1 #if !defined(_FX_JPEG_TURBO_)
2 /*
3  * jdmaster.c
4  *
5  * Copyright (C) 1991-1997, Thomas G. Lane.
6  * This file is part of the Independent JPEG Group's software.
7  * For conditions of distribution and use, see the accompanying README file.
8  *
9  * This file contains master control logic for the JPEG decompressor.
10  * These routines are concerned with selecting the modules to be executed
11  * and with determining the number of passes and the work to be done in each
12  * pass.
13  */
14 
15 #define JPEG_INTERNALS
16 #include "jinclude.h"
17 #include "jpeglib.h"
18 
19 
20 /* Private state */
21 
22 typedef struct {
23   struct jpeg_decomp_master pub; /* public fields */
24 
25   int pass_number;		/* # of passes completed */
26 
27   boolean using_merged_upsample; /* TRUE if using merged upsample/cconvert */
28 
29   /* Saved references to initialized quantizer modules,
30    * in case we need to switch modes.
31    */
32   struct jpeg_color_quantizer * quantizer_1pass;
33   struct jpeg_color_quantizer * quantizer_2pass;
34 } my_decomp_master;
35 
36 typedef my_decomp_master * my_master_ptr;
37 
38 
39 /*
40  * Determine whether merged upsample/color conversion should be used.
41  * CRUCIAL: this must match the actual capabilities of jdmerge.c!
42  */
43 
44 LOCAL(boolean)
use_merged_upsample(j_decompress_ptr cinfo)45 use_merged_upsample (j_decompress_ptr cinfo)
46 {
47 #ifdef UPSAMPLE_MERGING_SUPPORTED
48   /* Merging is the equivalent of plain box-filter upsampling */
49   if (cinfo->do_fancy_upsampling || cinfo->CCIR601_sampling)
50     return FALSE;
51   /* jdmerge.c only supports YCC=>RGB color conversion */
52   if (cinfo->jpeg_color_space != JCS_YCbCr || cinfo->num_components != 3 ||
53       cinfo->out_color_space != JCS_RGB ||
54       cinfo->out_color_components != RGB_PIXELSIZE)
55     return FALSE;
56   /* and it only handles 2h1v or 2h2v sampling ratios */
57   if (cinfo->comp_info[0].h_samp_factor != 2 ||
58       cinfo->comp_info[1].h_samp_factor != 1 ||
59       cinfo->comp_info[2].h_samp_factor != 1 ||
60       cinfo->comp_info[0].v_samp_factor >  2 ||
61       cinfo->comp_info[1].v_samp_factor != 1 ||
62       cinfo->comp_info[2].v_samp_factor != 1)
63     return FALSE;
64   /* furthermore, it doesn't work if we've scaled the IDCTs differently */
65   if (cinfo->comp_info[0].DCT_scaled_size != cinfo->min_DCT_scaled_size ||
66       cinfo->comp_info[1].DCT_scaled_size != cinfo->min_DCT_scaled_size ||
67       cinfo->comp_info[2].DCT_scaled_size != cinfo->min_DCT_scaled_size)
68     return FALSE;
69   /* ??? also need to test for upsample-time rescaling, when & if supported */
70   return TRUE;			/* by golly, it'll work... */
71 #else
72   return FALSE;
73 #endif
74 }
75 
76 
77 /*
78  * Compute output image dimensions and related values.
79  * NOTE: this is exported for possible use by application.
80  * Hence it mustn't do anything that can't be done twice.
81  * Also note that it may be called before the master module is initialized!
