nuclear@26: /*
nuclear@26:  * jdmaster.c
nuclear@26:  *
nuclear@26:  * Copyright (C) 1991-1997, Thomas G. Lane.
nuclear@26:  * This file is part of the Independent JPEG Group's software.
nuclear@26:  * For conditions of distribution and use, see the accompanying README file.
nuclear@26:  *
nuclear@26:  * This file contains master control logic for the JPEG decompressor.
nuclear@26:  * These routines are concerned with selecting the modules to be executed
nuclear@26:  * and with determining the number of passes and the work to be done in each
nuclear@26:  * pass.
nuclear@26:  */
nuclear@26: 
nuclear@26: #define JPEG_INTERNALS
nuclear@26: #include "jinclude.h"
nuclear@26: #include "jpeglib.h"
nuclear@26: 
nuclear@26: 
nuclear@26: /* Private state */
nuclear@26: 
nuclear@26: typedef struct {
nuclear@26:   struct jpeg_decomp_master pub; /* public fields */
nuclear@26: 
nuclear@26:   int pass_number;		/* # of passes completed */
nuclear@26: 
nuclear@26:   boolean using_merged_upsample; /* TRUE if using merged upsample/cconvert */
nuclear@26: 
nuclear@26:   /* Saved references to initialized quantizer modules,
nuclear@26:    * in case we need to switch modes.
nuclear@26:    */
nuclear@26:   struct jpeg_color_quantizer * quantizer_1pass;
nuclear@26:   struct jpeg_color_quantizer * quantizer_2pass;
nuclear@26: } my_decomp_master;
nuclear@26: 
nuclear@26: typedef my_decomp_master * my_master_ptr;
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Determine whether merged upsample/color conversion should be used.
nuclear@26:  * CRUCIAL: this must match the actual capabilities of jdmerge.c!
nuclear@26:  */
nuclear@26: 
nuclear@26: LOCAL(boolean)
nuclear@26: use_merged_upsample (j_decompress_ptr cinfo)
nuclear@26: {
nuclear@26: #ifdef UPSAMPLE_MERGING_SUPPORTED
nuclear@26:   /* Merging is the equivalent of plain box-filter upsampling */
nuclear@26:   if (cinfo->do_fancy_upsampling || cinfo->CCIR601_sampling)
nuclear@26:     return FALSE;
nuclear@26:   /* jdmerge.c only supports YCC=>RGB color conversion */
nuclear@26:   if (cinfo->jpeg_color_space != JCS_YCbCr || cinfo->num_components != 3 ||
nuclear@26:       cinfo->out_color_space != JCS_RGB ||
nuclear@26:       cinfo->out_color_components != RGB_PIXELSIZE)
nuclear@26:     return FALSE;
nuclear@26:   /* and it only handles 2h1v or 2h2v sampling ratios */
nuclear@26:   if (cinfo->comp_info[0].h_samp_factor != 2 ||
nuclear@26:       cinfo->comp_info[1].h_samp_factor != 1 ||
nuclear@26:       cinfo->comp_info[2].h_samp_factor != 1 ||
nuclear@26:       cinfo->comp_info[0].v_samp_factor >  2 ||
nuclear@26:       cinfo->comp_info[1].v_samp_factor != 1 ||
nuclear@26:       cinfo->comp_info[2].v_samp_factor != 1)
nuclear@26:     return FALSE;
nuclear@26:   /* furthermore, it doesn't work if we've scaled the IDCTs differently */
nuclear@26:   if (cinfo->comp_info[0].DCT_scaled_size != cinfo->min_DCT_scaled_size ||
nuclear@26:       cinfo->comp_info[1].DCT_scaled_size != cinfo->min_DCT_scaled_size ||
nuclear@26:       cinfo->comp_info[2].DCT_scaled_size != cinfo->min_DCT_scaled_size)
nuclear@26:     return FALSE;
nuclear@26:   /* ??? also need to test for upsample-time rescaling, when & if supported */
nuclear@26:   return TRUE;			/* by golly, it'll work... */
nuclear@26: #else
nuclear@26:   return FALSE;
nuclear@26: #endif
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Compute output image dimensions and related values.
