/*

 * jdinput.c

 *

 * Copyright (C) 1991-1997, Thomas G. Lane.

 * Modified 2002-2020 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 input control logic for the JPEG decompressor.

 * These routines are concerned with controlling the decompressor's input

 * processing (marker reading and coefficient decoding).  The actual input

 * reading is done in jdmarker.c, jdhuff.c, and jdarith.c.

 */

#define JPEG_INTERNALS

#include "jinclude.h"

#include "jpeglib.h"

/* Private state */

typedef struct {

  struct jpeg_input_controller pub; /* public fields */

  int inheaders;    /* Nonzero until first SOS is reached */

} my_input_controller;

typedef my_input_controller * my_inputctl_ptr;

/* Forward declarations */

METHODDEF(int) consume_markers JPP((j_decompress_ptr cinfo));

/*

 * Routines to calculate various quantities related to the size of the image.

 */

/*

 * Compute output 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_core_output_dimensions (j_decompress_ptr cinfo)

/* Do computations that are needed before master selection phase.

 * This function is used for transcoding and full decompression.

 */

{

#ifdef IDCT_SCALING_SUPPORTED

  int ci;

  jpeg_component_info *compptr;

  /* Compute actual output image dimensions and DCT scaling choices. */

  if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom) {

    /* Provide 1/block_size scaling */

    cinfo->output_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width, (long) cinfo->block_size);

    cinfo->output_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height, (long) cinfo->block_size);

    cinfo->min_DCT_h_scaled_size = 1;

    cinfo->min_DCT_v_scaled_size = 1;

  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 2) {

    /* Provide 2/block_size scaling */

    cinfo->output_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * 2L, (long) cinfo->block_size);

    cinfo->output_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * 2L, (long) cinfo->block_size);

    cinfo->min_DCT_h_scaled_size = 2;

    cinfo->min_DCT_v_scaled_size = 2;

  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 3) {

    /* Provide 3/block_size scaling */

    cinfo->output_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * 3L, (long) cinfo->block_size);

    cinfo->output_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * 3L, (long) cinfo->block_size);

    cinfo->min_DCT_h_scaled_size = 3;

    cinfo->min_DCT_v_scaled_size = 3;

  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 4) {

    /* Provide 4/block_size scaling */

    cinfo->output_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * 4L, (long) cinfo->block_size);

    cinfo->output_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * 4L, (long) cinfo->block_size);

    cinfo->min_DCT_h_scaled_size = 4;

    cinfo->min_DCT_v_scaled_size = 4;

  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 5) {

    /* Provide 5/block_size scaling */

    cinfo->output_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * 5L, (long) cinfo->block_size);

    cinfo->output_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * 5L, (long) cinfo->block_size);

    cinfo->min_DCT_h_scaled_size = 5;

    cinfo->min_DCT_v_scaled_size = 5;

  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 6) {

    /* Provide 6/block_size scaling */

    cinfo->output_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * 6L, (long) cinfo->block_size);

    cinfo->output_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * 6L, (long) cinfo->block_size);

    cinfo->min_DCT_h_scaled_size = 6;

    cinfo->min_DCT_v_scaled_size = 6;

  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 7) {

    /* Provide 7/block_size scaling */

    cinfo->output_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * 7L, (long) cinfo->block_size);

    cinfo->output_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * 7L, (long) cinfo->block_size);

    cinfo->min_DCT_h_scaled_size = 7;

    cinfo->min_DCT_v_scaled_size = 7;

  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 8) {

    /* Provide 8/block_size scaling */

    cinfo->output_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * 8L, (long) cinfo->block_size);

    cinfo->output_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * 8L, (long) cinfo->block_size);

    cinfo->min_DCT_h_scaled_size = 8;

    cinfo->min_DCT_v_scaled_size = 8;

