    /*
     * jcinit.c
     *
     * Copyright (C) 1991-1997, Thomas G. Lane.
     * Modified 2003-2017 by Guido Vollbeding.
     * This file is part of the Independent JPEG Group's software.
     * For conditions of distribution and use, see the accompanying README file.
     *
     * This file contains initialization logic for the JPEG compressor.
     * This routine is in charge of selecting the modules to be executed and
     * making an initialization call to each one.
     *
     * Logically, this code belongs in jcmaster.c.  It's split out because
     * linking this routine implies linking the entire compression library.
     * For a transcoding-only application, we want to be able to use jcmaster.c
     * without linking in the whole library.
     */

    #define JPEG_INTERNALS
    #include "jinclude.h"
    #include "jpeglib.h"

    /*
     * Compute JPEG image dimensions and related values.
     * NOTE: this is exported for possible use by application.
     * Hence it mustn't do anything that can't be done twice.
     */

    GLOBAL(void)
    jpeg_calc_jpeg_dimensions (j_compress_ptr cinfo)
    /* Do computations that are needed before master selection phase */
    {
      /* Sanity check on input image dimensions to prevent overflow in
       * following calculations.
       * We do check jpeg_width and jpeg_height in initial_setup in jcmaster.c,
       * but image_width and image_height can come from arbitrary data,
       * and we need some space for multiplication by block_size.
       */
      if (((long) cinfo->image_width >> 24) || ((long) cinfo->image_height >> 24))
        ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);

    #ifdef DCT_SCALING_SUPPORTED

      /* Compute actual JPEG image dimensions and DCT scaling choices. */
      if (cinfo->scale_num >= cinfo->scale_denom * cinfo->block_size) {
        /* Provide block_size/1 scaling */
        cinfo->jpeg_width = cinfo->image_width * cinfo->block_size;
        cinfo->jpeg_height = cinfo->image_height * cinfo->block_size;
        cinfo->min_DCT_h_scaled_size = 1;
        cinfo->min_DCT_v_scaled_size = 1;
      } else if (cinfo->scale_num * 2 >= cinfo->scale_denom * cinfo->block_size) {
        /* Provide block_size/2 scaling */
        cinfo->jpeg_width = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 2L);
        cinfo->jpeg_height = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 2L);
        cinfo->min_DCT_h_scaled_size = 2;
        cinfo->min_DCT_v_scaled_size = 2;
      } else if (cinfo->scale_num * 3 >= cinfo->scale_denom * cinfo->block_size) {
        /* Provide block_size/3 scaling */
        cinfo->jpeg_width = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 3L);
        cinfo->jpeg_height = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 3L);
        cinfo->min_DCT_h_scaled_size = 3;
        cinfo->min_DCT_v_scaled_size = 3;
      } else if (cinfo->scale_num * 4 >= cinfo->scale_denom * cinfo->block_size) {
        /* Provide block_size/4 scaling */
        cinfo->jpeg_width = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 4L);
        cinfo->jpeg_height = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 4L);
        cinfo->min_DCT_h_scaled_size = 4;
        cinfo->min_DCT_v_scaled_size = 4;
      } else if (cinfo->scale_num * 5 >= cinfo->scale_denom * cinfo->block_size) {
        /* Provide block_size/5 scaling */
        cinfo->jpeg_width = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 5L);
        cinfo->jpeg_height = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 5L);
        cinfo->min_DCT_h_scaled_size = 5;
        cinfo->min_DCT_v_scaled_size = 5;
      } else if (cinfo->scale_num * 6 >= cinfo->scale_denom * cinfo->block_size) {
        /* Provide block_size/6 scaling */
        cinfo->jpeg_width = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 6L);
        cinfo->jpeg_height = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 6L);
        cinfo->min_DCT_h_scaled_size = 6;
        cinfo->min_DCT_v_scaled_size = 6;
      } else if (cinfo->scale_num * 7 >= cinfo->scale_denom * cinfo->block_size) {
        /* Provide block_size/7 scaling */
        cinfo->jpeg_width = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 7L);
        cinfo->jpeg_height = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 7L);
        cinfo->min_DCT_h_scaled_size = 7;
        cinfo->min_DCT_v_scaled_size = 7;
      } else if (cinfo->scale_num * 8 >= cinfo->scale_denom * cinfo->block_size) {
        /* Provide block_size/8 scaling */
        cinfo->jpeg_width = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 8L);
        cinfo->jpeg_height = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 8L);
        cinfo->min_DCT_h_scaled_size = 8;
        cinfo->min_DCT_v_scaled_size = 8;
      } else if (cinfo->scale_num * 9 >= cinfo->scale_denom * cinfo->block_size) {
        /* Provide block_size/9 scaling */
        cinfo->jpeg_width = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 9L);
        cinfo->jpeg_height = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 9L);
        cinfo->min_DCT_h_scaled_size = 9;
        cinfo->min_DCT_v_scaled_size = 9;
      } else if (cinfo->scale_num * 10 >= cinfo->scale_denom * cinfo->block_size) {
        /* Provide block_size/10 scaling */
        cinfo->jpeg_width = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 10L);
        cinfo->jpeg_height = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 10L);
        cinfo->min_DCT_h_scaled_size = 10;
        cinfo->min_DCT_v_scaled_size = 10;
      } else if (cinfo->scale_num * 11 >= cinfo->scale_denom * cinfo->block_size) {
        /* Provide block_size/11 scaling */
        cinfo->jpeg_width = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 11L);
        cinfo->jpeg_height = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 11L);
        cinfo->min_DCT_h_scaled_size = 11;
        cinfo->min_DCT_v_scaled_size = 11;
      } else if (cinfo->scale_num * 12 >= cinfo->scale_denom * cinfo->block_size) {
        /* Provide block_size/12 scaling */
        cinfo->jpeg_width = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 12L);
        cinfo->jpeg_height = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 12L);
        cinfo->min_DCT_h_scaled_size = 12;
        cinfo->min_DCT_v_scaled_size = 12;
      } else if (cinfo->scale_num * 13 >= cinfo->scale_denom * cinfo->block_size) {
        /* Provide block_size/13 scaling */
        cinfo->jpeg_width = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 13L);
        cinfo->jpeg_height = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 13L);
        cinfo->min_DCT_h_scaled_size = 13;
        cinfo->min_DCT_v_scaled_size = 13;
      } else if (cinfo->scale_num * 14 >= cinfo->scale_denom * cinfo->block_size) {
        /* Provide block_size/14 scaling */
        cinfo->jpeg_width = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 14L);
        cinfo->jpeg_height = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 14L);
        cinfo->min_DCT_h_scaled_size = 14;
        cinfo->min_DCT_v_scaled_size = 14;
      } else if (cinfo->scale_num * 15 >= cinfo->scale_denom * cinfo->block_size) {
        /* Provide block_size/15 scaling */
        cinfo->jpeg_width = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 15L);
        cinfo->jpeg_height = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 15L);
        cinfo->min_DCT_h_scaled_size = 15;
        cinfo->min_DCT_v_scaled_size = 15;
      } else {
        /* Provide block_size/16 scaling */
        cinfo->jpeg_width = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 16L);
        cinfo->jpeg_height = (JDIMENSION)
          jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 16L);
        cinfo->min_DCT_h_scaled_size = 16;
        cinfo->min_DCT_v_scaled_size = 16;
      }

