lib-vst3/memorystream.cpp

Go to the documentation of this file.

//-----------------------------------------------------------------------------
// Project     : SDK Core
//
// Category    : Common Classes
// Filename    : public.sdk/source/common/memorystream.cpp
// Created by  : Steinberg, 03/2008
// Description : IBStream Implementation for memory blocks
//
//-----------------------------------------------------------------------------
// LICENSE
// (c) 2021, Steinberg Media Technologies GmbH, All Rights Reserved
//-----------------------------------------------------------------------------
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
// 
//   * Redistributions of source code must retain the above copyright notice, 
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation 
//     and/or other materials provided with the distribution.
//   * Neither the name of the Steinberg Media Technologies nor the names of its
//     contributors may be used to endorse or promote products derived from this 
//     software without specific prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
// IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 
// OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE  OF THIS SOFTWARE, EVEN IF ADVISED
// OF THE POSSIBILITY OF SUCH DAMAGE.
//-----------------------------------------------------------------------------
 
#include "memorystream.h"
#include "pluginterfaces/base/futils.h"
#include <stdlib.h>
 
namespace Steinberg {
 
//-----------------------------------------------------------------------------
IMPLEMENT_FUNKNOWN_METHODS (MemoryStream, IBStream, IBStream::iid)
static const TSize kMemGrowAmount = 4096;
 
//-----------------------------------------------------------------------------
MemoryStream::MemoryStream (void* data, TSize length)
: memory ((char*)data)
, memorySize (length)
, size (length)
, cursor (0)
, ownMemory (false)
, allocationError (false)
{ 
   FUNKNOWN_CTOR 
}
 
//-----------------------------------------------------------------------------
MemoryStream::MemoryStream ()
: memory (nullptr)
, memorySize (0)
, size (0)
, cursor (0)
, ownMemory (true)
, allocationError (false)
{
   FUNKNOWN_CTOR
}
 
//-----------------------------------------------------------------------------
MemoryStream::~MemoryStream () 
{ 
   if (ownMemory && memory)
      ::free (memory);
 
   FUNKNOWN_DTOR 
}
 
//-----------------------------------------------------------------------------
tresult PLUGIN_API MemoryStream::read (void* data, int32 numBytes, int32* numBytesRead)
{
   if (memory == nullptr)
   {
      if (allocationError)
         return kOutOfMemory;
      numBytes = 0;
   }
   else
   {     
      // Does read exceed size ?
      if (cursor + numBytes > size)
      {
         int32 maxBytes = int32 (size - cursor);
 
         // Has length become zero or negative ?
         if (maxBytes <= 0) 
         {
            cursor = size;
            numBytes = 0;
         }
         else
            numBytes = maxBytes;
      }
      
      if (numBytes)
      {
         memcpy (data, &memory[cursor], static_cast<size_t> (numBytes));
         cursor += numBytes;
      }
   }
 
   if (numBytesRead)
      *numBytesRead = numBytes;
 
   return kResultTrue;
}
 
//-----------------------------------------------------------------------------
tresult PLUGIN_API MemoryStream::write (void* buffer, int32 numBytes, int32* numBytesWritten)
{
   if (allocationError)
      return kOutOfMemory;
   if (buffer == nullptr)
      return kInvalidArgument;
 
   // Does write exceed size ?
   TSize requiredSize = cursor + numBytes;
   if (requiredSize > size) 
   {     
      if (requiredSize > memorySize)
         setSize (requiredSize);
      else
         size = requiredSize;
   }
   
   // Copy data
   if (memory && cursor >= 0 && numBytes > 0)
   {
      memcpy (&memory[cursor], buffer, static_cast<size_t> (numBytes));
      // Update cursor
      cursor += numBytes;
   }
   else
      numBytes = 0;
 
   if (numBytesWritten)
      *numBytesWritten = numBytes;
 
   return kResultTrue;
}
 
//-----------------------------------------------------------------------------
tresult PLUGIN_API MemoryStream::seek (int64 pos, int32 mode, int64* result)
{
   switch (mode) 
   {
      case kIBSeekSet:
         cursor = pos;
         break;
      case kIBSeekCur:
         cursor = cursor + pos;
         break;
      case kIBSeekEnd:
         cursor = size + pos;
         break;
   }
 
   if (ownMemory == false)
      if (cursor > memorySize)
         cursor = memorySize;
 
   if (result)
      *result = cursor;
 
   return kResultTrue;
}
 
//-----------------------------------------------------------------------------
tresult PLUGIN_API MemoryStream::tell  (int64* pos)
{
   if (!pos)
      return kInvalidArgument;
 
   *pos = cursor;
   return kResultTrue;
}
 
//------------------------------------------------------------------------
TSize MemoryStream::getSize () const
{
   return size;
}
 
//------------------------------------------------------------------------
void MemoryStream::setSize (TSize s)
{
   if (s <= 0)
   {
      if (ownMemory && memory)
         free (memory);
 
      memory = nullptr;
      memorySize = 0;
      size = 0;
      cursor = 0;
      return;
   }
 
   TSize newMemorySize = (((Max (memorySize, s) - 1) / kMemGrowAmount) + 1) * kMemGrowAmount;
   if (newMemorySize == memorySize)
   {
      size = s;
      return;
   }
 
   if (memory && ownMemory == false)
   {
      allocationError = true;
      return;  
   }
 
   ownMemory = true;
   char* newMemory = nullptr;
 
   if (memory)
   {
      newMemory = (char*)realloc (memory, (size_t)newMemorySize);
      if (newMemory == nullptr && newMemorySize > 0)
      {
         newMemory = (char*)malloc ((size_t)newMemorySize);
         if (newMemory)
         {
            memcpy (newMemory, memory, (size_t)Min (newMemorySize, memorySize));           
            free (memory);
         }     
      }
   }
   else
      newMemory = (char*)malloc ((size_t)newMemorySize);
 
   if (newMemory == nullptr)
   {
      if (newMemorySize > 0)
         allocationError = true;
 
      memory = nullptr;
      memorySize = 0;
      size = 0;
      cursor = 0;
   }
   else
   {
      memory = newMemory;
      memorySize = newMemorySize;
      size = s;
   }
}
 
//------------------------------------------------------------------------
char* MemoryStream::getData () const
{
   return memory;
}
 
//------------------------------------------------------------------------
char* MemoryStream::detachData ()
{
   if (ownMemory)
   {
      char* result = memory;
      memory = nullptr;
      memorySize = 0;
      size = 0;
      cursor = 0;
      return result;
   }
   return nullptr;
}
 
//------------------------------------------------------------------------
bool MemoryStream::truncate ()
{
   if (ownMemory == false)
      return false;
 
   if (memorySize == size)
      return true;
 
   memorySize = size;
   
   if (memorySize == 0)
   {
      if (memory)
      {
         free (memory);
         memory = nullptr;
      }
   }
   else
   {
      if (memory)
      {
         char* newMemory = (char*)realloc (memory, (size_t)memorySize);
         if (newMemory)
            memory = newMemory;
      }
   }
   return true;
}
 
//------------------------------------------------------------------------
bool MemoryStream::truncateToCursor ()
{
   size = cursor;
   return truncate ();
}
 
} // namespace