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include <tbset.h>
# USE_RULES -- Use the rules to expand the input table rows
#
# B.Simon 25-Apr-88 Original
# B.Simon 21-Jan-99 Modified to handle empty target tables
procedure use_rules (itp, otp, target, action, dbg, verbose)
pointer itp # i: Input table
pointer otp # i: Output table
pointer target # u: Table of rule targets
pointer action # u: Table of rule actions
int dbg # i: Debug file descriptor
bool verbose # i: Print diagnostic message
#--
int top, nrow, irow
pointer work
int tbpsta()
int initstack(), numstack(), find_rule(), apply_rule()
string tgtname "The following is the target table:"
string actname "The following is the action table:"
string isstart "The following row is read from the input table:"
string isdone "The following row is moved to the output table:"
begin
# Do straight copy if target table is empty
top = numstack (target)
if (top == 0) {
call no_rule (itp, otp)
return
}
# Print target and action tables
call dbg_rules (target, tgtname, 1, top, dbg)
top = numstack (action)
call dbg_rules (action, actname, 1, top, dbg)
# Create a work table, which is used to store
# intermediate results
work = initstack (itp, "_TARGET,_INDEX")
# Loop over each row in the input table
nrow = tbpsta (itp, TBL_NROWS)
do irow = 1, nrow {
call dbg_rules (itp, isstart, irow, irow, dbg)
# Push the next row from the input table
# into the work table. If it does not match
# any rule, write it to the output table.
call pushstack (work)
call movtbrow (itp, irow, work, 1)
if (find_rule (target, work) == 0) {
top = numstack (work)
call dbg_rules (work, isdone, top, top, dbg)
call movstack (work, otp)
}
# Apply the next instance of the rule to the
# row on top of the stack. If the result of the
# application of the rule does not match any other
# rule, write it to the output table.
while (numstack (work) > 0) {
if (apply_rule (target, action, work, dbg) == 0) {
top = numstack (work)
call dbg_rules (work, isdone, top, top, dbg)
call movstack (work, otp)
if (verbose && mod (numstack (otp), 25) == 0) {
call printf ("\r%d rows written to output table")
call pargi (numstack (otp))
call flush (STDOUT)
}
}
}
}
if (verbose) {
call printf ("\r%39w\r")
call flush (STDOUT)
}
call freestack (target)
call freestack (action)
call freestack (work)
end
# APPLY_RULE -- Expand the top work table row according to a rule
int procedure apply_rule (target, action, work, dbg)
pointer target # i: Table of rule targets
pointer action # i: Table of rule actions
pointer work # i: Table of intermediate results
int dbg # i: Debug file descriptor
#--
int wrow, trow, arow, last, rule
pointer tgt_ptr, idx_ptr, lst_ptr, use_ptr
string isrule "The following rule is applied:"
string notdone "To produce the row:"
int numstack(), find_rule()
begin
# Get column pointers of special columns
call tbcfnd (work, "_TARGET", tgt_ptr, 1)
call tbcfnd (work, "_INDEX", idx_ptr, 1)
call tbcfnd (target, "_LAST", lst_ptr, 1)
# Get the current row numbers for the work, target,
# and action tables
wrow = numstack (work)
call tbegti (work, tgt_ptr, wrow, trow)
call tbegti (work, idx_ptr, wrow, arow)
call tbegti (target, lst_ptr, trow, last)
# If the action row number is greater than the last action
# associated with the target, all the expansions for this
# rule have been performed. Pop the work table and mark the
# target row as unused.
if (arow > last) {
call popstack (work)
call tbcfnd (target, "_USED", use_ptr, 1)
call tbepti (target, use_ptr, trow, NO)
rule = trow
# Otherwise, duplicate the top row of the work table and
# overwrite the appropriate columns with the values stored
# in the action row. Increment the action row for next time.
# Initialize the special columns in the new row of the work
# table.
} else {
call pushstack (work)
call movtbrow (work, wrow, work, wrow+1)
call movtbrow (action, arow, work, wrow+1)
call tbepti (work, idx_ptr, wrow, arow+1) ## should be wrow+1 ??