  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 9) {

    /* Provide 9/block_size scaling */

    cinfo->output_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * 9L, (long) cinfo->block_size);

    cinfo->output_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * 9L, (long) cinfo->block_size);

    cinfo->min_DCT_h_scaled_size = 9;

    cinfo->min_DCT_v_scaled_size = 9;

  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 10) {

    /* Provide 10/block_size scaling */

    cinfo->output_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * 10L, (long) cinfo->block_size);

    cinfo->output_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * 10L, (long) cinfo->block_size);

    cinfo->min_DCT_h_scaled_size = 10;

    cinfo->min_DCT_v_scaled_size = 10;

  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 11) {

    /* Provide 11/block_size scaling */

    cinfo->output_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * 11L, (long) cinfo->block_size);

    cinfo->output_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * 11L, (long) cinfo->block_size);

    cinfo->min_DCT_h_scaled_size = 11;

    cinfo->min_DCT_v_scaled_size = 11;

  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 12) {

    /* Provide 12/block_size scaling */

    cinfo->output_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * 12L, (long) cinfo->block_size);

    cinfo->output_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * 12L, (long) cinfo->block_size);

    cinfo->min_DCT_h_scaled_size = 12;

    cinfo->min_DCT_v_scaled_size = 12;

  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 13) {

    /* Provide 13/block_size scaling */

    cinfo->output_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * 13L, (long) cinfo->block_size);

    cinfo->output_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * 13L, (long) cinfo->block_size);

    cinfo->min_DCT_h_scaled_size = 13;

    cinfo->min_DCT_v_scaled_size = 13;

  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 14) {

    /* Provide 14/block_size scaling */

    cinfo->output_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * 14L, (long) cinfo->block_size);

    cinfo->output_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * 14L, (long) cinfo->block_size);

    cinfo->min_DCT_h_scaled_size = 14;

    cinfo->min_DCT_v_scaled_size = 14;

  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 15) {

    /* Provide 15/block_size scaling */

    cinfo->output_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * 15L, (long) cinfo->block_size);

    cinfo->output_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * 15L, (long) cinfo->block_size);

    cinfo->min_DCT_h_scaled_size = 15;

    cinfo->min_DCT_v_scaled_size = 15;

  } else {

    /* Provide 16/block_size scaling */

    cinfo->output_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * 16L, (long) cinfo->block_size);

    cinfo->output_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * 16L, (long) cinfo->block_size);

    cinfo->min_DCT_h_scaled_size = 16;

    cinfo->min_DCT_v_scaled_size = 16;

  }

  /* Recompute dimensions of components */

  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;

       ci++, compptr++) {

    compptr->DCT_h_scaled_size = cinfo->min_DCT_h_scaled_size;

    compptr->DCT_v_scaled_size = cinfo->min_DCT_v_scaled_size;

  }

#else /* !IDCT_SCALING_SUPPORTED */

  /* Hardwire it to "no scaling" */

  cinfo->output_width = cinfo->image_width;

  cinfo->output_height = cinfo->image_height;

  /* initial_setup has already initialized DCT_scaled_size,

   * and has computed unscaled downsampled_width and downsampled_height.

   */

#endif /* IDCT_SCALING_SUPPORTED */

}

LOCAL(void)

initial_setup (j_decompress_ptr cinfo)

/* Called once, when first SOS marker is reached */

{

  int ci;

  jpeg_component_info *compptr;

  /* Make sure image isn't bigger than I can handle */

  if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||

      (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)

    ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);

  /* Only 8 to 12 bits data precision are supported for DCT based JPEG */

  if (cinfo->data_precision < 8 || cinfo->data_precision > 12)

    ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);

  /* Check that number of components won't exceed internal array sizes */

  if (cinfo->num_components > MAX_COMPONENTS)

    ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,

       MAX_COMPONENTS);

  /* Compute maximum sampling factors; check factor validity */

  cinfo->max_h_samp_factor = 1;

  cinfo->max_v_samp_factor = 1;

  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;

       ci++, compptr++) {

    if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||

  compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)

