| /* |
| * jcmainct.c |
| * |
| * This file was part of the Independent JPEG Group's software: |
| * Copyright (C) 1994-1996, Thomas G. Lane. |
| * Lossless JPEG Modifications: |
| * Copyright (C) 1999, Ken Murchison. |
| * libjpeg-turbo Modifications: |
| * Copyright (C) 2022, D. R. Commander. |
| * For conditions of distribution and use, see the accompanying README.ijg |
| * file. |
| * |
| * This file contains the main buffer controller for compression. |
| * The main buffer lies between the pre-processor and the JPEG |
| * compressor proper; it holds downsampled data in the JPEG colorspace. |
| */ |
| |
| #define JPEG_INTERNALS |
| #include "jinclude.h" |
| #include "jpeglib.h" |
| #include "jsamplecomp.h" |
| |
| |
| #if BITS_IN_JSAMPLE != 16 || defined(C_LOSSLESS_SUPPORTED) |
| |
| /* Private buffer controller object */ |
| |
| typedef struct { |
| struct jpeg_c_main_controller pub; /* public fields */ |
| |
| JDIMENSION cur_iMCU_row; /* number of current iMCU row */ |
| JDIMENSION rowgroup_ctr; /* counts row groups received in iMCU row */ |
| boolean suspended; /* remember if we suspended output */ |
| J_BUF_MODE pass_mode; /* current operating mode */ |
| |
| /* If using just a strip buffer, this points to the entire set of buffers |
| * (we allocate one for each component). In the full-image case, this |
| * points to the currently accessible strips of the virtual arrays. |
| */ |
| _JSAMPARRAY buffer[MAX_COMPONENTS]; |
| } my_main_controller; |
| |
| typedef my_main_controller *my_main_ptr; |
| |
| |
| /* Forward declarations */ |
| METHODDEF(void) process_data_simple_main(j_compress_ptr cinfo, |
| _JSAMPARRAY input_buf, |
| JDIMENSION *in_row_ctr, |
| JDIMENSION in_rows_avail); |
| |
| |
| /* |
| * Initialize for a processing pass. |
| */ |
| |
| METHODDEF(void) |
| start_pass_main(j_compress_ptr cinfo, J_BUF_MODE pass_mode) |
| { |
| my_main_ptr main_ptr = (my_main_ptr)cinfo->main; |
| |
| /* Do nothing in raw-data mode. */ |
| if (cinfo->raw_data_in) |
| return; |
| |
| if (pass_mode != JBUF_PASS_THRU) |
| ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
| |
| main_ptr->cur_iMCU_row = 0; /* initialize counters */ |
| main_ptr->rowgroup_ctr = 0; |
| main_ptr->suspended = FALSE; |
| main_ptr->pass_mode = pass_mode; /* save mode for use by process_data */ |
| main_ptr->pub._process_data = process_data_simple_main; |
| } |
| |
| |
| /* |
| * Process some data. |
| * This routine handles the simple pass-through mode, |
| * where we have only a strip buffer. |
| */ |
| |
| METHODDEF(void) |
| process_data_simple_main(j_compress_ptr cinfo, _JSAMPARRAY input_buf, |
| JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail) |
| { |
| my_main_ptr main_ptr = (my_main_ptr)cinfo->main; |
| JDIMENSION data_unit = cinfo->master->lossless ? 1 : DCTSIZE; |
| |
| while (main_ptr->cur_iMCU_row < cinfo->total_iMCU_rows) { |
| /* Read input data if we haven't filled the main buffer yet */ |
| if (main_ptr->rowgroup_ctr < data_unit) |
| (*cinfo->prep->_pre_process_data) (cinfo, input_buf, in_row_ctr, |
| in_rows_avail, main_ptr->buffer, |
| &main_ptr->rowgroup_ctr, data_unit); |
| |
| /* If we don't have a full iMCU row buffered, return to application for |
| * more data. Note that preprocessor will always pad to fill the iMCU row |
| * at the bottom of the image. |
| */ |
| if (main_ptr->rowgroup_ctr != data_unit) |
| return; |
| |
| /* Send the completed row to the compressor */ |
| if (!(*cinfo->coef->_compress_data) (cinfo, main_ptr->buffer)) { |
| /* If compressor did not consume the whole row, then we must need to |
| * suspend processing and return to the application. In this situation |
| * we pretend we didn't yet consume the last input row; otherwise, if |
| * it happened to be the last row of the image, the application would |
| * think we were done. |
| */ |
| if (!main_ptr->suspended) { |
| (*in_row_ctr)--; |
| main_ptr->suspended = TRUE; |
| } |
| return; |
| } |
| /* We did finish the row. Undo our little suspension hack if a previous |
| * call suspended; then mark the main buffer empty. |
| */ |
| if (main_ptr->suspended) { |
| (*in_row_ctr)++; |
| main_ptr->suspended = FALSE; |
| } |
| main_ptr->rowgroup_ctr = 0; |
| main_ptr->cur_iMCU_row++; |
| } |
| } |
| |
| |
| /* |
| * Initialize main buffer controller. |
| */ |
| |
| GLOBAL(void) |
| _jinit_c_main_controller(j_compress_ptr cinfo, boolean need_full_buffer) |
| { |
| my_main_ptr main_ptr; |
| int ci; |
| jpeg_component_info *compptr; |
| int data_unit = cinfo->master->lossless ? 1 : DCTSIZE; |
| |
| if (cinfo->data_precision != BITS_IN_JSAMPLE) |
| ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); |
| |
| main_ptr = (my_main_ptr) |
| (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, |
| sizeof(my_main_controller)); |
| cinfo->main = (struct jpeg_c_main_controller *)main_ptr; |
| main_ptr->pub.start_pass = start_pass_main; |
| |
| /* We don't need to create a buffer in raw-data mode. */ |
| if (cinfo->raw_data_in) |
| return; |
| |
| /* Create the buffer. It holds downsampled data, so each component |
| * may be of a different size. |
| */ |
| if (need_full_buffer) { |
| ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
| } else { |
| /* Allocate a strip buffer for each component */ |
| for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
| ci++, compptr++) { |
| main_ptr->buffer[ci] = (_JSAMPARRAY)(*cinfo->mem->alloc_sarray) |
| ((j_common_ptr)cinfo, JPOOL_IMAGE, |
| compptr->width_in_blocks * data_unit, |
| (JDIMENSION)(compptr->v_samp_factor * data_unit)); |
| } |
| } |
| } |
| |
| #endif /* BITS_IN_JSAMPLE != 16 || defined(C_LOSSLESS_SUPPORTED) */ |