nuclear@26:  * NOTE: this is exported for possible use by application.
nuclear@26:  * Hence it mustn't do anything that can't be done twice.
nuclear@26:  * Also note that it may be called before the master module is initialized!
nuclear@26:  */
nuclear@26: 
nuclear@26: GLOBAL(void)
nuclear@26: jpeg_calc_output_dimensions (j_decompress_ptr cinfo)
nuclear@26: /* Do computations that are needed before master selection phase */
nuclear@26: {
nuclear@26: #ifdef IDCT_SCALING_SUPPORTED
nuclear@26:   int ci;
nuclear@26:   jpeg_component_info *compptr;
nuclear@26: #endif
nuclear@26: 
nuclear@26:   /* Prevent application from calling me at wrong times */
nuclear@26:   if (cinfo->global_state != DSTATE_READY)
nuclear@26:     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
nuclear@26: 
nuclear@26: #ifdef IDCT_SCALING_SUPPORTED
nuclear@26: 
nuclear@26:   /* Compute actual output image dimensions and DCT scaling choices. */
nuclear@26:   if (cinfo->scale_num * 8 <= cinfo->scale_denom) {
nuclear@26:     /* Provide 1/8 scaling */
nuclear@26:     cinfo->output_width = (JDIMENSION)
nuclear@26:       jdiv_round_up((long) cinfo->image_width, 8L);
nuclear@26:     cinfo->output_height = (JDIMENSION)
nuclear@26:       jdiv_round_up((long) cinfo->image_height, 8L);
nuclear@26:     cinfo->min_DCT_scaled_size = 1;
nuclear@26:   } else if (cinfo->scale_num * 4 <= cinfo->scale_denom) {
nuclear@26:     /* Provide 1/4 scaling */
nuclear@26:     cinfo->output_width = (JDIMENSION)
nuclear@26:       jdiv_round_up((long) cinfo->image_width, 4L);
nuclear@26:     cinfo->output_height = (JDIMENSION)
nuclear@26:       jdiv_round_up((long) cinfo->image_height, 4L);
nuclear@26:     cinfo->min_DCT_scaled_size = 2;
nuclear@26:   } else if (cinfo->scale_num * 2 <= cinfo->scale_denom) {
nuclear@26:     /* Provide 1/2 scaling */
nuclear@26:     cinfo->output_width = (JDIMENSION)
nuclear@26:       jdiv_round_up((long) cinfo->image_width, 2L);
nuclear@26:     cinfo->output_height = (JDIMENSION)
nuclear@26:       jdiv_round_up((long) cinfo->image_height, 2L);
nuclear@26:     cinfo->min_DCT_scaled_size = 4;
nuclear@26:   } else {
nuclear@26:     /* Provide 1/1 scaling */
nuclear@26:     cinfo->output_width = cinfo->image_width;
nuclear@26:     cinfo->output_height = cinfo->image_height;
nuclear@26:     cinfo->min_DCT_scaled_size = DCTSIZE;
nuclear@26:   }
nuclear@26:   /* In selecting the actual DCT scaling for each component, we try to
nuclear@26:    * scale up the chroma components via IDCT scaling rather than upsampling.
nuclear@26:    * This saves time if the upsampler gets to use 1:1 scaling.
nuclear@26:    * Note this code assumes that the supported DCT scalings are powers of 2.
