4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1994-1998, Thomas G. Lane.
6 * Modified 2003-2010 by Guido Vollbeding.
7 * It was modified by The libjpeg-turbo Project to include only code relevant
9 * For conditions of distribution and use, see the accompanying README file.
11 * This file contains application interface code for the compression half
12 * of the JPEG library. These are the "minimum" API routines that may be
13 * needed in either the normal full-compression case or the transcoding-only
16 * Most of the routines intended to be called directly by an application
17 * are in this file or in jcapistd.c. But also see jcparam.c for
18 * parameter-setup helper routines, jcomapi.c for routines shared by
19 * compression and decompression, and jctrans.c for the transcoding case.
22 #define JPEG_INTERNALS
28 * Initialization of a JPEG compression object.
29 * The error manager must already be set up (in case memory manager fails).
33 jpeg_CreateCompress (j_compress_ptr cinfo, int version, size_t structsize)
37 /* Guard against version mismatches between library and caller. */
38 cinfo->mem = NULL; /* so jpeg_destroy knows mem mgr not called */
39 if (version != JPEG_LIB_VERSION)
40 ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version);
41 if (structsize != sizeof(struct jpeg_compress_struct))
42 ERREXIT2(cinfo, JERR_BAD_STRUCT_SIZE,
43 (int) sizeof(struct jpeg_compress_struct), (int) structsize);
45 /* For debugging purposes, we zero the whole master structure.
46 * But the application has already set the err pointer, and may have set
47 * client_data, so we have to save and restore those fields.
48 * Note: if application hasn't set client_data, tools like Purify may
52 struct jpeg_error_mgr * err = cinfo->err;
53 void * client_data = cinfo->client_data; /* ignore Purify complaint here */
54 MEMZERO(cinfo, sizeof(struct jpeg_compress_struct));
56 cinfo->client_data = client_data;
58 cinfo->is_decompressor = FALSE;
60 /* Initialize a memory manager instance for this object */
61 jinit_memory_mgr((j_common_ptr) cinfo);
63 /* Zero out pointers to permanent structures. */
64 cinfo->progress = NULL;
67 cinfo->comp_info = NULL;
69 for (i = 0; i < NUM_QUANT_TBLS; i++) {
70 cinfo->quant_tbl_ptrs[i] = NULL;
71 #if JPEG_LIB_VERSION >= 70
72 cinfo->q_scale_factor[i] = 100;
76 for (i = 0; i < NUM_HUFF_TBLS; i++) {
77 cinfo->dc_huff_tbl_ptrs[i] = NULL;
78 cinfo->ac_huff_tbl_ptrs[i] = NULL;
81 #if JPEG_LIB_VERSION >= 80
82 /* Must do it here for emit_dqt in case jpeg_write_tables is used */
83 cinfo->block_size = DCTSIZE;
84 cinfo->natural_order = jpeg_natural_order;
85 cinfo->lim_Se = DCTSIZE2-1;
88 cinfo->script_space = NULL;
90 cinfo->input_gamma = 1.0; /* in case application forgets */
93 cinfo->global_state = CSTATE_START;
98 * Destruction of a JPEG compression object
102 jpeg_destroy_compress (j_compress_ptr cinfo)
104 jpeg_destroy((j_common_ptr) cinfo); /* use common routine */
109 * Abort processing of a JPEG compression operation,
110 * but don't destroy the object itself.
114 jpeg_abort_compress (j_compress_ptr cinfo)
116 jpeg_abort((j_common_ptr) cinfo); /* use common routine */
121 * Forcibly suppress or un-suppress all quantization and Huffman tables.
122 * Marks all currently defined tables as already written (if suppress)
123 * or not written (if !suppress). This will control whether they get emitted
124 * by a subsequent jpeg_start_compress call.
126 * This routine is exported for use by applications that want to produce
127 * abbreviated JPEG datastreams. It logically belongs in jcparam.c, but
128 * since it is called by jpeg_start_compress, we put it here --- otherwise
129 * jcparam.o would be linked whether the application used it or not.
133 jpeg_suppress_tables (j_compress_ptr cinfo, boolean suppress)
139 for (i = 0; i < NUM_QUANT_TBLS; i++) {
140 if ((qtbl = cinfo->quant_tbl_ptrs[i]) != NULL)
141 qtbl->sent_table = suppress;
144 for (i = 0; i < NUM_HUFF_TBLS; i++) {
145 if ((htbl = cinfo->dc_huff_tbl_ptrs[i]) != NULL)
146 htbl->sent_table = suppress;
147 if ((htbl = cinfo->ac_huff_tbl_ptrs[i]) != NULL)
148 htbl->sent_table = suppress;
154 * Finish JPEG compression.
156 * If a multipass operating mode was selected, this may do a great deal of
157 * work including most of the actual output.
