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include <ctype.h>
include <tbset.h>
include "reloperr.h"
# NEWCOLNAM -- Create a new, unique column name
#
# This procedure receives as input an array of column pointers from two or
# more tables and an index into that array. If the name of the column pointed
# to by that index is unique, it is output as the new name. If it is not
# unique, a suffix of the form "_i" is appended to the name, where i is
# a digit which (hopefully) makes the name unique.
#
# B.Simon 3-Nov-87 first code
# B.Simon 4-Sep-90 Replaced call to strncmp with streq
procedure newcolnam (numcol, colptr, colidx, newnam, maxch)
int numcol # i: Number of column pointers
pointer colptr[ARB] # i: Array of column pointers
int colidx # i: Index to column to be renamed
char newnam[ARB] # o: New column name
int maxch # i: Maximum characters in new name
#--
int olen, nmatch, nbefore, icol
pointer sp, oldnam, colnam, errtxt
string notuniq "Cannot create a unique column name (%s)"
bool streq()
int strlen()
begin
# Allocate dynamic memory for strings
call smark (sp)
call salloc (oldnam, SZ_COLNAME, TY_CHAR)
call salloc (colnam, SZ_COLNAME, TY_CHAR)
call salloc (errtxt, SZ_LINE, TY_CHAR)
# Read column name pointed to by index
call tbcigt (colptr[colidx], TBL_COL_NAME, Memc[oldnam], SZ_COLNAME)
call strupr (Memc[oldnam])
# See if the name is unique, and if not, how many columns with
# the same name precede this one
nmatch = 0
nbefore = 0
do icol = 1, numcol {
call tbcigt (colptr[icol], TBL_COL_NAME, Memc[colnam], SZ_COLNAME)
call strupr (Memc[colnam])
if (streq (Memc[colnam], Memc[oldnam])) {
nmatch = nmatch + 1
if (icol <= colidx)
nbefore = nbefore + 1
}
}
# If the name is not unique, add a suffix of the form "_i"
if (nmatch > 1) {
# Check for ridiculous values of maxch
olen = min (maxch-2, strlen(Memc[oldnam]))
if (olen < 1) {
call sprintf (Memc[errtxt], SZ_LINE, notuniq)
call pargstr (Memc[oldnam])
call error (SYNTAX, Memc[errtxt])
}
# Add the suffix
Memc[oldnam+olen] = '_'
Memc[oldnam+olen+1] = TO_DIGIT (nbefore)
Memc[oldnam+olen+2] = EOS
# Make sure it is unique
do icol = 1, numcol {
call tbcigt (colptr[icol], TBL_COL_NAME, Memc[colnam],
SZ_COLNAME)
if (streq (Memc[oldnam], Memc[colnam])) {
call sprintf (Memc[errtxt], SZ_LINE, notuniq)
call pargstr (Memc[oldnam])
call error (SYNTAX, Memc[errtxt])
}
}
}
# Copy to the output string
call strcpy (Memc[oldnam], newnam, maxch)
call sfree (sp)
end
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