82  */
83 
84 GLOBAL(void)
jpeg_calc_output_dimensions(j_decompress_ptr cinfo)85 jpeg_calc_output_dimensions (j_decompress_ptr cinfo)
86 /* Do computations that are needed before master selection phase */
87 {
88 #ifdef IDCT_SCALING_SUPPORTED
89   int ci;
90   jpeg_component_info *compptr;
91 #endif
92 
93   /* Prevent application from calling me at wrong times */
94   if (cinfo->global_state != DSTATE_READY)
95     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
96 
97 #ifdef IDCT_SCALING_SUPPORTED
98 
99   /* Compute actual output image dimensions and DCT scaling choices. */
100   if (cinfo->scale_num * 8 <= cinfo->scale_denom) {
101     /* Provide 1/8 scaling */
102     cinfo->output_width = (JDIMENSION)
103       jdiv_round_up((long) cinfo->image_width, 8L);
104     cinfo->output_height = (JDIMENSION)
105       jdiv_round_up((long) cinfo->image_height, 8L);
106     cinfo->min_DCT_scaled_size = 1;
107   } else if (cinfo->scale_num * 4 <= cinfo->scale_denom) {
108     /* Provide 1/4 scaling */
109     cinfo->output_width = (JDIMENSION)
110       jdiv_round_up((long) cinfo->image_width, 4L);
111     cinfo->output_height = (JDIMENSION)
112       jdiv_round_up((long) cinfo->image_height, 4L);
113     cinfo->min_DCT_scaled_size = 2;
114   } else if (cinfo->scale_num * 2 <= cinfo->scale_denom) {
115     /* Provide 1/2 scaling */
116     cinfo->output_width = (JDIMENSION)
117       jdiv_round_up((long) cinfo->image_width, 2L);
118     cinfo->output_height = (JDIMENSION)
119       jdiv_round_up((long) cinfo->image_height, 2L);
120     cinfo->min_DCT_scaled_size = 4;
121   } else {
122     /* Provide 1/1 scaling */
123     cinfo->output_width = cinfo->image_width;
124     cinfo->output_height = cinfo->image_height;
125     cinfo->min_DCT_scaled_size = DCTSIZE;
126   }
127   /* In selecting the actual DCT scaling for each component, we try to
128    * scale up the chroma components via IDCT scaling rather than upsampling.
129    * This saves time if the upsampler gets to use 1:1 scaling.
130    * Note this code assumes that the supported DCT scalings are powers of 2.
131    */
132   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
133        ci++, compptr++) {
134     int ssize = cinfo->min_DCT_scaled_size;
135     while (ssize < DCTSIZE &&
136 	   (compptr->h_samp_factor * ssize * 2 <=
137 	    cinfo->max_h_samp_factor * cinfo->min_DCT_scaled_size) &&
138 	   (compptr->v_samp_factor * ssize * 2 <=
139 	    cinfo->max_v_samp_factor * cinfo->min_DCT_scaled_size)) {
140       ssize = ssize * 2;
141     }
142     compptr->DCT_scaled_size = ssize;
143   }
144 
145   /* Recompute downsampled dimensions of components;
146    * application needs to know these if using raw downsampled data.
147    */
148   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
149        ci++, compptr++) {
150     /* Size in samples, after IDCT scaling */
151     compptr->downsampled_width = (JDIMENSION)
152       jdiv_round_up((long) cinfo->image_width *
153 		    (long) (compptr->h_samp_factor * compptr->DCT_scaled_size),
154 		    (long) (cinfo->max_h_samp_factor * DCTSIZE));
155     compptr->downsampled_height = (JDIMENSION)
156       jdiv_round_up((long) cinfo->image_height *
157 		    (long) (compptr->v_samp_factor * compptr->DCT_scaled_size),
158 		    (long) (cinfo->max_v_samp_factor * DCTSIZE));
159   }
160 
161 #else /* !IDCT_SCALING_SUPPORTED */
162 
163   /* Hardwire it to "no scaling" */
164   cinfo->output_width = cinfo->image_width;
165   cinfo->output_height = cinfo->image_height;
166   /* jdinput.c has already initialized DCT_scaled_size to DCTSIZE,
167    * and has computed unscaled downsampled_width and downsampled_height.
