4.3BSD/usr/src/etc/sa.c
#ifndef lint
static char *sccsid = "@(#)sa.c 4.9 (Berkeley) 12/12/84";
#endif
/*
* Extensive modifications to internal data structures
* to allow arbitrary number of different commands and users added.
*
* Also allowed the digit option on the -v flag (interactive
* threshold compress) to be a digit string, so one can
* set the threshold > 9.
*
* Also added the -f flag, to force no interactive threshold
* compression with the -v flag.
*
* Robert Henry
* UC Berkeley
* 31jan81
*/
#include <stdio.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/acct.h>
#include <signal.h>
#include <utmp.h>
#include <pwd.h>
/* interpret command time accounting */
#define NC sizeof(acctbuf.ac_comm)
struct acct acctbuf;
int lflg;
int cflg;
int Dflg;
int dflg;
int iflg;
int jflg;
int Kflg;
int kflg;
int nflg;
int aflg;
int rflg;
int oflg;
int tflg;
int vflg;
int fflg;
int uflg;
int thres;
int sflg;
int bflg;
int mflg;
struct utmp utmp;
#define NAMELG (sizeof(utmp.ut_name)+1)
struct Olduser{
int Us_cnt;
double Us_ctime;
double Us_io;
double Us_imem;
};
struct user {
char name[NC]; /* this is <\001><user id><\000> */
struct Olduser oldu;
char us_name[NAMELG];
};
#define us_cnt oldu.Us_cnt
#define us_ctime oldu.Us_ctime
#define us_io oldu.Us_io
#define us_imem oldu.Us_imem
/*
* We protect ourselves from preposterous user id's by looking
* through the passwd file for the highest uid allocated, and
* then adding 10 to that.
* This prevents the user structure from growing too large.
*/
#define USERSLOP 10
int maxuser; /* highest uid from /etc/passwd, + 10 for slop*/
struct process {
char name[NC];
int count;
double realt;
double cput;
double syst;
double imem;
double io;
};
union Tab{
struct process p;
struct user u;
};
typedef union Tab cell;
int (*cmp)(); /* compares 2 cells; set to appropriate func */
cell *enter();
struct user *finduser();
struct user *wasuser();
/*
* Table elements are keyed by the name of the file exec'ed.
* Because on large systems, many files can be exec'ed,
* a static table size may grow to be too large.
*
* Table elements are allocated in chunks dynamically, linked
* together so that they may be retrieved sequentially.
*
* An index into the table structure is provided by hashing through
* a seperate hash table.
* The hash table is segmented, and dynamically extendable.
* Realize that the hash table and accounting information is kept
* in different segments!
*
* We have a linked list of hash table segments; within each
* segment we use a quadratic rehash that touches no more than 1/2
* of the buckets in the hash table when probing.
* If the probe does not find the desired symbol, it moves to the
* next segment, or allocates a new segment.
*
* Hash table segments are kept on the linked list with the first
* segment always first (that will probably contain the
* most frequently executed commands) and
* the last added segment immediately after the first segment,
* to hopefully gain something by locality of reference.
*
* We store the per user information in the same structure as
* the per exec'ed file information. This allows us to use the
* same managers for both, as the number of user id's may be very
* large.
* User information is keyed by the first character in the name
* being a '\001', followed by four bytes of (long extended)
* user id number, followed by a null byte.
* The actual user names are kept in a seperate field of the
* user structure, and is filled in upon demand later.
* Iteration through all users by low user id to high user id
* is done by just probing the table, which is gross.
*/
#define USERKEY '\001'
#define ISPROCESS(tp) (tp->p.name[0] && (tp->p.name[0] != USERKEY))
#define ISUSER(tp) (tp->p.name[0] && (tp->p.name[0] == USERKEY))
#define TABDALLOP 500
struct allocbox{
struct allocbox *nextalloc;
cell tabslots[TABDALLOP];
};
struct allocbox *allochead; /*head of chunk list*/
struct allocbox *alloctail; /*tail*/
struct allocbox *newbox; /*for creating a new chunk*/
cell *nexttab; /*next table element that is free*/
int tabsleft; /*slots left in current chunk*/
int ntabs;
/*
* Iterate through all symbols in the symbol table in declaration
* order.
* struct allocbox *allocwalk;
* cell *sp, *ub;
*
* sp points to the desired item, allocwalk and ub are there
* to make the iteration go.
*/
#define DECLITERATE(allocwalk, walkpointer, ubpointer) \
for(allocwalk = allochead; \
allocwalk != 0; \
allocwalk = allocwalk->nextalloc) \
for (walkpointer = &allocwalk->tabslots[0],\
ubpointer = &allocwalk->tabslots[TABDALLOP], \
ubpointer = ubpointer > ( (cell *)alloctail) \
? nexttab : ubpointer ;\
walkpointer < ubpointer; \
walkpointer++ )
#define TABCHUNKS(allocwalk, tabptr, size) \
for (allocwalk = allochead; \
allocwalk != 0; \
allocwalk = allocwalk->nextalloc) \
if ( \
(tabptr = &allocwalk->tabslots[0]), \
(size = \
( (&allocwalk->tabslots[TABDALLOP]) \
> ((cell *)alloctail) \
) \
? (nexttab - tabptr) : TABDALLOP \
), \
1 \
)
#define PROCESSITERATE(allocwalk, walkpointer, ubpointer) \
DECLITERATE(allocwalk, walkpointer, ubpointer) \
if (ISPROCESS(walkpointer))
#define USERITERATE(allocwalk, walkpointer, ubpointer) \
DECLITERATE(allocwalk, walkpointer, ubpointer) \
if (ISUSER(walkpointer))
/*
* When we have to sort the segmented accounting table, we
* create a vector of sorted queues that is merged
* to sort the entire accounting table.
*/
struct chunkdesc {
cell *chunk_tp;
int chunk_n;
};
/*
* Hash table segments and manager
*/
#define NHASH 1103
struct hashdallop {
int h_nused;
struct hashdallop *h_next;
cell *h_tab[NHASH];
};
struct hashdallop *htab; /* head of the list */
int htabinstall; /* install the symbol */
double treal;
double tcpu;
double tsys;
double tio;
double timem;
cell *junkp;
char *sname;
double ncom;
time_t expand();
char *getname();
/*
* usracct saves records of type Olduser.
* There is one record for every possible uid less than
* the largest uid seen in the previous usracct or in savacct.
* uid's that had no activity correspond to zero filled slots;
* thus one can index the file and get the user record out.
* It would be better to save only user information for users
* that the system knows about to save space, but that is not
* upward compatabile with the old system.
*
* In the old version of sa, uid's greater than 999 were not handled
* properly; this system will do that.
*/
#ifdef DEBUG
#define USRACCT "./usracct"
#define SAVACCT "./savacct"
#define ACCT "./acct"
#else
#define USRACCT "/usr/adm/usracct"
#define SAVACCT "/usr/adm/savacct"
#define ACCT "/usr/adm/acct"
#endif DEBUG
char *usracct = USRACCT;
char *savacct = SAVACCT;
int cellcmp();
cell *junkp = 0;
/*
* The threshold is built up from digits in the argv ;
* eg, -v1s0u1
* will build a value of thres of 101.
*
* If the threshold is zero after processing argv, it is set to 1
*/
int thres = 0;
int htabinstall = 1;
int maxuser = -1;
int (*cmp)();
/* we assume pagesize is at least 1k */
int pgdiv;
#define pgtok(x) ((x) / pgdiv)
extern tcmp(), ncmp(), bcmp(), dcmp(), Dcmp(), kcmp(), Kcmp();
extern double sum();
main(argc, argv)
char **argv;
{
FILE *ff;
double ft;
register struct allocbox *allocwalk;
register cell *tp, *ub;
int i, j, size, nchunks, smallest;
struct chunkdesc *chunkvector;
pgdiv = getpagesize() / 1024;
if (pgdiv == 0)
pgdiv = 1;
maxuser = USERSLOP + getmaxuid();
tabinit();
cmp = tcmp;
if (argc>1)
if (argv[1][0]=='-') {
argv++;
argc--;
for(i=1; argv[0][i]; i++)
switch(argv[0][i]) {
case 'o':
oflg++;
break;
case 'i':
iflg++;
break;
case 'b':
bflg++;
cmp = bcmp;
break;
case 'l':
lflg++;
break;
case 'c':
cflg++;
break;
case 'd':
dflg++;
cmp = dcmp;
break;
case 'D':
Dflg++;
cmp = Dcmp;
break;
case 'j':
jflg++;
break;
case 'k':
kflg++;
cmp = kcmp;
break;
case 'K':
Kflg++;
cmp = Kcmp;
break;
case 'n':
nflg++;
cmp = ncmp;
break;
case 'a':
aflg++;
break;
case 'r':
rflg++;
break;
case 't':
tflg++;
break;
case 's':
sflg++;
aflg++;
break;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
thres = thres * 10 + (argv[0][i]-'0');
break;
case 'v':
vflg++;
break;
case 'f':
fflg++; /* force v option; no tty interaction */
break;
case 'u':
uflg++;
break;
case 'm':
mflg++;
break;
case 'U':
case 'S':
if (i != 1 || argv[0][2]) { /* gross! */
fprintf(stderr, "-U and -S options must be separate\n");
exit(1);
}
argc++, argv--; /* backup - yuk */
goto doUS;
default:
fprintf(stderr, "Invalid option %c\n", argv[0][1]);
exit(1);
}
}
#define optfile(f) {if (argc < 2) \
{ fprintf(stderr, "Missing filename\n"); exit(1); } \
argc--, argv++; f = argv[0]; }
doUS:
for (argc--, argv++; argc && argv[0][0] == '-'; argc--, argv++) {
switch(argv[0][1]) {
case 'U':
optfile(usracct);
break;
case 'S':
optfile(savacct);
break;
default:
fprintf(stderr, "Invalid option %c\n", argv[0][1]);
exit(1);
}
}
if (thres == 0)
thres = 1;
if (iflg==0)
init();
if (argc<1)
doacct(ACCT);
else while (argc--)
doacct(*argv++);
if (uflg) {
return;
}
/*
* cleanup pass
* put junk together
*/
if (vflg)
strip();
if(!aflg)
PROCESSITERATE(allocwalk, tp, ub){
for(j=0; j<NC; j++)
if(tp->p.name[j] == '?')
goto yes;
if(tp->p.count != 1)
continue;
yes:
if(junkp == 0)
junkp = enter("***other");
junkp->p.count += tp->p.count;
junkp->p.realt += tp->p.realt;
junkp->p.cput += tp->p.cput;
junkp->p.syst += tp->p.syst;
junkp->p.imem += tp->p.imem;
junkp->p.io += tp->p.io;
tp->p.name[0] = 0;
}
if (sflg) {
signal(SIGINT, SIG_IGN);
if ((ff = fopen(usracct, "w")) != NULL) {
static struct user ZeroUser = {0};
struct user *up;
int uid;
/*
* Write out just enough user slots,
* filling with zero slots for users that
* weren't found.
* The file can be indexed directly by uid
* to get the correct record.
*/
for (uid = 0; uid < maxuser; uid++){
if ( (up = wasuser(uid)) != 0)
fwrite((char *)&(up->oldu),
sizeof(struct Olduser),1,ff);
else
fwrite((char *)&(ZeroUser.oldu),
sizeof(struct Olduser),1,ff);
}
}
if ((ff = fopen(savacct, "w")) == NULL) {
printf("Can't save\n");
exit(0);
}
PROCESSITERATE(allocwalk, tp, ub)
fwrite((char *)&(tp->p), sizeof(struct process), 1, ff);
fclose(ff);
creat(sname, 0644);
signal(SIGINT, SIG_DFL);
}
/*
* sort and print
*/
if (mflg) {
printmoney();
exit(0);
}
column(ncom, treal, tcpu, tsys, timem, tio);
printf("\n");
/*
* the fragmented table is sorted by sorting each fragment
* and then merging.
*/
nchunks = 0;
TABCHUNKS(allocwalk, tp, size){
qsort(tp, size, sizeof(cell), cellcmp);
nchunks ++;
}
chunkvector = (struct chunkdesc *)calloc(nchunks,
sizeof(struct chunkdesc));
nchunks = 0;
TABCHUNKS(allocwalk, tp, size){
chunkvector[nchunks].chunk_tp = tp;
chunkvector[nchunks].chunk_n = size;
nchunks++;
}
for(; nchunks; ){
/*
* Find the smallest element at the head of the queues.
*/
smallest = 0;
for (i = 1; i < nchunks; i++){
if (cellcmp(chunkvector[i].chunk_tp,
chunkvector[smallest].chunk_tp) < 0)
smallest = i;
}
tp = chunkvector[smallest].chunk_tp++;
/*
* If this queue is drained, drop the chunk count,
* and readjust the queues.
*/
if (--chunkvector[smallest].chunk_n == 0){
nchunks--;
for (i = smallest; i < nchunks; i++)
chunkvector[i] = chunkvector[i+1];
}
if (ISPROCESS(tp)){
ft = tp->p.count;
column(ft, tp->p.realt, tp->p.cput,
tp->p.syst, tp->p.imem, tp->p.io);
printf(" %.14s\n", tp->p.name);
}
} /* iterate to merge the lists */
}
printmoney()
{
register i;
register char *cp;
register struct user *up;
getnames(); /* fetches all of the names! */
for (i = 0; i < maxuser; i++) {
if ( (up = wasuser(i)) != 0){
if (up->us_cnt) {
if (up->us_name[0])
printf("%-8s", up->us_name);
else
printf("%-8d", i);
printf("%7u %9.2fcpu %10.0ftio %12.0fk*sec\n",
up->us_cnt, up->us_ctime / 60,
up->us_io,
up->us_imem / AHZ);
}
}
}
}
column(n, a, b, c, d, e)
double n, a, b, c, d, e;
{
printf("%8.0f", n);
if(cflg) {
if(n == ncom)
printf("%9s", ""); else
printf("%8.2f%%", 100.*n/ncom);
}
col(n, a, treal, "re");
if (oflg)
col(n, 60*AHZ*(b/(b+c)), tcpu+tsys, "u/s");
else if(lflg) {
col(n, b, tcpu, "u");
col(n, c, tsys, "s");
} else
col(n, b+c, tcpu+tsys, "cp");
if(tflg)
printf("%8.1fre/cp", a/(b+c));
if(dflg || !Dflg)
printf("%10.0favio", e/(n?n:1));
else
printf("%10.0ftio", e);
if (kflg || !Kflg)
printf("%10.0fk", d/((b+c)!=0.0?(b+c):1.0));
else
printf("%10.0fk*sec", d/AHZ);
}
col(n, a, m, cp)
double n, a, m;
char *cp;
{
if(jflg)
printf("%11.2f%s", a/(n*(double)AHZ), cp); else
printf("%11.2f%s", a/(60.*(double)AHZ), cp);
if(cflg) {
if(a == m)
printf("%9s", ""); else
printf("%8.2f%%", 100.*a/m);
}
}
doacct(f)
char *f;
{
FILE *ff;
long x, y, z;
struct acct fbuf;
register char *cp;
register int c;
register struct user *up;
register cell *tp;
#ifdef DEBUG
int nrecords = 0;
#endif DEBUG
if (sflg && sname) {
printf("Only 1 file with -s\n");
exit(0);
}
if (sflg)
sname = f;
if ((ff = fopen(f, "r"))==NULL) {
printf("Can't open %s\n", f);
return;
}
while (fread((char *)&fbuf, sizeof(fbuf), 1, ff) == 1) {