      ERREXIT(cinfo, JERR_BAD_SAMPLING);

    cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,

           compptr->h_samp_factor);

    cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,

           compptr->v_samp_factor);

  }

  /* Derive block_size, natural_order, and lim_Se */

  if (cinfo->is_baseline || (cinfo->progressive_mode &&

      cinfo->comps_in_scan)) { /* no pseudo SOS marker */

    cinfo->block_size = DCTSIZE;

    cinfo->natural_order = jpeg_natural_order;

    cinfo->lim_Se = DCTSIZE2-1;

  } else

    switch (cinfo->Se) {

    case (1*1-1):

      cinfo->block_size = 1;

      cinfo->natural_order = jpeg_natural_order; /* not needed */

      cinfo->lim_Se = cinfo->Se;

      break;

    case (2*2-1):

      cinfo->block_size = 2;

      cinfo->natural_order = jpeg_natural_order2;

      cinfo->lim_Se = cinfo->Se;

      break;

    case (3*3-1):

      cinfo->block_size = 3;

      cinfo->natural_order = jpeg_natural_order3;

      cinfo->lim_Se = cinfo->Se;

      break;

    case (4*4-1):

      cinfo->block_size = 4;

      cinfo->natural_order = jpeg_natural_order4;

      cinfo->lim_Se = cinfo->Se;

      break;

    case (5*5-1):

      cinfo->block_size = 5;

      cinfo->natural_order = jpeg_natural_order5;

      cinfo->lim_Se = cinfo->Se;

      break;

    case (6*6-1):

      cinfo->block_size = 6;

      cinfo->natural_order = jpeg_natural_order6;

      cinfo->lim_Se = cinfo->Se;

      break;

    case (7*7-1):

      cinfo->block_size = 7;

      cinfo->natural_order = jpeg_natural_order7;

      cinfo->lim_Se = cinfo->Se;

      break;

    case (8*8-1):

      cinfo->block_size = 8;

      cinfo->natural_order = jpeg_natural_order;

      cinfo->lim_Se = DCTSIZE2-1;

      break;

    case (9*9-1):

      cinfo->block_size = 9;

      cinfo->natural_order = jpeg_natural_order;

      cinfo->lim_Se = DCTSIZE2-1;

      break;

    case (10*10-1):

      cinfo->block_size = 10;

      cinfo->natural_order = jpeg_natural_order;

      cinfo->lim_Se = DCTSIZE2-1;

      break;

    case (11*11-1):

      cinfo->block_size = 11;

      cinfo->natural_order = jpeg_natural_order;

      cinfo->lim_Se = DCTSIZE2-1;

      break;

    case (12*12-1):

      cinfo->block_size = 12;

      cinfo->natural_order = jpeg_natural_order;

      cinfo->lim_Se = DCTSIZE2-1;

      break;

    case (13*13-1):

      cinfo->block_size = 13;

      cinfo->natural_order = jpeg_natural_order;

      cinfo->lim_Se = DCTSIZE2-1;

      break;

    case (14*14-1):

      cinfo->block_size = 14;

      cinfo->natural_order = jpeg_natural_order;

      cinfo->lim_Se = DCTSIZE2-1;

      break;

    case (15*15-1):

      cinfo->block_size = 15;

      cinfo->natural_order = jpeg_natural_order;

      cinfo->lim_Se = DCTSIZE2-1;

      break;

    case (16*16-1):

      cinfo->block_size = 16;

      cinfo->natural_order = jpeg_natural_order;

      cinfo->lim_Se = DCTSIZE2-1;

      break;

    default:

      ERREXIT4(cinfo, JERR_BAD_PROGRESSION,

         cinfo->Ss, cinfo->Se, cinfo->Ah, cinfo->Al);

    }

  /* We initialize DCT_scaled_size and min_DCT_scaled_size to block_size.