nuclear@26:    */
nuclear@26:   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@26:        ci++, compptr++) {
nuclear@26:     int ssize = cinfo->min_DCT_scaled_size;
nuclear@26:     while (ssize < DCTSIZE &&
nuclear@26: 	   (compptr->h_samp_factor * ssize * 2 <=
nuclear@26: 	    cinfo->max_h_samp_factor * cinfo->min_DCT_scaled_size) &&
nuclear@26: 	   (compptr->v_samp_factor * ssize * 2 <=
nuclear@26: 	    cinfo->max_v_samp_factor * cinfo->min_DCT_scaled_size)) {
nuclear@26:       ssize = ssize * 2;
nuclear@26:     }
nuclear@26:     compptr->DCT_scaled_size = ssize;
nuclear@26:   }
nuclear@26: 
nuclear@26:   /* Recompute downsampled dimensions of components;
nuclear@26:    * application needs to know these if using raw downsampled data.
nuclear@26:    */
nuclear@26:   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@26:        ci++, compptr++) {
nuclear@26:     /* Size in samples, after IDCT scaling */
nuclear@26:     compptr->downsampled_width = (JDIMENSION)
nuclear@26:       jdiv_round_up((long) cinfo->image_width *
nuclear@26: 		    (long) (compptr->h_samp_factor * compptr->DCT_scaled_size),
nuclear@26: 		    (long) (cinfo->max_h_samp_factor * DCTSIZE));
nuclear@26:     compptr->downsampled_height = (JDIMENSION)
nuclear@26:       jdiv_round_up((long) cinfo->image_height *
nuclear@26: 		    (long) (compptr->v_samp_factor * compptr->DCT_scaled_size),
nuclear@26: 		    (long) (cinfo->max_v_samp_factor * DCTSIZE));
nuclear@26:   }
nuclear@26: 
nuclear@26: #else /* !IDCT_SCALING_SUPPORTED */
nuclear@26: 
nuclear@26:   /* Hardwire it to "no scaling" */
nuclear@26:   cinfo->output_width = cinfo->image_width;
nuclear@26:   cinfo->output_height = cinfo->image_height;
nuclear@26:   /* jdinput.c has already initialized DCT_scaled_size to DCTSIZE,
nuclear@26:    * and has computed unscaled downsampled_width and downsampled_height.
nuclear@26:    */
nuclear@26: 
nuclear@26: #endif /* IDCT_SCALING_SUPPORTED */
nuclear@26: 
nuclear@26:   /* Report number of components in selected colorspace. */
nuclear@26:   /* Probably this should be in the color conversion module... */
nuclear@26:   switch (cinfo->out_color_space) {
nuclear@26:   case JCS_GRAYSCALE:
nuclear@26:     cinfo->out_color_components = 1;
nuclear@26:     break;
nuclear@26:   case JCS_RGB:
nuclear@26: #if RGB_PIXELSIZE != 3
nuclear@26:     cinfo->out_color_components = RGB_PIXELSIZE;
nuclear@26:     break;
nuclear@26: #endif /* else share code with YCbCr */
nuclear@26:   case JCS_YCbCr:
nuclear@26:     cinfo->out_color_components = 3;
nuclear@26:     break;
nuclear@26:   case JCS_CMYK:
nuclear@26:   case JCS_YCCK:
nuclear@26:     cinfo->out_color_components = 4;
nuclear@26:     break;
nuclear@26:   default:			/* else must be same colorspace as in file */
nuclear@26:     cinfo->out_color_components = cinfo->num_components;
nuclear@26:     break;
nuclear@26:   }
nuclear@26:   cinfo->output_components = (cinfo->quantize_colors ? 1 :
nuclear@26: 			      cinfo->out_color_components);
nuclear@26: 
nuclear@26:   /* See if upsampler will want to emit more than one row at a time */
nuclear@26:   if (use_merged_upsample(cinfo))
nuclear@26:     cinfo->rec_outbuf_height = cinfo->max_v_samp_factor;
nuclear@26:   else
nuclear@26:     cinfo->rec_outbuf_height = 1;
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Several decompression processes need to range-limit values to the range
nuclear@26:  * 0..MAXJSAMPLE; the input value may fall somewhat outside this range
nuclear@26:  * due to noise introduced by quantization, roundoff error, etc.  These
nuclear@26:  * processes are inner loops and need to be as fast as possible.  On most
nuclear@26:  * machines, particularly CPUs with pipelines or instruction prefetch,
nuclear@26:  * a (subscript-check-less) C table lookup
nuclear@26:  *		x = sample_range_limit[x];
nuclear@26:  * is faster than explicit tests
nuclear@26:  *		if (x < 0)  x = 0;
nuclear@26:  *		else if (x > MAXJSAMPLE)  x = MAXJSAMPLE;
nuclear@26:  * These processes all use a common table prepared by the routine below.
