* @brief from current line/request, go back one, the next read will * get the current request * * @param reader * @return int */
| 347 | * @return int |
| 348 | */ |
| 349 | int go_back_one_req(reader_t *const reader) { |
| 350 | switch (reader->trace_format) { |
| 351 | case TXT_TRACE_FORMAT:; |
| 352 | ssize_t curr_offset = ftell(reader->file); |
| 353 | if (curr_offset <= reader->trace_start_offset) { |
| 354 | // we are at the start of the file |
| 355 | return 1; |
| 356 | } |
| 357 | |
| 358 | ssize_t max_seek_size = curr_offset - reader->trace_start_offset; |
| 359 | ssize_t seek_size = 0; |
| 360 | ssize_t total_seek_size = 0; |
| 361 | bool found = false; |
| 362 | while (!found && total_seek_size < max_seek_size) { |
| 363 | seek_size = MIN(PER_SEEK_SIZE, max_seek_size - total_seek_size); |
| 364 | total_seek_size += seek_size; |
| 365 | fseek(reader->file, -seek_size, SEEK_CUR); |
| 366 | ssize_t read_size = |
| 367 | fread(reader->line_buf, 1, seek_size - 1, reader->file); |
| 368 | reader->line_buf[read_size - 1] = 0; |
| 369 | char *last_line_end = strrchr(reader->line_buf, '\n'); |
| 370 | |
| 371 | if (last_line_end == NULL) { |
| 372 | // three possible cases |
| 373 | // 1. reach the trace start |
| 374 | // 2. line is too long and has not found \n |
| 375 | // 3. error case |
| 376 | if (seek_size < PER_SEEK_SIZE) { |
| 377 | // case 1 reach the trace start |
| 378 | fseek(reader->file, reader->trace_start_offset, SEEK_SET); |
| 379 | |
| 380 | return 0; |
| 381 | } else if (total_seek_size < max_seek_size) { |
| 382 | // case 2 line is too long and has not found \n |
| 383 | fseek(reader->file, -PER_SEEK_SIZE, SEEK_CUR); |
| 384 | |
| 385 | } else { |
| 386 | WARN("go_back_one_req cannot find the request above\n"); |
| 387 | return 1; |
| 388 | } |
| 389 | } else { |
| 390 | found = true; |
| 391 | int pos = last_line_end + 2 - reader->line_buf; |
| 392 | fseek(reader->file, -(seek_size - pos), SEEK_CUR); |
| 393 | return 0; |
| 394 | } |
| 395 | } |
| 396 | break; |
| 397 | case BINARY_TRACE_FORMAT: |
| 398 | if (reader->mmap_offset >= |
| 399 | reader->trace_start_offset + reader->item_size) { |
| 400 | reader->mmap_offset -= (reader->item_size); |
| 401 | return 0; |
| 402 | } else { |
| 403 | return 1; |
| 404 | } |
| 405 | break; |
| 406 | default: |
no outgoing calls