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%{
#include <stdio.h>
#include <stdint.h>
#define BEGIN_T 1
#define END_T 2
#define NUM_T 3
#define VAR_T 4
#define HASHSIZE 100
typedef struct symnode_struct {
struct symnode_struct *next;
char *name;
} symnode_t;
symnode_t *sym_insert(char *var);
symnode_t *sym_lookup(char *var);
%}
VAR [a-zA-Z][a-zA-Z\_\-0-9]*
TAL [0-9]+
%%
begin {printf("Found a BEGIN\n"); return BEGIN_T;}
end {printf("Found a END\n"); return END_T;}
{VAR} {printf("Found a variable %s\n", yytext);
if( !sym_lookup(yytext) ) {
printf("Not found inserting\n");
sym_insert(yytext);
}
return VAR_T;}
{TAL} {printf("Found a number %d\n", strtol(yytext, NULL, 10)); return NUM_T;}
%%
symnode_t *symlist[HASHSIZE];
unsigned int hash(char *s) {
uint32_t hv = 0;
for( int i = 0; s[i] != '\0'; i++ ) {
// take MSB 6 bits of hv and xors with LSB of s[i]
uint32_t v = ( hv >> 26 ) ^ (s[i] & 0x3f);
// Push those back on hv
hv = (hv << 4) | v;
}
// Return appropriate size
return hv % HASHSIZE;
}
symnode_t *sym_insert(char *var) {
unsigned int index = hash(var);
// Save old value
symnode_t *oldSym = symlist[index];
// Make new
symlist[index] = malloc(sizeof(symnode_t));
if( symlist[index] == NULL ) {
// If malloc failed
symlist[index] = oldSym;
return NULL;
}
// Link old one
symlist[index]->next = oldSym;
symlist[index]->name = var;
return symlist[index];
}
symnode_t *sym_lookup(char *var) {
unsigned int index = hash(var);
symnode_t *n = symlist[index];
// Look trough list
while(n != NULL && strcmp(n->name, var) != 0) {
n = n->next;
}
return n;
}
int main(void) {
for(;;) {
int t = yylex();
printf("yylex: %d\n", t);
if( t == END_T ) {
break;
}
}
return 0;
}
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