xref: /plan9/sys/src/cmd/gs/jpeg/jcmainct.c (revision 7dd7cddf99dd7472612f1413b4da293630e6b1bc)
1*7dd7cddfSDavid du Colombier /*
2*7dd7cddfSDavid du Colombier  * jcmainct.c
3*7dd7cddfSDavid du Colombier  *
4*7dd7cddfSDavid du Colombier  * Copyright (C) 1994-1996, Thomas G. Lane.
5*7dd7cddfSDavid du Colombier  * This file is part of the Independent JPEG Group's software.
6*7dd7cddfSDavid du Colombier  * For conditions of distribution and use, see the accompanying README file.
7*7dd7cddfSDavid du Colombier  *
8*7dd7cddfSDavid du Colombier  * This file contains the main buffer controller for compression.
9*7dd7cddfSDavid du Colombier  * The main buffer lies between the pre-processor and the JPEG
10*7dd7cddfSDavid du Colombier  * compressor proper; it holds downsampled data in the JPEG colorspace.
11*7dd7cddfSDavid du Colombier  */
12*7dd7cddfSDavid du Colombier 
13*7dd7cddfSDavid du Colombier #define JPEG_INTERNALS
14*7dd7cddfSDavid du Colombier #include "jinclude.h"
15*7dd7cddfSDavid du Colombier #include "jpeglib.h"
16*7dd7cddfSDavid du Colombier 
17*7dd7cddfSDavid du Colombier 
18*7dd7cddfSDavid du Colombier /* Note: currently, there is no operating mode in which a full-image buffer
19*7dd7cddfSDavid du Colombier  * is needed at this step.  If there were, that mode could not be used with
20*7dd7cddfSDavid du Colombier  * "raw data" input, since this module is bypassed in that case.  However,
21*7dd7cddfSDavid du Colombier  * we've left the code here for possible use in special applications.
22*7dd7cddfSDavid du Colombier  */
23*7dd7cddfSDavid du Colombier #undef FULL_MAIN_BUFFER_SUPPORTED
24*7dd7cddfSDavid du Colombier 
25*7dd7cddfSDavid du Colombier 
26*7dd7cddfSDavid du Colombier /* Private buffer controller object */
27*7dd7cddfSDavid du Colombier 
28*7dd7cddfSDavid du Colombier typedef struct {
29*7dd7cddfSDavid du Colombier   struct jpeg_c_main_controller pub; /* public fields */
30*7dd7cddfSDavid du Colombier 
31*7dd7cddfSDavid du Colombier   JDIMENSION cur_iMCU_row;	/* number of current iMCU row */
32*7dd7cddfSDavid du Colombier   JDIMENSION rowgroup_ctr;	/* counts row groups received in iMCU row */
33*7dd7cddfSDavid du Colombier   boolean suspended;		/* remember if we suspended output */
34*7dd7cddfSDavid du Colombier   J_BUF_MODE pass_mode;		/* current operating mode */
35*7dd7cddfSDavid du Colombier 
36*7dd7cddfSDavid du Colombier   /* If using just a strip buffer, this points to the entire set of buffers
37*7dd7cddfSDavid du Colombier    * (we allocate one for each component).  In the full-image case, this
38*7dd7cddfSDavid du Colombier    * points to the currently accessible strips of the virtual arrays.
39*7dd7cddfSDavid du Colombier    */
40*7dd7cddfSDavid du Colombier   JSAMPARRAY buffer[MAX_COMPONENTS];
41*7dd7cddfSDavid du Colombier 
42*7dd7cddfSDavid du Colombier #ifdef FULL_MAIN_BUFFER_SUPPORTED
43*7dd7cddfSDavid du Colombier   /* If using full-image storage, this array holds pointers to virtual-array
44*7dd7cddfSDavid du Colombier    * control blocks for each component.  Unused if not full-image storage.