call dbg_rules (target, isrule, trow, trow, dbg)
call dbg_rules (work, notdone, wrow+1, wrow+1, dbg)
rule = find_rule (target, work)
}
return (rule)
end
# FIND_RULE -- Find the target row which matches the top work table row
int procedure find_rule (target, work)
pointer target # i: Table of rule targets
pointer work # i: Table of intermediate results
#--
bool match, nullflg
int icol, jcol, tcol, wcol, trow, irow, wrow, used, first
pointer sp, tarptr, wrkptr, colname, tarval, wrkval
pointer use_ptr, fst_ptr, tgt_ptr, idx_ptr, iw
bool strne()
int tbpsta(), strlen()
pointer tbcnum(), numstack()
begin
# Get number of columns in tables
tcol = tbpsta (target, TBL_NCOLS)
wcol = tbpsta (work, TBL_NCOLS)
# Allocate dynamic memory
call smark (sp)
call salloc (tarptr, tcol, TY_INT)
call salloc (wrkptr, tcol, TY_INT)
call salloc (colname, SZ_COLNAME, TY_CHAR)
call salloc (tarval, SZ_LINE, TY_CHAR)
call salloc (wrkval, SZ_LINE, TY_CHAR)
# Create arrays of corresponding column pointers
# in the target and work tables
jcol = 0
do icol = 1, tcol {
Memi[tarptr+jcol] = tbcnum (target, icol)
call tbcigt (Memi[tarptr+jcol), TBL_COL_NAME,
Memc[colname], SZ_COLNAME)
call tbcfnd (work, Memc[colname], Memi[wrkptr+jcol], 1)
if (Memc[colname] != '_' && Memi[wrkptr+jcol] != NULL)
jcol = jcol + 1
}
# Get pointers to special columns
call tbcfnd (target, "_USED", use_ptr, 1)
call tbcfnd (target, "_FIRST", fst_ptr, 1)
call tbcfnd (work, "_TARGET", tgt_ptr,1)
call tbcfnd (work, "_INDEX", idx_ptr, 1)
# Search for a match in the target table
# with the top row of the work table
match = false
wrow = numstack (work)
trow = tbpsta (target, TBL_NROWS)
do irow = 1, trow {
call tbegti (target, use_ptr, irow, used)
if (used == NO) {
# Compare each non-null column of the target row
# to the work row
match = true
do icol = 1, jcol {
call tbrgtt (target, Memi[tarptr+icol-1], Memc[tarval],
nullflg, SZ_LINE, 1, irow)
if (! nullflg) {
call tbegtt (work, Memi[wrkptr+icol-1], wrow,
Memc[wrkval], SZ_LINE)
iw = strlen (Memc[wrkval]) + wrkval - 1
while (Memc[iw] == ' ')
iw = iw - 1
Memc[iw+1] = EOS
if (strne (Memc[tarval], Memc[wrkval])) {
match = false
break
}
}
}
# If the rows match, mark the target row as used
# and initialize the special columns in the work row
if (match) {
call tbepti (target, use_ptr, irow, YES)
call tbegti (target, fst_ptr, irow, first)
call tbepti (work, idx_ptr, wrow, first)
call tbepti (work, tgt_ptr, wrow, irow)
break
}
}
}
call sfree (sp)
# If a match was found, return the target row number matched
if (match)
return (irow)
else
return (0)
end
# NO_RULE -- Do a straight copy when ther are no expansion rules
procedure no_rule (itp, otp)
pointer itp # i: Input table
pointer otp # i: Output table
#--
int irow, nrow
int tbpsta()
begin
nrow = tbpsta (itp, TBL_NROWS)
do irow = 1, nrow
call tbrcpy (itp,otp, irow, irow)
end
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