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Diffstat (limited to 'jpg/jcprepct.c')
| -rw-r--r-- | jpg/jcprepct.c | 358 |
1 files changed, 0 insertions, 358 deletions
diff --git a/jpg/jcprepct.c b/jpg/jcprepct.c deleted file mode 100644 index be44cc4..0000000 --- a/jpg/jcprepct.c +++ /dev/null @@ -1,358 +0,0 @@ -/* - * jcprepct.c - * - * Copyright (C) 1994-1996, Thomas G. Lane. - * This file is part of the Independent JPEG Group's software. - * For conditions of distribution and use, see the accompanying README file. - * - * This file contains the compression preprocessing controller. - * This controller manages the color conversion, downsampling, - * and edge expansion steps. - * - * Most of the complexity here is associated with buffering input rows - * as required by the downsampler. See the comments at the head of - * jcsample.c for the downsampler's needs. - */ - -#define JPEG_INTERNALS -#include "jinclude.h" -#include "jpeglib.h" - - -/* At present, jcsample.c can request context rows only for smoothing. - * In the future, we might also need context rows for CCIR601 sampling - * or other more-complex downsampling procedures. The code to support - * context rows should be compiled only if needed. - */ -#ifdef INPUT_SMOOTHING_SUPPORTED -#define CONTEXT_ROWS_SUPPORTED -#endif - - -/* - * For the simple (no-context-row) case, we just need to buffer one - * row group's worth of pixels for the downsampling step. At the bottom of - * the image, we pad to a full row group by replicating the last pixel row. - * The downsampler's last output row is then replicated if needed to pad - * out to a full iMCU row. - * - * When providing context rows, we must buffer three row groups' worth of - * pixels. Three row groups are physically allocated, but the row pointer - * arrays are made five row groups high, with the extra pointers above and - * below "wrapping around" to point to the last and first real row groups. - * This allows the downsampler to access the proper context rows. - * At the top and bottom of the image, we create dummy context rows by - * copying the first or last real pixel row. This copying could be avoided - * by pointer hacking as is done in jdmainct.c, but it doesn't seem worth the - * trouble on the compression side. - */ - - -/* Private buffer controller object */ - -typedef struct { - struct jpeg_c_prep_controller pub; /* public fields */ - - /* Downsampling input buffer. This buffer holds color-converted data - * until we have enough to do a downsample step. - */ - JSAMPARRAY color_buf[MAX_COMPONENTS]; - - JDIMENSION rows_to_go; /* counts rows remaining in source image */ - int next_buf_row; /* index of next row to store in color_buf */ - -#ifdef CONTEXT_ROWS_SUPPORTED /* only needed for context case */ - int this_row_group; /* starting row index of group to process */ - int next_buf_stop; /* downsample when we reach this index */ -#endif -} my_prep_controller; - -typedef my_prep_controller * my_prep_ptr; - - -/* - * Initialize for a processing pass. - */ - -METHODDEF(void) -start_pass_prep (j_compress_ptr cinfo, J_BUF_MODE pass_mode) -{ - my_prep_ptr prep = (my_prep_ptr) cinfo->prep; - - if (pass_mode != JBUF_PASS_THRU) - ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); - - /* Initialize total-height counter for detecting bottom of image */ - prep->rows_to_go = cinfo->image_height; - /* Mark the conversion buffer empty */ - prep->next_buf_row = 0; -#ifdef CONTEXT_ROWS_SUPPORTED - /* Preset additional state variables for context mode. - * These aren't used in non-context mode, so we needn't test which mode. - */ - prep->this_row_group = 0; - /* Set next_buf_stop to stop after two row groups have been read in. */ - prep->next_buf_stop = 2 * cinfo->max_v_samp_factor; -#endif -} - - -/* - * Expand an image vertically from height input_rows to height output_rows, - * by duplicating the bottom row. - */ - -LOCAL(void) -expand_bottom_edge (JSAMPARRAY image_data, JDIMENSION num_cols, - int input_rows, int output_rows) -{ - register int row; - - for (row = input_rows; row < output_rows; row++) { - jcopy_sample_rows(image_data, input_rows-1, image_data, row, - 1, num_cols); - } -} - - -/* - * Process some data in the simple no-context case. - * - * Preprocessor output data is counted in "row groups". A row group - * is defined to be v_samp_factor sample rows of each component. - * Downsampling will produce this much data from each max_v_samp_factor - * input rows. - */ - -METHODDEF(void) -pre_process_data (j_compress_ptr cinfo, - JSAMPARRAY input_buf, JDIMENSION *in_row_ctr, - JDIMENSION in_rows_avail, - JSAMPIMAGE output_buf, JDIMENSION *out_row_group_ctr, - JDIMENSION out_row_groups_avail) -{ - my_prep_ptr prep = (my_prep_ptr) cinfo->prep; - int numrows, ci; - JDIMENSION inrows; - jpeg_component_info * compptr; - - while (*in_row_ctr < in_rows_avail && - *out_row_group_ctr < out_row_groups_avail) { - /* Do color conversion to fill the conversion buffer. */ - inrows = in_rows_avail - *in_row_ctr; - numrows = cinfo->max_v_samp_factor - prep->next_buf_row; - numrows = (int) MIN((JDIMENSION) numrows, inrows); - (*cinfo->cconvert->color_convert) (cinfo, input_buf + *in_row_ctr, - prep->color_buf, - (JDIMENSION) prep->next_buf_row, - numrows); - *in_row_ctr += numrows; - prep->next_buf_row += numrows; - prep->rows_to_go -= numrows; - /* If at bottom of image, pad to fill the conversion buffer. */ - if (prep->rows_to_go == 0 && - prep->next_buf_row < cinfo->max_v_samp_factor) { - for (ci = 0; ci < cinfo->num_components; ci++) { - expand_bottom_edge(prep->color_buf[ci], cinfo->image_width, - prep->next_buf_row, cinfo->max_v_samp_factor); - } - prep->next_buf_row = cinfo->max_v_samp_factor; - } - /* If we've filled the conversion buffer, empty it. */ - if (prep->next_buf_row == cinfo->max_v_samp_factor) { - (*cinfo->downsample->downsample) (cinfo, - prep->color_buf, (JDIMENSION) 0, - output_buf, *out_row_group_ctr); - prep->next_buf_row = 0; - (*out_row_group_ctr)++; - } - /* If at bottom of image, pad the output to a full iMCU height. - * Note we assume the caller is providing a one-iMCU-height output buffer! - */ - if (prep->rows_to_go == 0 && - *out_row_group_ctr < out_row_groups_avail) { - for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; - ci++, compptr++) { - numrows = (compptr->v_samp_factor * compptr->DCT_v_scaled_size) / - cinfo->min_DCT_v_scaled_size; - expand_bottom_edge(output_buf[ci], - compptr->width_in_blocks * compptr->DCT_h_scaled_size, - (int) (*out_row_group_ctr * numrows), - (int) (out_row_groups_avail * numrows)); - } - *out_row_group_ctr = out_row_groups_avail; - break; /* can exit outer loop without test */ - } - } -} - - -#ifdef CONTEXT_ROWS_SUPPORTED - -/* - * Process some data in the context case. - */ - -METHODDEF(void) -pre_process_context (j_compress_ptr cinfo, - JSAMPARRAY input_buf, JDIMENSION *in_row_ctr, - JDIMENSION in_rows_avail, - JSAMPIMAGE output_buf, JDIMENSION *out_row_group_ctr, - JDIMENSION out_row_groups_avail) -{ - my_prep_ptr prep = (my_prep_ptr) cinfo->prep; - int numrows, ci; - int buf_height = cinfo->max_v_samp_factor * 3; - JDIMENSION inrows; - - while (*out_row_group_ctr < out_row_groups_avail) { - if (*in_row_ctr < in_rows_avail) { - /* Do color conversion to fill the conversion buffer. */ - inrows = in_rows_avail - *in_row_ctr; - numrows = prep->next_buf_stop - prep->next_buf_row; - numrows = (int) MIN((JDIMENSION) numrows, inrows); - (*cinfo->cconvert->color_convert) (cinfo, input_buf + *in_row_ctr, - prep->color_buf, - (JDIMENSION) prep->next_buf_row, - numrows); - /* Pad at top of image, if first time through */ - if (prep->rows_to_go == cinfo->image_height) { - for (ci = 0; ci < cinfo->num_components; ci++) { - int row; - for (row = 1; row <= cinfo->max_v_samp_factor; row++) { - jcopy_sample_rows(prep->color_buf[ci], 0, - prep->color_buf[ci], -row, - 1, cinfo->image_width); - } - } - } - *in_row_ctr += numrows; - prep->next_buf_row += numrows; - prep->rows_to_go -= numrows; - } else { - /* Return for more data, unless we are at the bottom of the image. */ - if (prep->rows_to_go != 0) - break; - /* When at bottom of image, pad