source: python/trunk/Python/asdl.c

#include "Python.h"
#include "asdl.h"

asdl_seq *
asdl_seq_new(int size, PyArena *arena)
{
    asdl_seq *seq = NULL;
    size_t n = (size ? (sizeof(void *) * (size - 1)) : 0);

    /* check size is sane */
    if (size < 0 || size == INT_MIN ||
        (size && ((size - 1) > (PY_SIZE_MAX / sizeof(void *))))) {
        PyErr_NoMemory();
        return NULL;
    }

    /* check if size can be added safely */
    if (n > PY_SIZE_MAX - sizeof(asdl_seq)) {
        PyErr_NoMemory();
        return NULL;
    }

    n += sizeof(asdl_seq);

    seq = (asdl_seq *)PyArena_Malloc(arena, n);
    if (!seq) {
        PyErr_NoMemory();
        return NULL;
    }
    memset(seq, 0, n);
    seq->size = size;
    return seq;
}

asdl_int_seq *
asdl_int_seq_new(int size, PyArena *arena)
{
    asdl_int_seq *seq = NULL;
    size_t n = (size ? (sizeof(void *) * (size - 1)) : 0);

    /* check size is sane */
    if (size < 0 || size == INT_MIN ||
        (size && ((size - 1) > (PY_SIZE_MAX / sizeof(void *))))) {
            PyErr_NoMemory();
            return NULL;
    }

    /* check if size can be added safely */
    if (n > PY_SIZE_MAX - sizeof(asdl_seq)) {
        PyErr_NoMemory();
        return NULL;
    }

    n += sizeof(asdl_seq);

    seq = (asdl_int_seq *)PyArena_Malloc(arena, n);
    if (!seq) {
        PyErr_NoMemory();
        return NULL;
    }
    memset(seq, 0, n);
    seq->size = size;
    return seq;
}