   * In the full decompressor,

   * this will be overridden by jpeg_calc_output_dimensions in jdmaster.c;

   * but in the transcoder,

   * jpeg_calc_output_dimensions is not used, so we must do it here.

   */

  cinfo->min_DCT_h_scaled_size = cinfo->block_size;

  cinfo->min_DCT_v_scaled_size = cinfo->block_size;

  /* Compute dimensions of components */

  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;

       ci++, compptr++) {

    compptr->DCT_h_scaled_size = cinfo->block_size;

    compptr->DCT_v_scaled_size = cinfo->block_size;

    /* Size in DCT blocks */

    compptr->width_in_blocks = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,

        (long) (cinfo->max_h_samp_factor * cinfo->block_size));

    compptr->height_in_blocks = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,

        (long) (cinfo->max_v_samp_factor * cinfo->block_size));

    /* downsampled_width and downsampled_height will also be overridden by

     * jdmaster.c if we are doing full decompression.  The transcoder library

     * doesn't use these values, but the calling application might.

     */

    /* Size in samples */

    compptr->downsampled_width = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,

        (long) cinfo->max_h_samp_factor);

    compptr->downsampled_height = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,

        (long) cinfo->max_v_samp_factor);

    /* Mark component needed, until color conversion says otherwise */

    compptr->component_needed = TRUE;

    /* Mark no quantization table yet saved for component */

    compptr->quant_table = NULL;

  }

  /* Compute number of fully interleaved MCU rows. */

  cinfo->total_iMCU_rows = (JDIMENSION)

    jdiv_round_up((long) cinfo->image_height,

            (long) (cinfo->max_v_samp_factor * cinfo->block_size));

  /* Decide whether file contains multiple scans */

  if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode)

    cinfo->inputctl->has_multiple_scans = TRUE;

  else

    cinfo->inputctl->has_multiple_scans = FALSE;

}

LOCAL(void)

per_scan_setup (j_decompress_ptr cinfo)

/* Do computations that are needed before processing a JPEG scan */

/* cinfo->comps_in_scan and cinfo->cur_comp_info[] were set from SOS marker */

{

  int ci, mcublks, tmp;

  jpeg_component_info *compptr;

  if (cinfo->comps_in_scan == 1) {

    /* Noninterleaved (single-component) scan */

    compptr = cinfo->cur_comp_info[0];

    /* Overall image size in MCUs */

    cinfo->MCUs_per_row = compptr->width_in_blocks;

    cinfo->MCU_rows_in_scan = compptr->height_in_blocks;

    /* For noninterleaved scan, always one block per MCU */

    compptr->MCU_width = 1;

    compptr->MCU_height = 1;

    compptr->MCU_blocks = 1;

    compptr->MCU_sample_width = compptr->DCT_h_scaled_size;

    compptr->last_col_width = 1;

    /* For noninterleaved scans, it is convenient to define last_row_height

     * as the number of block rows present in the last iMCU row.

     */

    tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);

    if (tmp == 0) tmp = compptr->v_samp_factor;

    compptr->last_row_height = tmp;

    /* Prepare array describing MCU composition */

    cinfo->blocks_in_MCU = 1;

    cinfo->MCU_membership[0] = 0;

  } else {

    /* Interleaved (multi-component) scan */

    if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)

      ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,

         MAX_COMPS_IN_SCAN);

    /* Overall image size in MCUs */

    cinfo->MCUs_per_row = (JDIMENSION)

      jdiv_round_up((long) cinfo->image_width,

        (long) (cinfo->max_h_samp_factor * cinfo->block_size));

    cinfo->MCU_rows_in_scan = cinfo->total_iMCU_rows;

    cinfo->blocks_in_MCU = 0;

    for (ci = 0; ci < cinfo->comps_in_scan; ci++) {

      compptr = cinfo->cur_comp_info[ci];

