Use std::span (backported) and std::byte to make our buffers safer

4 files changed, 16 insertions, 13 deletions

diff --git a/src/codecs/CMakeLists.txt b/src/codecs/CMakeLists.txt
index 4f89f370..9677e459 100644
--- a/src/codecs/CMakeLists.txt
+++ b/src/codecs/CMakeLists.txt
@@ -1,7 +1,7 @@
 idf_component_register(
   SRCS "codec.cpp" "mad.cpp"
   INCLUDE_DIRS "include"
-  REQUIRES "result")
+  REQUIRES "result" "span")
 
 add_dependencies("${COMPONENT_LIB}" libmad)
 target_compile_options("${COMPONENT_LIB}" PRIVATE ${EXTRA_WARNINGS})
diff --git a/src/codecs/include/codec.hpp b/src/codecs/include/codec.hpp
index 764b63fc..bbb621f5 100644
--- a/src/codecs/include/codec.hpp
+++ b/src/codecs/include/codec.hpp
@@ -9,6 +9,7 @@
 #include <utility>
 
 #include "result.hpp"
+#include "span.hpp"
 
 namespace codecs {
 
@@ -30,7 +31,7 @@ class ICodec {
 
   virtual auto ResetForNewStream() -> void = 0;
 
-  virtual auto SetInput(uint8_t* buffer, std::size_t length) -> void = 0;
+  virtual auto SetInput(cpp::span<std::byte> input) -> void = 0;
 
   /*
    * Returns the codec's next read position within the input buffer. If the
@@ -56,7 +57,7 @@ class ICodec {
    * written. If this returns false, then this method should be called again
    * after flushing the output buffer.
    */
-  virtual auto WriteOutputSamples(uint8_t* output, std::size_t output_length)
+  virtual auto WriteOutputSamples(cpp::span<std::byte> output)
       -> std::pair<std::size_t, bool> = 0;
 };
 
diff --git a/src/codecs/include/mad.hpp b/src/codecs/include/mad.hpp
index aa24f3c9..6077314c 100644
--- a/src/codecs/include/mad.hpp
+++ b/src/codecs/include/mad.hpp
@@ -5,6 +5,7 @@
 #include <string>
 
 #include "mad.h"
+#include "span.hpp"
 
 #include "codec.hpp"
 
@@ -18,10 +19,10 @@ class MadMp3Decoder : public ICodec {
   auto CanHandleFile(const std::string& path) -> bool override;
   auto GetOutputFormat() -> OutputFormat override;
   auto ResetForNewStream() -> void override;
-  auto SetInput(uint8_t* buffer, std::size_t length) -> void override;
+  auto SetInput(cpp::span<std::byte> input) -> void override;
   auto GetInputPosition() -> std::size_t override;
   auto ProcessNextFrame() -> cpp::result<bool, ProcessingError> override;
-  auto WriteOutputSamples(uint8_t* output, std::size_t output_length)
+  auto WriteOutputSamples(cpp::span<std::byte> output)
       -> std::pair<std::size_t, bool> override;
 
  private:
diff --git a/src/codecs/mad.cpp b/src/codecs/mad.cpp
index 4afc9a77..a8c2fb11 100644
--- a/src/codecs/mad.cpp
+++ b/src/codecs/mad.cpp
@@ -51,8 +51,10 @@ auto MadMp3Decoder::ResetForNewStream() -> void {
   has_decoded_header_ = false;
 }
 
-auto MadMp3Decoder::SetInput(uint8_t* buffer, std::size_t length) -> void {
-  mad_stream_buffer(&stream_, buffer, length);
+auto MadMp3Decoder::SetInput(cpp::span<std::byte> input) -> void {
+  mad_stream_buffer(&stream_,
+                    reinterpret_cast<const unsigned char*>(input.data()),
+                    input.size());
 }
 
 auto MadMp3Decoder::GetInputPosition() -> std::size_t {
@@ -101,8 +103,7 @@ auto MadMp3Decoder::ProcessNextFrame() -> cpp::result<bool, ProcessingError> {
   return false;
 }
 
-auto MadMp3Decoder::WriteOutputSamples(uint8_t* output,
-                                       std::size_t output_length)
+auto MadMp3Decoder::WriteOutputSamples(cpp::span<std::byte> output)
     -> std::pair<std::size_t, bool> {
   size_t output_byte = 0;
   // First ensure that we actually have some samples to send off.
@@ -111,16 +112,16 @@ auto MadMp3Decoder::WriteOutputSamples(uint8_t* output,
   }
 
   while (current_sample_ < synth_.pcm.length) {
-    if (output_byte + (3 * synth_.pcm.channels) >= output_length) {
+    if (output_byte + (3 * synth_.pcm.channels) >= output.size()) {
       return std::make_pair(output_byte, false);
     }
 
     for (int channel = 0; channel < synth_.pcm.channels; channel++) {
       uint32_t sample_24 =
           scaleTo24Bits(synth_.pcm.samples[channel][current_sample_]);
-      output[output_byte++] = (sample_24 >> 0) & 0xff;
-      output[output_byte++] = (sample_24 >> 8) & 0xff;
-      output[output_byte++] = (sample_24 >> 16) & 0xff;
+      output[output_byte++] = static_cast<std::byte>(sample_24 >> 0);
+      output[output_byte++] = static_cast<std::byte>(sample_24 >> 8);
+      output[output_byte++] = static_cast<std::byte>(sample_24 >> 16);
     }
     current_sample_++;
   }