nuclear@26:  *
nuclear@26:  * For most steps we can mathematically guarantee that the initial value
nuclear@26:  * of x is within MAXJSAMPLE+1 of the legal range, so a table running from
nuclear@26:  * -(MAXJSAMPLE+1) to 2*MAXJSAMPLE+1 is sufficient.  But for the initial
nuclear@26:  * limiting step (just after the IDCT), a wildly out-of-range value is 
nuclear@26:  * possible if the input data is corrupt.  To avoid any chance of indexing
nuclear@26:  * off the end of memory and getting a bad-pointer trap, we perform the
nuclear@26:  * post-IDCT limiting thus:
nuclear@26:  *		x = range_limit[x & MASK];
nuclear@26:  * where MASK is 2 bits wider than legal sample data, ie 10 bits for 8-bit
nuclear@26:  * samples.  Under normal circumstances this is more than enough range and
nuclear@26:  * a correct output will be generated; with bogus input data the mask will
nuclear@26:  * cause wraparound, and we will safely generate a bogus-but-in-range output.
nuclear@26:  * For the post-IDCT step, we want to convert the data from signed to unsigned
nuclear@26:  * representation by adding CENTERJSAMPLE at the same time that we limit it.
nuclear@26:  * So the post-IDCT limiting table ends up looking like this:
nuclear@26:  *   CENTERJSAMPLE,CENTERJSAMPLE+1,...,MAXJSAMPLE,
nuclear@26:  *   MAXJSAMPLE (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
nuclear@26:  *   0          (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
nuclear@26:  *   0,1,...,CENTERJSAMPLE-1
nuclear@26:  * Negative inputs select values from the upper half of the table after
nuclear@26:  * masking.
nuclear@26:  *
nuclear@26:  * We can save some space by overlapping the start of the post-IDCT table
nuclear@26:  * with the simpler range limiting table.  The post-IDCT table begins at
nuclear@26:  * sample_range_limit + CENTERJSAMPLE.
nuclear@26:  *
nuclear@26:  * Note that the table is allocated in near data space on PCs; it's small
nuclear@26:  * enough and used often enough to justify this.
nuclear@26:  */
nuclear@26: 
nuclear@26: LOCAL(void)
nuclear@26: prepare_range_limit_table (j_decompress_ptr cinfo)
nuclear@26: /* Allocate and fill in the sample_range_limit table */
nuclear@26: {
nuclear@26:   JSAMPLE * table;
nuclear@26:   int i;
nuclear@26: 
nuclear@26:   table = (JSAMPLE *)
nuclear@26:     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@26: 		(5 * (MAXJSAMPLE+1) + CENTERJSAMPLE) * SIZEOF(JSAMPLE));
nuclear@26:   table += (MAXJSAMPLE+1);	/* allow negative subscripts of simple table */
nuclear@26:   cinfo->sample_range_limit = table;
nuclear@26:   /* First segment of "simple" table: limit[x] = 0 for x < 0 */
nuclear@26:   MEMZERO(table - (MAXJSAMPLE+1), (MAXJSAMPLE+1) * SIZEOF(JSAMPLE));
nuclear@26:   /* Main part of "simple" table: limit[x] = x */
nuclear@26:   for (i = 0; i <= MAXJSAMPLE; i++)
nuclear@26:     table[i] = (JSAMPLE) i;
nuclear@26:   table += CENTERJSAMPLE;	/* Point to where post-IDCT table starts */
nuclear@26:   /* End of simple table, rest of first half of post-IDCT table */
nuclear@26:   for (i = CENTERJSAMPLE; i < 2*(MAXJSAMPLE+1); i++)
nuclear@26:     table[i] = MAXJSAMPLE;
nuclear@26:   /* Second half of post-IDCT table */
nuclear@26:   MEMZERO(table + (2 * (MAXJSAMPLE+1)),
nuclear@26: 	  (2 * (MAXJSAMPLE+1) - CENTERJSAMPLE) * SIZEOF(JSAMPLE));
nuclear@26:   MEMCOPY(table + (4 * (MAXJSAMPLE+1) - CENTERJSAMPLE),
nuclear@26: 	  cinfo->sample_range_limit, CENTERJSAMPLE * SIZEOF(JSAMPLE));
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Master selection of decompression modules.
