void image_from_file()

in jpegloader.c [23:80]

• 45 lines of code
• 5 McCabe index (conditional complexity)

void image_from_file(ImageObject* self, FILE* file) {
    struct jpeg_decompress_struct state = { 0 };
    struct accimage_jpeg_error_mgr jpeg_error;
    unsigned char* buffer = NULL;

    state.err = jpeg_std_error(&jpeg_error.pub);
    jpeg_error.pub.error_exit = accimage_jpeg_error_exit;
    if (setjmp(jpeg_error.setjmp_buffer)) {
        char error_message[JMSG_LENGTH_MAX];
        (*state.err->format_message)((j_common_ptr) &state, error_message);
        PyErr_Format(PyExc_IOError, "JPEG decoding failed: %s", error_message);
        goto cleanup;
    }

    jpeg_create_decompress(&state);
    jpeg_stdio_src(&state, file);
    jpeg_read_header(&state, TRUE);

    state.dct_method = JDCT_ISLOW;
    state.output_components = 3;
    state.out_color_components = 3;
    state.out_color_space = JCS_RGB;

    jpeg_start_decompress(&state);

    buffer = malloc(state.output_components * state.output_width * state.output_height);
    if (buffer == NULL) {
        PyErr_NoMemory();
        goto cleanup;
    }

    while (state.output_scanline < state.output_height) {
        unsigned char* row = buffer + state.output_scanline * state.output_width * state.output_components;
        jpeg_read_scanlines(&state, &row, 1);
    }

    jpeg_finish_decompress(&state);

    /* Success. Commit object state */
    self->buffer = buffer;
    buffer = NULL;

    self->channels = 3;
    self->height = state.output_height;
    self->width = state.output_width;
    self->row_stride = state.output_width;
    self->y_offset = 0;
    self->x_offset = 0;

cleanup:
    jpeg_destroy_decompress(&state);

    free(buffer);

    if (file != NULL) {
        fclose(file);
    }
}