CGBuffer.h

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// Note that this is modified Apple source code, and not in its entireity (some classes are, some aren't), 
// but we might as well leave it in here, even though it doesn't sound like we have to.
// -bob

#include <mach/mach.h>
#include <Carbon/Carbon.h>
// Celestia's DPRINTF is different than Carbon's
#undef DPRINTF
#include <celutil/debug.h>

class CGFrame : public CGRect
{
public:

        CGFrame(float x0, float y0, float w, float h)
        {
                *this = CGRectMake(x0,y0,w,h);
        }
        
        explicit CGFrame(float w = 0, float h = 0)
        {
                *this = CGRectMake(0,0,w,h);
        }
        
        CGFrame(const Rect& rect)
        {
                origin.x = rect.left, size.width = rect.right - rect.left;
                origin.y = rect.top, size.height = rect.bottom - rect.top;
        }
        
        CGFrame(const CGRect& copy)
        {
                origin = copy.origin;
                size = copy.size;
        }
        
        CGFrame(const CGSize& size)
        {
                origin.x = origin.y = 0;
                this->size = size;
        }
        
        CGFrame(float x, float y, const CGSize& size)
        {
                *this = CGRectMake(x, y, size.width, size.height);
        }
        
        CGFrame(const CGPoint& pos, const CGSize& size)
        {
                *this = CGRectMake(pos.x, pos.y, size.width, size.height);
        }       
        
        void Offset(float dx, float dy)
        {
                origin.x += dx, origin.y += dy;
        }
        
        void Inset(float dx, float dy)
        {
                origin.x += dx, origin.y += dy;
                size.width -= dx*2, size.height -= dy*2;
        }
};

class MemoryBuffer
{
  size_t size;
  int ref_count;

  MemoryBuffer(char* const data, size_t size) : size(size), ref_count(1), data(data)
  {
  }

  ~MemoryBuffer()
  {
    vm_deallocate((vm_map_t) mach_task_self(), (vm_address_t) data, size);
  }

public:

  friend class _MemoryBuffer; // to shut the compiler up

  char* const data;

  MemoryBuffer* Retain()
  {
    ++ref_count;
    return this;
  }

  void Release()
  {
    if (--ref_count == 0)
      delete this;
  }

  static MemoryBuffer* Create(size_t size)
  {
    char* data;
    kern_return_t err = vm_allocate((vm_map_t) mach_task_self(), (vm_address_t*) &data, size, TRUE);

    return (err == KERN_SUCCESS) ? new MemoryBuffer(data, size) : NULL;
  }
};

class Datafile
{
    int ref_count;
    FILE* file;
    
public:        
    MemoryBuffer* data_buffer;
    unsigned long data_size;

    Datafile() : ref_count(1), file(NULL), data_buffer(NULL), data_size(0)
    {
    }

    ~Datafile()
    {
        Reset();
    }

    Datafile* Retain()
    {
        ++ref_count;
        return this;
    }
    
    void Release()
    {
        if (--ref_count==0) 
            delete this;
    }
    
    int Open(const char* path)
    {
        file = fopen(path,"r");
        if (!file) {
            DPRINTF(0,"Datafile::Open() - Couldn't open %s\n", path);
            Reset();
            return 0;
        }
        fseek(file, 0, SEEK_END);
        data_size = ftell(file);
        data_buffer = MemoryBuffer::Create(data_size);
        if (!data_buffer) {
            DPRINTF(0,"Datafile::Open() - Couldn't allocate MemoryBuffer of size %d\n", data_size);
            Reset();
            return 0;
        }
        //DPRINTF(0,"Datafile::Open() - Successfully opened '%s' %d bytes\n", path, data_size);
        return 1;
    }
    
    int Read()
    {
        if ((file == NULL) || (data_buffer == NULL) || (data_size == 0)) {
            DPRINTF(0,"Datafile::Read() - No file open, file of zero size, or no valid MemoryBuffer\n");
            Reset();
            return 0;
        }
        
        fseek(file, 0, SEEK_SET);        
        if (fread((void*)data_buffer->data, 1, data_size, file) != data_size) {
            DPRINTF(0,"Datafile::Read() - Didn't read to finish?");
            Reset();
            return 0;
        }
        
