1 /* 2 ** USB_rle.h 3 ** 4 ** Copyright 1999, Be Incorporated. All Rights Reserved. 5 ** 6 */ 7 8 #ifndef _USB_RLE_H 9 #define _USB_RLE_H 10 11 #ifdef __cplusplus 12 extern "C" { 13 #endif 14 15 struct _usbd_param_hdr; 16 17 /* 18 Run Length encoding records for isochronous IN transfers. 19 20 Run Length encoding records are used to identify which samples in 21 the buffer are good which are bad and which are missing. 22 Bad bytes are not extracted from the buffer, but are padded to next 23 nearest sample boundary. The ultimate consumer of the buffer 24 should also receive the RLE array. 25 26 RLE records are constructed based on the following rules: 27 28 1. an RLE record contains a sample count and a status 29 (good, bad, missing or unknown). A buffer has 30 associated with it an array of rle records. The number of 31 rle records available is specified in the RLE header. The 32 number used is also in the RLE header. 33 34 2. Within the scope of a buffer, successive packets with the 35 same completion status are represented with (1) rle record. 36 For example, after three transactions which have completion 37 status of success, the byte count in the rle record for this 38 position in the data stream represents the bytes received in 39 all three packets. 40 41 3. New rle records are initialized each time the status for a 42 given packet differs from that of the previous packet. 43 44 */ 45 46 #define RLE_GOOD 1 47 #define RLE_BAD 2 48 #define RLE_MISSING 3 49 #define RLE_UNKNOWN 4 50 51 /* 52 Name: rle 53 Purpose: used to represent the state of a portion of a data buffer 54 Fields: 55 rle_status will contain only the values: RLE_GOOD, RLE_BAD, RLE_MISSING 56 sample_count the number of usb samples in the buffer associated with this rle 57 record. 58 Notes: 59 If the buffer length field in queue_buffer_single structure changes to an 60 uint32 from uin16, then the sample_count data type must 61 track this change. 62 */ 63 typedef struct rle { 64 uint16 rle_status; 65 uint16 sample_count; 66 } rle; 67 68 69 /* 70 Name: rlea 71 Purpose: used as the primary rle information data structure between the 72 USB driver stack and a consuming client. 73 74 Fields: 75 length the number of rle records available in this structure. 76 num_valid filled in by the USB driver. indicates the number of valid 77 records filled. 78 rles[] unconstrained array of rle records. 79 */ 80 typedef struct rlea { 81 uint16 length; 82 uint16 num_valid; 83 rle rles[1]; 84 } rlea; 85 86 87 #ifdef __cplusplus 88 } 89 #endif 90 91 #endif 92