45*7dd7cddfSDavid du Colombier    */
46*7dd7cddfSDavid du Colombier   jvirt_sarray_ptr whole_image[MAX_COMPONENTS];
47*7dd7cddfSDavid du Colombier #endif
48*7dd7cddfSDavid du Colombier } my_main_controller;
49*7dd7cddfSDavid du Colombier 
50*7dd7cddfSDavid du Colombier typedef my_main_controller * my_main_ptr;
51*7dd7cddfSDavid du Colombier 
52*7dd7cddfSDavid du Colombier 
53*7dd7cddfSDavid du Colombier /* Forward declarations */
54*7dd7cddfSDavid du Colombier METHODDEF(void) process_data_simple_main
55*7dd7cddfSDavid du Colombier 	JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,
56*7dd7cddfSDavid du Colombier 	     JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));
57*7dd7cddfSDavid du Colombier #ifdef FULL_MAIN_BUFFER_SUPPORTED
58*7dd7cddfSDavid du Colombier METHODDEF(void) process_data_buffer_main
59*7dd7cddfSDavid du Colombier 	JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,
60*7dd7cddfSDavid du Colombier 	     JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));
61*7dd7cddfSDavid du Colombier #endif
62*7dd7cddfSDavid du Colombier 
63*7dd7cddfSDavid du Colombier 
64*7dd7cddfSDavid du Colombier /*
65*7dd7cddfSDavid du Colombier  * Initialize for a processing pass.
66*7dd7cddfSDavid du Colombier  */
67*7dd7cddfSDavid du Colombier 
68*7dd7cddfSDavid du Colombier METHODDEF(void)
start_pass_main(j_compress_ptr cinfo,J_BUF_MODE pass_mode)69*7dd7cddfSDavid du Colombier start_pass_main (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
70*7dd7cddfSDavid du Colombier {
71*7dd7cddfSDavid du Colombier   my_main_ptr main = (my_main_ptr) cinfo->main;
72*7dd7cddfSDavid du Colombier 
73*7dd7cddfSDavid du Colombier   /* Do nothing in raw-data mode. */
74*7dd7cddfSDavid du Colombier   if (cinfo->raw_data_in)
75*7dd7cddfSDavid du Colombier     return;
76*7dd7cddfSDavid du Colombier 
77*7dd7cddfSDavid du Colombier   main->cur_iMCU_row = 0;	/* initialize counters */
78*7dd7cddfSDavid du Colombier   main->rowgroup_ctr = 0;
79*7dd7cddfSDavid du Colombier   main->suspended = FALSE;
80*7dd7cddfSDavid du Colombier   main->pass_mode = pass_mode;	/* save mode for use by process_data */
81*7dd7cddfSDavid du Colombier 
82*7dd7cddfSDavid du Colombier   switch (pass_mode) {
83*7dd7cddfSDavid du Colombier   case JBUF_PASS_THRU:
84*7dd7cddfSDavid du Colombier #ifdef FULL_MAIN_BUFFER_SUPPORTED
85*7dd7cddfSDavid du Colombier     if (main->whole_image[0] != NULL)
86*7dd7cddfSDavid du Colombier       ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
87*7dd7cddfSDavid du Colombier #endif
88*7dd7cddfSDavid du Colombier     main->pub.process_data = process_data_simple_main;
89*7dd7cddfSDavid du Colombier     break;
90*7dd7cddfSDavid du Colombier #ifdef FULL_MAIN_BUFFER_SUPPORTED
91*7dd7cddfSDavid du Colombier   case JBUF_SAVE_SOURCE:
92*7dd7cddfSDavid du Colombier   case JBUF_CRANK_DEST:
93*7dd7cddfSDavid du Colombier   case JBUF_SAVE_AND_PASS:
94*7dd7cddfSDavid du Colombier     if (main->whole_image[0] == NULL)
95*7dd7cddfSDavid du Colombier       ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
96*7dd7cddfSDavid du Colombier     main->pub.process_data = process_data_buffer_main;
97*7dd7cddfSDavid du Colombier     break;
98*7dd7cddfSDavid du Colombier #endif
99*7dd7cddfSDavid du Colombier   default:
100*7dd7cddfSDavid du Colombier     ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
101*7dd7cddfSDavid du Colombier     break;
102*7dd7cddfSDavid du Colombier   }
103*7dd7cddfSDavid du Colombier }
104*7dd7cddfSDavid du Colombier 
105*7dd7cddfSDavid du Colombier 
106*7dd7cddfSDavid du Colombier /*
107*7dd7cddfSDavid du Colombier  * Process some data.
