromBytesStrict<int16_t>(std::span{buffer}.first(nbytes)));
 		[[maybe_unused]] ssize_t ignored = write(1, buffer, nbytes);
 	}