* Master selection of decompression modules. * This is done once at jpeg_start_decompress time.  We determine * which modules will be used and give them appropriate initialization calls. * We also initialize the decompressor input side to begin consuming data. * * Since jpeg_read_header has finished, we know what is in the SOF * and (first) SOS markers.  We also have all the application parameter * settings. */LOCAL(void)master_selection (j_decompress_ptr cinfo){  my_master_ptr master = (my_master_ptr) cinfo->master;  boolean use_c_buffer;  long samplesperrow;  JDIMENSION jd_samplesperrow;  /* Initialize dimensions and other stuff */  jpeg_calc_output_dimensions(cinfo);  prepare_range_limit_table(cinfo);  /* Width of an output scanline must be representable as JDIMENSION. */  samplesperrow = (long) cinfo->output_width * (long) cinfo->out_color_components;  jd_samplesperrow = (JDIMENSION) samplesperrow;  if ((long) jd_samplesperrow != samplesperrow)    ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);  /* Initialize my private state */  master->pass_number = 0;  master->using_merged_upsample = use_merged_upsample(cinfo);  /* Color quantizer selection */  master->quantizer_1pass = NULL;  master->quantizer_2pass = NULL;  /* No mode changes if not using buffered-image mode. */  if (! cinfo->quantize_colors || ! cinfo->buffered_image) {    cinfo->enable_1pass_quant = FALSE;    cinfo->enable_external_quant = FALSE;    cinfo->enable_2pass_quant = FALSE;  }  if (cinfo->quantize_colors) {    if (cinfo->raw_data_out)      ERREXIT(cinfo, JERR_NOTIMPL);    /* 2-pass quantizer only works in 3-component color space. */    if (cinfo->out_color_components != 3) {      cinfo->enable_1pass_quant = TRUE;      cinfo->enable_external_quant = FALSE;      cinfo->enable_2pass_quant = FALSE;      cinfo->colormap = NULL;    } else if (cinfo->colormap != NULL) {      cinfo->enable_external_quant = TRUE;    } else if (cinfo->two_pass_quantize) {      cinfo->enable_2pass_quant = TRUE;    } else {      cinfo->enable_1pass_quant = TRUE;    }  }  /* Post-processing: in particular, color conversion first */  if (! cinfo->raw_data_out) {    if (master->using_merged_upsample) {#ifdef UPSAMPLE_MERGING_SUPPORTED      jinit_merged_upsampler(cinfo); /* does color conversion too */#else      ERREXIT(cinfo, JERR_NOT_COMPILED);#endif    } else {      jinit_color_deconverter(cinfo);      jinit_upsampler(cinfo);    }    jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant);  }  /* Inverse DCT */  jinit_inverse_dct(cinfo);  /* Entropy decoding: either Huffman or arithmetic coding. */  if (cinfo->arith_code) {    ERREXIT(cinfo, JERR_ARITH_NOTIMPL);  } else {    if (cinfo->progressive_mode) {#ifdef D_PROGRESSIVE_SUPPORTED      jinit_phuff_decoder(cinfo);#else      ERREXIT(cinfo, JERR_NOT_COMPILED);#endif    } else      jinit_huff_decoder(cinfo);  }  /* Initialize principal buffer controllers. */  use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image;  jinit_d_coef_controller(cinfo, use_c_buffer);  if (! cinfo->raw_data_out)    jinit_d_main_controller(cinfo, FALSE /* never need full buffer here */);  /* We can now tell the memory manager to allocate virtual arrays. */  (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);  /* Initialize input side of decompressor to consume first scan. */  (*cinfo->inputctl->start_input_pass) (cinfo);#ifdef D_MULTISCAN_FILES_SUPPORTED  /* If jpeg_start_decompress will read the whole file, initialize   * progress monitoring appropriately.  The input step is counted   * as one pass.   */  if (cinfo->progress != NULL && ! cinfo->buffered_image &&      cinfo->inputctl->has_multiple_scans) {    int nscans;    /* Estimate number of scans to set pass_limit. */    if (cinfo->progressive_mode) {      /* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */      nscans = 2 + 3 * cinfo->num_components;    } else {      /* For a nonprogressive multiscan file, estimate 1 scan per component. */      nscans = cinfo->num_components;    }    cinfo->progress->pass_counter = 0L;    cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans;    cinfo->progress->completed_passes = 0;    cinfo->progress->total_passes = (cinfo->enable_2pass_quant ? 