      /* Sampling factors give # of blocks of component in each MCU */

      compptr->MCU_width = compptr->h_samp_factor;

      compptr->MCU_height = compptr->v_samp_factor;

      compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;

      compptr->MCU_sample_width = compptr->MCU_width * compptr->DCT_h_scaled_size;

      /* Figure number of non-dummy blocks in last MCU column & row */

      tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);

      if (tmp == 0) tmp = compptr->MCU_width;

      compptr->last_col_width = tmp;

      tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);

      if (tmp == 0) tmp = compptr->MCU_height;

      compptr->last_row_height = tmp;

      /* Prepare array describing MCU composition */

      mcublks = compptr->MCU_blocks;

      if (cinfo->blocks_in_MCU + mcublks > D_MAX_BLOCKS_IN_MCU)

  ERREXIT(cinfo, JERR_BAD_MCU_SIZE);

      while (mcublks-- > 0) {

  cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;

      }

    }

  }

}

/*

 * Save away a copy of the Q-table referenced by each component present

 * in the current scan, unless already saved during a prior scan.

 *

 * In a multiple-scan JPEG file, the encoder could assign different components

 * the same Q-table slot number, but change table definitions between scans

 * so that each component uses a different Q-table.  (The IJG encoder is not

 * currently capable of doing this, but other encoders might.)  Since we want

 * to be able to dequantize all the components at the end of the file, this

 * means that we have to save away the table actually used for each component.

 * We do this by copying the table at the start of the first scan containing

 * the component.

 * The JPEG spec prohibits the encoder from changing the contents of a Q-table

 * slot between scans of a component using that slot.  If the encoder does so

 * anyway, this decoder will simply use the Q-table values that were current

 * at the start of the first scan for the component.

 *

 * The decompressor output side looks only at the saved quant tables,

 * not at the current Q-table slots.

 */

LOCAL(void)

latch_quant_tables (j_decompress_ptr cinfo)

{

  int ci, qtblno;

  jpeg_component_info *compptr;

  JQUANT_TBL * qtbl;

  for (ci = 0; ci < cinfo->comps_in_scan; ci++) {

    compptr = cinfo->cur_comp_info[ci];

    /* No work if we already saved Q-table for this component */

    if (compptr->quant_table != NULL)

      continue;

    /* Make sure specified quantization table is present */

    qtblno = compptr->quant_tbl_no;

    if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS ||

  cinfo->quant_tbl_ptrs[qtblno] == NULL)

      ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno);

    /* OK, save away the quantization table */

    qtbl = (JQUANT_TBL *) (*cinfo->mem->alloc_small)

      ((j_common_ptr) cinfo, JPOOL_IMAGE, SIZEOF(JQUANT_TBL));

    MEMCOPY(qtbl, cinfo->quant_tbl_ptrs[qtblno], SIZEOF(JQUANT_TBL));

    compptr->quant_table = qtbl;

  }

}

/*

 * Initialize the input modules to read a scan of compressed data.

 * The first call to this is done by jdmaster.c after initializing

 * the entire decompressor (during jpeg_start_decompress).

 * Subsequent calls come from consume_markers, below.

 */

METHODDEF(void)

start_input_pass (j_decompress_ptr cinfo)

{

  per_scan_setup(cinfo);

  latch_quant_tables(cinfo);

  (*cinfo->entropy->start_pass) (cinfo);

  (*cinfo->coef->start_input_pass) (cinfo);

  cinfo->inputctl->consume_input = cinfo->coef->consume_data;

}

/*

 * Finish up after inputting a compressed-data scan.

 * This is called by the coefficient controller after it's read all

 * the expected data of the scan.

 */

METHODDEF(void)

finish_input_pass (j_decompress_ptr cinfo)

{

  (*cinfo->entropy->finish_pass) (cinfo);

  cinfo->inputctl->consume_input = consume_markers;

}

/*

 * Read JPEG markers before, between, or after compressed-data scans.

 * Change state as necessary when a new scan is reached.

 * Return value is JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.

