1802       png_ptr->prev_row = (png_bytep)png_calloc(png_ptr,  in png_write_start_row()
1920          if (png_ptr->prev_row != NULL)  in png_write_finish_row()
1921             png_memset(png_ptr->prev_row, 0,  in png_write_finish_row()
2149    png_bytep prev_row, row_buf;  in png_write_find_filter()  local
2170    prev_row = png_ptr->prev_row;  in png_write_find_filter()
2378            pp = prev_row + 1; i < row_bytes;  in png_write_find_filter()
2426            pp = prev_row + 1; i < row_bytes; i++)  in png_write_find_filter()
2480            pp = prev_row + 1; i < bpp; i++)  in png_write_find_filter()
2531            pp = prev_row + 1; i < bpp; i++)  in png_write_find_filter()
2592            pp = prev_row + 1; i < bpp; i++)  in png_write_find_filter()
2597       for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)  in png_write_find_filter()
2664            pp = prev_row + 1; i < bpp; i++)  in png_write_find_filter()
2671       for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)  in png_write_find_filter()
2810    if (png_ptr->prev_row != NULL)  in png_write_filtered_row()
2814       tptr = png_ptr->prev_row;  in png_write_filtered_row()
2815       png_ptr->prev_row = png_ptr->row_buf;  in png_write_filtered_row()