#
# SearchDb: Search a database for the entries which have certain strings
#
#  Usage: SearchDb( {word1, word2, ..}, {word3,..}, ... )
#
#	will return all the entries (as an Entry() data structure)
#	which contain one word of each of the sets.
#
#	Each argument can be a string or a set of strings.  A set
#	of strings is interpreted as an ``or'' of strings to match
#
#				Gaston H. Gonnet (March 1991)
SearchDb := proc( s1:{string,set(string)} )
  if not type(DB, database) then
    error('DB should be assigned a database') fi;

  #  Fill entry vector
  ev := CreateArray(1..nargs);
  for i to nargs do
    if type(args[i],string) then
         ev[i] := CreateArray(1..1)
    elif type(args[i],set(string)) then
         if length(args[i]) = 0 then error('empty set') fi;
         ev[i] := CreateArray(1..length(args[i]))
    else error('invalid arguments') fi
  od;
  
  maxmin := 1;  res := [];
  while maxmin <= DB[TotEntries] do
    flag := true;
    for i to nargs do
      jmin := 1;
      for j to length(ev[i]) do
	if ev[i,j] < maxmin then
	  SearchString( If( type(args[i],string), args[i], args[i,j] ),
		     DB[entry,maxmin]+DB[string] );
	  if " < 0 then ev[i,j] := DB[TotEntries]+1
	  else ev[i,j] := GetEntryNumber( DB[entry,maxmin]+" ) fi
	fi;
	if ev[i,j] < ev[i,jmin] then jmin := j fi
      od;
      if ev[i,jmin] > maxmin then
	flag := false;
	maxmin := ev[i,jmin];
	if maxmin > DB[TotEntries] then break fi
      fi
    od;
    
    if flag then res := append(res, Entry(maxmin));  maxmin := maxmin+1 fi
  od;
  op(res)
end:



#
#  SearchID: find an entry with the given ID
#
#	returns an Entry data structure with the entry which
#	matches the ID.
#	If it is not found, it returns NULL
#
#				Gaston H. Gonnet (Sep 23rd, 2001)
#
SearchID := proc( pat:string )
global SearchID_table,SearchID_DBname;
if not type(DB,database) then error('no database loaded, use ReadDb')
elif not (type(SearchID_table,list) and SearchID_DBname = DB[FileName]) then
     SearchID_DBname := DB[FileName];
     t := CreateArray(1..DB[TotEntries],'');
     for i to DB[TotEntries] do
	 t[i] := SearchTag('ID',DB[string,DB[entry,i]+1..DB[entry,i+1]]) od;
     SearchID_table := sort(t);
     fi;

lo := 0;  hi := DB[TotEntries];
while hi-lo > 1 do
     j := round((lo+hi)/2);
     if pat <= SearchID_table[j] then hi := j else lo := j fi
     od;
if hi>0 then
     t := SearchID_table[hi];
     lp := length(pat);
     if t=pat or length(t) > lp and t[1..lp+1] = pat . ';' then
          Entry(GetEntryNumber(GetOffset(SearchID_table[hi]))) fi
fi;
end:
#
#  SearchID: find an entry with the given ID
#
#	version with table(), too slow still
#
#				Gaston H. Gonnet (Oct 29rd, 2003)
#
#SearchID := proc( pat:string )
#global SearchID_table,SearchID_DBname;
#if not type(DB,database) then error('no database loaded, use ReadDb')
#elif not (type(SearchID_table,list) and SearchID_DBname = DB[FileName]) then
#     SearchID_DBname := DB[FileName];
#     SearchID_table := table();
#     for i to DB[TotEntries] do
#	 SearchID_table[
#	    SearchTag('ID',DB[string,DB[entry,i]+1..DB[entry,i+1]])] := i od;
#     fi;
#
#r := SearchID_table[pat];
#if type(r,posint) then r else NULL fi;
#end:



#
#  SearchAC: find an entry with the given AC
#
#	returns an Entry string which has a matching AC field
#	If it is not found, it returns NULL
#
#				Gaston H. Gonnet (Sep 23rd, 2001)
#
module external SearchAC;
local SearchAC_table,SearchAC_DBname;

SearchAC := proc( pat:string )
global SearchAC_table,SearchAC_DBname;
if not type(DB,database) then error('no database loaded, use ReadDb')
elif not (type(SearchAC_table,list) and SearchAC_DBname = DB[FileName]) then
     SearchAC_DBname := DB[FileName];
     t := [];
     for i to DB[TotEntries] do
	 z := SearchTag('AC',DB[string,DB[entry,i]+1..DB[entry,i+1]]);
	 if SearchString(';',z) < 0 then t := append(t,z)
	 else do  j := SearchString(';',z);
	          if j < 0 then break fi;
	          t := append(t,z[1..j+1]);
	          z := j+2+z
	          od
	      fi
	 od;
     SearchAC_table := sort(t);
     fi;

lo := 0;  hi := length(SearchAC_table);
while hi-lo > 1 do
     j := round((lo+hi)/2);
     if pat <= SearchAC_table[j] then hi := j else lo := j fi
     od;
if hi>0 and SearchAC_table[hi] = pat then
     Entry(GetEntryNumber(GetOffset(SearchAC_table[hi])))
elif pat[-1..-1] <> ';' then SearchAC(pat.';')
else return() fi
end:
end: