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/* Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
//#include "../bootProto.h"
/*
* FNCACHE -- Maintain a cache of system logical filenames (e.g., <config.h>)
* and their associated virtual filenames (e.g., "host$hlib/config.h").
* This can greatly reduce the amount of time required to resolve references
* to system include files in dependency file lists.
*
* External entry points:
*
* nc = m_sysfile (lname, fname, maxch) # return file name
* m_fninit (debug) # initialize cache
*/
#define MAX_FILES 20 /* size of the cache */
#define SZ_LNAME 32 /* size of logical name */
#define SZ_FNAME 32 /* size of virtual file name */
#define EOS '\0'
struct _sysfile { /* cache list element structure */
struct _sysfile *uplnk;
struct _sysfile *dnlnk;
int nrefs; /* number of references */
int chksum; /* speeds searches */
char lname[SZ_LNAME+1]; /* logical name */
char fname[SZ_FNAME+1]; /* file name */
};
struct _sysfile fncache[MAX_FILES]; /* the cache */
struct _sysfile *fn_head; /* doubly linked list */
struct _sysfile *fn_tail;
int fn_hits, fn_misses;
struct _sysfile *fn_unlink();
struct _sysfile *fn_tohead();
struct _sysfile *fn_totail();
extern int os_sysfile (char *sysfile, char *fname, int maxch);
int m_sysfile (char *lname, char *fname, int maxch);
void m_fninit (int debug);
int fn_chksum (char *s);
int fn_strncpy (char *out, char *in, int maxch);
/* M_SYSFILE -- Search for the named system file and return the virtual file
* name in the output string if the system file is found. This is functionally
* equivalent to os_sysfile().
*/
int
m_sysfile (
char *lname, /* logical name of system file */
char *fname, /* receives virtual file name */
int maxch
)
{
register struct _sysfile *fn;
register int chksum;
int fnlen;
/* Look in the cache first. For a small cache a linear search is
* plenty fast enough.
*/
chksum = fn_chksum (lname);
for (fn=fn_head; fn != NULL; fn=fn->dnlnk)
if (fn->chksum == chksum && strcmp (lname, fn->lname) == 0) {
fn_tohead (fn_unlink (fn));
fn->nrefs++;
fn_hits++;
return (fn_strncpy (fname, fn->fname, maxch));
}
/* Cache miss. Don't put in cache it name is too long.
*/
fn_misses++;
fnlen = os_sysfile (lname, fname, maxch);
if (fnlen > SZ_FNAME || strlen(lname) > SZ_LNAME)
return (fnlen);
/* Put fname in the cache. Reuse slot at tail of list.
*/
fn = fn_tohead (fn_unlink (fn_tail));
strcpy (fn->lname, lname);
strcpy (fn->fname, fname);
fn->chksum = fn_chksum (lname);
fn->nrefs = 1;
return (fnlen);
}
/* M_FNINIT -- Initialize (clear) the sysfile cache.
*/
void
m_fninit (int debug)
{
register struct _sysfile *fn;
register int i;
int total;
if (debug) {
char lname[SZ_FNAME+1];
total = fn_hits + fn_misses;
printf ("file name cache: %d hits, %d misses, %d%% of %d\n",
fn_hits, fn_misses, (total ? fn_hits * 100 / total : 0), total);
for (fn=fn_head; fn != NULL; fn=fn->dnlnk)
if (fn->lname[0]) {
sprintf (lname, "<%s>", fn->lname);
printf ("%3d (%05d) %-20s => %s\n",
fn->nrefs, fn->chksum, lname, fn->fname);
}
fn_hits = 0;
fn_misses = 0;
fflush (stdout);
}
fn = fn_head = fn_tail = &fncache[0];
fn->uplnk = NULL;
fn->dnlnk = NULL;
fn->nrefs = 0;
fn->chksum = -1;
fn->lname[0] = EOS;
for (i=1; i < MAX_FILES; i++) {
fn = fn_tohead (&fncache[i]);
fn->lname[0] = EOS;
fn->chksum = -1;
fn->nrefs = 0;
}
}
/* FN_TOHEAD -- Link a sysfile struct at the head of the list.
*/
struct _sysfile *
fn_tohead (register struct _sysfile *fn)
{
if (fn != fn_head) {
fn->uplnk = NULL;
fn->dnlnk = fn_head;
fn_head->uplnk = fn;
fn_head = fn;
}
return (fn);
}
/* FN_TOTAIL -- Link a sysfile struct at the tail of the list.
*/
struct _sysfile *
fn_totail (register struct _sysfile *fn)
{
if (fn != fn_tail) {
fn->uplnk = fn_tail;
fn->dnlnk = NULL;
fn_tail->dnlnk = fn;
fn_tail = fn;
}
return (fn);
}
/* FN_UNLINK -- Unlink an sysfile struct.
*/
struct _sysfile *
fn_unlink (register struct _sysfile *fn)
{
if (fn == fn_head)
fn_head = fn->dnlnk;
if (fn == fn_tail)
fn_tail = fn->uplnk;
if (fn->uplnk)
fn->uplnk->dnlnk = fn->dnlnk;
if (fn->dnlnk)
fn->dnlnk->uplnk = fn->uplnk;
return (fn);
}
/* FN_CHKSUM -- Compute the checksum of a character string.
*/
int
fn_chksum (char *s)
{
register int sum=0;
while (*s)
sum += *s++;
return (sum);
}
/* FN_STRNCPY -- Copy up to maxch characters from a string and return the
* number of characters copied as the function value.
*/
int
fn_strncpy (
char *out,
char *in,
int maxch
)
{
register char *ip, *op;
register int n;
for (ip=in, op=out, n=maxch; --n >= 0 && (*op++ = *ip++); )
;
return (op-1 - out);
}
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