1 /*
2 * jcapimin.c
3 *
4 * Copyright (C) 1994-1995, Thomas G. Lane.
5 * This file is part of the Independent JPEG Group's software.
6 * For conditions of distribution and use, see the accompanying README file.
7 *
8 * This file contains application interface code for the compression half
9 * of the JPEG library. These are the "minimum" API routines that may be
10 * needed in either the normal full-compression case or the transcoding-only
11 * case.
12 *
13 * Most of the routines intended to be called directly by an application
14 * are in this file or in jcapistd.c. But also see jcparam.c for
15 * parameter-setup helper routines, jcomapi.c for routines shared by
16 * compression and decompression, and jctrans.c for the transcoding case.
17 */
18
19 #define JPEG_INTERNALS
20 #include "jinclude.h"
21 #include "jpeglib.h"
22
23
24 /*
25 * Initialization of a JPEG compression object.
26 * The error manager must already be set up (in case memory manager fails).
27 */
28
29 GLOBAL void
jpeg_create_compress(j_compress_ptr cinfo)30 jpeg_create_compress (j_compress_ptr cinfo)
31 {
32 int i;
33
34 /* For debugging purposes, zero the whole master structure.
35 * But error manager pointer is already there, so save and restore it.
36 */
37 {
38 struct jpeg_error_mgr * err = cinfo->err;
39 MEMZERO(cinfo, SIZEOF(struct jpeg_compress_struct));
40 cinfo->err = err;
41 }
42 cinfo->is_decompressor = FALSE;
43
44 /* Initialize a memory manager instance for this object */
45 jinit_memory_mgr((j_common_ptr) cinfo);
46
47 /* Zero out pointers to permanent structures. */
48 cinfo->progress = NULL;
49 cinfo->dest = NULL;
50
51 cinfo->comp_info = NULL;
52
53 for (i = 0; i < NUM_QUANT_TBLS; i++)
54 cinfo->quant_tbl_ptrs[i] = NULL;
55
56 for (i = 0; i < NUM_HUFF_TBLS; i++) {
57 cinfo->dc_huff_tbl_ptrs[i] = NULL;
58 cinfo->ac_huff_tbl_ptrs[i] = NULL;
59 }
60
61 cinfo->input_gamma = 1.0; /* in case application forgets */
62
63 /* OK, I'm ready */
64 cinfo->global_state = CSTATE_START;
65 }
66
67
68 /*
69 * Destruction of a JPEG compression object
70 */
71
72 GLOBAL void
jpeg_destroy_compress(j_compress_ptr cinfo)73 jpeg_destroy_compress (j_compress_ptr cinfo)
74 {
75 jpeg_destroy((j_common_ptr) cinfo); /* use common routine */
76 }
77
78
79 /*
80 * Abort processing of a JPEG compression operation,
81 * but don't destroy the object itself.
82 */
83
84 GLOBAL void
jpeg_abort_compress(j_compress_ptr cinfo)85 jpeg_abort_compress (j_compress_ptr cinfo)
86 {
87 jpeg_abort((j_common_ptr) cinfo); /* use common routine */
88 }
89
90
91 /*
92 * Forcibly suppress or un-suppress all quantization and Huffman tables.
93 * Marks all currently defined tables as already written (if suppress)
94 * or not written (if !suppress). This will control whether they get emitted
95 * by a subsequent jpeg_start_compress call.
96 *
97 * This routine is exported for use by applications that want to produce
98 * abbreviated JPEG datastreams. It logically belongs in jcparam.c, but
99 * since it is called by jpeg_start_compress, we put it here --- otherwise
100 * jcparam.o would be linked whether the application used it or not.
101 */
102
103 GLOBAL void
jpeg_suppress_tables(j_compress_ptr cinfo,boolean suppress)104 jpeg_suppress_tables (j_compress_ptr cinfo, boolean suppress)
105 {
106 int i;
107 JQUANT_TBL * qtbl;
108 JHUFF_TBL * htbl;
109
110 for (i = 0; i < NUM_QUANT_TBLS; i++) {
111 if ((qtbl = cinfo->quant_tbl_ptrs[i]) != NULL)
112 qtbl->sent_table = suppress;
113 }
114
115 for (i = 0; i < NUM_HUFF_TBLS; i++) {
116 if ((htbl = cinfo->dc_huff_tbl_ptrs[i]) != NULL)
117 htbl->sent_table = suppress;
118 if ((htbl = cinfo->ac_huff_tbl_ptrs[i]) != NULL)
119 htbl->sent_table = suppress;
120 }
121 }
122
123
124 /*
125 * Finish JPEG compression.
