--- /dev/null
+/*
+ * jcmainct.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 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"
+
+
+/* Note: currently, there is no operating mode in which a full-image buffer
+ * is needed at this step. If there were, that mode could not be used with
+ * "raw data" input, since this module is bypassed in that case. However,
+ * we've left the code here for possible use in special applications.
+ */
+#undef FULL_MAIN_BUFFER_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];
+
+#ifdef FULL_MAIN_BUFFER_SUPPORTED
+ /* If using full-image storage, this array holds pointers to virtual-array
+ * control blocks for each component. Unused if not full-image storage.
+ */
+ jvirt_sarray_ptr whole_image[MAX_COMPONENTS];
+#endif
+} my_main_controller;
+
+typedef my_main_controller * my_main_ptr;
+
+
+/* Forward declarations */
+METHODDEF(void) process_data_simple_main
+ JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,
+ JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));
+#ifdef FULL_MAIN_BUFFER_SUPPORTED
+METHODDEF(void) process_data_buffer_main
+ JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,
+ JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));
+#endif
+
+
+/*
+ * Initialize for a processing pass.
+ */
+
+METHODDEF(void)
+start_pass_main (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
+{
+ my_main_ptr main = (my_main_ptr) cinfo->main;
+
+ /* Do nothing in raw-data mode. */
+ if (cinfo->raw_data_in)
+ return;
+
+ main->cur_iMCU_row = 0; /* initialize counters */
+ main->rowgroup_ctr = 0;
+ main->suspended = FALSE;
+ main->pass_mode = pass_mode; /* save mode for use by process_data */
+
+ switch (pass_mode) {
+ case JBUF_PASS_THRU:
+#ifdef FULL_MAIN_BUFFER_SUPPORTED
+ if (main->whole_image[0] != NULL)
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+#endif
+ main->pub.process_data = process_data_simple_main;
+ break;
+#ifdef FULL_MAIN_BUFFER_SUPPORTED
+ case JBUF_SAVE_SOURCE:
+ case JBUF_CRANK_DEST:
+ case JBUF_SAVE_AND_PASS:
+ if (main->whole_image[0] == NULL)
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+ main->pub.process_data = process_data_buffer_main;
+ break;
+#endif
+ default:
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+ break;
+ }
+}
+
+
+/*
+ * 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 = (my_main_ptr) cinfo->main;
+
+ while (main->cur_iMCU_row < cinfo->total_iMCU_rows) {
+ /* Read input data if we haven't filled the main buffer yet */
+ if (main->rowgroup_ctr < DCTSIZE)
+ (*cinfo->prep->pre_process_data) (cinfo,
+ input_buf, in_row_ctr, in_rows_avail,
+ main->buffer, &main->rowgroup_ctr,
+ (JDIMENSION) DCTSIZE);
+
+ /* 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->rowgroup_ctr != DCTSIZE)
+ return;
+
+ /* Send the completed row to the compressor */
+ if (! (*cinfo->coef->compress_data) (cinfo, main->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->suspended) {
+ (*in_row_ctr)--;
+ main->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->suspended) {
+ (*in_row_ctr)++;
+ main->suspended = FALSE;
+ }
+ main->rowgroup_ctr = 0;
+ main->cur_iMCU_row++;
+ }
+}
+
+
+#ifdef FULL_MAIN_BUFFER_SUPPORTED
+
+/*
+ * Process some data.
+ * This routine handles all of the modes that use a full-size buffer.
+ */
+
+METHODDEF(void)
+process_data_buffer_main (j_compress_ptr cinfo,
+ JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
+ JDIMENSION in_rows_avail)
+{
+ my_main_ptr main = (my_main_ptr) cinfo->main;
+ int ci;
+ jpeg_component_info *compptr;
+ boolean writing = (main->pass_mode != JBUF_CRANK_DEST);
+
+ while (main->cur_iMCU_row < cinfo->total_iMCU_rows) {
+ /* Realign the virtual buffers if at the start of an iMCU row. */
+ if (main->rowgroup_ctr == 0) {
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ main->buffer[ci] = (*cinfo->mem->access_virt_sarray)
+ ((j_common_ptr) cinfo, main->whole_image[ci],
+ main->cur_iMCU_row * (compptr->v_samp_factor * DCTSIZE),
+ (JDIMENSION) (compptr->v_samp_factor * DCTSIZE), writing);
+ }
+ /* In a read pass, pretend we just read some source data. */
+ if (! writing) {
+ *in_row_ctr += cinfo->max_v_samp_factor * DCTSIZE;
+ main->rowgroup_ctr = DCTSIZE;
+ }
+ }
+
+ /* If a write pass, read input data until the current iMCU row is full. */
+ /* Note: preprocessor will pad if necessary to fill the last iMCU row. */
+ if (writing) {
+ (*cinfo->prep->pre_process_data) (cinfo,
+ input_buf, in_row_ctr, in_rows_avail,
+ main->buffer, &main->rowgroup_ctr,
+ (JDIMENSION) DCTSIZE);
+ /* Return to application if we need more data to fill the iMCU row. */
+ if (main->rowgroup_ctr < DCTSIZE)
+ return;
+ }
+
+ /* Emit data, unless this is a sink-only pass. */
+ if (main->pass_mode != JBUF_SAVE_SOURCE) {
+ if (! (*cinfo->coef->compress_data) (cinfo, main->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->suspended) {
+ (*in_row_ctr)--;
+ main->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->suspended) {
+ (*in_row_ctr)++;
+ main->suspended = FALSE;
+ }
+ }
+
+ /* If get here, we are done with this iMCU row. Mark buffer empty. */
+ main->rowgroup_ctr = 0;
+ main->cur_iMCU_row++;
+ }
+}
+
+#endif /* FULL_MAIN_BUFFER_SUPPORTED */
+
+
+/*
+ * Initialize main buffer controller.
+ */
+
+GLOBAL(void)
+jinit_c_main_controller (j_compress_ptr cinfo, boolean need_full_buffer)
+{
+ my_main_ptr main;
+ int ci;
+ jpeg_component_info *compptr;
+
+ main = (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;
+ main->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) {
+#ifdef FULL_MAIN_BUFFER_SUPPORTED
+ /* Allocate a full-image virtual array for each component */
+ /* Note we pad the bottom to a multiple of the iMCU height */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ main->whole_image[ci] = (*cinfo->mem->request_virt_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
+ compptr->width_in_blocks * DCTSIZE,
+ (JDIMENSION) jround_up((long) compptr->height_in_blocks,
+ (long) compptr->v_samp_factor) * DCTSIZE,
+ (JDIMENSION) (compptr->v_samp_factor * DCTSIZE));
+ }
+#else
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+#endif
+ } else {
+#ifdef FULL_MAIN_BUFFER_SUPPORTED
+ main->whole_image[0] = NULL; /* flag for no virtual arrays */
+#endif
+ /* Allocate a strip buffer for each component */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ main->buffer[ci] = (*cinfo->mem->alloc_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ compptr->width_in_blocks * DCTSIZE,
+ (JDIMENSION) (compptr->v_samp_factor * DCTSIZE));
+ }
+ }
+}
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