FileSystemImageSource.cc

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#include "FileSystemImageSource.h"
#include "Shared/ImageUtil.h"
#include "Shared/debuget.h"
#include <sys/types.h>
#include <sys/mman.h>

//better to put this here instead of the header
using namespace std; 

void FileSystemImageSource::ImageInfo::prepare() {
  if(prepared)
    return;
  if(data==NULL) {
    // load the file from disk
    FileInfo::prepare();
    if(data==NULL)
      return;
    
    // get the image info
    width=height=components=0;
    size_t totalSize=0;
    char * imgbuf = ((char*)NULL)-1;
    
    image_util::decodeImage(data,size,width,height,components,imgbuf,totalSize); // this call fails (no allocation), but sets image info

    totalSize = width*height*components;
    // using mmap to allocate space so we can still use mlock/munlock on it later
    imgbuf = static_cast<char*>(mmap(NULL,totalSize,PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_ANON,-1,0));
    if(imgbuf==MAP_FAILED) {
      std::string err="FileSystemImageSource::ImageInfo::prepare() unable to mmap allocation for image decompression of ";
      err+=filename;
      perror(err.c_str());
      FileInfo::release();
      return;
    }
    
    // decompress the image for real this time:
    if(!image_util::decodeImage(data,size,width,height,components,imgbuf,totalSize)) {
      cerr << "Image decompression failed for " << filename << endl;
      munmap(imgbuf,totalSize); // error, give up and clear our memory usage
      FileInfo::release();
      return; // don't fall through to the prepare() below!
    }
    
    // replace the raw compressed data with the uncompressed image
    FileInfo::release();
    setData(imgbuf,totalSize);
  }
  FileInfo::prepare();
}

/*! @file
 * @brief 
 * @author Ethan Tira-Thompson (ejt) (Creator)
 */