commit patch greatly improving the detection of format of raw audio files, by Philipp Sibler

src/import/MultiFormatReader.cpp

@@ -0,0 +1,143 @@
+/**********************************************************************
+
+  Audacity: A Digital Audio Editor
+
+  MultiFormatReader.cpp
+
+  Philipp Sibler
+
+******************************************************************//**
+
+\class MultiFormatReader
+\brief MultiFormatReader reads raw audio files in different formats and 
+machine endianness representations.
+
+*//*******************************************************************/
+
+#include <exception>
+#include <stdexcept>
+#include <cstring>
+#include <stdint.h>
+#include <cstdio>
+
+#include <wx/defs.h>
+
+#include "MultiFormatReader.h"
+
+MultiFormatReader::MultiFormatReader(const char* filename)
+   : mpFid(NULL)
+{
+   mpFid = fopen(filename, "rb");
+      
+   if (mpFid == NULL)
+   {
+      throw std::runtime_error("Error opening file");
+   }
+}
+
+MultiFormatReader::~MultiFormatReader()
+{
+   if (mpFid != NULL)
+   {
+      fclose(mpFid);
+   }
+}
+
+void MultiFormatReader::Reset()
+{
+   if (mpFid != NULL)
+   {
+      rewind(mpFid);
+   }
+}
+
+size_t MultiFormatReader::ReadSamples(void* buffer, size_t len,
+                    MultiFormatReader::FormatT format,
+                    MachineEndianness::EndiannessT end)
+{
+   return ReadSamples(buffer, len, 1, format, end);
+}
+
+   
+size_t MultiFormatReader::ReadSamples(void* buffer, size_t len, size_t stride,
+                    MultiFormatReader::FormatT format,
+                    MachineEndianness::EndiannessT end)
+{
+   bool swapflag = (mEnd.Which() != end);
+   size_t actRead;
+   
+   switch(format)
+   {
+      case Int8:
+      case Uint8:
+         actRead = Read(buffer, 1, len, stride);
+         break;
+      case Int16:
+      case Uint16:
+         actRead = Read(buffer, 2, len, stride);
+         if(swapflag) SwapBytes(buffer, 2, len);
+         break;
+      case Int32:
+      case Uint32:
+      case Float:
+         actRead = Read(buffer, 4, len, stride);
+         if(swapflag) SwapBytes(buffer, 4, len);
+         break;
+      case Double:
+         actRead = Read(buffer, 8, len, stride);
+         if(swapflag) SwapBytes(buffer, 8, len);
+         break;
+      default:
+         break;
+   }
+
+   return actRead;
+}
+
+size_t MultiFormatReader::Read(void* buffer, size_t size, size_t len, size_t stride)
+{
+   size_t actRead = 0;
+   uint8_t* pWork = (uint8_t*) buffer;
+   
+   if (stride > 1)
+   {
+      // There are gaps between consecutive samples,
+      // so do a scattered read
+      for (size_t n = 0; n < len; n++)
+      {
+         actRead += fread(&(pWork[n*size]), size, 1, mpFid);
+         fseek(mpFid, (stride - 1) * size, SEEK_CUR);
+      }
+   }
+   else
+   {
+      // Just do a linear read
+      actRead = fread(buffer, size, len, mpFid);
+   }
+
+   return actRead;
+}
+
+   
+void MultiFormatReader::SwapBytes(void* buffer, size_t size, size_t len)
+{
+   uint8_t* pResBuffer = (uint8_t*) buffer;
+   uint8_t* pCurBuffer;
+   
+   if (size > 8)
+   {
+      throw std::runtime_error("SwapBytes Exception: Format width exceeding 8 bytes.");
+   }
+   
+   for (size_t i = 0; i < len; i++)
+   {
+      pCurBuffer = &(pResBuffer[i*size]);
+      memcpy(mSwapBuffer, &(pCurBuffer[0]), size);
+      
+      for (size_t n = 0; n < size; n++)
+      {
+         pCurBuffer[n] = mSwapBuffer[size - n - 1];   
+      }
+   }
+}
+