108*7dd7cddfSDavid du Colombier  * This routine handles the simple pass-through mode,
109*7dd7cddfSDavid du Colombier  * where we have only a strip buffer.
110*7dd7cddfSDavid du Colombier  */
111*7dd7cddfSDavid du Colombier 
112*7dd7cddfSDavid du Colombier METHODDEF(void)
process_data_simple_main(j_compress_ptr cinfo,JSAMPARRAY input_buf,JDIMENSION * in_row_ctr,JDIMENSION in_rows_avail)113*7dd7cddfSDavid du Colombier process_data_simple_main (j_compress_ptr cinfo,
114*7dd7cddfSDavid du Colombier 			  JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
115*7dd7cddfSDavid du Colombier 			  JDIMENSION in_rows_avail)
116*7dd7cddfSDavid du Colombier {
117*7dd7cddfSDavid du Colombier   my_main_ptr main = (my_main_ptr) cinfo->main;
118*7dd7cddfSDavid du Colombier 
119*7dd7cddfSDavid du Colombier   while (main->cur_iMCU_row < cinfo->total_iMCU_rows) {
120*7dd7cddfSDavid du Colombier     /* Read input data if we haven't filled the main buffer yet */
121*7dd7cddfSDavid du Colombier     if (main->rowgroup_ctr < DCTSIZE)
122*7dd7cddfSDavid du Colombier       (*cinfo->prep->pre_process_data) (cinfo,
123*7dd7cddfSDavid du Colombier 					input_buf, in_row_ctr, in_rows_avail,
124*7dd7cddfSDavid du Colombier 					main->buffer, &main->rowgroup_ctr,
125*7dd7cddfSDavid du Colombier 					(JDIMENSION) DCTSIZE);
126*7dd7cddfSDavid du Colombier 
127*7dd7cddfSDavid du Colombier     /* If we don't have a full iMCU row buffered, return to application for
128*7dd7cddfSDavid du Colombier      * more data.  Note that preprocessor will always pad to fill the iMCU row
129*7dd7cddfSDavid du Colombier      * at the bottom of the image.
130*7dd7cddfSDavid du Colombier      */
131*7dd7cddfSDavid du Colombier     if (main->rowgroup_ctr != DCTSIZE)
132*7dd7cddfSDavid du Colombier       return;
133*7dd7cddfSDavid du Colombier 
134*7dd7cddfSDavid du Colombier     /* Send the completed row to the compressor */
135*7dd7cddfSDavid du Colombier     if (! (*cinfo->coef->compress_data) (cinfo, main->buffer)) {
136*7dd7cddfSDavid du Colombier       /* If compressor did not consume the whole row, then we must need to
137*7dd7cddfSDavid du Colombier        * suspend processing and return to the application.  In this situation
138*7dd7cddfSDavid du Colombier        * we pretend we didn't yet consume the last input row; otherwise, if
139*7dd7cddfSDavid du Colombier        * it happened to be the last row of the image, the application would
140*7dd7cddfSDavid du Colombier        * think we were done.
141*7dd7cddfSDavid du Colombier        */
142*7dd7cddfSDavid du Colombier       if (! main->suspended) {
143*7dd7cddfSDavid du Colombier 	(*in_row_ctr)--;
144*7dd7cddfSDavid du Colombier 	main->suspended = TRUE;
145*7dd7cddfSDavid du Colombier       }
146*7dd7cddfSDavid du Colombier       return;
147*7dd7cddfSDavid du Colombier     }
148*7dd7cddfSDavid du Colombier     /* We did finish the row.  Undo our little suspension hack if a previous
149*7dd7cddfSDavid du Colombier      * call suspended; then mark the main buffer empty.