nuclear@26:  * This is done once at jpeg_start_decompress time.  We determine
nuclear@26:  * which modules will be used and give them appropriate initialization calls.
nuclear@26:  * We also initialize the decompressor input side to begin consuming data.
nuclear@26:  *
nuclear@26:  * Since jpeg_read_header has finished, we know what is in the SOF
nuclear@26:  * and (first) SOS markers.  We also have all the application parameter
nuclear@26:  * settings.
nuclear@26:  */
nuclear@26: 
nuclear@26: LOCAL(void)
nuclear@26: master_selection (j_decompress_ptr cinfo)
nuclear@26: {
nuclear@26:   my_master_ptr master = (my_master_ptr) cinfo->master;
nuclear@26:   boolean use_c_buffer;
nuclear@26:   long samplesperrow;
nuclear@26:   JDIMENSION jd_samplesperrow;
nuclear@26: 
nuclear@26:   /* Initialize dimensions and other stuff */
nuclear@26:   jpeg_calc_output_dimensions(cinfo);
nuclear@26:   prepare_range_limit_table(cinfo);
nuclear@26: 
nuclear@26:   /* Width of an output scanline must be representable as JDIMENSION. */
nuclear@26:   samplesperrow = (long) cinfo->output_width * (long) cinfo->out_color_components;
nuclear@26:   jd_samplesperrow = (JDIMENSION) samplesperrow;
nuclear@26:   if ((long) jd_samplesperrow != samplesperrow)
nuclear@26:     ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
nuclear@26: 
nuclear@26:   /* Initialize my private state */
nuclear@26:   master->pass_number = 0;
nuclear@26:   master->using_merged_upsample = use_merged_upsample(cinfo);
nuclear@26: 
nuclear@26:   /* Color quantizer selection */
nuclear@26:   master->quantizer_1pass = NULL;
nuclear@26:   master->quantizer_2pass = NULL;
nuclear@26:   /* No mode changes if not using buffered-image mode. */
nuclear@26:   if (! cinfo->quantize_colors || ! cinfo->buffered_image) {
nuclear@26:     cinfo->enable_1pass_quant = FALSE;
nuclear@26:     cinfo->enable_external_quant = FALSE;
nuclear@26:     cinfo->enable_2pass_quant = FALSE;
nuclear@26:   }
nuclear@26:   if (cinfo->quantize_colors) {
nuclear@26:     if (cinfo->raw_data_out)
nuclear@26:       ERREXIT(cinfo, JERR_NOTIMPL);
nuclear@26:     /* 2-pass quantizer only works in 3-component color space. */
nuclear@26:     if (cinfo->out_color_components != 3) {
nuclear@26:       cinfo->enable_1pass_quant = TRUE;
nuclear@26:       cinfo->enable_external_quant = FALSE;
nuclear@26:       cinfo->enable_2pass_quant = FALSE;
nuclear@26:       cinfo->colormap = NULL;
nuclear@26:     } else if (cinfo->colormap != NULL) {
nuclear@26:       cinfo->enable_external_quant = TRUE;
nuclear@26:     } else if (cinfo->two_pass_quantize) {
nuclear@26:       cinfo->enable_2pass_quant = TRUE;
nuclear@26:     } else {
nuclear@26:       cinfo->enable_1pass_quant = TRUE;
nuclear@26:     }
nuclear@26: 
nuclear@26:     if (cinfo->enable_1pass_quant) {
nuclear@26: #ifdef QUANT_1PASS_SUPPORTED
nuclear@26:       jinit_1pass_quantizer(cinfo);
nuclear@26:       master->quantizer_1pass = cinfo->cquantize;