        //DPRINTF(0,"Datafile::Read() - Successfully read all %d bytes into buffer\n",data_size);
        return 1;
    }
    
    void Close()
    {
        if (file) {
            fclose(file);
            file = NULL;
        }
    }
    
    void Reset()
    {
        Close();
        if (data_buffer) {
            data_buffer->Release();
            data_buffer = NULL;
        }
    }
};

class CGBuffer
{
        Datafile file;
        CGImageRef image_ref;
        CGContextRef context_ref;

        int ref_count;

        void Init()
        {
                ref_count = 1;
                buffer = NULL;
                image_ref = NULL;
                context_ref = NULL;
                image_finished = false;
        }

        bool CreateCGContext()
        {
                if (context_ref)
                {
                        CGContextRelease(context_ref);
                        context_ref = NULL;
                }

                if (buffer)
                {
                        buffer->Release();
                        buffer = NULL;
                }

                size_t buffer_rowbytes = (size_t)(image_size.width * ((image_depth == 8) ? 1 : 4)); //CGImageGetBytesPerRow(image_ref);
        
                buffer = MemoryBuffer::Create(buffer_rowbytes * (size_t)image_size.height); 

                if (!buffer)
                        return false;

                CGColorSpaceRef colorspace_ref = (image_depth == 8) ? CGColorSpaceCreateDeviceGray() : CGColorSpaceCreateDeviceRGB();
                
                if (!colorspace_ref)
                        return false;
                
                CGImageAlphaInfo alpha_info = (image_depth == 8) ? kCGImageAlphaNone : kCGImageAlphaPremultipliedLast; //kCGImageAlphaLast; //RGBA format

                context_ref = CGBitmapContextCreate(buffer->data, (size_t)image_size.width, (size_t)image_size.height, 8, buffer_rowbytes, colorspace_ref, alpha_info);

                if (context_ref)
                {
                        CGContextSetFillColorSpace(context_ref, colorspace_ref);
                        CGContextSetStrokeColorSpace(context_ref, colorspace_ref);
                        // move down, and flip vertically 
                        // to turn postscript style coordinates to "screen style"
                        CGContextTranslateCTM(context_ref, 0.0, image_size.height);
                        CGContextScaleCTM(context_ref, 1.0, -1.0);
                }
                
                CGColorSpaceRelease(colorspace_ref);
                colorspace_ref = NULL;

                return !!context_ref;
        }

        void RenderCGImage(const CGRect& dst_rect)
        {
                if (!context_ref || !image_ref)
                        return;
                        
                CGContextDrawImage(context_ref, dst_rect, image_ref);
        }
        
public:

        MemoryBuffer* buffer;
        CGSize image_size;
        size_t image_depth;
        bool image_finished;
        
        CGBuffer(const char* path)
        {
                Init();
                Open(path);
        }

        ~CGBuffer()
        {
                Reset();
        }

        CGBuffer* Retain()
        {
                ++ref_count;
                return this;
        }

        void Release()
        {
                if (--ref_count == 0)
                        delete this;
        }

        bool Open(const char* path)
        {
                file.Reset();
                return file.Open(path);
        }

        bool LoadJPEG()
        {
                if (!file.Read())
                        return false;

                file.Close();

                CGDataProviderRef src_provider_ref = CGDataProviderCreateWithData(this, file.data_buffer->data, file.data_size, NULL);

                if (!src_provider_ref)
                        return false;

                image_ref = CGImageCreateWithJPEGDataProvider(src_provider_ref, NULL, true, kCGRenderingIntentDefault);

                CGDataProviderRelease(src_provider_ref);
                src_provider_ref = NULL;

                if (!image_ref)
                        return false;

                image_size = CGSizeMake(CGImageGetWidth(image_ref), CGImageGetHeight(image_ref));
                image_depth = CGImageGetBitsPerPixel(image_ref);
                
                return !!image_ref;
        }

        bool Render()
        {
                if (!image_ref)
                        return false;
                
                if (!CreateCGContext())
                        return false;
        
                RenderCGImage(CGFrame(image_size));
                
                CGContextRelease(context_ref);
                context_ref = NULL;

                CGImageRelease(image_ref);
                image_ref = NULL;
                
                file.Reset();

                return true;
        }
        
        void Reset()
        {
                if (buffer)
                {
                        buffer->Release();
                        buffer = NULL;
                }

                if (image_ref)
                {
                        CGImageRelease(image_ref);
                        image_ref = NULL;
                }
                
                if (context_ref)
                {
                        CGContextRelease(context_ref);
                        context_ref = NULL;
                }
        }
};

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