/*
 * Run-time data structures.
 */

/*
 * Structures common to the compiler and interpreter.
 */

/*
 * Run-time error numbers and text.
 */
struct errtab {
   int err_no;			/* error number */
   char *errmsg;		/* error message */
   };

/*
 * Descriptor
 */
struct descrip {		/* descriptor */
   word dword;			/*   type field */
   union {
      word integr;		/*   integer value */
      char *sptr;		/*   pointer to character string */
      union block *bptr;	/*   pointer to a block */
      dptr descptr;		/*   pointer to a descriptor */
      } vword;
   };

struct sdescrip {
   word length;			/*   length of string */
   char *string;		/*   pointer to string */
   };

/*
 * Heap Blocks
 */

struct b_bignum {		/* large integer block */
   word title;			/*   T_Lrgint */
   word blksize;		/*   block size */
   word msd, lsd;		/*   most and least significant digits */
   int sign;			/*   sign; 0 positive, 1 negative */
   DIGIT digits[1];		/*   digits */
   };

struct b_real {			/* real block */
   word title;			/*   T_Real */
   double realval;		/*   value */
   };

struct b_cset {			/* cset block */
   word title;			/*   T_Cset */
   word size;			/*   size of cset */
   unsigned int bits[CsetSize];		/*   array of bits */
   };

struct b_file {			/* file block */
   word title;			/*   T_File */
   FILE *fd;			/*   Unix file descriptor */
   word status;			/*   file status */
   struct descrip fname;	/*   file name (string qualifier) */
   };

struct b_lelem {		/* list-element block */
   word title;			/*   T_Lelem */
   word blksize;		/*   size of block */
   union block *listprev;	/*   previous list-element block */
   union block *listnext;	/*   next list-element block */
   word nslots;			/*   total number of slots */
   word first;			/*   index of first used slot */
   word nused;			/*   number of used slots */
   struct descrip lslots[1];	/*   array of slots */
   };

struct b_list {			/* list-header block */
   word title;			/*   T_List */
   word size;			/*   current list size */
   word id;			/*   identification number */
   union block *listhead;	/*   pointer to first list-element block */
   union block *listtail;	/*   pointer to last list-element block */
   };

struct b_proc {			/* procedure block */
   word title;			/*   T_Proc */
   word blksize;		/*   size of block */
   union {			/*   entry points for */
      int (*ccode)();		/*     C routines */
      uword ioff;		/*     and icode as offset */
      pointer icode;		/*     and icode as absolute pointer */
      } entryp;

   word nparam;			/*   number of parameters */
   word ndynam;			/*   number of dynamic locals */
   word nstatic;		/*   number of static locals */
   word fstatic;		/*   index (in global table) of first static */

   struct descrip pname;	/*   procedure name (string qualifier) */
   struct descrip lnames[1];	/*   list of local names (qualifiers) */
   };

struct b_record {		/* record block */
   word title;			/*   T_Record */
   word blksize;		/*   size of block */
   word id;			/*   identification number */
   union block *recdesc;	/*   pointer to record constructor */
   struct descrip fields[1];	/*   fields */
   };

/*
 * Alternate uses for procedure block fields, applied to records.
 */
#define nfields	nparam		/* number of fields */
#define recnum nstatic		/* record number */
#define recid fstatic		/* record serial number */
#define recname	pname		/* record name */

struct b_selem {		/* set-element block */
   word title;			/*   T_Selem */
   union block *clink;		/*   hash chain link */
   uword hashnum;		/*   hash number */
   struct descrip setmem;	/*   the element */
   };

/*
 * A set header must be a proper prefix of a table header,
 *  and a set element must be a proper prefix of a table element.
 */
struct b_set {			/* set-header block */
   word title;			/*   T_Set */
   word size;			/*   size of the set */
   word id;			/*   identification number */
   word mask;			/*   mask for slot num, equals n slots - 1 */
   struct b_slots *hdir[HSegs];	/*   directory of hash slot segments */
   };

struct b_table {		/* table-header block */
   word title;			/*   T_Table */
   word size;			/*   current table size */
   word id;			/*   identification number */
   word mask;			/*   mask for slot num, equals n slots - 1 */
   struct b_slots *hdir[HSegs];	/*   directory of hash slot segments */
   struct descrip defvalue;	/*   default table element value */
   };