nuclear@26: #else
nuclear@26:       ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@26: #endif
nuclear@26:     }
nuclear@26: 
nuclear@26:     /* We use the 2-pass code to map to external colormaps. */
nuclear@26:     if (cinfo->enable_2pass_quant || cinfo->enable_external_quant) {
nuclear@26: #ifdef QUANT_2PASS_SUPPORTED
nuclear@26:       jinit_2pass_quantizer(cinfo);
nuclear@26:       master->quantizer_2pass = cinfo->cquantize;
nuclear@26: #else
nuclear@26:       ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@26: #endif
nuclear@26:     }
nuclear@26:     /* If both quantizers are initialized, the 2-pass one is left active;
nuclear@26:      * this is necessary for starting with quantization to an external map.
nuclear@26:      */
nuclear@26:   }
nuclear@26: 
nuclear@26:   /* Post-processing: in particular, color conversion first */
nuclear@26:   if (! cinfo->raw_data_out) {
nuclear@26:     if (master->using_merged_upsample) {
nuclear@26: #ifdef UPSAMPLE_MERGING_SUPPORTED
nuclear@26:       jinit_merged_upsampler(cinfo); /* does color conversion too */
nuclear@26: #else
nuclear@26:       ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@26: #endif
nuclear@26:     } else {
nuclear@26:       jinit_color_deconverter(cinfo);
nuclear@26:       jinit_upsampler(cinfo);
nuclear@26:     }
nuclear@26:     jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant);
nuclear@26:   }
nuclear@26:   /* Inverse DCT */
nuclear@26:   jinit_inverse_dct(cinfo);
nuclear@26:   /* Entropy decoding: either Huffman or arithmetic coding. */
nuclear@26:   if (cinfo->arith_code) {
nuclear@26:     ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
nuclear@26:   } else {
nuclear@26:     if (cinfo->progressive_mode) {
nuclear@26: #ifdef D_PROGRESSIVE_SUPPORTED
nuclear@26:       jinit_phuff_decoder(cinfo);
nuclear@26: #else
nuclear@26:       ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@26: #endif
nuclear@26:     } else
nuclear@26:       jinit_huff_decoder(cinfo);
nuclear@26:   }
nuclear@26: 
nuclear@26:   /* Initialize principal buffer controllers. */
nuclear@26:   use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image;
nuclear@26:   jinit_d_coef_controller(cinfo, use_c_buffer);
nuclear@26: 
nuclear@26:   if (! cinfo->raw_data_out)
nuclear@26:     jinit_d_main_controller(cinfo, FALSE /* never need full buffer here */);
nuclear@26: 
nuclear@26:   /* We can now tell the memory manager to allocate virtual arrays. */
nuclear@26:   (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
nuclear@26: 
nuclear@26:   /* Initialize input side of decompressor to consume first scan. */
nuclear@26:   (*cinfo->inputctl->start_input_pass) (cinfo);
nuclear@26: 
nuclear@26: #ifdef D_MULTISCAN_FILES_SUPPORTED
nuclear@26:   /* If jpeg_start_decompress will read the whole file, initialize
nuclear@26:    * progress monitoring appropriately.  The input step is counted
nuclear@26:    * as one pass.
