
#include <stdlib.h> /* for calloc, free */

#include "header.h"

extern struct SN_env* SN_create_env(int S_size, int I_size) {
    struct SN_env* z = (struct SN_env*)calloc(1, sizeof(struct SN_env));
    if (z == NULL)
        return NULL;
    z->p = create_s();
    if (z->p == NULL)
        goto error;
    if (S_size) {
        int i;
        z->S = (symbol**)calloc(S_size, sizeof(symbol*));
        if (z->S == NULL)
            goto error;

        for (i = 0; i < S_size; i++) {
            z->S[i] = create_s();
            if (z->S[i] == NULL)
                goto error;
        }
    }

    if (I_size) {
        z->I = (int*)calloc(I_size, sizeof(int));
        if (z->I == NULL)
            goto error;
    }

    return z;
error:
    SN_close_env(z, S_size);
    return NULL;
}

extern void SN_close_env(struct SN_env* z, int S_size) {
    if (z == NULL)
        return;
    if (S_size) {
        int i;
        for (i = 0; i < S_size; i++) {
            lose_s(z->S[i]);
        }
        free(z->S);
    }
    free(z->I);
    if (z->p)
        lose_s(z->p);
    free(z);
}

extern int SN_set_current(struct SN_env* z, int size, const symbol* s) {
    int err = replace_s(z, 0, z->l, size, s, NULL);
    z->c = 0;
    return err;
}
