cpp

#include "mycpp/hash.h"

#include "mycpp/gc_str.h"

#include "mycpp/gc_tuple.h"

unsigned fnv1(const char* data, int len) {

  // FNV-1 from http://www.isthe.com/chongo/tech/comp/fnv/#FNV-1

  unsigned h = 2166136261;     // 32-bit FNV-1 offset basis

  constexpr int p = 16777619;  // 32-bit FNV-1 prime

  for (int i = 0; i < len; i++) {

    h *= p;

    // log("1. h = %d", h);

    h ^= data[i];

    // log("2. h = %d", h);

  }

  return h;

}

unsigned hash_key(BigStr* s) {

  return s->hash(fnv1);

}

unsigned hash_key(int n) {

  return n;

}

unsigned hash_key(Tuple2<int, int>* t1) {

  return t1->at0() + t1->at1();

}

unsigned hash_key(Tuple2<BigStr*, int>* t1) {

  return t1->at0()->hash(fnv1) + t1->at1();

}

// e.g. for Dict<Token*, int>, hash the pointer itself, which means we use

// object IDENTITY, not value.

unsigned hash_key(void* p) {

  return fnv1(reinterpret_cast<const char*>(&p), sizeof(void*));

}