-- RCMap.mesa
-- Last Modified By Paul Rovner On 22-Jul-81 9:43:28

RCMap: DEFINITIONS
= BEGIN


-- TYPES

Base: TYPE = LONG BASE POINTER;
Limit: CARDINAL = 40000B; -- plenty

Object: TYPE = RECORD
[ map: SELECT type: * FROM
null => [], -- NOTE assumed one word
ref => [], -- NOTE assumed one word
controlLink => [], -- NOTE assumed one word
oneRef => -- NOTE assumed one word
[ offset: [0..componentLength) ← 0],
simple => -- NOTE assumed one word
[ length: [0..simpleLength] ← 0,
refs: PACKED ARRAY [0..simpleLength) OF BOOLEAN ← ALL[FALSE]],
nonVariant =>
[ complete: BOOLEAN ← FALSE,
nComponents: [0..componentLength/2) ← 0,
components: ARRAY [0..0) OF RCField],
variant => -- NOTE the specified RCMap for each variant includes all common parts
[ complete: BOOLEAN ← FALSE,
nVariants: [0..componentLength/2) ← 0,
fdTag: FieldDescriptor ← [],
variants: ARRAY [0..0) OF Index -- indexed by tag value
],
array =>
[ wordsPerElement: [0..componentLength) ← 0,
nElements: CARDINAL ← 0,
rcmi: Index ← nullIndex
],
sequence =>
[ wordsPerElement: [0..componentLength) ← 0,
fdLength: FieldDescriptor ← [], -- actual number of elements is stored here
commonPart: Index ← nullIndex,
dataOffset: CARDINAL ← 0, -- actual data begins here
rcmi: Index ← nullIndex
],
ENDCASE
];

RCField: TYPE = RECORD -- describes an RC field in a record
[ wordOffset: CARDINAL ← 0|NULL,
rcmi: Index ← nullIndex|NULL
];

FieldDescriptor: TYPE = RECORD -- "fd"
[ wordOffset: INTEGER ← 0,
bitFirst: [0..15] ← 0, -- 4 bits
bitCount: [1..32] ← 1, -- 5 bits
fill: [0..177B] ← 0 -- 7 bits
];


Index: TYPE = Base RELATIVE POINTER [0..Limit) TO Object;
VIndex: TYPE = Base RELATIVE POINTER [0..Limit) TO variant Object;
NVIndex: TYPE = Base RELATIVE POINTER [0..Limit) TO nonVariant Object;
AIndex: TYPE = Base RELATIVE POINTER [0..Limit) TO array Object;
SeqIndex: TYPE = Base RELATIVE POINTER [0..Limit) TO sequence Object;
SimpIndex: TYPE = Base RELATIVE POINTER [0..Limit) TO simple Object;
OneRefIndex: TYPE = Base RELATIVE POINTER [0..Limit) TO oneRef Object;
NullIndex: TYPE = Base RELATIVE POINTER [0..Limit) TO null Object;
RefIndex: TYPE = Base RELATIVE POINTER [0..Limit) TO ref Object;
ControlLinkIndex: TYPE = Base RELATIVE POINTER [0..Limit) TO controlLink Object;


-- CONSTANTS

componentMaxIndex: CARDINAL = LAST[CARDINAL]/16; -- leave room for Object.type in length word
componentLength: CARDINAL = componentMaxIndex+1;
simpleMaxIndex: CARDINAL = 7; -- 4 bits for Object.type, 4 for length, 8 BOOLEANs
simpleLength: CARDINAL = simpleMaxIndex+1;

invalidIndex: Index = LAST[Index]; -- guaranteed to be an invalid Index
nullIndex: NullIndex = LOOPHOLE[0]; -- always at index 0 in the Base
refIndex: RefIndex = LOOPHOLE[1]; -- always at index 1 in the Base
controlLinkIndex: ControlLinkIndex = LOOPHOLE[2]; -- always at index 2 in the Base

END.