JehanneOS/mksh
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• rework hash table interna to avoid gcc-4.1 on Debian etch bug

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• also improve behaviour with _a lot_ (>2²⁸) entries
• while here, improve comments and whitespace
This commit is contained in:
tg
2011-06-05 19:58:21 +00:00
parent 3695f9b259
commit e0fb8dc431
6 changed files with 151 additions and 126 deletions
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90
main.c
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@ -33,7 +33,7 @@
#include <locale.h>
#endif
__RCSID("$MirOS: src/bin/mksh/main.c,v 1.192 2011/06/04 16:42:30 tg Exp $");
__RCSID("$MirOS: src/bin/mksh/main.c,v 1.193 2011/06/05 19:58:18 tg Exp $");
extern char **environ;
@ -206,8 +206,9 @@ main(int argc, const char *argv[])
ccp = empty_argv[0];
/* define built-in commands and see if we were called as one */
ktinit(&builtins, APERM,
/* must be 80% of 2^n (currently 44 builtins) */ 64);
ktinit(APERM, &builtins,
/* currently 50 builtins -> 80% of 64 (2^6) */
6);
for (i = 0; mkshbuiltins[i].name != NULL; i++)
if (!strcmp(ccp, builtin(mkshbuiltins[i].name,
mkshbuiltins[i].func)))
@ -235,10 +236,10 @@ main(int argc, const char *argv[])
coproc_init();
/* set up variable and command dictionaries */
ktinit(&taliases, APERM, 0);
ktinit(&aliases, APERM, 0);
ktinit(APERM, &taliases, 0);
ktinit(APERM, &aliases, 0);
#ifndef MKSH_NOPWNAM
ktinit(&homedirs, APERM, 0);
ktinit(APERM, &homedirs, 0);
#endif
/* define shell keywords */
@ -1442,53 +1443,48 @@ maketemp(Area *ap, Temp_type type, struct temp **tlist)
* but with a slightly tweaked implementation written from scratch.
*/
#define INIT_TBLS 8 /* initial table size (power of 2) */
#define INIT_TBLSHIFT 3 /* initial table shift (2^3 = 8) */
#define PERTURB_SHIFT 5 /* see Python 2.5.4 Objects/dictobject.c */
static void texpand(struct table *, size_t);
static void tgrow(struct table *);
static int tnamecmp(const void *, const void *);
static struct tbl *ktscan(struct table *, const char *, uint32_t,
struct tbl ***);
static void
texpand(struct table *tp, size_t nsize)
tgrow(struct table *tp)
{
size_t i, j, osize = tp->size, perturb;
size_t i, j, osize, mask, perturb;
struct tbl *tblp, **pp;
struct tbl **ntblp, **otblp = tp->tbls;
i = 1;
i <<= 30;
if (nsize > i)
if (tp->tshift > 29)
internal_errorf("hash table size limit reached");
ntblp = alloc2(nsize, sizeof(struct tbl *), tp->areap);
memset(ntblp, 0, nsize * sizeof(struct tbl *));
tp->size = nsize;
if (nsize == i) {
/* cannot be grown any more, use a fixed value */
tp->nfree = i - 65536;
} else /* (nsize < 2^30) */ {
/* table can get 80% full */
tp->nfree = (nsize * 4) / 5;
}
/* calculate old size, new shift and new size */
osize = 1 << (tp->tshift++);
i = osize << 1;
ntblp = alloc2(i, sizeof(struct tbl *), tp->areap);
/* multiplication cannot overflow: alloc2 checked that */
memset(ntblp, 0, i * sizeof(struct tbl *));
/* table can get 80% full except when reaching its limit */
tp->nfree = (tp->tshift == 30) ? 0x3FFF0000UL : ((i * 4) / 5);
tp->tbls = ntblp;
if (otblp == NULL)
return;
/* from here on nsize := mask */
nsize--;
mask = i - 1;
for (i = 0; i < osize; i++)
if ((tblp = otblp[i]) != NULL) {
if ((tblp->flag & DEFINED)) {
/* search for free hash table slot */
j = (perturb = tblp->ua.hval) & nsize;
j = (perturb = tblp->ua.hval) & mask;
goto find_first_empty_slot;
find_next_empty_slot:
j = (j << 2) + j + perturb + 1;
perturb >>= PERTURB_SHIFT;
find_first_empty_slot:
pp = &ntblp[j & nsize];
pp = &ntblp[j & mask];
if (*pp != NULL)
goto find_next_empty_slot;
/* found an empty hash table slot */
@ -1502,23 +1498,23 @@ texpand(struct table *tp, size_t nsize)
}
void
ktinit(struct table *tp, Area *ap, size_t tsize)
ktinit(Area *ap, struct table *tp, uint8_t initshift)
{
tp->areap = ap;
tp->tbls = NULL;
tp->size = tp->nfree = 0;
if (tsize)
texpand(tp, tsize);
tp->tshift = ((initshift > INIT_TBLSHIFT) ?
initshift : INIT_TBLSHIFT) - 1;
tgrow(tp);
}
/* table, name (key) to search for, hash(name), rv pointer to tbl ptr */
static struct tbl *
struct tbl *
ktscan(struct table *tp, const char *name, uint32_t h, struct tbl ***ppp)
{
size_t j, perturb, mask;
struct tbl **pp, *p;
mask = tp->size - 1;
mask = (1 << (tp->tshift)) - 1;
/* search for hash table slot matching name */
j = (perturb = h) & mask;
goto find_first_slot;
@ -1536,13 +1532,6 @@ ktscan(struct table *tp, const char *name, uint32_t h, struct tbl ***ppp)
return (p);
}
/* table, name (key) to search for, hash(n) */
struct tbl *
ktsearch(struct table *tp, const char *n, uint32_t h)
{
return (tp->size ? ktscan(tp, n, h, NULL) : NULL);
}
/* table, name (key) to enter, hash(n) */
struct tbl *
ktenter(struct table *tp, const char *n, uint32_t h)
@ -1550,15 +1539,13 @@ ktenter(struct table *tp, const char *n, uint32_t h)
struct tbl **pp, *p;
size_t len;
if (tp->size == 0)
texpand(tp, INIT_TBLS);
Search:
if ((p = ktscan(tp, n, h, &pp)))
return (p);
if (tp->nfree == 0) {
/* too full */
texpand(tp, 2 * tp->size);
tgrow(tp);
goto Search;
}
@ -1583,7 +1570,7 @@ ktenter(struct table *tp, const char *n, uint32_t h)
void
ktwalk(struct tstate *ts, struct table *tp)
{
ts->left = tp->size;
ts->left = 1 << (tp->tshift);
ts->next = tp->tbls;
}
@ -1613,16 +1600,19 @@ ktsort(struct table *tp)
size_t i;
struct tbl **p, **sp, **dp;
/* tp->size + 1 will not overflow */
p = alloc2(tp->size + 1, sizeof(struct tbl *), ATEMP);
/*
* since the table is never entirely full, no need to reserve
* additional space for the trailing NULL appended below
*/
i = 1 << (tp->tshift);
p = alloc2(i, sizeof(struct tbl *), ATEMP);
sp = tp->tbls; /* source */
dp = p; /* dest */
i = (size_t)tp->size;
while (i--)
if ((*dp = *sp++) != NULL && (((*dp)->flag & DEFINED) ||
((*dp)->flag & ARRAY)))
dp++;
qsort(p, (i = dp - p), sizeof(void *), tnamecmp);
qsort(p, (i = dp - p), sizeof(struct tbl *), tnamecmp);
p[i] = NULL;
return (p);
}