<![CDATA[
// saved from url
// http://www-cs.canisius.edu/PL_TUTORIALS/C++/EXAMPLES/MRD/SRC/command.c -->
//-------------------------------- command.c -------------------------------
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "expressions.h"
#include "relation.h"
extern parseline parms;
/*
SELECT
select oldrelation newrelation field1 > value1 or field2 = field2 ...
0 1 2 3 4 5 6 7 8 9
*/
void select_command ()
{
char oldrelation[100];
speclist comps;
relation *oldr, *newr;
strcpy (oldrelation, parms.word(1));
oldr = new relation;
oldr->load (oldrelation);
comps.addspec (' ', parms.word(3), parms.word(4), parms.word(5));
int wordsleft = parms.size() - 6;
int k = 6;
while (wordsleft > 0) {
comps.addspec ((parms.word(k))[0], parms.word(k+1),
parms.word(k+2), parms.word(k+3));
k += 4;
wordsleft -= 4;
}
newr = oldr->select (comps);
newr->save (parms.word(2));
delete oldr;
delete newr;
}
/*
CROSS
cross relation1 relation2 newrelation
0 1 2 3
*/
void cross_command ()
{
char rel1name[100], rel2name[100];
relation *rel1, *rel2, *newrel;
strcpy (rel1name, parms.word(1));
rel1 = new relation;
rel1->load (rel1name);
strcpy (rel2name, parms.word(2));
rel2 = new relation;
rel2->load (rel2name);
newrel = rel1->cross(rel2);
newrel->save (parms.word(3));
delete rel1;
delete rel2;
delete newrel;
}
/*
JOIN
join relation1 field1 relation2 field2 newrelation
0 1 2 3 4 5
*/
void join_command ()
{
char rel1name[100], rel2name[100];
relation *rel1, *rel2, *newrel;
char field1[50], field2[50];
strcpy (rel1name, parms.word(1));
rel1 = new relation;
rel1->load (rel1name);
strcpy (field1, parms.word(2));
strcpy (rel2name, parms.word(3));
rel2 = new relation;
rel2->load (rel2name);
strcpy (field2, parms.word(4));
newrel = rel1->ejoin(rel2, field1, field2);
newrel->save (parms.word(5));
delete rel1;
delete rel2;
delete newrel;
}
/*
DIFF
diff relation1 field1 relation2 field2 newrelation
0 1 2 3 4 5
*/
void diff_command ()
{
relation old1, old2, *newone;
old1.load (parms.word(1));
old2.load (parms.word(3));
newone = old1.difference (parms.word(2), &old2, parms.word(4));
newone->save (parms.word(5));
delete newone;
}
/*
PROJECT
project relation1 newrelation field1 field2 field3 ...
0 1 2 3 4 5
*/
void project_command ()
{
char fieldnames[1000];
relation *oldr, *newr;
oldr = new relation;
oldr->load (parms.word(1));
int wordsleft = parms.size() - 3;
int i = 3;
strcpy (fieldnames, "");
while (wordsleft > 0) {
strcat (fieldnames, parms.word(i));
strcat (fieldnames, " ");
i++;
wordsleft--;
}
newr = oldr->project (fieldnames);
newr->save (parms.word(2));
delete newr;
delete oldr;
}
/*
APPEND
append relation1 relation2 newrelation
0 1 2 3
*/
void append_command ()
{
char rel1name[100], rel2name[100];
relation *rel1, *rel2;
strcpy (rel1name, parms.word(1));
rel1 = new relation;
rel1->load (rel1name);
strcpy (rel2name, parms.word(2));
rel2 = new relation;
rel2->load (rel2name);
rel1->append(rel2);
rel1->save (parms.word(3));
delete rel1;
delete rel2;
}
/*
PRINT
print relation1
0 1
*/
void print_command ()
{
relation *oldr;
oldr = new relation;
oldr->load (parms.word(1));
printf ("\n\n");
oldr->printheader (stdout);
oldr->print();
printf ("\n\n");
delete oldr;
}
/*
INFO
info relation1
0 1
*/
void info_command ()
{
relation *oldr;
oldr = new relation;
oldr->load (parms.word(1));
oldr->info();
delete oldr;
}
/*
SORT
sort oldrelation newrelation aord field1
0 1 2 3 4
aord=a or d (for ascending or descending order)
*/
void sort_command ()
{