struct b_slots {		/* set/table hash slots */
   word title;			/*   T_Slots */
   word blksize;		/*   size of block */
   union block *hslots[HSlots];	/*   array of slots (HSlots * 2^n entries) */
   };

struct b_telem {		/* table-element block */
   word title;			/*   T_Telem */
   union block *clink;		/*   hash chain link */
   uword hashnum;		/*   for ordering chain */
   struct descrip tref;		/*   entry value */
   struct descrip tval;		/*   assigned value */
   };

struct b_tvsubs {		/* substring trapped variable block */
   word title;			/*   T_Tvsubs */
   word sslen;			/*   length of substring */
   word sspos;			/*   position of substring */
   struct descrip ssvar;	/*   variable that substring is from */
   };

struct b_tvtbl {		/* table element trapped variable block */
   word title;			/*   T_Tvtbl */
   union block *clink;		/*   pointer to table header block */
   uword hashnum;		/*   hash number */
   struct descrip tref;		/*   entry value */
   };

struct b_external {		/* external block */
   word title;			/*   T_External */
   word blksize;		/*   size of block */
   word id;			/*   identification number */
   struct b_extlfuns *funcs;	/*   dispatch table; distinguishes extl types */
   word data[];			/*   actual external data */
   };

struct astkblk {		  /* co-expression activator-stack block */
   int nactivators;		  /*   valid activator entries in this block */
   struct astkblk *astk_nxt;	  /*   next activator block */
   struct actrec {		  /*   activator record */
      word acount;		  /*     number of calls by this activator */
      struct b_coexpr *activator; /*     the activator itself */
      } arec[ActStkBlkEnts];
   };

/*
 * Structure for keeping set/table generator state across a suspension.
 */
struct hgstate {		/* hashed-structure generator state */
   int segnum;			/* current segment number */
   word slotnum;		/* current slot number */
   word tmask;			/* structure mask before suspension */
   word sgmask[HSegs];		/* mask in use when the segment was created */
   uword sghash[HSegs];		/* hashnum in process when seg was created */
   };

/*
 * Structure for chaining tended descriptors.
 */
struct tend_desc {
   struct tend_desc *previous;
   int num;
   struct descrip d[1]; /* actual size of array indicated by num */
   };

/*
 * Structure for mapping string names of functions and operators to block
 * addresses.
 */
struct pstrnm {
   char *pstrep;
   struct b_proc *pblock;
   };

struct dpair {
   struct descrip dr;
   struct descrip dv;
   };

/*
 * Structure for dispatching to user-provided C functions
 * associated with external data.  Any entry can be null.
 */
struct b_extlfuns {
   int (*extlcmp)  (int argc, dptr argv);
   int (*extlcopy) (int argc, dptr argv);
   int (*extlname) (int argc, dptr argv);
   int (*extlimage)(int argc, dptr argv);
   };

/*
 * Allocated memory region structure.  Each program has linked lists of
 * string and block regions.
 */
struct region {
   word  size;				/* allocated region size in bytes */
   char *base;				/* start of region */
   char *end;				/* end of region */
   char *free;				/* free pointer */
   struct region *prev, *next;		/* forms a linked list of regions */
   struct region *Gprev, *Gnext;	/* global (all programs) lists */
   };

#ifdef Double
   /*
    * Data type the same size as a double but without alignment requirements.
    */
   struct size_dbl {
      char s[sizeof(double)];
      };
#endif					/* Double */

/*
 * when debugging is enabled a debug struct is placed after the tended
 *  descriptors in the procedure frame.
 */
struct debug {
   struct b_proc *proc;
   char *old_fname;
   int old_line;
   };

union numeric {			/* long integers or real numbers */
   long integer;
   double real;
   struct b_bignum *big;
   };

/*
 * Declarations for entries in tables associating icode location with
 *  source program location.
 */
struct ipc_fname {
   word ipc;		/* offset of instruction into code region */
   word fname;		/* offset of file name into string region */
   };

struct ipc_line {
   word ipc;		/* offset of instruction into code region */
   int line;		/* line number */
   };

