Machine-Independent MDL for TOPS-20 and VAX.

[pdp10-muddle.git] / mim / development / mim / vax / mimlib / l-query-base.mud

diff --git a/mim/development/mim/vax/mimlib/l-query-base.mud b/mim/development/mim/vax/mimlib/l-query-base.mud
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+;"*****************************************************************************
+
+  This file defines a means for mapping over all records in LOCAL library.
+  Used by iterative queries in L-QUERY and the server for handling the same
+  over the network.
+
+  L-QUERY-BASE.MUD: EDIT HISTORY                            Machine Independent
+
+  COMPILATION: Spliced in at compile time.
+
+  JUN84   [Shane] - Created.
+  8OCT84  [Shane] - Commented, cleaned up.
+
+  ****************************************************************************"
+
+;"MAP-RECORDS --
+  Effect:    Create a state descriptor for NEXT-RECORD (somewhat like
+            ASSOCIATIONS). The state descriptor is a UVECTOR with the
+            following format:
+
+            [next-bucket bucket-cdr last-bucket]
+
+            where next-bucket is the file address of the next bucket in
+                  the hash table to examine (initially the first bucket).
+                  bucket-cdr is the file address of the next cons in the
+                  current bucket if it contained a list, else nil (0).
+                  (initially nil).
+                  last-bucket is the file address of the last bucket in
+                  the hash table.
+   Modifies: STATE, LIB (the channel access pointer).
+   Returns:  state descriptor (UVECTOR).
+   Requires: LIB is channel to correctly formatted library file (as defined
+            in LIBRARY.FORMAT), size(STATE) >= 3.
+   Note:     The offsets are defined in L-DEFS.MUD."
+
+<DEFINE MAP-RECORDS (LIB:<CHANNEL 'DISK>
+                    "OPT" (STATE:<UVECTOR [3 FIX]> <IUVECTOR 3>))
+   ;"The address of the first bucket is DIR-HDRLEN. The address of the
+     last bucket is DIR-HDRLEN+DIR-TABSIZ-1. Point to DIR-TABSIZ and read."
+   <SETADR .LIB ,DIR-TABSIZ>
+   <LAST-BUCKET .STATE <+ <RDWRD .LIB>:FIX %<- ,DIR-HDRLEN 1>>>
+   <BUCKET-CDR .STATE 0>
+   <NEXT-BUCKET .STATE ,DIR-HDRLEN>>
+\f
+;"NEXT-RECORD --
+  Effect:   Determine the file address of the next record in the iteration
+           over the library. Addresses are yielded in bucket order, position
+           in bucket list (if bucket contains a list).
+  Modifies: STATE, LIB (the channel access pointer).
+  Returns:  File address of next record in sequence if any, else false.
+  Requires: LIB is channel to correctly formatted library file (as defined in
+           LIBRARY.FORMAT), STATE is a state descriptor created by MAP-RECORDS
+           and modified by NEXT-RECORD (only!)."
+
+<DEFINE NEXT-RECORD (LIB:<CHANNEL 'DISK> STATE:<UVECTOR [3 FIX]>)
+   <REPEAT ((LAST:FIX <LAST-BUCKET .STATE>) (BKT:FIX <NEXT-BUCKET .STATE>)
+           (BCDR:FIX <BUCKET-CDR .STATE>) BCAR:FIX "NAME" NEXTR)
+      <COND (<N==? .BCDR 0>                    ;"Are we in a list?"
+            <SETADR .LIB .BCDR   >            ;"Point to cons."
+            <SET BCAR <RDWRD .LIB>>           ;"Pointer to car."
+            <SET BCDR <RDWRD .LIB>>           ;"Pointer to cdr."
+            <COND (<TESTBIT .BCAR ,BKT-P>     ;"Package?"
+                   <NEXT-BUCKET .STATE .BKT>  ;"Set things up for next time."
+                   <BUCKET-CDR .STATE .BCDR>
+                   <RETURN <ADDRESS .BCAR> .NEXTR>)
+                  (T
+                   <AGAIN .NEXTR>)>)          ;"Check out the cdr."
+           (T                                 ;"Empty bucket or end of list."
+            <REPEAT ()
+               <COND (<G? .BKT .LAST>         ;"Every bucket done?"
+                      <NEXT-BUCKET .STATE .BKT>
+                      <BUCKET-CDR .STATE 0>
+                      <RETURN %<> .NEXTR>)
+                     (T
+                      <SETADR .LIB .BKT>       ;"Point to next bucket."
+                      <SET BKT <+ .BKT 1>>     ;"Bump next."
+                      <SET BCAR <RDWRD .LIB>>  ;"Read current bucket."
+                      <COND (<TESTBIT .BCAR ,BKT-M>    ;"List?"
+                             <SET BCDR <ADDRESS .BCAR>>
+                             <RETURN>)     ;"Check out first cons above."
+                            (<TESTBIT .BCAR ,BKT-P>    ;"Package?"
+                             <NEXT-BUCKET .STATE .BKT>;"Next."
+                             <BUCKET-CDR .STATE 0>     ;"Not in list."
+                             <RETURN <ADDRESS .BCAR> .NEXTR>)>)>>)>>>