150*7dd7cddfSDavid du Colombier      */
151*7dd7cddfSDavid du Colombier     if (main->suspended) {
152*7dd7cddfSDavid du Colombier       (*in_row_ctr)++;
153*7dd7cddfSDavid du Colombier       main->suspended = FALSE;
154*7dd7cddfSDavid du Colombier     }
155*7dd7cddfSDavid du Colombier     main->rowgroup_ctr = 0;
156*7dd7cddfSDavid du Colombier     main->cur_iMCU_row++;
157*7dd7cddfSDavid du Colombier   }
158*7dd7cddfSDavid du Colombier }
159*7dd7cddfSDavid du Colombier 
160*7dd7cddfSDavid du Colombier 
161*7dd7cddfSDavid du Colombier #ifdef FULL_MAIN_BUFFER_SUPPORTED
162*7dd7cddfSDavid du Colombier 
163*7dd7cddfSDavid du Colombier /*
164*7dd7cddfSDavid du Colombier  * Process some data.
165*7dd7cddfSDavid du Colombier  * This routine handles all of the modes that use a full-size buffer.
166*7dd7cddfSDavid du Colombier  */
167*7dd7cddfSDavid du Colombier 
168*7dd7cddfSDavid du Colombier METHODDEF(void)
process_data_buffer_main(j_compress_ptr cinfo,JSAMPARRAY input_buf,JDIMENSION * in_row_ctr,JDIMENSION in_rows_avail)169*7dd7cddfSDavid du Colombier process_data_buffer_main (j_compress_ptr cinfo,
170*7dd7cddfSDavid du Colombier 			  JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
171*7dd7cddfSDavid du Colombier 			  JDIMENSION in_rows_avail)
172*7dd7cddfSDavid du Colombier {
173*7dd7cddfSDavid du Colombier   my_main_ptr main = (my_main_ptr) cinfo->main;
174*7dd7cddfSDavid du Colombier   int ci;
175*7dd7cddfSDavid du Colombier   jpeg_component_info *compptr;
176*7dd7cddfSDavid du Colombier   boolean writing = (main->pass_mode != JBUF_CRANK_DEST);
177*7dd7cddfSDavid du Colombier 
178*7dd7cddfSDavid du Colombier   while (main->cur_iMCU_row < cinfo->total_iMCU_rows) {
179*7dd7cddfSDavid du Colombier     /* Realign the virtual buffers if at the start of an iMCU row. */
180*7dd7cddfSDavid du Colombier     if (main->rowgroup_ctr == 0) {
181*7dd7cddfSDavid du Colombier       for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
182*7dd7cddfSDavid du Colombier 	   ci++, compptr++) {
183*7dd7cddfSDavid du Colombier 	main->buffer[ci] = (*cinfo->mem->access_virt_sarray)
184*7dd7cddfSDavid du Colombier 	  ((j_common_ptr) cinfo, main->whole_image[ci],
185*7dd7cddfSDavid du Colombier 	   main->cur_iMCU_row * (compptr->v_samp_factor * DCTSIZE),
186*7dd7cddfSDavid du Colombier 	   (JDIMENSION) (compptr->v_samp_factor * DCTSIZE), writing);
187*7dd7cddfSDavid du Colombier       }
188*7dd7cddfSDavid du Colombier       /* In a read pass, pretend we just read some source data. */
189*7dd7cddfSDavid du Colombier       if (! writing) {
190*7dd7cddfSDavid du Colombier 	*in_row_ctr += cinfo->max_v_samp_factor * DCTSIZE;
191*7dd7cddfSDavid du Colombier 	main->rowgroup_ctr = DCTSIZE;
192*7dd7cddfSDavid du Colombier       }
193*7dd7cddfSDavid du Colombier     }
194*7dd7cddfSDavid du Colombier 
195*7dd7cddfSDavid du Colombier     /* If a write pass, read input data until the current iMCU row is full. */