168    */
169 
170 #endif /* IDCT_SCALING_SUPPORTED */
171 
172   /* Report number of components in selected colorspace. */
173   /* Probably this should be in the color conversion module... */
174   switch (cinfo->out_color_space) {
175   case JCS_GRAYSCALE:
176     cinfo->out_color_components = 1;
177     break;
178   case JCS_RGB:
179 #if RGB_PIXELSIZE != 3
180     cinfo->out_color_components = RGB_PIXELSIZE;
181     break;
182 #endif /* else share code with YCbCr */
183   case JCS_YCbCr:
184     cinfo->out_color_components = 3;
185     break;
186   case JCS_CMYK:
187   case JCS_YCCK:
188     cinfo->out_color_components = 4;
189     break;
190   default:			/* else must be same colorspace as in file */
191     cinfo->out_color_components = cinfo->num_components;
192     break;
193   }
194   cinfo->output_components = (cinfo->quantize_colors ? 1 :
195 			      cinfo->out_color_components);
196 
197   /* See if upsampler will want to emit more than one row at a time */
198   if (use_merged_upsample(cinfo))
199     cinfo->rec_outbuf_height = cinfo->max_v_samp_factor;
200   else
201     cinfo->rec_outbuf_height = 1;
202 }
203 
204 
205 /*
206  * Several decompression processes need to range-limit values to the range
207  * 0..MAXJSAMPLE; the input value may fall somewhat outside this range
208  * due to noise introduced by quantization, roundoff error, etc.  These
209  * processes are inner loops and need to be as fast as possible.  On most
210  * machines, particularly CPUs with pipelines or instruction prefetch,
211  * a (subscript-check-less) C table lookup
212  *		x = sample_range_limit[x];
213  * is faster than explicit tests
214  *		if (x < 0)  x = 0;
215  *		else if (x > MAXJSAMPLE)  x = MAXJSAMPLE;
216  * These processes all use a common table prepared by the routine below.
217  *
218  * For most steps we can mathematically guarantee that the initial value
219  * of x is within MAXJSAMPLE+1 of the legal range, so a table running from
220  * -(MAXJSAMPLE+1) to 2*MAXJSAMPLE+1 is sufficient.  But for the initial
221  * limiting step (just after the IDCT), a wildly out-of-range value is
222  * possible if the input data is corrupt.  To avoid any chance of indexing
223  * off the end of memory and getting a bad-pointer trap, we perform the
224  * post-IDCT limiting thus:
225  *		x = range_limit[x & MASK];
226  * where MASK is 2 bits wider than legal sample data, ie 10 bits for 8-bit
227  * samples.  Under normal circumstances this is more than enough range and
228  * a correct output will be generated; with bogus input data the mask will
229  * cause wraparound, and we will safely generate a bogus-but-in-range output.
230  * For the post-IDCT step, we want to convert the data from signed to unsigned
231  * representation by adding CENTERJSAMPLE at the same time that we limit it.
232  * So the post-IDCT limiting table ends up looking like this:
233  *   CENTERJSAMPLE,CENTERJSAMPLE+1,...,MAXJSAMPLE,
234  *   MAXJSAMPLE (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
235  *   0          (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
236  *   0,1,...,CENTERJSAMPLE-1
237  * Negative inputs select values from the upper half of the table after
238  * masking.
239  *
240  * We can save some space by overlapping the start of the post-IDCT table
241  * with the simpler range limiting table.  The post-IDCT table begins at
242  * sample_range_limit + CENTERJSAMPLE.
243  *
244  * Note that the table is allocated in near data space on PCs; it's small
245  * enough and used often enough to justify this.
246  */
247 
248 LOCAL(void)
prepare_range_limit_table(j_decompress_ptr cinfo)249 prepare_range_limit_table (j_decompress_ptr cinfo)
250 /* Allocate and fill in the sample_range_limit table */
251 {
252   JSAMPLE * table;
253   int i;
254 
255   table = (JSAMPLE *)
256     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
257 		(5 * (MAXJSAMPLE+1) + CENTERJSAMPLE) * SIZEOF(JSAMPLE));
258   table += (MAXJSAMPLE+1);	/* allow negative subscripts of simple table */
259   cinfo->sample_range_limit = table;
260   /* First segment of "simple" table: limit[x] = 0 for x < 0 */
261   MEMZERO(table - (MAXJSAMPLE+1), (MAXJSAMPLE+1) * SIZEOF(JSAMPLE));
262   /* Main part of "simple" table: limit[x] = x */
263   for (i = 0; i <= MAXJSAMPLE; i++)
264     table[i] = (JSAMPLE) i;
265   table += CENTERJSAMPLE;	/* Point to where post-IDCT table starts */
266   /* End of simple table, rest of first half of post-IDCT table */
267   for (i = CENTERJSAMPLE; i < 2*(MAXJSAMPLE+1); i++)
268     table[i] = MAXJSAMPLE;
269   /* Second half of post-IDCT table */
270   MEMZERO(table + (2 * (MAXJSAMPLE+1)),
271 	  (2 * (MAXJSAMPLE+1) - CENTERJSAMPLE) * SIZEOF(JSAMPLE));
272   MEMCOPY(table + (4 * (MAXJSAMPLE+1) - CENTERJSAMPLE),
273 	  cinfo->sample_range_limit, CENTERJSAMPLE * SIZEOF(JSAMPLE));
274 }
275 
276 
277 /*
278  * Master selection of decompression modules.