nuclear@26:    */
nuclear@26:   if (cinfo->progress != NULL && ! cinfo->buffered_image &&
nuclear@26:       cinfo->inputctl->has_multiple_scans) {
nuclear@26:     int nscans;
nuclear@26:     /* Estimate number of scans to set pass_limit. */
nuclear@26:     if (cinfo->progressive_mode) {
nuclear@26:       /* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */
nuclear@26:       nscans = 2 + 3 * cinfo->num_components;
nuclear@26:     } else {
nuclear@26:       /* For a nonprogressive multiscan file, estimate 1 scan per component. */
nuclear@26:       nscans = cinfo->num_components;
nuclear@26:     }
nuclear@26:     cinfo->progress->pass_counter = 0L;
nuclear@26:     cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans;
nuclear@26:     cinfo->progress->completed_passes = 0;
nuclear@26:     cinfo->progress->total_passes = (cinfo->enable_2pass_quant ? 3 : 2);
nuclear@26:     /* Count the input pass as done */
nuclear@26:     master->pass_number++;
nuclear@26:   }
nuclear@26: #endif /* D_MULTISCAN_FILES_SUPPORTED */
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Per-pass setup.
nuclear@26:  * This is called at the beginning of each output pass.  We determine which
nuclear@26:  * modules will be active during this pass and give them appropriate
nuclear@26:  * start_pass calls.  We also set is_dummy_pass to indicate whether this
nuclear@26:  * is a "real" output pass or a dummy pass for color quantization.
nuclear@26:  * (In the latter case, jdapistd.c will crank the pass to completion.)
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: prepare_for_output_pass (j_decompress_ptr cinfo)
nuclear@26: {
nuclear@26:   my_master_ptr master = (my_master_ptr) cinfo->master;
nuclear@26: 
nuclear@26:   if (master->pub.is_dummy_pass) {
nuclear@26: #ifdef QUANT_2PASS_SUPPORTED
nuclear@26:     /* Final pass of 2-pass quantization */
nuclear@26:     master->pub.is_dummy_pass = FALSE;
nuclear@26:     (*cinfo->cquantize->start_pass) (cinfo, FALSE);
nuclear@26:     (*cinfo->post->start_pass) (cinfo, JBUF_CRANK_DEST);
nuclear@26:     (*cinfo->main->start_pass) (cinfo, JBUF_CRANK_DEST);
nuclear@26: #else
nuclear@26:     ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@26: #endif /* QUANT_2PASS_SUPPORTED */
nuclear@26:   } else {
nuclear@26:     if (cinfo->quantize_colors && cinfo->colormap == NULL) {
nuclear@26:       /* Select new quantization method */
nuclear@26:       if (cinfo->two_pass_quantize && cinfo->enable_2pass_quant) {
nuclear@26: 	cinfo->cquantize = master->quantizer_2pass;
nuclear@26: 	master->pub.is_dummy_pass = TRUE;
nuclear@26:       } else if (cinfo->enable_1pass_quant) {
nuclear@26: 	cinfo->cquantize = master->quantizer_1pass;
nuclear@26:       } else {
nuclear@26: 	ERREXIT(cinfo, JERR_MODE_CHANGE);
nuclear@26:       }
nuclear@26:     }
nuclear@26:     (*cinfo->idct->start_pass) (cinfo);
nuclear@26:     (*cinfo->coef->start_output_pass) (cinfo);
nuclear@26:     if (! cinfo->raw_data_out) {
nuclear@26:       if (! master->using_merged_upsample)
nuclear@26: 	(*cinfo->cconvert->start_pass) (cinfo);
nuclear@26:       (*cinfo->upsample->start_pass) (cinfo);
nuclear@26:       if (cinfo->quantize_colors)
nuclear@26: 	(*cinfo->cquantize->start_pass) (cinfo, master->pub.is_dummy_pass);
nuclear@26:       (*cinfo->post->start_pass) (cinfo,
nuclear@26: 	    (master->pub.is_dummy_pass ? JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
nuclear@26:       (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
nuclear@26:     }
nuclear@26:   }
nuclear@26: 
nuclear@26:   /* Set up progress monitor's pass info if present */
nuclear@26:   if (cinfo->progress != NULL) {
nuclear@26:     cinfo->progress->completed_passes = master->pass_number;
nuclear@26:     cinfo->progress->total_passes = master->pass_number +
nuclear@26: 				    (master->pub.is_dummy_pass ? 2 : 1);
nuclear@26:     /* In buffered-image mode, we assume one more output pass if EOI not
nuclear@26:      * yet reached, but no more passes if EOI has been reached.