3 : 2);    /* Count the input pass as done */    master->pass_number++;  }#endif /* D_MULTISCAN_FILES_SUPPORTED */}/* * Per-pass setup. * This is called at the beginning of each output pass.  We determine which * modules will be active during this pass and give them appropriate * start_pass calls.  We also set is_dummy_pass to indicate whether this * is a "real" output pass or a dummy pass for color quantization. * (In the latter case, jdapi.c will crank the pass to completion.) */METHODDEF(void)prepare_for_output_pass (j_decompress_ptr cinfo){  my_master_ptr master = (my_master_ptr) cinfo->master;  if (master->pub.is_dummy_pass) {#ifdef QUANT_2PASS_SUPPORTED    /* Final pass of 2-pass quantization */    master->pub.is_dummy_pass = FALSE;    (*cinfo->cquantize->start_pass) (cinfo, FALSE);    (*cinfo->post->start_pass) (cinfo, JBUF_CRANK_DEST);    (*cinfo->main->start_pass) (cinfo, JBUF_CRANK_DEST);#else    ERREXIT(cinfo, JERR_NOT_COMPILED);#endif /* QUANT_2PASS_SUPPORTED */  } else {    if (cinfo->quantize_colors && cinfo->colormap == NULL) {      /* Select new quantization method */      if (cinfo->two_pass_quantize && cinfo->enable_2pass_quant) {	cinfo->cquantize = master->quantizer_2pass;	master->pub.is_dummy_pass = TRUE;      } else if (cinfo->enable_1pass_quant) {	cinfo->cquantize = master->quantizer_1pass;      } else {	ERREXIT(cinfo, JERR_MODE_CHANGE);      }    }    (*cinfo->idct->start_pass) (cinfo);    (*cinfo->coef->start_output_pass) (cinfo);    if (! cinfo->raw_data_out) {      if (! master->using_merged_upsample)	(*cinfo->cconvert->start_pass) (cinfo);      (*cinfo->upsample->start_pass) (cinfo);      if (cinfo->quantize_colors)	(*cinfo->cquantize->start_pass) (cinfo, master->pub.is_dummy_pass);      (*cinfo->post->start_pass) (cinfo,	    (master->pub.is_dummy_pass ? JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));      (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);    }  }  /* Set up progress monitor's pass info if present */  if (cinfo->progress != NULL) {    cinfo->progress->completed_passes = master->pass_number;    cinfo->progress->total_passes = master->pass_number +				    (master->pub.is_dummy_pass ? 2 : 1);    /* In buffered-image mode, we assume one more output pass if EOI not     * yet reached, but no more passes if EOI has been reached.     */    if (cinfo->buffered_image && ! cinfo->inputctl->eoi_reached) {      cinfo->progress->total_passes += (cinfo->enable_2pass_quant ? 2 : 1);    }  }}/* * Finish up at end of an output pass. */METHODDEF(void)finish_output_pass (j_decompress_ptr cinfo){  my_master_ptr master = (my_master_ptr) cinfo->master;  if (cinfo->quantize_colors)    (*cinfo->cquantize->finish_pass) (cinfo);  master->pass_number++;}#ifdef D_MULTISCAN_FILES_SUPPORTED/* * Switch to a new external colormap between output passes. */GLOBAL(void)jpeg_new_colormap (j_decompress_ptr cinfo){  my_master_ptr master = (my_master_ptr) cinfo->master;  /* Prevent application from calling me at wrong times */  if (cinfo->global_state != DSTATE_BUFIMAGE)    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);  if (cinfo->quantize_colors && cinfo->enable_external_quant &&      cinfo->colormap != NULL) {    /* Select 2-pass quantizer for external colormap use */    cinfo->cquantize = master->quantizer_2pass;    /* Notify quantizer of colormap change */    (*cinfo->cquantize->new_color_map) (cinfo);    master->pub.is_dummy_pass = FALSE; /* just in case */  } else    ERREXIT(cinfo, JERR_MODE_CHANGE);}#endif /* D_MULTISCAN_FILES_SUPPORTED *//* * Initialize master decompression control and select active modules. * This is performed at the start of jpeg_start_decompress. */GLOBAL(void)jinit_master_decompress (j_decompress_ptr cinfo){  my_master_ptr master;  master = (my_master_ptr)      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,				  SIZEOF(my_decomp_master));  cinfo->master = (struct jpeg_decomp_master *) master;  master->pub.prepare_for_output_pass = prepare_for_output_pass;  master->pub.finish_output_pass = finish_output_pass;  master->pub.is_dummy_pass = FALSE;  master_selection(cinfo);}