279  * This is done once at jpeg_start_decompress time.  We determine
280  * which modules will be used and give them appropriate initialization calls.
281  * We also initialize the decompressor input side to begin consuming data.
282  *
283  * Since jpeg_read_header has finished, we know what is in the SOF
284  * and (first) SOS markers.  We also have all the application parameter
285  * settings.
286  */
287 
288 LOCAL(void)
master_selection(j_decompress_ptr cinfo)289 master_selection (j_decompress_ptr cinfo)
290 {
291   my_master_ptr master = (my_master_ptr) cinfo->master;
292   boolean use_c_buffer;
293   long samplesperrow;
294   JDIMENSION jd_samplesperrow;
295 
296   /* Initialize dimensions and other stuff */
297   jpeg_calc_output_dimensions(cinfo);
298   prepare_range_limit_table(cinfo);
299 
300   /* Width of an output scanline must be representable as JDIMENSION. */
301   samplesperrow = (long) cinfo->output_width * (long) cinfo->out_color_components;
302   jd_samplesperrow = (JDIMENSION) samplesperrow;
303   if ((long) jd_samplesperrow != samplesperrow)
304     ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
305 
306   /* Initialize my private state */
307   master->pass_number = 0;
308   master->using_merged_upsample = use_merged_upsample(cinfo);
309 
310   /* Color quantizer selection */
311   master->quantizer_1pass = NULL;
312   master->quantizer_2pass = NULL;
313   /* No mode changes if not using buffered-image mode. */
314   if (! cinfo->quantize_colors || ! cinfo->buffered_image) {
315     cinfo->enable_1pass_quant = FALSE;
316     cinfo->enable_external_quant = FALSE;
317     cinfo->enable_2pass_quant = FALSE;
318   }
319   if (cinfo->quantize_colors) {
320     if (cinfo->raw_data_out)
321       ERREXIT(cinfo, JERR_NOTIMPL);
322     /* 2-pass quantizer only works in 3-component color space. */
323     if (cinfo->out_color_components != 3) {
324       cinfo->enable_1pass_quant = TRUE;
325       cinfo->enable_external_quant = FALSE;
326       cinfo->enable_2pass_quant = FALSE;
327       cinfo->colormap = NULL;
328     } else if (cinfo->colormap != NULL) {
329       cinfo->enable_external_quant = TRUE;
330     } else if (cinfo->two_pass_quantize) {
331       cinfo->enable_2pass_quant = TRUE;
332     } else {
333       cinfo->enable_1pass_quant = TRUE;
334     }
335 
336     if (cinfo->enable_1pass_quant) {
337 #ifdef QUANT_1PASS_SUPPORTED
338       jinit_1pass_quantizer(cinfo);
339       master->quantizer_1pass = cinfo->cquantize;
340 #else
341       ERREXIT(cinfo, JERR_NOT_COMPILED);
342 #endif
343     }
344 
345     /* We use the 2-pass code to map to external colormaps. */
346     if (cinfo->enable_2pass_quant || cinfo->enable_external_quant) {
347 #ifdef QUANT_2PASS_SUPPORTED
348       jinit_2pass_quantizer(cinfo);
349       master->quantizer_2pass = cinfo->cquantize;
350 #else
351       ERREXIT(cinfo, JERR_NOT_COMPILED);
352 #endif
353     }
354     /* If both quantizers are initialized, the 2-pass one is left active;
355      * this is necessary for starting with quantization to an external map.