196*7dd7cddfSDavid du Colombier     /* Note: preprocessor will pad if necessary to fill the last iMCU row. */
197*7dd7cddfSDavid du Colombier     if (writing) {
198*7dd7cddfSDavid du Colombier       (*cinfo->prep->pre_process_data) (cinfo,
199*7dd7cddfSDavid du Colombier 					input_buf, in_row_ctr, in_rows_avail,
200*7dd7cddfSDavid du Colombier 					main->buffer, &main->rowgroup_ctr,
201*7dd7cddfSDavid du Colombier 					(JDIMENSION) DCTSIZE);
202*7dd7cddfSDavid du Colombier       /* Return to application if we need more data to fill the iMCU row. */
203*7dd7cddfSDavid du Colombier       if (main->rowgroup_ctr < DCTSIZE)
204*7dd7cddfSDavid du Colombier 	return;
205*7dd7cddfSDavid du Colombier     }
206*7dd7cddfSDavid du Colombier 
207*7dd7cddfSDavid du Colombier     /* Emit data, unless this is a sink-only pass. */
208*7dd7cddfSDavid du Colombier     if (main->pass_mode != JBUF_SAVE_SOURCE) {
209*7dd7cddfSDavid du Colombier       if (! (*cinfo->coef->compress_data) (cinfo, main->buffer)) {
210*7dd7cddfSDavid du Colombier 	/* If compressor did not consume the whole row, then we must need to
211*7dd7cddfSDavid du Colombier 	 * suspend processing and return to the application.  In this situation
212*7dd7cddfSDavid du Colombier 	 * we pretend we didn't yet consume the last input row; otherwise, if
213*7dd7cddfSDavid du Colombier 	 * it happened to be the last row of the image, the application would
214*7dd7cddfSDavid du Colombier 	 * think we were done.
215*7dd7cddfSDavid du Colombier 	 */
216*7dd7cddfSDavid du Colombier 	if (! main->suspended) {
217*7dd7cddfSDavid du Colombier 	  (*in_row_ctr)--;
218*7dd7cddfSDavid du Colombier 	  main->suspended = TRUE;
219*7dd7cddfSDavid du Colombier 	}
220*7dd7cddfSDavid du Colombier 	return;
221*7dd7cddfSDavid du Colombier       }
222*7dd7cddfSDavid du Colombier       /* We did finish the row.  Undo our little suspension hack if a previous
223*7dd7cddfSDavid du Colombier        * call suspended; then mark the main buffer empty.
224*7dd7cddfSDavid du Colombier        */
225*7dd7cddfSDavid du Colombier       if (main->suspended) {
226*7dd7cddfSDavid du Colombier 	(*in_row_ctr)++;
227*7dd7cddfSDavid du Colombier 	main->suspended = FALSE;
228*7dd7cddfSDavid du Colombier       }
229*7dd7cddfSDavid du Colombier     }
230*7dd7cddfSDavid du Colombier 
231*7dd7cddfSDavid du Colombier     /* If get here, we are done with this iMCU row.  Mark buffer empty. */
232*7dd7cddfSDavid du Colombier     main->rowgroup_ctr = 0;
233*7dd7cddfSDavid du Colombier     main->cur_iMCU_row++;
234*7dd7cddfSDavid du Colombier   }
235*7dd7cddfSDavid du Colombier }
236*7dd7cddfSDavid du Colombier 
237*7dd7cddfSDavid du Colombier #endif /* FULL_MAIN_BUFFER_SUPPORTED */
238*7dd7cddfSDavid du Colombier 
239*7dd7cddfSDavid du Colombier 
240*7dd7cddfSDavid du Colombier /*
241*7dd7cddfSDavid du Colombier  * Initialize main buffer controller.
