#include "symtab.h"
#include <stdlib.h>
#include <string.h>

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 = symbolarray[index];

    // Make new
    symbolarray[index] = malloc(sizeof(symnode_t));
    if (symbolarray[index] == NULL) {
        // If malloc failed
        symbolarray[index] = oldSym;
        return NULL;
    }

    // Link old one
    symbolarray[index]->next = oldSym;
    symbolarray[index]->name = var;

    return symbolarray[index];
}

symnode_t *sym_lookup(char *var)
{
    unsigned int index = hash(var);
    symnode_t *n = symbolarray[index];

    // Look trough list
    while (n != NULL && strcmp(n->name, var) != 0) {
        n = n->next;
    }

    return n;
}