char oldrelation[100];
char whichfield[50];
relation *oldr;
strcpy (oldrelation, parms.word(1));
oldr = new relation;
oldr->load (oldrelation);
strcpy (whichfield, parms.word(4));
oldr->sort(whichfield, (parms.word(3))[0] == 'a');
oldr->save(parms.word(2));
delete oldr;
}
/*
STATS
stats oldrelation newrelation field1
0 1 2 3
*/
void stats_command ()
{
char oldrelation[100];
char whichfield[50];
relation *oldr, *newr;
strcpy (oldrelation, parms.word(1));
oldr = new relation;
oldr->load (oldrelation);
strcpy (whichfield, parms.word(3));
newr = oldr->summarystats(whichfield);
newr->save(parms.word(2));
delete oldr;
delete newr;
}
/*
NUMBER
number oldrelation newrelation
0 1 2
*/
void number_command ()
{
relation *oldr, *newr;
oldr = new relation;
oldr->load (parms.word(1));
newr = oldr->addseqnums();
newr->save(parms.word(2));
delete oldr;
delete newr;
}
/*
UNIQUE
unique oldrelation newrelation
0 1 2
*/
void unique_command ()
{
relation *oldr, *newr;
oldr = new relation;
oldr->load (parms.word(1));
newr = oldr->copy();
newr->unique();
newr->save(parms.word(2));
delete oldr;
delete newr;
}
/*
ADDRECORD
addrecord relation
0 1
*/
static void add_command ()
{
relation current;
current.load (parms.word(1));
current.addrecord();
current.save (parms.word(1));
}
/*
CHANGEVALUE
changevalue relation recnum fieldname newvalue
0 1 2 3 4
*/
static void change_command ()
{
relation current;
current.load (parms.word(1));
int recnum = atoi(parms.word(2));
if (recnum >= current.numrecords) {
printf ("Not that many records!\n");
return;
}
current.setcurrent(recnum);
current.setvalue (parms.word(3), parms.word(4));
current.save (parms.word(1));
}
/*
RENAMEFIELD
renamefield relation fieldname newname
0 1 2 3
*/
void rename_field_command ()
{
relation current;
current.load (parms.word(1));
if (current.findfield(parms.word(2)) == -1) {
printf ("No such field!\n");
return;
}
if (current.findfield(parms.word(3)) != -1) {
printf ("There is already a field with this name!\n");
return;
}
current.changefieldname (parms.word(2), parms.word(3));
current.save (parms.word(1));
}
/*
CHANGEWIDTH
changewidth relation fieldname newwidth
0 1 2 3
*/
void change_printwidth_command()
{
relation current;
char fieldname[50];
current.load (parms.word(1));
strcpy (fieldname, parms.word(2));
if (current.findfield(fieldname) == -1) {
printf ("No such field!\n");
return;
}
current.changefieldwidth(fieldname, atoi(parms.word(3)));
current.save (parms.word(1));
}
/*
DELETERECORD
deleterecord relation recnum
0 1 2
*/
static void del_command ()
{
relation current;
current.load(parms.word(1));
current.delrecord (atoi(parms.word(2)));
current.save(parms.word(1));
}
/*
ADDFIELD
addfield relation fieldname datatype printwidth defaultvalue
0 1 2 3 4 5
*/
static void addfield_command ()
{
relation current;
current.load (parms.word(1));
char fieldname[50], datatype;
strcpy (fieldname, parms.word(2));
int width = atoi(parms.word(4));
datatype = (parms.word(3))[0];
current.addfield (fieldname, current.numfields, datatype, width);
char defaultvalue[100];
strcpy (defaultvalue, parms.word(5));
for (int i=0; i<current.numrecords; i++)
current.addfieldvalue (parms.word(2), i, defaultvalue);
current.save (parms.word(1));
}
// The following is very tricky. The parseline class allows a lookup
// function to be passed in as a parameter, but it can only have a
// single parameter, a character string, so we cannot also have a relation
// parameter. Thus, this HAS to be a global variable.
