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/*
 * jcmaster.c
 *
 * Copyright (C) 1991-1997, Thomas G. Lane.
 * Modified 2003-2013 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 master control logic for the JPEG compressor.
 * These routines are concerned with parameter validation, initial setup,
 * and inter-pass control (determining the number of passes and the work 
 * to be done in each pass).
 */

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


/* Private state */

typedef enum {
	main_pass,		/* input data, also do first output step */
	huff_opt_pass,		/* Huffman code optimization pass */
	output_pass		/* data output pass */
} c_pass_type;

typedef struct {
  struct jpeg_comp_master pub;	/* public fields */

  c_pass_type pass_type;	/* the type of the current pass */

  int pass_number;		/* # of passes completed */
  int total_passes;		/* total # of passes needed */

  int scan_number;		/* current index in scan_info[] */
} my_comp_master;

typedef my_comp_master * my_master_ptr;


/*
 * Support routines that do various essential calculations.
 */

/*
 * 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 */
{
#ifdef DCT_SCALING_SUPPORTED

  /* Sanity check on input image dimensions to prevent overflow in
   * following calculation.
   * We do check jpeg_width and jpeg_height in initial_setup below,
   * 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);

  /* 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;