Commit e0e18dea5433e600ea92d60814f13efa40a0d7dd
2024-12-18T12:50:38
Ensure methods called by global funcs are init'd If a hypothetical calling application does something really stupid and changes cinfo->data_precision after calling jpeg_start_*compress(), then the precision-specific methods called by jpeg_write_scanlines(), jpeg_write_raw_data(), jpeg_finish_compress(), jpeg_read_scanlines(), jpeg_read_raw_data(), or jpeg_start_output() may not be initialized. Ensure that the first precision-specific method (which will always be cinfo->main->process_data*(), cinfo->coef->compress_data*(), or cinfo->coef->decompress_data()) called by any global function that may be called after jpeg_start_*compress() is initialized and non-NULL. This increases the likelihood (but does not guarantee) that a hypothetical stupid calling application will fail gracefully rather than segfault if it changes cinfo->data_precision after calling jpeg_start_*compress(). A hypothetical stupid calling application can still bork itself by changing cinfo->data_precision after initializing the source manager but before calling jpeg_start_compress(), or after initializing the destination manager but before calling jpeg_start_decompress().