to fill the conversion buffer. */ - if (prep->next_buf_row < prep->next_buf_stop) { - for (ci = 0; ci < cinfo->num_components; ci++) { - expand_bottom_edge(prep->color_buf[ci], cinfo->image_width, - prep->next_buf_row, prep->next_buf_stop); - } - prep->next_buf_row = prep->next_buf_stop; - } - } - /* If we've gotten enough data, downsample a row group. */ - if (prep->next_buf_row == prep->next_buf_stop) { - (*cinfo->downsample->downsample) (cinfo, - prep->color_buf, - (JDIMENSION) prep->this_row_group, - output_buf, *out_row_group_ctr); - (*out_row_group_ctr)++; - /* Advance pointers with wraparound as necessary. */ - prep->this_row_group += cinfo->max_v_samp_factor; - if (prep->this_row_group >= buf_height) - prep->this_row_group = 0; - if (prep->next_buf_row >= buf_height) - prep->next_buf_row = 0; - prep->next_buf_stop = prep->next_buf_row + cinfo->max_v_samp_factor; - } - } -} - - -/* - * Create the wrapped-around downsampling input buffer needed for context mode. - */ - -LOCAL(void) -create_context_buffer (j_compress_ptr cinfo) -{ - my_prep_ptr prep = (my_prep_ptr) cinfo->prep; - int rgroup_height = cinfo->max_v_samp_factor; - int ci, i; - jpeg_component_info * compptr; - JSAMPARRAY true_buffer, fake_buffer; - - /* Grab enough space for fake row pointers for all the components; - * we need five row groups' worth of pointers for each component. - */ - fake_buffer = (JSAMPARRAY) - (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, - (cinfo->num_components * 5 * rgroup_height) * - SIZEOF(JSAMPROW)); - - for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; - ci++, compptr++) { - /* Allocate the actual buffer space (3 row groups) for this component. - * We make the buffer wide enough to allow the downsampler to edge-expand - * horizontally within the buffer, if it so chooses. - */ - true_buffer = (*cinfo->mem->alloc_sarray) - ((j_common_ptr) cinfo, JPOOL_IMAGE, - (JDIMENSION) (((long) compptr->width_in_blocks * - cinfo->min_DCT_h_scaled_size * - cinfo->max_h_samp_factor) / compptr->h_samp_factor), - (JDIMENSION) (3 * rgroup_height)); - /* Copy true buffer row pointers into the middle of the fake row array */ - MEMCOPY(fake_buffer + rgroup_height, true_buffer, - 3 * rgroup_height * SIZEOF(JSAMPROW)); - /* Fill in the above and below wraparound pointers */ - for (i = 0; i < rgroup_height; i++) { - fake_buffer[i] = true_buffer[2 * rgroup_height + i]; - fake_buffer[4 * rgroup_height + i] = true_buffer[i]; - } - prep->color_buf[ci] = fake_buffer + rgroup_height; - fake_buffer += 5 * rgroup_height; /* point to space for next component */ - } -} - -#endif /* CONTEXT_ROWS_SUPPORTED */ - - -/* - * Initialize preprocessing controller. - */ - -GLOBAL(void) -jinit_c_prep_controller (j_compress_ptr cinfo, boolean need_full_buffer) -{ - my_prep_ptr prep; - int ci; - jpeg_component_info * compptr; - - if (need_full_buffer) /* safety check */ - ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); - - prep = (my_prep_ptr) - (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, - SIZEOF(my_prep_controller)); - cinfo->prep = (struct jpeg_c_prep_controller *) prep; - prep->pub.start_pass = start_pass_prep; - - /* Allocate the color conversion buffer. - * We make the buffer wide enough to allow the downsampler to edge-expand - * horizontally within the buffer, if it so chooses. - */ - if (cinfo->downsample->need_context_rows) { - /* Set up to provide context rows */ -#ifdef CONTEXT_ROWS_SUPPORTED - prep->pub.pre_process_data = pre_process_context; - create_context_buffer(cinfo); -#else - ERREXIT(cinfo, JERR_NOT_COMPILED); -#endif - } else { - /* No context, just make it tall enough for one row group */ - prep->pub.pre_process_data = pre_process_data; - for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; - ci++, compptr++) { - prep->color_buf[ci] = (*cinfo->mem->alloc_sarray) - ((j_common_ptr) cinfo, JPOOL_IMAGE, - (JDIMENSION) (((long) compptr->width_in_blocks * - cinfo->min_DCT_h_scaled_size * - cinfo->max_h_samp_factor) / compptr->h_samp_factor), - (JDIMENSION) cinfo->max_v_samp_factor); - } - } -} |