diff options
| -rw-r--r-- | HISTORY | 2 | ||||
| -rw-r--r-- | device.c | 25 | ||||
| -rw-r--r-- | device.h | 5 |
3 files changed, 21 insertions, 11 deletions
@@ -4788,3 +4788,5 @@ Video Disk Recorder Revision History - Added "-fPIC" to the compiler options in Make.config.template when compiling plugins (thanks to Udo Richter). If you use your own Make.config file, you may want to add these lines there, too. +- Added some comment to cDevice::GetDevice() to explain how the individual + conditions are put together to make a decision on which device to use. @@ -4,7 +4,7 @@ * See the main source file 'vdr.c' for copyright information and * how to reach the author. * - * $Id: device.c 1.130 2006/05/27 11:14:42 kls Exp $ + * $Id: device.c 1.131 2006/06/15 09:59:40 kls Exp $ */ #include "device.h" @@ -281,19 +281,26 @@ cDevice *cDevice::GetDevice(int Index) cDevice *cDevice::GetDevice(const cChannel *Channel, int Priority, bool *NeedsDetachReceivers) { cDevice *d = NULL; - uint Impact = 0xFFFFFFFF; + uint Impact = 0xFFFFFFFF; // we're looking for a device with the least impact for (int i = 0; i < numDevices; i++) { bool ndr; if (device[i]->ProvidesChannel(Channel, Priority, &ndr)) { // this device is basicly able to do the job + // Put together an integer number that reflects the "impact" using + // this device would have on the overall system. Each condition is represented + // by one bit in the number (or several bits, if the condition is actually + // a numeric value). The sequence in which the conditions are listed corresponds + // to their individual severity, where the one listed first will make the most + // difference, because it results in the most significant bit of the result. uint imp = 0; - imp <<= 1; imp |= !device[i]->Receiving() || ndr; - imp <<= 1; imp |= device[i]->Receiving(); - imp <<= 1; imp |= device[i] == ActualDevice(); - imp <<= 1; imp |= device[i]->IsPrimaryDevice(); - imp <<= 1; imp |= device[i]->HasDecoder(); - imp <<= 8; imp |= min(max(device[i]->Priority() + MAXPRIORITY, 0), 0xFF); - imp <<= 8; imp |= min(max(device[i]->ProvidesCa(Channel), 0), 0xFF); + imp <<= 1; imp |= !device[i]->Receiving() || ndr; // use receiving devices if we don't need to detach existing receivers + imp <<= 1; imp |= device[i]->Receiving(); // avoid devices that are receiving + imp <<= 1; imp |= device[i] == ActualDevice(); // avoid the actual device (in case of Transfer Mode) + imp <<= 1; imp |= device[i]->IsPrimaryDevice(); // avoid the primary device + imp <<= 1; imp |= device[i]->HasDecoder(); // avoid full featured cards + imp <<= 8; imp |= min(max(device[i]->Priority() + MAXPRIORITY, 0), 0xFF); // use the device with the lowest priority (+MAXPRIORITY to assure that values -99..99 can be used) + imp <<= 8; imp |= min(max(device[i]->ProvidesCa(Channel), 0), 0xFF); // use the device that provides the lowest number of conditional access methods if (imp < Impact) { + // This device has less impact than any previous one, so we take it. Impact = imp; d = device[i]; if (NeedsDetachReceivers) @@ -4,7 +4,7 @@ * See the main source file 'vdr.c' for copyright information and * how to reach the author. * - * $Id: device.h 1.78 2006/05/28 15:04:24 kls Exp $ + * $Id: device.h 1.79 2006/06/15 09:32:48 kls Exp $ */ #ifndef __DEVICE_H @@ -130,7 +130,8 @@ public: ///< \return A pointer to the device, or NULL if the Index was invalid. static cDevice *GetDevice(const cChannel *Channel, int Priority = -1, bool *NeedsDetachReceivers = NULL); ///< Returns a device that is able to receive the given Channel at the - ///< given Priority. + ///< given Priority, with the least impact on active recordings and + ///< live viewing. ///< See ProvidesChannel() for more information on how ///< priorities are handled, and the meaning of NeedsDetachReceivers. static void Shutdown(void); |