relation *xcurrent;
static double mylookup (char *fieldname)
{
if (xcurrent->findfield (fieldname) == -1) {
printf ("No such field: %s\n", fieldname);
return 0.0;
}
return xcurrent->getvalueD (fieldname);
}
/*
CALCFIELD
calcfield oldrelation fieldname "arithmetic expression"
0 1 2 3
*/
static void calcfield_command ()
{
xcurrent = new relation;
xcurrent->load (parms.word(1));
char fieldname[100];
strcpy (fieldname, parms.word(2));
if (xcurrent->findfield(fieldname) == -1) {
printf ("No such field.\n");
return;
}
char expression[2000];
strcpy (expression, parms.word(3));
arithparser ap;
/* Now go through the relation and change each field */
xcurrent->setcurrent (0); /* rewind */
while (1) {
double newvalue = ap.parse (expression, mylookup);
xcurrent->setvalue (fieldname, newvalue);
if (xcurrent->atend()) break;
xcurrent->advance();
}
xcurrent->save (parms.word(1));
delete xcurrent;
}
/*
RETYPE
retype oldrelation field1 field2
0 1 2 3
*/
static void retype_field_command ()
{
relation current;
current.load (parms.word(1));
char field1[100], field2[100];
strcpy (field1, parms.word(2));
strcpy (field2, parms.word(3));
if (current.findfield(field1) == -1) {
printf ("No such field as %s\n", field1);
return;
}
if (current.findfield(field2) == -1) {
printf ("No such field as %s\n", field2);
return;
}
char type1 = current.getfieldtype(field1);
char type2 = current.getfieldtype(field2);
if (type1 == type2) {
printf ("These are the same type. No conversion necessary.\n");
return;
}
/* Now go through the relation and put into field2 the value
of field1 converted to the new type */
current.setcurrent (0); /* rewind */
if (type1 == 'c' && type2 == 'd') {
while (1) {
double newvalue = atof (current.getvalueC(field1));
current.setvalue (field2, newvalue);
if (current.atend()) break;
current.advance();
}
}
else if (type1 == 'c' && type2 == 'i') {
while (1) {
int newvalue = atoi (current.getvalueC(field1));
current.setvalue (field2, newvalue);
if (current.atend()) break;
current.advance();
}
}
else if (type1 == 'd' && type2 == 'i') {
while (1) {
int newvalue = int(current.getvalueD(field1));
current.setvalue (field2, newvalue);
if (current.atend()) break;
current.advance();
}
}
else if (type1 == 'd' && type2 == 'c') {
while (1) {
char newvalue[100];
sprintf (newvalue, "%15.6f", current.getvalueD(field1));
current.setvalue (field2, newvalue);
if (current.atend()) break;
current.advance();
}
}
else if (type1 == 'i' && type2 == 'd') {
while (1) {
double newvalue = double (current.getvalueI(field1));
current.setvalue (field2, newvalue);
if (current.atend()) break;
current.advance();
}
}
else if (type1 == 'i' && type2 == 'c') {
while (1) {
char newvalue[100];
sprintf (newvalue, "%d", current.getvalueI(field1));
current.setvalue (field2, newvalue);
if (current.atend()) break;
current.advance();
}
}
current.save (parms.word(1));
}
void mrdcommand (char *line)
{
parms.set(line);
if (strcmp (parms.word(0), "select") == 0)
select_command ();
else if (strcmp (parms.word(0), "project") == 0)
project_command ();
else if (strcmp (parms.word(0), "cross") == 0)
cross_command ();
else if (strcmp (parms.word(0), "join") == 0)
join_command ();
else if (strcmp (parms.word(0), "diff") == 0)
diff_command ();
else if (strcmp (parms.word(0), "append") == 0)
append_command ();
else if (strcmp (parms.word(0), "print") == 0)
print_command ();
else if (strcmp (parms.word(0), "sort") == 0)
sort_command ();
else if (strcmp (parms.word(0), "stats") == 0)
stats_command ();
else if (strcmp (parms.word(0), "number") == 0)
number_command ();
else if (strcmp (parms.word(0), "unique") == 0)
unique_command ();
else if (strcmp (parms.word(0), "addrecord") == 0)
add_command ();
else if (strcmp (parms.word(0), "changevalue") == 0)
change_command ();
else if (strcmp (parms.word(0), "renamefield") == 0)
rename_field_command ();
else if (strcmp (parms.word(0), "changewidth") == 0)
change_printwidth_command ();
else if (strcmp (parms.word(0), "deleterecord") == 0)
del_command ();
else if (strcmp (parms.word(0), "addfield") == 0)
addfield_command ();
else if (strcmp (parms.word(0), "calcfield") == 0)
calcfield_command ();
else if (strcmp (parms.word(0), "retype") == 0)
retype_field_command ();
else if (strcmp (parms.word(0), "info") == 0)
info_command ();
else printf ("Unrecognized command!\n");
}
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