#ifdef DEBUG
if (++nrecords % 1000 == 0)
printf("Input record from %s number %d\n",
f, nrecords);
#endif DEBUG
for (cp = fbuf.ac_comm; *cp && cp < &fbuf.ac_comm[NC]; cp++)
if (!isascii(*cp) || iscntrl(*cp))
*cp = '?';
if (cp == fbuf.ac_comm)
*cp++ = '?';
if (fbuf.ac_flag&AFORK) {
if (cp >= &fbuf.ac_comm[NC])
cp = &fbuf.ac_comm[NC-1];
*cp++ = '*';
}
if (cp < &fbuf.ac_comm[NC])
*cp = '\0';
x = expand(fbuf.ac_utime) + expand(fbuf.ac_stime);
y = pgtok((u_short)fbuf.ac_mem);
z = expand(fbuf.ac_io) / AHZ;
if (uflg) {
printf("%3d %6.2f cpu %8luk mem %6ld io %.*s\n",
fbuf.ac_uid, x/(double)AHZ, y, z, NC, fbuf.ac_comm);
continue;
}
up = finduser(fbuf.ac_uid);
if (up == 0)
continue; /* preposterous user id */
up->us_cnt++;
up->us_ctime += x/(double)AHZ;
up->us_imem += x * y;
up->us_io += z;
ncom += 1.0;
tp = enter(fbuf.ac_comm);
tp->p.imem += x * y;
timem += x * y;
tp->p.count++;
x = expand(fbuf.ac_etime);
tp->p.realt += x;
treal += x;
x = expand(fbuf.ac_utime);
tp->p.cput += x;
tcpu += x;
x = expand(fbuf.ac_stime);
tp->p.syst += x;
tsys += x;
tp->p.io += z;
tio += z;
}
fclose(ff);
}
/*
* Generalized cell compare routine, to cast out users
*/
cellcmp(p1, p2)
cell *p1, *p2;
{
if (ISPROCESS(p1)){
if (ISPROCESS(p2))
return((*cmp)(p1, p2));
return(-1);
}
if (ISPROCESS(p2))
return(1);
return(0);
}
ncmp(p1, p2)
cell *p1, *p2;
{
if(p1->p.count == p2->p.count)
return(tcmp(p1, p2));
if(rflg)
return(p1->p.count - p2->p.count);
return(p2->p.count - p1->p.count);
}
bcmp(p1, p2)
cell *p1, *p2;
{
double f1, f2;
double sum();
f1 = sum(p1)/p1->p.count;
f2 = sum(p2)/p2->p.count;
if(f1 < f2) {
if(rflg)
return(-1);
return(1);
}
if(f1 > f2) {
if(rflg)
return(1);
return(-1);
}
return(0);
}
Kcmp(p1, p2)
cell *p1, *p2;
{
if (p1->p.imem < p2->p.imem) {
if(rflg)
return(-1);
return(1);
}
if (p1->p.imem > p2->p.imem) {
if(rflg)
return(1);
return(-1);
}
return(0);
}
kcmp(p1, p2)
cell *p1, *p2;
{
double a1, a2;
a1 = p1->p.imem / ((p1->p.cput+p1->p.syst)?(p1->p.cput+p1->p.syst):1);
a2 = p2->p.imem / ((p2->p.cput+p2->p.syst)?(p2->p.cput+p2->p.syst):1);
if (a1 < a2) {
if(rflg)
return(-1);
return(1);
}
if (a1 > a2) {
if(rflg)
return(1);
return(-1);
}
return(0);
}
dcmp(p1, p2)
cell *p1, *p2;
{
double a1, a2;
a1 = p1->p.io / (p1->p.count?p1->p.count:1);
a2 = p2->p.io / (p2->p.count?p2->p.count:1);
if (a1 < a2) {
if(rflg)
return(-1);
return(1);
}
if (a1 > a2) {
if(rflg)
return(1);
return(-1);
}
return(0);
}
Dcmp(p1, p2)
cell *p1, *p2;
{
if (p1->p.io < p2->p.io) {
if(rflg)
return(-1);
return(1);
}
