Index: third_party/libjpeg_turbo/jcprepct.c |
=================================================================== |
--- third_party/libjpeg_turbo/jcprepct.c (revision 0) |
+++ third_party/libjpeg_turbo/jcprepct.c (revision 0) |
@@ -0,0 +1,354 @@ |
+/* |
+ * 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++) { |
+ expand_bottom_edge(output_buf[ci], |
+ compptr->width_in_blocks * DCTSIZE, |
+ (int) (*out_row_group_ctr * compptr->v_samp_factor), |
+ (int) (out_row_groups_avail * compptr->v_samp_factor)); |
+ } |
+ *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 * DCTSIZE * |
+ 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 * DCTSIZE * |
+ cinfo->max_h_samp_factor) / compptr->h_samp_factor), |
+ (JDIMENSION) cinfo->max_v_samp_factor); |
+ } |
+ } |
+} |