126 *
127 * If a multipass operating mode was selected, this may do a great deal of
128 * work including most of the actual output.
129 */
130
131 GLOBAL void
jpeg_finish_compress(j_compress_ptr cinfo)132 jpeg_finish_compress (j_compress_ptr cinfo)
133 {
134 JDIMENSION iMCU_row;
135
136 if (cinfo->global_state == CSTATE_SCANNING ||
137 cinfo->global_state == CSTATE_RAW_OK) {
138 /* Terminate first pass */
139 if (cinfo->next_scanline < cinfo->image_height)
140 ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);
141 (*cinfo->master->finish_pass) (cinfo);
142 } else if (cinfo->global_state != CSTATE_WRCOEFS)
143 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
144 /* Perform any remaining passes */
145 while (! cinfo->master->is_last_pass) {
146 (*cinfo->master->prepare_for_pass) (cinfo);
147 for (iMCU_row = 0; iMCU_row < cinfo->total_iMCU_rows; iMCU_row++) {
148 if (cinfo->progress != NULL) {
149 cinfo->progress->pass_counter = (long) iMCU_row;
150 cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows;
151 (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
152 }
153 /* We bypass the main controller and invoke coef controller directly;
154 * all work is being done from the coefficient buffer.
155 */
156 if (! (*cinfo->coef->compress_data) (cinfo, (JSAMPIMAGE) NULL))
157 ERREXIT(cinfo, JERR_CANT_SUSPEND);
158 }
159 (*cinfo->master->finish_pass) (cinfo);
160 }
161 /* Write EOI, do final cleanup */
162 (*cinfo->marker->write_file_trailer) (cinfo);
163 (*cinfo->dest->term_destination) (cinfo);
164 /* We can use jpeg_abort to release memory and reset global_state */
165 jpeg_abort((j_common_ptr) cinfo);
166 }
167
168
169 /*
170 * Write a special marker.
171 * This is only recommended for writing COM or APPn markers.
172 * Must be called after jpeg_start_compress() and before
173 * first call to jpeg_write_scanlines() or jpeg_write_raw_data().
174 */
175
176 GLOBAL void
jpeg_write_marker(j_compress_ptr cinfo,int marker,const JOCTET * dataptr,unsigned int datalen)177 jpeg_write_marker (j_compress_ptr cinfo, int marker,
178 const JOCTET *dataptr, unsigned int datalen)
179 {
180 if (cinfo->next_scanline != 0 ||
181 (cinfo->global_state != CSTATE_SCANNING &&
182 cinfo->global_state != CSTATE_RAW_OK &&
183 cinfo->global_state != CSTATE_WRCOEFS))
184 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
185
186 (*cinfo->marker->write_any_marker) (cinfo, marker, dataptr, datalen);
187 }
188
189
190 /*
191 * Alternate compression function: just write an abbreviated table file.
192 * Before calling this, all parameters and a data destination must be set up.
193 *
194 * To produce a pair of files containing abbreviated tables and abbreviated
195 * image data, one would proceed as follows:
196 *
197 * initialize JPEG object
198 * set JPEG parameters
199 * set destination to table file
200 * jpeg_write_tables(cinfo);
201 * set destination to image file
202 * jpeg_start_compress(cinfo, FALSE);
203 * write data...
204 * jpeg_finish_compress(cinfo);
205 *
206 * jpeg_write_tables has the side effect of marking all tables written
207 * (same as jpeg_suppress_tables(..., TRUE)). Thus a subsequent start_compress
208 * will not re-emit the tables unless it is passed write_all_tables=TRUE.
209 */
210
211 GLOBAL void
jpeg_write_tables(j_compress_ptr cinfo)212 jpeg_write_tables (j_compress_ptr cinfo)
213 {
214 if (cinfo->global_state != CSTATE_START)
215 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
216
217 /* (Re)initialize error mgr and destination modules */
218 (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
219 (*cinfo->dest->init_destination) (cinfo);
220 /* Initialize the marker writer ... bit of a crock to do it here. */
221 jinit_marker_writer(cinfo);
222 /* Write them tables! */
223 (*cinfo->marker->write_tables_only) (cinfo);
224 /* And clean up. */
225 (*cinfo->dest->term_destination) (cinfo);
226 /* We can use jpeg_abort to release memory. */
227 jpeg_abort((j_common_ptr) cinfo);
228 }
229