    #else /* !DCT_SCALING_SUPPORTED */

      /* Hardwire it to "no scaling" */
      cinfo->jpeg_width = cinfo->image_width;
      cinfo->jpeg_height = cinfo->image_height;
      cinfo->min_DCT_h_scaled_size = DCTSIZE;
      cinfo->min_DCT_v_scaled_size = DCTSIZE;

    #endif /* DCT_SCALING_SUPPORTED */
    }

    /*
     * Master selection of compression modules.
     * This is done once at the start of processing an image.  We determine
     * which modules will be used and give them appropriate initialization calls.
     */

    GLOBAL(void)
    jinit_compress_master (j_compress_ptr cinfo)
    {
      long samplesperrow;
      JDIMENSION jd_samplesperrow;

      /* For now, precision must match compiled-in value... */
      if (cinfo->data_precision != BITS_IN_JSAMPLE)
        ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);

      /* Sanity check on input image dimensions */
      if (cinfo->image_height <= 0 || cinfo->image_width <= 0 ||
          cinfo->input_components <= 0)
        ERREXIT(cinfo, JERR_EMPTY_IMAGE);

      /* Width of an input scanline must be representable as JDIMENSION. */
      samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
      jd_samplesperrow = (JDIMENSION) samplesperrow;
      if ((long) jd_samplesperrow != samplesperrow)
        ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);

      /* Compute JPEG image dimensions and related values. */
      jpeg_calc_jpeg_dimensions(cinfo);

      /* Initialize master control (includes parameter checking/processing) */
      jinit_c_master_control(cinfo, FALSE /* full compression */);

      /* Preprocessing */
      if (! cinfo->raw_data_in) {
        jinit_color_converter(cinfo);
        jinit_downsampler(cinfo);
        jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */);
      }
      /* Forward DCT */
      jinit_forward_dct(cinfo);
      /* Entropy encoding: either Huffman or arithmetic coding. */
      if (cinfo->arith_code)
        jinit_arith_encoder(cinfo);
      else {
        jinit_huff_encoder(cinfo);
      }

      /* Need a full-image coefficient buffer in any multi-pass mode. */
      jinit_c_coef_controller(cinfo,
    		(boolean) (cinfo->num_scans > 1 || cinfo->optimize_coding));
      jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);

      jinit_marker_writer(cinfo);

      /* We can now tell the memory manager to allocate virtual arrays. */
      (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);

      /* Write the datastream header (SOI) immediately.
       * Frame and scan headers are postponed till later.
       * This lets application insert special markers after the SOI.
       */
      (*cinfo->marker->write_file_header) (cinfo);
    }