1 /* BEGIN INCLUDE FILE dm_cm_basic_ci.incl.pl1 */ 2 3 /* DESCRIPTION: 4 5 The collection_manager_ manages the structure of the addressable 6 portion of a control interval. The addressable portion is that portion of 7 a control interval which the file_manager_ will allow the 8 collection_manager_ to address. In this description control interval will 9 be used to mean the addressable portion of a control interval. 10 11 A control interval is divided into four parts: the header, the datum 12 position table (also known as the slot table or slots), un-used space and 13 used space. The beginning of the header is at offset 0, and the end of the 14 used space is at the end of the control interval (curently offset 4072). 15 Pictoriarly, a control interval is structured as follows: 16 17 ---------------------------------------------------------------------- 18 | || | | | | | || || | / / | |/| | | 19 | Header || | slot | || un-used space || |/ / /| |/| | | 20 | || | table | || || | / / | |/| | | 21 | || | | | | | || || |/ / /| |/| | | 22 ---------------------------------------------------------------------- 23 ^ ^ ^ ^ ^ ^ ^ 24 | | | | | | | 25 | |...........|.......|...| 26 start of used space| | | | 27 | | each| 28 scattered free space| is a used 29 datum 30 31 The basic_control_interval structure describes the header 32 (basic_control_interval.header, bci_header) and the slots 33 (basic_control_interval.datum_position_table, datum_slot for one only). 34 Each datum_slot contains the offset (in bytes) and the length (in bits) of 35 a datum in the used space. If the offset is equal to FREE_SLOT (declared 36 in dm_cm_basic_ci_const.incl.pl1), the slot is un-used. The slot also 37 contains flags describing the type of datum (see dm_cm_datum.incl.pl1). 38 */ 39 40 /* HISTORY: 41 Written by Matthew Pierret, 02/07/82. 42 Modified: 43 03/25/82 by Matthew Pierret: Fixed alignment differences basic_control_interval 44 and its sub-structures. 45 06/14/82 by Matthew Pierret: Removed common header and buffers. Changed 46 basic_ci_header to bci_header. Added previous_control_interval. 47 07/12/82 by Matthew Pierret: Changed collection_id to be bit (36) aligned. 48 10/29/82 by Matthew Pierret: Added flags to datum slots. 49 11/10/82 by Matthew Pierret: Removed continued_datum_is_present flag, as it 50 is not used. 51 03/28/84 by Matthew Pierret: Added the constants BCI_HEADER_LENGTH_IN_BYTES 52 and DATUM_POSITION_TABLE_OFFSET_IN_BYTES. 53 */ 54 55 /* format: style2 */ 56 dcl 1 basic_control_interval 57 aligned based (basic_control_interval_ptr), 58 2 header like bci_header, 59 2 datum_position_table 60 (0 refer (basic_control_interval.number_of_datums)) like datum_slot; 61 62 63 dcl 1 bci_header aligned based (bci_header_ptr), 64 2 layout_type char (4) aligned, 65 2 collection_id bit (36) aligned, 66 2 next_control_interval 67 fixed bin (24) uns unal, 68 2 previous_control_interval 69 fixed bin (24) uns unal, 70 2 flags unal, 71 3 continuation_datum_is_present 72 bit (1) unal, 73 3 free_slot_is_present 74 bit (1) unal, 75 3 must_be_zero bit (4) unal, /* reserved */ 76 2 scattered_free_space 77 fixed bin (17) unal, 78 2 start_of_used_space 79 fixed bin (17) unal, 80 2 number_of_datums fixed bin (17) unal; 81 82 dcl 1 datum_slot aligned based (datum_slot_ptr), 83 2 flags unal, 84 3 special_format_datum 85 bit (1) unal, /* reserved */ 86 3 is_continued bit (1) unal, 87 3 is_continuation bit (1) unal, 88 3 mbz bit (1) unal, /* reserved */ 89 2 offset_in_bytes fixed bin (15) uns unal, 90 2 length_in_bits fixed bin (17) uns unal; 91 92 dcl basic_control_interval_ptr 93 ptr; 94 dcl bci_header_ptr ptr; 95 dcl datum_slot_ptr ptr; 96 97 dcl BASIC_CI_LAYOUT_1 char (4) aligned init ("bci1") internal static options (constant); 98 99 /* END INCLUDE FILE dm_cm_basic_ci.incl.pl1 */