 *

 * The consume_input method pointer points either here or to the

 * coefficient controller's consume_data routine, depending on whether

 * we are reading a compressed data segment or inter-segment markers.

 *

 * Note: This function should NOT return a pseudo SOS marker (with zero

 * component number) to the caller.  A pseudo marker received by

 * read_markers is processed and then skipped for other markers.

 */

METHODDEF(int)

consume_markers (j_decompress_ptr cinfo)

{

  my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;

  int val;

  if (inputctl->pub.eoi_reached) /* After hitting EOI, read no further */

    return JPEG_REACHED_EOI;

  for (;;) {     /* Loop to pass pseudo SOS marker */

    val = (*cinfo->marker->read_markers) (cinfo);

    switch (val) {

    case JPEG_REACHED_SOS: /* Found SOS */

      if (inputctl->inheaders) { /* 1st SOS */

  if (inputctl->inheaders == 1)

    initial_setup(cinfo);

  if (cinfo->comps_in_scan == 0) { /* pseudo SOS marker */

    inputctl->inheaders = 2;

    break;

  }

  inputctl->inheaders = 0;

  /* Note: start_input_pass must be called by jdmaster.c

   * before any more input can be consumed.  jdapimin.c is

   * responsible for enforcing this sequencing.

   */

      } else {     /* 2nd or later SOS marker */

  if (! inputctl->pub.has_multiple_scans)

    ERREXIT(cinfo, JERR_EOI_EXPECTED); /* Oops, I wasn't expecting this! */

  if (cinfo->comps_in_scan == 0) /* unexpected pseudo SOS marker */

    break;

  start_input_pass(cinfo);

      }

      return val;

    case JPEG_REACHED_EOI: /* Found EOI */

      inputctl->pub.eoi_reached = TRUE;

      if (inputctl->inheaders) { /* Tables-only datastream, apparently */

  if (cinfo->marker->saw_SOF)

    ERREXIT(cinfo, JERR_SOF_NO_SOS);

      } else {

  /* Prevent infinite loop in coef ctlr's decompress_data routine

   * if user set output_scan_number larger than number of scans.

   */

  if (cinfo->output_scan_number > cinfo->input_scan_number)

    cinfo->output_scan_number = cinfo->input_scan_number;

      }

      return val;

    case JPEG_SUSPENDED:

      return val;

    default:

      return val;

    }

  }

}

/*

 * Reset state to begin a fresh datastream.

 */

METHODDEF(void)

reset_input_controller (j_decompress_ptr cinfo)

{

  my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;

  inputctl->pub.consume_input = consume_markers;

  inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */

  inputctl->pub.eoi_reached = FALSE;

  inputctl->inheaders = 1;

  /* Reset other modules */

  (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);

  (*cinfo->marker->reset_marker_reader) (cinfo);

  /* Reset progression state -- would be cleaner if entropy decoder did this */

  cinfo->coef_bits = NULL;

}

/*

 * Initialize the input controller module.

 * This is called only once, when the decompression object is created.

 */

GLOBAL(void)

jinit_input_controller (j_decompress_ptr cinfo)

{

  my_inputctl_ptr inputctl;

  /* Create subobject in permanent pool */

  inputctl = (my_inputctl_ptr) (*cinfo->mem->alloc_small)

    ((j_common_ptr) cinfo, JPOOL_PERMANENT, SIZEOF(my_input_controller));

  cinfo->inputctl = &inputctl->pub;

  /* Initialize method pointers */

  inputctl->pub.consume_input = consume_markers;

  inputctl->pub.reset_input_controller = reset_input_controller;

  inputctl->pub.start_input_pass = start_input_pass;

  inputctl->pub.finish_input_pass = finish_input_pass;

  /* Initialize state: can't use reset_input_controller since we don't

   * want to try to reset other modules yet.

   */

  inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */

  inputctl->pub.eoi_reached = FALSE;

  inputctl->inheaders = 1;

}