if (p1->p.io > p2->p.io) {
if(rflg)
return(1);
return(-1);
}
return(0);
}
tcmp(p1, p2)
cell *p1, *p2;
{
extern double sum();
double f1, f2;
f1 = sum(p1);
f2 = sum(p2);
if(f1 < f2) {
if(rflg)
return(-1);
return(1);
}
if(f1 > f2) {
if(rflg)
return(1);
return(-1);
}
return(0);
}
double sum(p)
cell *p;
{
if(p->p.name[0] == 0)
return(0.0);
return( p->p.cput + p->p.syst);
}
init()
{
struct user userbuf;
struct process tbuf;
register cell *tp;
register struct user *up;
int uid;
FILE *f;
if ((f = fopen(savacct, "r")) == NULL)
goto gshm;
while (fread((char *)&tbuf, sizeof(struct process), 1, f) == 1) {
tp = enter(tbuf.name);
ncom += tbuf.count;
tp->p.count = tbuf.count;
treal += tbuf.realt;
tp->p.realt = tbuf.realt;
tcpu += tbuf.cput;
tp->p.cput = tbuf.cput;
tsys += tbuf.syst;
tp->p.syst = tbuf.syst;
tio += tbuf.io;
tp->p.io = tbuf.io;
timem += tbuf.imem;
tp->p.imem = tbuf.imem;
}
fclose(f);
gshm:
if ((f = fopen(usracct, "r")) == NULL)
return;
for(uid = 0;
fread((char *)&(userbuf.oldu), sizeof(struct Olduser), 1, f) == 1;
uid++){
if (userbuf.us_cnt){
up = finduser(uid);
if (up == 0)
continue; /* preposterous user id */
up->oldu = userbuf.oldu;
}
}
fclose(f);
}
strip()
{
int c;
register struct allocbox *allocwalk;
register cell *tp, *ub, *junkp;
if (fflg)
printf("Categorizing commands used %d times or fewer as **junk**\n",
thres);
junkp = enter("**junk**");
PROCESSITERATE(allocwalk, tp, ub){
if (tp->p.name[0] && tp->p.count <= thres) {
if (!fflg)
printf("%.14s--", tp->p.name);
if (fflg || ((c=getchar())=='y')) {
tp->p.name[0] = '\0';
junkp->p.count += tp->p.count;
junkp->p.realt += tp->p.realt;
junkp->p.cput += tp->p.cput;
junkp->p.syst += tp->p.syst;
junkp->p.imem += tp->p.imem;
junkp->p.io += tp->p.io;
}
if (!fflg)
while (c && c!='\n')
c = getchar();
}
}
}
time_t
expand(t)
unsigned t;
{
register time_t nt;
nt = t&017777;
t >>= 13;
while (t!=0) {
t--;
nt <<= 3;
}
return(nt);
}
static char UserKey[NAMELG + 2];
char *
makekey(uid)
int uid;
{
sprintf(UserKey+1, "%04x", uid);
UserKey[0] = USERKEY;
return(UserKey);
}
struct user *
wasuser(uid)
int uid;
{
struct user *tp;
htabinstall = 0;
tp = finduser(uid);
htabinstall = 1;
return(tp);
}
/*
* Only call this if you really want to insert it in the table!
*/
struct user *
finduser(uid)
int uid;
{
if (uid > maxuser){
fprintf(stderr, "Preposterous user id, %d: ignored\n", uid);
return(0);
}
return((struct user*)enter(makekey(uid)));
}
/*
* Set the names of all users in the password file.
* We will later not print those that didn't do anything.
