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	symtab.c - 9base - revived minimalist port of Plan 9 userland to Unix
	git clone git://git.suckless.org/9base
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	---
	symtab.c (1610B)
	---
	1 #include "mk.h"
	2
	3 #define NHASH 4099
	4 #define HASHMUL 79L /* this is a good value */
	5 static Symtab *hash[NHASH];
	6
	7 void
	8 syminit(void)
	9 {
	10 Symtab *s, ss, *next;
	11
	12 for(s = hash; s < &hash[NHASH]; s++){
	13 for(ss = *s; ss; ss = next){
	14 next = ss->next;
	15 free((char *)ss);
	16 }
	17 *s = 0;
	18 }
	19 }
	20
	21 Symtab *
	22 symlook(char sym, int space, void install)
	23 {
	24 long h;
	25 char *p;
	26 Symtab *s;
	27
	28 for(p = sym, h = space; p; h += p++)
	29 h *= HASHMUL;
	30 if(h < 0)
	31 h = ~h;
	32 h %= NHASH;
	33 for(s = hash[h]; s; s = s->next)
	34 if((s->space == space) && (strcmp(s->name, sym) == 0))
	35 return(s);
	36 if(install == 0)
	37 return(0);
	38 s = (Symtab *)Malloc(sizeof(Symtab));
	39 s->space = space;
	40 s->name = sym;
	41 s->u.ptr = install;
	42 s->next = hash[h];
	43 hash[h] = s;
	44 return(s);
	45 }
	46
	47 void
	48 symdel(char *sym, int space)
	49 {
	50 long h;
	51 char *p;
	52 Symtab s, ls;
	53
	54 /* multiple memory leaks */
	55
	56 for(p = sym, h = space; p; h += p++)
	57 h *= HASHMUL;
	58 if(h < 0)
	59 h = ~h;
	60 h %= NHASH;
	61 for(s = hash[h], ls = 0; s; ls = s, s = s->next)
	62 if((s->space == space) && (strcmp(s->name, sym) == 0)){
	63 if(ls)
	64 ls->next = s->next;
	65 else
	66 hash[h] = s->next;
	67 free((char *)s);
	68 }
	69 }
	70
	71 void
	72 symtraverse(int space, void (fn)(Symtab))
	73 {
	74 Symtab *s, ss;
	75
	76 for(s = hash; s < &hash[NHASH]; s++)
	77 for(ss = *s; ss; ss = ss->next)
	78 if(ss->space == space)
	79 (*fn)(ss);
	80 }
	81
	82 void
	83 symstat(void)
	84 {
	85 Symtab *s, ss;
	86 int n;
	87 int l[1000];
	88
	89 memset((char *)l, 0, sizeof(l));
	90 for(s = hash; s < &hash[NHASH]; s++){
	91 for(ss = *s, n = 0; ss; ss = ss->next)
	92 n++;
	93 l[n]++;
	94 }
	95 for(n = 0; n < 1000; n++)
	96 if(l[n]) Bprint(&bout, "%ld of length %d\n", l[n], n);
	97 }