/*=============================================================================
 *
 *
 * Basic algorithms for XOD lists
 *
 *
 =============================================================================*/

#ifndef XOD_LIST_FUNCS_H
#define XOD_LIST_FUNCS_H

#include "listViews.h"

namespace xod {

/*
 * Folds a list from left. Also known as "reduce".
 */
template<typename T, typename TR>
TR foldl(List<T> xs, TR (*func)(TR, T), TR acc) {
    for (auto it = xs.iterate(); it; ++it)
        acc = func(acc, *it);
    return acc;
}

template<typename T> size_t lengthReducer(size_t len, T) {
    return len + 1;
}

/*
 * Computes length of a list.
 */
template<typename T> size_t length(List<T> xs) {
    return foldl(xs, lengthReducer<T>, (size_t)0);
}

template<typename T> T* dumpReducer(T* buff, T x) {
    *buff = x;
    return buff + 1;
}

/*
 * Copies a list content into a memory buffer.
 *
 * It is expected that `outBuff` has enough size to fit all the data.
 */
template<typename T> size_t dump(List<T> xs, T* outBuff) {
    T* buffEnd = foldl(xs, dumpReducer, outBuff);
    return buffEnd - outBuff;
}

/*
 * Compares two lists.
 */
template<typename T> bool equal(List<T> lhs, List<T> rhs) {
    auto lhsIt = lhs.iterate();
    auto rhsIt = rhs.iterate();

    for (; lhsIt && rhsIt; ++lhsIt, ++rhsIt) {
        if (*lhsIt != *rhsIt) return false;
    }

    return !lhsIt && !rhsIt;
}

template<typename T> bool operator == (List<T> lhs, List<T> rhs) {
  return equal(lhs, rhs);
}

} // namespace xod

#endif