Function cbm_mem_resolve_budget

src/foundation/mem.c:198–246

}

cbm_mem_budget_t cbm_mem_resolve_budget(size_t total_ram, double ram_fraction,
                                        const char *budget_mb) {
    if (ram_fraction <= 0.0 || ram_fraction > MAX_RAM_FRACTION) {
        ram_fraction = DEFAULT_RAM_FRACTION;
    }
    cbm_mem_budget_t result = {
        .budget = (size_t)((double)total_ram * ram_fraction),
        .source = "ram_fraction",
        .clamped = false,
        .invalid = false,
        .hard_capped = false,
    };

    if (budget_mb == NULL || budget_mb[0] == '\0') {
        return result; /* no override → fraction-derived budget */
    }

    /* Strict parse, matching the src/foundation/limits.c convention: reject
     * trailing garbage (`*end`), overflow (errno==ERANGE), and non-positive
     * values. This turns a fat-fingered value (e.g. "8GB", or a 20-digit typo)
     * into a clean fallback-with-warning rather than a silently wrong budget. */
    errno = 0;
    char *end = NULL;
    long long want_mb = strtoll(budget_mb, &end, CBM_DECIMAL_BASE);
    if (errno != 0 || end == budget_mb || *end != '\0' || want_mb <= 0) {
        result.invalid = true; /* keep the fraction-derived budget */
        return result;
    }

    result.source = "CBM_MEM_BUDGET_MB";
    size_t want = (size_t)want_mb;
    if (total_ram > 0) {
        /* Compare in MiB space so a valid-but-huge request (e.g. 2^44 MiB, which
         * would overflow the ×MiB byte multiply) clamps cleanly to total_ram. */
        if (want > total_ram / MB_DIVISOR) {
            result.budget = total_ram;
            result.clamped = true;
        } else {
            result.budget = want * MB_DIVISOR;
        }
    } else if (want > SIZE_MAX / MB_DIVISOR) {
        /* RAM detection failed (no clamp target) and the request is
         * astronomically large — cap at SIZE_MAX rather than wrap. */
        result.budget = SIZE_MAX;
    } else {
        result.budget = want * MB_DIVISOR;
    }
    return result;
}

cbm_mem_budget_t cbm_mem_resolve_budget_capped(size_t total_ram, double ram_fraction,
                                               const char *budget_mb, size_t hard_cap_bytes) {