int BN_lshift(BIGNUM *r, const BIGNUM *a, int n)
{
    int i, nw, lb, rb;
    BN_ULONG *t, *f;
    BN_ULONG l;
    bn_check_top(r);
    bn_check_top(a);
    if (n < 0) {
        BNerr(BN_F_BN_LSHIFT, BN_R_INVALID_SHIFT);
        return 0;
    }
    r->neg = a->neg;
    nw = n / BN_BITS2;
    if (bn_wexpand(r, a->top + nw + 1) == NULL)
        return (0);
    lb = n % BN_BITS2;
    rb = BN_BITS2 - lb;
    f = a->d;
    t = r->d;
    t[a->top + nw] = 0;
    if (lb == 0)
        for (i = a->top - 1; i >= 0; i--)
            t[nw + i] = f[i];
    else
        for (i = a->top - 1; i >= 0; i--) {
            l = f[i];
            t[nw + i + 1] |= (l >> rb) & BN_MASK2;
            t[nw + i] = (l << lb) & BN_MASK2;
        }
    memset(t, 0, sizeof(*t) * nw);
    r->top = a->top + nw + 1;
    bn_correct_top(r);
    bn_check_top(r);
    return (1);
}
['static int file_lshift(STANZA *s)\n{\n    BIGNUM *a = getBN(s, "A");\n    BIGNUM *lshift = getBN(s, "LShift");\n    BIGNUM *ret = BN_new();\n    int n = 0;\n    int st = 0;\n    if (a == NULL || lshift == NULL || ret == NULL || !getint(s, &n, "N"))\n        goto err;\n    if (!BN_lshift(ret, a, n)\n            || !equalBN("A << N", lshift, ret)\n            || !BN_rshift(ret, lshift, n)\n            || !equalBN("A >> N", a, ret))\n        goto err;\n    st = 1;\nerr:\n    BN_free(a);\n    BN_free(lshift);\n    BN_free(ret);\n    return st;\n}', 'static int getint(STANZA *s, int *out, const char *attribute)\n{\n    BIGNUM *ret = getBN(s, attribute);\n    BN_ULONG word;\n    int st = 0;\n    if (ret == NULL)\n        goto err;\n    if ((word = BN_get_word(ret)) > INT_MAX)\n        goto err;\n    *out = (int)word;\n    st = 1;\nerr:\n    BN_free(ret);\n    return st;\n}', 'int BN_lshift(BIGNUM *r, const BIGNUM *a, int n)\n{\n    int i, nw, lb, rb;\n    BN_ULONG *t, *f;\n    BN_ULONG l;\n    bn_check_top(r);\n    bn_check_top(a);\n    if (n < 0) {\n        BNerr(BN_F_BN_LSHIFT, BN_R_INVALID_SHIFT);\n        return 0;\n    }\n    r->neg = a->neg;\n    nw = n / BN_BITS2;\n    if (bn_wexpand(r, a->top + nw + 1) == NULL)\n        return (0);\n    lb = n % BN_BITS2;\n    rb = BN_BITS2 - lb;\n    f = a->d;\n    t = r->d;\n    t[a->top + nw] = 0;\n    if (lb == 0)\n        for (i = a->top - 1; i >= 0; i--)\n            t[nw + i] = f[i];\n    else\n        for (i = a->top - 1; i >= 0; i--) {\n            l = f[i];\n            t[nw + i + 1] |= (l >> rb) & BN_MASK2;\n            t[nw + i] = (l << lb) & BN_MASK2;\n        }\n    memset(t, 0, sizeof(*t) * nw);\n    r->top = a->top + nw + 1;\n    bn_correct_top(r);\n    bn_check_top(r);\n    return (1);\n}', 'BIGNUM *bn_wexpand(BIGNUM *a, int words)\n{\n    return (words <= a->dmax) ? a : bn_expand2(a, words);\n}']