MultiStreamingDecoder: remove PrefixStream

Author: pschatzmann

src/AudioTools/AudioCodecs/StreamingDecoder.h

@@ -8,99 +8,6 @@
 
 namespace audio_tools {
 
-/**
- * @brief Stream that combines prefix data with original stream
- * 
- * Useful for format detection where some data needs to be preserved.
- * 
- * @ingroup io
- * @author Phil Schatzmann
- * @copyright GPLv3
- */
-class PrefixStream : public Stream {
- public:
-  /// Default constructor - call setData() before use
-  PrefixStream() 
-    : prefix_data_(nullptr), prefix_len_(0), prefix_pos_(0), original_stream_(nullptr) {}
-  
-  /// Constructor with prefix data and original stream
-  PrefixStream(const uint8_t* prefix_data, size_t prefix_len, Stream& original_stream) 
-    : prefix_data_(prefix_data), prefix_len_(prefix_len), prefix_pos_(0), original_stream_(&original_stream) {}
-
-  /// Sets the prefix data and original stream
-  void setData(const uint8_t* prefix_data, size_t prefix_len, Stream& original_stream) {
-    prefix_data_ = prefix_data;
-    prefix_len_ = prefix_len;
-    prefix_pos_ = 0;
-    original_stream_ = &original_stream;
-  }
-
-  /// Returns total bytes available (prefix + original stream)
-  virtual int available() override {
-    int remaining_prefix = prefix_len_ - prefix_pos_;
-    if (original_stream_ != nullptr) {
-      return remaining_prefix + original_stream_->available();
-    }
-    return remaining_prefix;
-  }
-
-  /// Reads a single byte
-  virtual int read() override {
-    if (prefix_pos_ < prefix_len_) {
-      return prefix_data_[prefix_pos_++];
-    }
-    if (original_stream_ != nullptr) {
-      return original_stream_->read();
-    }
-    return -1;
-  }
-
-  /// Peeks at next byte without consuming it
-  virtual int peek() override {
-    if (prefix_pos_ < prefix_len_) {
-      return prefix_data_[prefix_pos_];
-    }
-    if (original_stream_ != nullptr) {
-      return original_stream_->peek();
-    }
-    return -1;
-  }
-
-  /// Reads multiple bytes into buffer
-  virtual size_t readBytes(uint8_t* buffer, size_t length) override {
-    size_t bytes_read = 0;
-    
-    // First, read from prefix data
-    if (prefix_pos_ < prefix_len_) {
-      size_t prefix_available = prefix_len_ - prefix_pos_;
-      size_t prefix_to_read = (length < prefix_available) ? length : prefix_available;
-      memcpy(buffer, prefix_data_ + prefix_pos_, prefix_to_read);
-      prefix_pos_ += prefix_to_read;
-      bytes_read += prefix_to_read;
-      buffer += prefix_to_read;
-      length -= prefix_to_read;
-    }
-    
-    // Then read from original stream if more data is needed
-    if (length > 0 && original_stream_ != nullptr) {
-      bytes_read += original_stream_->readBytes(buffer, length);
-    }
-    
-    return bytes_read;
-  }
-
-  /// Write operations not supported
-  virtual size_t write(uint8_t) override { return 0; }
-  virtual size_t write(const uint8_t*, size_t) override { return 0; }
-  virtual void flush() override {}
-
- private:
-  const uint8_t* prefix_data_;  ///< Prefix data buffer
-  size_t prefix_len_;           ///< Length of prefix data
-  size_t prefix_pos_;           ///< Current position in prefix
-  Stream* original_stream_;     ///< Original stream
-};
-
 /**
  * @brief A Streaming Decoder where we provide both the input and output
  * as streams.
@@ -821,8 +728,7 @@ class MultiStreamingDecoder : public StreamingDecoder {
       nullptr;  ///< Optional MIME source for custom logic
   Stream *p_data_source = nullptr; ///< effective data source for decoder
 
-  PrefixStream prefix_stream; ///< Instance of prefix stream (uses placement new on prefix_stream_storage)
-
+  BufferedStream buffered_stream{0};  ///< Buffered stream for data preservation
   const char* toStr(const char* str){
     return str == nullptr ? "" : str;
   }
@@ -872,15 +778,16 @@ class MultiStreamingDecoder : public StreamingDecoder {
         p_data_source = p_input;
       } else {
         // Option 2: Auto-detect MIME type by analyzing stream content
+        // Redirect the decoder to use the buffered stream
+        // we use the buffered stream as input
         assert(p_input != nullptr);
+        buffered_stream.setStream(*p_input);
+        buffered_stream.resize(DEFAULT_BUFFER_SIZE);
+        p_data_source = &buffered_stream;
 
-        // Read a sample of data for MIME detection
-        // Allocate buffer for MIME detection sample (160 bytes is sufficient
-        // for most audio format headers to be identified)
+        // This requires reading a sample of data to identify the format
         detection_buffer.resize(160);
-        size_t bytesRead = p_input->readBytes(detection_buffer.data(), detection_buffer.size());
-        
-        // If no data is available, we cannot proceed with detection
+        size_t bytesRead = buffered_stream.peekBytes(detection_buffer.data(), detection_buffer.size());        // If no data is available, we cannot proceed with detection
         if (bytesRead == 0) return false;
 
         // Feed the sample data to the MIME detector for format analysis
@@ -889,10 +796,6 @@ class MultiStreamingDecoder : public StreamingDecoder {
         mime = mime_detector.mime();
         LOGI("mime from detector: %s", toStr(mime));
 
-        // Create a prefix stream that combines the detection data with the original stream
-        // This ensures the decoder receives the complete stream including the bytes used for detection
-        prefix_stream.setData(detection_buffer.data(), bytesRead, *p_input);
-        p_data_source = &prefix_stream;
       }
 
       // Process the detected/provided MIME type