*/
getnames()
{
register struct user *tp;
register struct passwd *pw;
struct passwd *getpwent();
setpwent();
while (pw = getpwent()){
/* use first name in passwd file for duplicate uid's */
if ((tp = wasuser(pw->pw_uid)) != 0 && !isalpha(tp->us_name[0]))
strncpy(tp->us_name, pw->pw_name, NAMELG);
}
endpwent();
}
int
getmaxuid()
{
register struct user *tp;
register struct passwd *pw;
struct passwd *getpwent();
int maxuid = -1;
setpwent();
while(pw = getpwent()){
if (pw->pw_uid > maxuid)
maxuid = pw->pw_uid;
}
endpwent();
return(maxuid);
}
tabinit()
{
allochead = 0;
alloctail = 0;
nexttab = 0;
tabsleft = 0;
htab = 0;
ntabs = 0;
htaballoc(); /* get the first part of the hash table */
}
#define ALLOCQTY sizeof (struct allocbox)
cell *
taballoc()
{
if (tabsleft == 0){
newbox = (struct allocbox *)calloc(1, ALLOCQTY);
tabsleft = TABDALLOP;
nexttab = &newbox->tabslots[0];
if (alloctail == 0){
allochead = alloctail = newbox;
} else {
alloctail->nextalloc = newbox;
alloctail = newbox;
}
}
--tabsleft;
++ntabs;
#ifdef DEBUG
if (ntabs % 100 == 0)
printf("##Accounting table slot # %d\n", ntabs);
#endif DEBUG
return(nexttab++);
}
htaballoc()
{
register struct hashdallop *new;
#ifdef DEBUG
static int ntables = 0;
printf("%%%New hash table chunk allocated, number %d\n", ++ntables);
#endif DEBUG
new = (struct hashdallop *)calloc(1, sizeof (struct hashdallop));
if (htab == 0)
htab = new;
else { /* add AFTER the 1st slot */
new->h_next = htab->h_next;
htab->h_next = new;
}
}
#define HASHCLOGGED (NHASH / 2)
/*
* Lookup a symbol passed in as the argument.
*
* We take pains to avoid function calls; this function
* is called quite frequently, and the calling overhead
* contributes significantly to the overall execution speed of sa.
*/
cell *
enter(name)
char *name;
{
static int initialprobe;
register cell **hp;
register char *from, *to;
register int len, nprobes;
static struct hashdallop *hdallop, *emptyhd;
static cell **emptyslot, **hp_ub;
emptyslot = 0;
for (nprobes = 0, from = name, len = 0;
*from && len < NC;
nprobes <<= 2, nprobes += *from++, len++)
continue;
nprobes += from[-1] << 5;
nprobes %= NHASH;
if (nprobes < 0)
nprobes += NHASH;
initialprobe = nprobes;
for (hdallop = htab; hdallop != 0; hdallop = hdallop->h_next){
for (hp = &(hdallop->h_tab[initialprobe]),
nprobes = 1,
hp_ub = &(hdallop->h_tab[NHASH]);
(*hp) && (nprobes < NHASH);
hp += nprobes,
hp -= (hp >= hp_ub) ? NHASH:0,
nprobes += 2)
{
from = name;
to = (*hp)->p.name;
for (len = 0; (len<NC) && *from; len++)
if (*from++ != *to++)
goto nextprobe;
if (len >= NC) /*both are maximal length*/
return(*hp);
if (*to == 0) /*assert *from == 0*/
return(*hp);
nextprobe: ;
}
if (*hp == 0 && emptyslot == 0 &&
hdallop->h_nused < HASHCLOGGED) {
emptyslot = hp;
emptyhd = hdallop;
}
}
if (emptyslot == 0) {
htaballoc();
hdallop = htab->h_next; /* aren't we smart! */
hp = &hdallop->h_tab[initialprobe];
} else {
hdallop = emptyhd;
hp = emptyslot;
}
if (htabinstall){
*hp = taballoc();
hdallop->h_nused++;
for(len = 0, from = name, to = (*hp)->p.name; (len<NC); len++)
if ((*to++ = *from++) == '\0')
break;
return(*hp);
}
return(0);
}