242*7dd7cddfSDavid du Colombier  */
243*7dd7cddfSDavid du Colombier 
244*7dd7cddfSDavid du Colombier GLOBAL(void)
jinit_c_main_controller(j_compress_ptr cinfo,boolean need_full_buffer)245*7dd7cddfSDavid du Colombier jinit_c_main_controller (j_compress_ptr cinfo, boolean need_full_buffer)
246*7dd7cddfSDavid du Colombier {
247*7dd7cddfSDavid du Colombier   my_main_ptr main;
248*7dd7cddfSDavid du Colombier   int ci;
249*7dd7cddfSDavid du Colombier   jpeg_component_info *compptr;
250*7dd7cddfSDavid du Colombier 
251*7dd7cddfSDavid du Colombier   main = (my_main_ptr)
252*7dd7cddfSDavid du Colombier     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
253*7dd7cddfSDavid du Colombier 				SIZEOF(my_main_controller));
254*7dd7cddfSDavid du Colombier   cinfo->main = (struct jpeg_c_main_controller *) main;
255*7dd7cddfSDavid du Colombier   main->pub.start_pass = start_pass_main;
256*7dd7cddfSDavid du Colombier 
257*7dd7cddfSDavid du Colombier   /* We don't need to create a buffer in raw-data mode. */
258*7dd7cddfSDavid du Colombier   if (cinfo->raw_data_in)
259*7dd7cddfSDavid du Colombier     return;
260*7dd7cddfSDavid du Colombier 
261*7dd7cddfSDavid du Colombier   /* Create the buffer.  It holds downsampled data, so each component
262*7dd7cddfSDavid du Colombier    * may be of a different size.
263*7dd7cddfSDavid du Colombier    */
264*7dd7cddfSDavid du Colombier   if (need_full_buffer) {
265*7dd7cddfSDavid du Colombier #ifdef FULL_MAIN_BUFFER_SUPPORTED
266*7dd7cddfSDavid du Colombier     /* Allocate a full-image virtual array for each component */
267*7dd7cddfSDavid du Colombier     /* Note we pad the bottom to a multiple of the iMCU height */
268*7dd7cddfSDavid du Colombier     for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
269*7dd7cddfSDavid du Colombier 	 ci++, compptr++) {
270*7dd7cddfSDavid du Colombier       main->whole_image[ci] = (*cinfo->mem->request_virt_sarray)
271*7dd7cddfSDavid du Colombier 	((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
272*7dd7cddfSDavid du Colombier 	 compptr->width_in_blocks * DCTSIZE,
273*7dd7cddfSDavid du Colombier 	 (JDIMENSION) jround_up((long) compptr->height_in_blocks,
274*7dd7cddfSDavid du Colombier 				(long) compptr->v_samp_factor) * DCTSIZE,
275*7dd7cddfSDavid du Colombier 	 (JDIMENSION) (compptr->v_samp_factor * DCTSIZE));
276*7dd7cddfSDavid du Colombier     }
277*7dd7cddfSDavid du Colombier #else
278*7dd7cddfSDavid du Colombier     ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
279*7dd7cddfSDavid du Colombier #endif
280*7dd7cddfSDavid du Colombier   } else {
281*7dd7cddfSDavid du Colombier #ifdef FULL_MAIN_BUFFER_SUPPORTED
282*7dd7cddfSDavid du Colombier     main->whole_image[0] = NULL; /* flag for no virtual arrays */
283*7dd7cddfSDavid du Colombier #endif
284*7dd7cddfSDavid du Colombier     /* Allocate a strip buffer for each component */
285*7dd7cddfSDavid du Colombier     for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
286*7dd7cddfSDavid du Colombier 	 ci++, compptr++) {
287*7dd7cddfSDavid du Colombier       main->buffer[ci] = (*cinfo->mem->alloc_sarray)
288*7dd7cddfSDavid du Colombier 	((j_common_ptr) cinfo, JPOOL_IMAGE,
289*7dd7cddfSDavid du Colombier 	 compptr->width_in_blocks * DCTSIZE,
290*7dd7cddfSDavid du Colombier 	 (JDIMENSION) (compptr->v_samp_factor * DCTSIZE));
291*7dd7cddfSDavid du Colombier     }
292*7dd7cddfSDavid du Colombier   }
293*7dd7cddfSDavid du Colombier }
294