161 jpeg_finish_compress (j_compress_ptr cinfo)
165 if (cinfo->global_state == CSTATE_SCANNING ||
166 cinfo->global_state == CSTATE_RAW_OK) {
167 /* Terminate first pass */
168 if (cinfo->next_scanline < cinfo->image_height)
169 ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);
170 (*cinfo->master->finish_pass) (cinfo);
171 } else if (cinfo->global_state != CSTATE_WRCOEFS)
172 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
173 /* Perform any remaining passes */
174 while (! cinfo->master->is_last_pass) {
175 (*cinfo->master->prepare_for_pass) (cinfo);
176 for (iMCU_row = 0; iMCU_row < cinfo->total_iMCU_rows; iMCU_row++) {
177 if (cinfo->progress != NULL) {
178 cinfo->progress->pass_counter = (long) iMCU_row;
179 cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows;
180 (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
182 /* We bypass the main controller and invoke coef controller directly;
183 * all work is being done from the coefficient buffer.
185 if (! (*cinfo->coef->compress_data) (cinfo, (JSAMPIMAGE) NULL))
186 ERREXIT(cinfo, JERR_CANT_SUSPEND);
188 (*cinfo->master->finish_pass) (cinfo);
190 /* Write EOI, do final cleanup */
191 (*cinfo->marker->write_file_trailer) (cinfo);
192 (*cinfo->dest->term_destination) (cinfo);
193 /* We can use jpeg_abort to release memory and reset global_state */
194 jpeg_abort((j_common_ptr) cinfo);
199 * Write a special marker.
200 * This is only recommended for writing COM or APPn markers.
201 * Must be called after jpeg_start_compress() and before
202 * first call to jpeg_write_scanlines() or jpeg_write_raw_data().
206 jpeg_write_marker (j_compress_ptr cinfo, int marker,
207 const JOCTET *dataptr, unsigned int datalen)
209 void (*write_marker_byte) (j_compress_ptr info, int val);
211 if (cinfo->next_scanline != 0 ||
212 (cinfo->global_state != CSTATE_SCANNING &&
213 cinfo->global_state != CSTATE_RAW_OK &&
214 cinfo->global_state != CSTATE_WRCOEFS))
215 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
217 (*cinfo->marker->write_marker_header) (cinfo, marker, datalen);
218 write_marker_byte = cinfo->marker->write_marker_byte; /* copy for speed */
220 (*write_marker_byte) (cinfo, *dataptr);
225 /* Same, but piecemeal. */
228 jpeg_write_m_header (j_compress_ptr cinfo, int marker, unsigned int datalen)
230 if (cinfo->next_scanline != 0 ||
231 (cinfo->global_state != CSTATE_SCANNING &&
232 cinfo->global_state != CSTATE_RAW_OK &&
233 cinfo->global_state != CSTATE_WRCOEFS))
234 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
236 (*cinfo->marker->write_marker_header) (cinfo, marker, datalen);
240 jpeg_write_m_byte (j_compress_ptr cinfo, int val)
242 (*cinfo->marker->write_marker_byte) (cinfo, val);
247 * Alternate compression function: just write an abbreviated table file.
248 * Before calling this, all parameters and a data destination must be set up.
250 * To produce a pair of files containing abbreviated tables and abbreviated
251 * image data, one would proceed as follows:
253 * initialize JPEG object
254 * set JPEG parameters
255 * set destination to table file
256 * jpeg_write_tables(cinfo);
257 * set destination to image file
258 * jpeg_start_compress(cinfo, FALSE);
260 * jpeg_finish_compress(cinfo);
262 * jpeg_write_tables has the side effect of marking all tables written
263 * (same as jpeg_suppress_tables(..., TRUE)). Thus a subsequent start_compress
264 * will not re-emit the tables unless it is passed write_all_tables=TRUE.
268 jpeg_write_tables (j_compress_ptr cinfo)
270 if (cinfo->global_state != CSTATE_START)
271 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
273 /* (Re)initialize error mgr and destination modules */
274 (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
275 (*cinfo->dest->init_destination) (cinfo);
276 /* Initialize the marker writer ... bit of a crock to do it here. */
277 jinit_marker_writer(cinfo);
278 /* Write them tables! */
279 (*cinfo->marker->write_tables_only) (cinfo);
281 (*cinfo->dest->term_destination) (cinfo);
283 * In library releases up through v6a, we called jpeg_abort() here to free
284 * any working memory allocated by the destination manager and marker
285 * writer. Some applications had a problem with that: they allocated space
286 * of their own from the library memory manager, and didn't want it to go
287 * away during write_tables. So now we do nothing. This will cause a
288 * memory leak if an app calls write_tables repeatedly without doing a full
289 * compression cycle or otherwise resetting the JPEG object. However, that
290 * seems less bad than unexpectedly freeing memory in the normal case.
291 * An app that prefers the old behavior can call jpeg_abort for itself after
292 * each call to jpeg_write_tables().