Delete the old Ogre DataStream class
scrawl
10 years ago
parent
227c7bb55f
commit
da690c91b3
@ -1,182 +0,0 @@
|
||||
#include "constrainedfiledatastream.hpp"
|
||||
#include "lowlevelfile.hpp"
|
||||
|
||||
#include <stdexcept>
|
||||
#include <cassert>
|
||||
|
||||
#include <stdint.h>
|
||||
|
||||
namespace {
|
||||
|
||||
class ConstrainedDataStream : public Ogre::DataStream {
|
||||
public:
|
||||
|
||||
static const size_t sBufferSize = 4096; // somewhat arbitrary though 64KB buffers didn't seem to improve performance any
|
||||
static const size_t sBufferThreshold = 1024; // reads larger than this bypass buffering as cost of memcpy outweighs cost of system call
|
||||
|
||||
ConstrainedDataStream(const Ogre::String &fname, size_t start, size_t length)
|
||||
: Ogre::DataStream(fname)
|
||||
{
|
||||
mFile.open (fname.c_str ());
|
||||
mSize = length != 0xFFFFFFFF ? length : mFile.size () - start;
|
||||
|
||||
mPos = 0;
|
||||
mOrigin = start;
|
||||
mExtent = start + mSize;
|
||||
|
||||
mBufferOrigin = 0;
|
||||
mBufferExtent = 0;
|
||||
}
|
||||
|
||||
|
||||
size_t read(void* buf, size_t count)
|
||||
{
|
||||
try
|
||||
{
|
||||
assert (mPos <= mSize);
|
||||
|
||||
uint8_t * out = reinterpret_cast <uint8_t *> (buf);
|
||||
|
||||
size_t posBeg = mOrigin + mPos;
|
||||
size_t posEnd = posBeg + count;
|
||||
|
||||
if (posEnd > mExtent)
|
||||
posEnd = mExtent;
|
||||
|
||||
size_t posCur = posBeg;
|
||||
|
||||
while (posCur != posEnd)
|
||||
{
|
||||
size_t readLeft = posEnd - posCur;
|
||||
|
||||
if (posCur < mBufferOrigin || posCur >= mBufferExtent)
|
||||
{
|
||||
if (readLeft >= sBufferThreshold || (posCur == mOrigin && posEnd == mExtent))
|
||||
{
|
||||
assert (mFile.tell () == mBufferExtent);
|
||||
|
||||
if (posCur != mBufferExtent)
|
||||
mFile.seek (posCur);
|
||||
|
||||
posCur += mFile.read (out, readLeft);
|
||||
|
||||
mBufferOrigin = mBufferExtent = posCur;
|
||||
|
||||
mPos = posCur - mOrigin;
|
||||
|
||||
return posCur - posBeg;
|
||||
}
|
||||
else
|
||||
{
|
||||
size_t newBufferOrigin;
|
||||
|
||||
if ((posCur < mBufferOrigin) && (mBufferOrigin - posCur < sBufferSize))
|
||||
newBufferOrigin = std::max (mOrigin, mBufferOrigin > sBufferSize ? mBufferOrigin - sBufferSize : 0);
|
||||
else
|
||||
newBufferOrigin = posCur;
|
||||
|
||||
fill (newBufferOrigin);
|
||||
}
|
||||
}
|
||||
|
||||
size_t xfer = std::min (readLeft, mBufferExtent - posCur);
|
||||
|
||||
memcpy (out, mBuffer + (posCur - mBufferOrigin), xfer);
|
||||
|
||||
posCur += xfer;
|
||||
out += xfer;
|
||||
}
|
||||
|
||||
count = posEnd - posBeg;
|
||||
mPos += count;
|
||||
return count;
|
||||
}
|
||||
catch (std::exception& e)
|
||||
{
|
||||
std::stringstream error;
|
||||
error << "Failed to read '" << mName << "': " << e.what();
|
||||
throw std::runtime_error(error.str());
|
||||
}
|
||||
}
|
||||
|
||||
void skip(long count)
|
||||
{
|
||||
assert (mPos <= mSize);
|
||||
|
||||
if((count >= 0 && (size_t)count <= mSize-mPos) ||
|
||||
(count < 0 && (size_t)-count <= mPos))
|
||||
mPos += count;
|
||||
}
|
||||
|
||||
void seek(size_t pos)
|
||||
{
|
||||
assert (mPos <= mSize);
|
||||
|
||||
if (pos < mSize)
|
||||
mPos = pos;
|
||||
}
|
||||
|
||||
virtual size_t tell() const
|
||||
{
|
||||
assert (mPos <= mSize);
|
||||
|
||||
return mPos;
|
||||
}
|
||||
|
||||
virtual bool eof() const
|
||||
{
|
||||
assert (mPos <= mSize);
|
||||
|
||||
return mPos == mSize;
|
||||
}
|
||||
|
||||
virtual void close()
|
||||
{
|
||||
mFile.close();
|
||||
}
|
||||
|
||||
private:
|
||||
|
||||
void fill (size_t newOrigin)
|
||||
{
|
||||
assert (mFile.tell () == mBufferExtent);
|
||||
|
||||
size_t newExtent = newOrigin + sBufferSize;
|
||||
|
||||
if (newExtent > mExtent)
|
||||
newExtent = mExtent;
|
||||
|
||||
size_t oldExtent = mBufferExtent;
|
||||
|
||||
if (newOrigin != oldExtent)
|
||||
mFile.seek (newOrigin);
|
||||
|
||||
mBufferOrigin = mBufferExtent = newOrigin;
|
||||
|
||||
size_t amountRequested = newExtent - newOrigin;
|
||||
|
||||
size_t amountRead = mFile.read (mBuffer, amountRequested);
|
||||
|
||||
if (amountRead != amountRequested)
|
||||
throw std::runtime_error ("An unexpected condition occurred while reading from a file.");
|
||||
|
||||
mBufferExtent = newExtent;
|
||||
}
|
||||
|
||||
LowLevelFile mFile;
|
||||
|
||||
size_t mOrigin;
|
||||
size_t mExtent;
|
||||
size_t mPos;
|
||||
|
||||
uint8_t mBuffer [sBufferSize];
|
||||
size_t mBufferOrigin;
|
||||
size_t mBufferExtent;
|
||||
};
|
||||
|
||||
} // end of unnamed namespace
|
||||
|
||||
Ogre::DataStreamPtr openConstrainedFileDataStream (char const * filename, size_t offset, size_t length)
|
||||
{
|
||||
return Ogre::DataStreamPtr(new ConstrainedDataStream(filename, offset, length));
|
||||
}
|
||||
@ -1,8 +0,0 @@
|
||||
#ifndef COMPONENTS_FILES_CONSTRAINEDFILEDATASTREAM_HPP
|
||||
#define COMPONENTS_FILES_CONSTRAINEDFILEDATASTREAM_HPP
|
||||
|
||||
#include <OgreDataStream.h>
|
||||
|
||||
Ogre::DataStreamPtr openConstrainedFileDataStream (char const * filename, size_t offset = 0, size_t length = 0xFFFFFFFF);
|
||||
|
||||
#endif // COMPONENTS_FILES_CONSTRAINEDFILEDATASTREAM_HPP
|
||||
Loading…
Reference in New Issue