Function sz_py_replace_strings_allocator

python/stringzilla.c:853–900

* @brief Helper function to replace the memory allocator in a `Strs` object. * This reallocates existing string data using the new allocator. * * This may change the layout of the `Strs` layout: * - `STRS_U32_TAPE_VIEW` becomes `STRS_U32_TAPE`. * - `STRS_U64_TAPE_VIEW` becomes `STRS_U64_TAPE`. * - `STRS_U32_TAPE` remains, if the allocator is different. * - `STRS_U64_TAPE` re

 *  - `STRS_FRAGMENTED` becomes a `STRS_U32_TAPE` or `STRS_U64_TAPE` depending on the content size.
 */
SZ_DYNAMIC sz_bool_t sz_py_replace_strings_allocator(PyObject *object, sz_memory_allocator_t *allocator) {
    if (!object || !allocator) return sz_false_k;
    if (!PyObject_TypeCheck(object, &StrsType)) return sz_false_k;

    Strs *strs = (Strs *)object;

    // Get the current allocator based on layout
    sz_memory_allocator_t old_allocator;
    switch (strs->layout) {
    case STRS_U32_TAPE: old_allocator = strs->data.u32_tape.allocator; break;
    case STRS_U64_TAPE: old_allocator = strs->data.u64_tape.allocator; break;
    case STRS_FRAGMENTED: old_allocator = strs->data.fragmented.allocator; break;
    case STRS_U32_TAPE_VIEW:
    case STRS_U64_TAPE_VIEW:
        // Traverse parent chain until we find an allocator
        {
            Strs *up = strs;
            while (up && (up->layout == STRS_U32_TAPE_VIEW || up->layout == STRS_U64_TAPE_VIEW)) {
                PyObject *parent =
                    (up->layout == STRS_U32_TAPE_VIEW) ? up->data.u32_tape_view.parent : up->data.u64_tape_view.parent;
                if (!parent || !PyObject_TypeCheck(parent, &StrsType)) break;
                up = (Strs *)parent;
            }

            // Extract allocator from the owning layout we found
            if (up && up->layout == STRS_U32_TAPE) { old_allocator = up->data.u32_tape.allocator; }
            else if (up && up->layout == STRS_U64_TAPE) { old_allocator = up->data.u64_tape.allocator; }
            else if (up && up->layout == STRS_FRAGMENTED) { old_allocator = up->data.fragmented.allocator; }
            else { sz_memory_allocator_init_default(&old_allocator); } // Final fallback
        }
        break;
    default: sz_memory_allocator_init_default(&old_allocator); break;
    }

    // Check if the allocators are the same - no need to reallocate
    if (sz_memory_allocator_equal(&old_allocator, allocator)) return sz_true_k;

    // Handle different Strs layouts using dedicated functions
    switch (strs->layout) {
    case STRS_U32_TAPE: return sz_py_replace_u32_tape_allocator(strs, &old_allocator, allocator);
    case STRS_U64_TAPE: return sz_py_replace_u64_tape_allocator(strs, &old_allocator, allocator);
    case STRS_U32_TAPE_VIEW: return sz_py_replace_u32_tape_view_allocator(strs, allocator);
    case STRS_U64_TAPE_VIEW: return sz_py_replace_u64_tape_view_allocator(strs, allocator);
    case STRS_FRAGMENTED: return sz_py_replace_fragmented_allocator(strs, &old_allocator, allocator);
    }

    return sz_false_k; // Should never reach here
}

/**
 *  @brief  Helper function to wrap the current exception with a custom prefix message.