forked from teamnwah/openmw-tes3coop
Delete the old Ogre DataStream class
scrawl
10 years ago
parent
227c7bb55f
commit
da690c91b3
@ -1,182 +0,0 @@
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#include "constrainedfiledatastream.hpp"
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#include "lowlevelfile.hpp"
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#include <stdexcept>
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#include <cassert>
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#include <stdint.h>
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namespace {
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class ConstrainedDataStream : public Ogre::DataStream {
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public:
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static const size_t sBufferSize = 4096; // somewhat arbitrary though 64KB buffers didn't seem to improve performance any
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static const size_t sBufferThreshold = 1024; // reads larger than this bypass buffering as cost of memcpy outweighs cost of system call
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ConstrainedDataStream(const Ogre::String &fname, size_t start, size_t length)
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: Ogre::DataStream(fname)
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{
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mFile.open (fname.c_str ());
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mSize = length != 0xFFFFFFFF ? length : mFile.size () - start;
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mPos = 0;
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mOrigin = start;
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mExtent = start + mSize;
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mBufferOrigin = 0;
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mBufferExtent = 0;
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}
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size_t read(void* buf, size_t count)
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{
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try
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{
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assert (mPos <= mSize);
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uint8_t * out = reinterpret_cast <uint8_t *> (buf);
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size_t posBeg = mOrigin + mPos;
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size_t posEnd = posBeg + count;
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if (posEnd > mExtent)
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posEnd = mExtent;
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size_t posCur = posBeg;
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while (posCur != posEnd)
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{
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size_t readLeft = posEnd - posCur;
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if (posCur < mBufferOrigin || posCur >= mBufferExtent)
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{
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if (readLeft >= sBufferThreshold || (posCur == mOrigin && posEnd == mExtent))
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{
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assert (mFile.tell () == mBufferExtent);
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if (posCur != mBufferExtent)
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mFile.seek (posCur);
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posCur += mFile.read (out, readLeft);
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mBufferOrigin = mBufferExtent = posCur;
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mPos = posCur - mOrigin;
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return posCur - posBeg;
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}
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else
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{
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size_t newBufferOrigin;
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if ((posCur < mBufferOrigin) && (mBufferOrigin - posCur < sBufferSize))
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newBufferOrigin = std::max (mOrigin, mBufferOrigin > sBufferSize ? mBufferOrigin - sBufferSize : 0);
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else
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newBufferOrigin = posCur;
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fill (newBufferOrigin);
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}
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}
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size_t xfer = std::min (readLeft, mBufferExtent - posCur);
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memcpy (out, mBuffer + (posCur - mBufferOrigin), xfer);
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posCur += xfer;
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out += xfer;
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}
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count = posEnd - posBeg;
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mPos += count;
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return count;
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}
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catch (std::exception& e)
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{
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std::stringstream error;
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error << "Failed to read '" << mName << "': " << e.what();
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throw std::runtime_error(error.str());
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}
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}
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void skip(long count)
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{
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assert (mPos <= mSize);
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if((count >= 0 && (size_t)count <= mSize-mPos) ||
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(count < 0 && (size_t)-count <= mPos))
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mPos += count;
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}
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void seek(size_t pos)
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{
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assert (mPos <= mSize);
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if (pos < mSize)
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mPos = pos;
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}
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virtual size_t tell() const
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{
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assert (mPos <= mSize);
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return mPos;
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}
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virtual bool eof() const
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{
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assert (mPos <= mSize);
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return mPos == mSize;
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}
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virtual void close()
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{
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mFile.close();
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}
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private:
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void fill (size_t newOrigin)
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{
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assert (mFile.tell () == mBufferExtent);
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size_t newExtent = newOrigin + sBufferSize;
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if (newExtent > mExtent)
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newExtent = mExtent;
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size_t oldExtent = mBufferExtent;
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if (newOrigin != oldExtent)
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mFile.seek (newOrigin);
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mBufferOrigin = mBufferExtent = newOrigin;
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size_t amountRequested = newExtent - newOrigin;
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size_t amountRead = mFile.read (mBuffer, amountRequested);
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if (amountRead != amountRequested)
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throw std::runtime_error ("An unexpected condition occurred while reading from a file.");
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mBufferExtent = newExtent;
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}
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LowLevelFile mFile;
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size_t mOrigin;
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size_t mExtent;
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size_t mPos;
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uint8_t mBuffer [sBufferSize];
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size_t mBufferOrigin;
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size_t mBufferExtent;
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};
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} // end of unnamed namespace
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Ogre::DataStreamPtr openConstrainedFileDataStream (char const * filename, size_t offset, size_t length)
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{
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return Ogre::DataStreamPtr(new ConstrainedDataStream(filename, offset, length));
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}
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@ -1,8 +0,0 @@
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#ifndef COMPONENTS_FILES_CONSTRAINEDFILEDATASTREAM_HPP
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#define COMPONENTS_FILES_CONSTRAINEDFILEDATASTREAM_HPP
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#include <OgreDataStream.h>
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Ogre::DataStreamPtr openConstrainedFileDataStream (char const * filename, size_t offset = 0, size_t length = 0xFFFFFFFF);
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#endif // COMPONENTS_FILES_CONSTRAINEDFILEDATASTREAM_HPP
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