356      */
357   }
358 
359   /* Post-processing: in particular, color conversion first */
360   if (! cinfo->raw_data_out) {
361     if (master->using_merged_upsample) {
362 #ifdef UPSAMPLE_MERGING_SUPPORTED
363       jinit_merged_upsampler(cinfo); /* does color conversion too */
364 #else
365       ERREXIT(cinfo, JERR_NOT_COMPILED);
366 #endif
367     } else {
368       jinit_color_deconverter(cinfo);
369       jinit_upsampler(cinfo);
370     }
371     jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant);
372   }
373   /* Inverse DCT */
374   jinit_inverse_dct(cinfo);
375   /* Entropy decoding: either Huffman or arithmetic coding. */
376   if (cinfo->arith_code) {
377     ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
378   } else {
379     if (cinfo->progressive_mode) {
380 #ifdef D_PROGRESSIVE_SUPPORTED
381       jinit_phuff_decoder(cinfo);
382 #else
383       ERREXIT(cinfo, JERR_NOT_COMPILED);
384 #endif
385     } else
386       jinit_huff_decoder(cinfo);
387   }
388 
389   /* Initialize principal buffer controllers. */
390   use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image;
391   jinit_d_coef_controller(cinfo, use_c_buffer);
392 
393   if (! cinfo->raw_data_out)
394     jinit_d_main_controller(cinfo, FALSE /* never need full buffer here */);
395 
396   /* We can now tell the memory manager to allocate virtual arrays. */
397   (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
398 
399   /* Initialize input side of decompressor to consume first scan. */
400   (*cinfo->inputctl->start_input_pass) (cinfo);
401 
402 #ifdef D_MULTISCAN_FILES_SUPPORTED
403   /* If jpeg_start_decompress will read the whole file, initialize
404    * progress monitoring appropriately.  The input step is counted
405    * as one pass.
406    */
407   if (cinfo->progress != NULL && ! cinfo->buffered_image &&
408       cinfo->inputctl->has_multiple_scans) {
409     int nscans;
410     /* Estimate number of scans to set pass_limit. */
411     if (cinfo->progressive_mode) {
412       /* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */
413       nscans = 2 + 3 * cinfo->num_components;
414     } else {
415       /* For a nonprogressive multiscan file, estimate 1 scan per component. */
416       nscans = cinfo->num_components;
417     }
418     cinfo->progress->pass_counter = 0L;
419     cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans;
420     cinfo->progress->completed_passes = 0;
421     cinfo->progress->total_passes = (cinfo->enable_2pass_quant ? 3 : 2);
422     /* Count the input pass as done */
423     master->pass_number++;
424   }
425 #endif /* D_MULTISCAN_FILES_SUPPORTED */
426 }
427 
428 
429 /*
430  * Per-pass setup.
431  * This is called at the beginning of each output pass.  We determine which
432  * modules will be active during this pass and give them appropriate
433  * start_pass calls.  We also set is_dummy_pass to indicate whether this
434  * is a "real" output pass or a dummy pass for color quantization.
435  * (In the latter case, jdapistd.c will crank the pass to completion.)