nuclear@26:      */
nuclear@26:     if (cinfo->buffered_image && ! cinfo->inputctl->eoi_reached) {
nuclear@26:       cinfo->progress->total_passes += (cinfo->enable_2pass_quant ? 2 : 1);
nuclear@26:     }
nuclear@26:   }
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Finish up at end of an output pass.
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: finish_output_pass (j_decompress_ptr cinfo)
nuclear@26: {
nuclear@26:   my_master_ptr master = (my_master_ptr) cinfo->master;
nuclear@26: 
nuclear@26:   if (cinfo->quantize_colors)
nuclear@26:     (*cinfo->cquantize->finish_pass) (cinfo);
nuclear@26:   master->pass_number++;
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: #ifdef D_MULTISCAN_FILES_SUPPORTED
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Switch to a new external colormap between output passes.
nuclear@26:  */
nuclear@26: 
nuclear@26: GLOBAL(void)
nuclear@26: jpeg_new_colormap (j_decompress_ptr cinfo)
nuclear@26: {
nuclear@26:   my_master_ptr master = (my_master_ptr) cinfo->master;
nuclear@26: 
nuclear@26:   /* Prevent application from calling me at wrong times */
nuclear@26:   if (cinfo->global_state != DSTATE_BUFIMAGE)
nuclear@26:     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
nuclear@26: 
nuclear@26:   if (cinfo->quantize_colors && cinfo->enable_external_quant &&
nuclear@26:       cinfo->colormap != NULL) {
nuclear@26:     /* Select 2-pass quantizer for external colormap use */
nuclear@26:     cinfo->cquantize = master->quantizer_2pass;
nuclear@26:     /* Notify quantizer of colormap change */
nuclear@26:     (*cinfo->cquantize->new_color_map) (cinfo);
nuclear@26:     master->pub.is_dummy_pass = FALSE; /* just in case */
nuclear@26:   } else
nuclear@26:     ERREXIT(cinfo, JERR_MODE_CHANGE);
nuclear@26: }
nuclear@26: 
nuclear@26: #endif /* D_MULTISCAN_FILES_SUPPORTED */
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Initialize master decompression control and select active modules.
nuclear@26:  * This is performed at the start of jpeg_start_decompress.
nuclear@26:  */
nuclear@26: 
nuclear@26: GLOBAL(void)
nuclear@26: jinit_master_decompress (j_decompress_ptr cinfo)
nuclear@26: {
nuclear@26:   my_master_ptr master;
nuclear@26: 
nuclear@26:   master = (my_master_ptr)
nuclear@26:       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@26: 				  SIZEOF(my_decomp_master));
nuclear@26:   cinfo->master = (struct jpeg_decomp_master *) master;
nuclear@26:   master->pub.prepare_for_output_pass = prepare_for_output_pass;
nuclear@26:   master->pub.finish_output_pass = finish_output_pass;
nuclear@26: 
nuclear@26:   master->pub.is_dummy_pass = FALSE;
nuclear@26: 
nuclear@26:   master_selection(cinfo);
nuclear@26: }