--- /dev/null
+/*
+ * jcapistd.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 application interface code for the compression half
+ * of the JPEG library. These are the "standard" API routines that are
+ * used in the normal full-compression case. They are not used by a
+ * transcoding-only application. Note that if an application links in
+ * jpeg_start_compress, it will end up linking in the entire compressor.
+ * We thus must separate this file from jcapimin.c to avoid linking the
+ * whole compression library into a transcoder.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/*
+ * Compression initialization.
+ * Before calling this, all parameters and a data destination must be set up.
+ *
+ * We require a write_all_tables parameter as a failsafe check when writing
+ * multiple datastreams from the same compression object. Since prior runs
+ * will have left all the tables marked sent_table=TRUE, a subsequent run
+ * would emit an abbreviated stream (no tables) by default. This may be what
+ * is wanted, but for safety's sake it should not be the default behavior:
+ * programmers should have to make a deliberate choice to emit abbreviated
+ * images. Therefore the documentation and examples should encourage people
+ * to pass write_all_tables=TRUE; then it will take active thought to do the
+ * wrong thing.
+ */
+
+GLOBAL(void)
+jpeg_start_compress (j_compress_ptr cinfo, boolean write_all_tables)
+{
+ if (cinfo->global_state != CSTATE_START)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+
+ if (write_all_tables)
+ jpeg_suppress_tables(cinfo, FALSE); /* mark all tables to be written */
+
+ /* (Re)initialize error mgr and destination modules */
+ (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
+ (*cinfo->dest->init_destination) (cinfo);
+ /* Perform master selection of active modules */
+ jinit_compress_master(cinfo);
+ /* Set up for the first pass */
+ (*cinfo->master->prepare_for_pass) (cinfo);
+ /* Ready for application to drive first pass through jpeg_write_scanlines
+ * or jpeg_write_raw_data.
+ */
+ cinfo->next_scanline = 0;
+ cinfo->global_state = (cinfo->raw_data_in ? CSTATE_RAW_OK : CSTATE_SCANNING);
+}
+
+
+/*
+ * Write some scanlines of data to the JPEG compressor.
+ *
+ * The return value will be the number of lines actually written.
+ * This should be less than the supplied num_lines only in case that
+ * the data destination module has requested suspension of the compressor,
+ * or if more than image_height scanlines are passed in.
+ *
+ * Note: we warn about excess calls to jpeg_write_scanlines() since
+ * this likely signals an application programmer error. However,
+ * excess scanlines passed in the last valid call are *silently* ignored,
+ * so that the application need not adjust num_lines for end-of-image
+ * when using a multiple-scanline buffer.
+ */
+
+GLOBAL(JDIMENSION)
+jpeg_write_scanlines (j_compress_ptr cinfo, JSAMPARRAY scanlines,
+ JDIMENSION num_lines)
+{
+ JDIMENSION row_ctr, rows_left;
+
+ if (cinfo->global_state != CSTATE_SCANNING)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+ if (cinfo->next_scanline >= cinfo->image_height)
+ WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
+
+ /* Call progress monitor hook if present */
+ if (cinfo->progress != NULL) {
+ cinfo->progress->pass_counter = (long) cinfo->next_scanline;
+ cinfo->progress->pass_limit = (long) cinfo->image_height;
+ (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
+ }
+
+ /* Give master control module another chance if this is first call to
+ * jpeg_write_scanlines. This lets output of the frame/scan headers be
+ * delayed so that application can write COM, etc, markers between
+ * jpeg_start_compress and jpeg_write_scanlines.
+ */
+ if (cinfo->master->call_pass_startup)
+ (*cinfo->master->pass_startup) (cinfo);
+
+ /* Ignore any extra scanlines at bottom of image. */
+ rows_left = cinfo->image_height - cinfo->next_scanline;
+ if (num_lines > rows_left)
+ num_lines = rows_left;
+
+ row_ctr = 0;
+ (*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, num_lines);
+ cinfo->next_scanline += row_ctr;
+ return row_ctr;
+}
+
+
+/*
+ * Alternate entry point to write raw data.
+ * Processes exactly one iMCU row per call, unless suspended.
+ */
+
+GLOBAL(JDIMENSION)
+jpeg_write_raw_data (j_compress_ptr cinfo, JSAMPIMAGE data,
+ JDIMENSION num_lines)
+{
+ JDIMENSION lines_per_iMCU_row;
+
+ if (cinfo->global_state != CSTATE_RAW_OK)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+ if (cinfo->next_scanline >= cinfo->image_height) {
+ WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
+ return 0;
+ }
+
+ /* Call progress monitor hook if present */
+ if (cinfo->progress != NULL) {
+ cinfo->progress->pass_counter = (long) cinfo->next_scanline;
+ cinfo->progress->pass_limit = (long) cinfo->image_height;
+ (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
+ }
+
+ /* Give master control module another chance if this is first call to
+ * jpeg_write_raw_data. This lets output of the frame/scan headers be
+ * delayed so that application can write COM, etc, markers between
+ * jpeg_start_compress and jpeg_write_raw_data.
+ */
+ if (cinfo->master->call_pass_startup)
+ (*cinfo->master->pass_startup) (cinfo);
+
+ /* Verify that at least one iMCU row has been passed. */
+ lines_per_iMCU_row = cinfo->max_v_samp_factor * DCTSIZE;
+ if (num_lines < lines_per_iMCU_row)
+ ERREXIT(cinfo, JERR_BUFFER_SIZE);
+
+ /* Directly compress the row. */
+ if (! (*cinfo->coef->compress_data) (cinfo, data)) {
+ /* If compressor did not consume the whole row, suspend processing. */
+ return 0;
+ }
+
+ /* OK, we processed one iMCU row. */
+ cinfo->next_scanline += lines_per_iMCU_row;
+ return lines_per_iMCU_row;
+}
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