436  */
437 
438 METHODDEF(void)
prepare_for_output_pass(j_decompress_ptr cinfo)439 prepare_for_output_pass (j_decompress_ptr cinfo)
440 {
441   my_master_ptr master = (my_master_ptr) cinfo->master;
442 
443   if (master->pub.is_dummy_pass) {
444 #ifdef QUANT_2PASS_SUPPORTED
445     /* Final pass of 2-pass quantization */
446     master->pub.is_dummy_pass = FALSE;
447     (*cinfo->cquantize->start_pass) (cinfo, FALSE);
448     (*cinfo->post->start_pass) (cinfo, JBUF_CRANK_DEST);
449     (*cinfo->main->start_pass) (cinfo, JBUF_CRANK_DEST);
450 #else
451     ERREXIT(cinfo, JERR_NOT_COMPILED);
452 #endif /* QUANT_2PASS_SUPPORTED */
453   } else {
454     if (cinfo->quantize_colors && cinfo->colormap == NULL) {
455       /* Select new quantization method */
456       if (cinfo->two_pass_quantize && cinfo->enable_2pass_quant) {
457 	cinfo->cquantize = master->quantizer_2pass;
458 	master->pub.is_dummy_pass = TRUE;
459       } else if (cinfo->enable_1pass_quant) {
460 	cinfo->cquantize = master->quantizer_1pass;
461       } else {
462 	ERREXIT(cinfo, JERR_MODE_CHANGE);
463       }
464     }
465     (*cinfo->idct->start_pass) (cinfo);
466     (*cinfo->coef->start_output_pass) (cinfo);
467     if (! cinfo->raw_data_out) {
468       if (! master->using_merged_upsample)
469 	(*cinfo->cconvert->start_pass) (cinfo);
470       (*cinfo->upsample->start_pass) (cinfo);
471       if (cinfo->quantize_colors)
472 	(*cinfo->cquantize->start_pass) (cinfo, master->pub.is_dummy_pass);
473       (*cinfo->post->start_pass) (cinfo,
474 	    (master->pub.is_dummy_pass ? JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
475       (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
476     }
477   }
478 
479   /* Set up progress monitor's pass info if present */
480   if (cinfo->progress != NULL) {
481     cinfo->progress->completed_passes = master->pass_number;
482     cinfo->progress->total_passes = master->pass_number +
483 				    (master->pub.is_dummy_pass ? 2 : 1);
484     /* In buffered-image mode, we assume one more output pass if EOI not
485      * yet reached, but no more passes if EOI has been reached.
486      */
487     if (cinfo->buffered_image && ! cinfo->inputctl->eoi_reached) {
488       cinfo->progress->total_passes += (cinfo->enable_2pass_quant ? 2 : 1);
489     }
490   }
491 }
492 
493 
494 /*
495  * Finish up at end of an output pass.
496  */
497 
498 METHODDEF(void)
finish_output_pass(j_decompress_ptr cinfo)499 finish_output_pass (j_decompress_ptr cinfo)
500 {
501   my_master_ptr master = (my_master_ptr) cinfo->master;
502 
503   if (cinfo->quantize_colors)
504     (*cinfo->cquantize->finish_pass) (cinfo);
505   master->pass_number++;
506 }
507 
508 
509 #ifdef D_MULTISCAN_FILES_SUPPORTED
510 
511 /*
512  * Switch to a new external colormap between output passes.
513  */
514 
515 GLOBAL(void)
jpeg_new_colormap(j_decompress_ptr cinfo)516 jpeg_new_colormap (j_decompress_ptr cinfo)
517 {
518   my_master_ptr master = (my_master_ptr) cinfo->master;
519 
520   /* Prevent application from calling me at wrong times */
521   if (cinfo->global_state != DSTATE_BUFIMAGE)
522     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
523 
524   if (cinfo->quantize_colors && cinfo->enable_external_quant &&
525       cinfo->colormap != NULL) {
526     /* Select 2-pass quantizer for external colormap use */
527     cinfo->cquantize = master->quantizer_2pass;
528     /* Notify quantizer of colormap change */
529     (*cinfo->cquantize->new_color_map) (cinfo);
530     master->pub.is_dummy_pass = FALSE; /* just in case */
531   } else
532     ERREXIT(cinfo, JERR_MODE_CHANGE);
533 }
534 
535 #endif /* D_MULTISCAN_FILES_SUPPORTED */
536 
537 
538 /*
539  * Initialize master decompression control and select active modules.
540  * This is performed at the start of jpeg_start_decompress.
541  */
542 
543 GLOBAL(void)
jinit_master_decompress(j_decompress_ptr cinfo)544 jinit_master_decompress (j_decompress_ptr cinfo)
545 {
546   my_master_ptr master;
547 
548   master = (my_master_ptr)
549       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
550 				  SIZEOF(my_decomp_master));
551   cinfo->master = (struct jpeg_decomp_master *) master;
552   master->pub.prepare_for_output_pass = prepare_for_output_pass;
553   master->pub.finish_output_pass = finish_output_pass;
554 
555   master->pub.is_dummy_pass = FALSE;
556 
557   master_selection(cinfo);
558 }
559 
560 #endif //_FX_JPEG_TURBO_
561