/*
 * Frame markers
 */
struct ef_marker {		/* expression frame marker */
   inst ef_failure;		/*   failure ipc */
   struct ef_marker *ef_efp;	/*   efp */
   struct gf_marker *ef_gfp;	/*   gfp */
   word ef_ilevel;		/*   ilevel */
   };

struct pf_marker {		/* procedure frame marker */
   word pf_nargs;		/*   number of arguments */
   struct pf_marker *pf_pfp;	/*   saved pfp */
   struct ef_marker *pf_efp;	/*   saved efp */
   struct gf_marker *pf_gfp;	/*   saved gfp */
   dptr pf_argp;		/*   saved argp */
   inst pf_ipc;			/*   saved ipc */
   word pf_ilevel;		/*   saved ilevel */
   dptr pf_scan;		/*   saved scanning environment */
   struct descrip pf_locals[1];	/*   descriptors for locals */
   };

struct gf_marker {		/* generator frame marker */
   word gf_gentype;		/*   type */
   struct ef_marker *gf_efp;	/*   efp */
   struct gf_marker *gf_gfp;	/*   gfp */
   inst gf_ipc;			/*   ipc */
   struct pf_marker *gf_pfp;	/*   pfp */
   dptr gf_argp;		/*   argp */
   };

/*
 * Generator frame marker dummy -- used only for sizing "small"
 *  generator frames where procedure information need not be saved.
 *  The first five members here *must* be identical to those for
 *  gf_marker.
 */
struct gf_smallmarker {		/* generator frame marker */
   word gf_gentype;		/*   type */
   struct ef_marker *gf_efp;	/*   efp */
   struct gf_marker *gf_gfp;	/*   gfp */
   inst gf_ipc;			/*   ipc */
   };

/*
 * b_iproc blocks are used to statically initialize information about
 *  functions.	They are identical to b_proc blocks except for
 *  the pname field which is a sdescrip (simple/string descriptor) instead
 *  of a descrip.  This is done because unions cannot be initialized.
 */

struct b_iproc {		/* procedure block */
   word ip_title;		/*   T_Proc */
   word ip_blksize;		/*   size of block */
   int (*ip_entryp)();		/*   entry point (code) */
   word ip_nparam;		/*   number of parameters */
   word ip_ndynam;		/*   number of dynamic locals */
   word ip_nstatic;		/*   number of static locals */
   word ip_fstatic;		/*   index (in global table) of first static */

   struct sdescrip ip_pname;	/*   procedure name (string qualifier) */
   struct descrip ip_lnames[1];	/*   list of local names (qualifiers) */
   };

struct b_coexpr {		/* co-expression stack block */
   word title;			/*   T_Coexpr */
   word size;			/*   number of results produced */
   word id;			/*   identification number */
   struct b_coexpr *nextstk;	/*   pointer to next allocated stack */
   struct pf_marker *es_pfp;	/*   current pfp */
   struct ef_marker *es_efp;	/*   efp */
   struct gf_marker *es_gfp;	/*   gfp */
   struct tend_desc *es_tend;	/*   current tended pointer */
   dptr es_argp;		/*   argp */
   inst es_ipc;			/*   ipc */
   word es_ilevel;		/*   interpreter level */
   word *es_sp;			/*   sp */
   dptr tvalloc;		/*   where to place transmitted value */
   struct descrip freshblk;	/*   refresh block pointer */
   struct astkblk *es_actstk;	/*   pointer to activation stack structure */
   word cstate[2];		/*   was C state, now rswitch data */
   };

struct b_refresh {		/* co-expression block */
   word title;			/*   T_Refresh */
   word blksize;		/*   size of block */
   word *ep;			/*   entry point */
   word numlocals;		/*   number of locals */
   struct pf_marker pfmkr;	/*   marker for enclosing procedure */
   struct descrip elems[1];	/*   arguments and locals, including Arg0 */
   };


union block {			/* general block */
   struct b_real realblk;
   struct b_cset cset;
   struct b_file file;
   struct b_proc proc;
   struct b_list list;
   struct b_lelem lelem;
   struct b_table table;
   struct b_telem telem;
   struct b_set set;
   struct b_selem selem;
   struct b_record record;
   struct b_tvsubs tvsubs;
   struct b_tvtbl tvtbl;
   struct b_refresh refresh;
   struct b_coexpr coexpr;
   struct b_external externl;
   struct b_slots slots;
   struct b_bignum bignumblk;
   };