ref: 29ceb0ed7c98fa120b8421aafe1babd0baa95c69
dir: /symbol.c/
#include <stdint.h> #include <stdint.h> #include <stdlib.h> #include <string.h> #include "cc.h" #define NR_SYM_HASH 32 uint8_t curctx; uint8_t namespace = NS_KEYWORD + 1 ; static struct symtab { Symbol *head; Symbol *htab[NR_SYM_HASH]; } symtab [NR_NAMESPACES]; static inline uint8_t hash(register const char *s) { register uint8_t h, ch; for (h = 0; ch = *s++; h += ch) /* nothing */; return h & NR_SYM_HASH - 1; } void freesyms(uint8_t ns) { static struct symtab *tbl; register Symbol *sym; tbl = &symtab[ns]; for (sym = tbl->head; sym; sym = sym->next) { if (sym->ctx <= curctx) break; tbl->htab[hash(sym->name)] = sym->hash; free(sym->name); free(sym); } } void context(void (*fun)(void)) { uint8_t ns; ns = namespace; ++curctx; fun(); --curctx; namespace = ns; freesyms(NS_IDEN); freesyms(NS_TAG); } Symbol * lookup(register char *s, uint8_t ns) { extern union yystype yylval; static struct symtab *tbl; register Symbol *sym; tbl = &symtab[(ns >= NR_NAMESPACES) ? NS_IDEN : ns]; for (sym = tbl->htab[hash(s)]; sym; sym = sym->hash) { register char *t = sym->name; if (sym->ns == ns && t && *t == *s && !strcmp(t, s)) return sym; } return NULL; } Symbol * install(char *s, uint8_t ns) { register Symbol *sym; register Symbol **t; struct symtab *tbl; static short id; if (ns == NS_KEYWORD) { ns = NS_IDEN; } else { ++id; if (s != NULL) s = xstrdup(s); } sym = xcalloc(1, sizeof(*sym)); sym->name = s; sym->ctx = curctx; sym->token = IDEN; sym->ns = ns; sym->id = id; tbl = &symtab[(ns >= NR_NAMESPACES) ? NS_IDEN : ns]; sym->next = tbl->head; tbl->head = sym; if (s != NULL) { t = &tbl->htab[hash(s)]; sym->hash = *t; *t = sym; } return sym; }