src/add-ons/media/media-add-ons/usb_webcam/addons/uvc/UVCDeframer.cpp

   1 /*
   2  * Copyright 2011, Gabriel Hartmann, gabriel.hartmann@gmail.com.
   3  * Distributed under the terms of the MIT License.
   4  */
   5
   6
   7 #include "UVCDeframer.h"
   8
   9 #include "CamDebug.h"
  10 #include "CamDevice.h"
  11
  12 #include <Autolock.h>
  13
  14
  15 #define MAX_TAG_LEN CAMDEFRAMER_MAX_TAG_LEN
  16 #define MAXFRAMEBUF CAMDEFRAMER_MAX_QUEUED_FRAMES
  17
  18
  19 UVCDeframer::UVCDeframer(CamDevice* device)
  20         : CamDeframer(device),
  21         fFrameCount(0),
  22         fID(0)
  23 {
  24 }
  25
  26
  27 UVCDeframer::~UVCDeframer()
  28 {
  29 }
  30
  31
  32 ssize_t
  33 UVCDeframer::Write(const void* buffer, size_t size)
  34 {
  35         const uint8* buf = (const uint8*)buffer;
  36         int payloadSize = size - buf[0]; // total length - header length
  37
  38         // This packet is just a header
  39         if (size == buf[0])
  40                 return 0;
  41
  42         // Allocate frame
  43         if (!fCurrentFrame) {
  44                 BAutolock l(fLocker);
  45                 if (fFrames.CountItems() < MAXFRAMEBUF)
  46                         fCurrentFrame = AllocFrame();
  47                 else {
  48                         printf("Dropped %ld bytes. Too many queued frames.)\n", size);
  49                         return size;
  50                 }
  51         }
  52
  53         // Write payload to buffer
  54         fInputBuffer.Write(&buf[buf[0]], payloadSize);
  55
  56         // If end of frame add frame to list of frames
  57         if ((buf[1] & 2) || (buf[1] & 1) != fID) {
  58                 fID = buf[1] & 1;
  59                 fFrameCount++;
  60                 buf = (uint8*)fInputBuffer.Buffer();
  61                 fCurrentFrame->Write(buf, fInputBuffer.BufferLength());
  62                 fFrames.AddItem(fCurrentFrame);
  63                 release_sem(fFrameSem);
  64                 fCurrentFrame = NULL;
  65         }
  66
  67         return size;
  68 }
  69
  70
  71 void
  72 UVCDeframer::_PrintBuffer(const void* buffer, size_t size)
  73 {
  74         uint8* b = (uint8*)buffer;
  75         for (size_t i = 0; i < size; i++)
  76                 printf("0x%x\t", b[i]);
  77         printf("\n");
  78 }
  79