/*

 * jdinput.c

 *

 * This file was part of the Independent JPEG Group's software:

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

 * Lossless JPEG Modifications:

 * Copyright (C) 1999, Ken Murchison.

 * libjpeg-turbo Modifications:

 * Copyright (C) 2010, 2016, 2018, 2022, 2024, D. R. Commander.

 * Copyright (C) 2015, Google, Inc.

 * For conditions of distribution and use, see the accompanying README.ijg

 * 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/difference decoding).

 * The actual input reading is done in jdmarker.c, jdhuff.c, jdphuff.c,

 * and jdlhuff.c.

 */

#define JPEG_INTERNALS

#include "jinclude.h"

#include "jpeglib.h"

#include "jpegapicomp.h"

/* Private state */

typedef struct {

  struct jpeg_input_controller pub; /* public fields */

  boolean inheaders;            /* TRUE until first SOS is reached */

} my_input_controller;

typedef my_input_controller *my_inputctl_ptr;

/* Forward declarations */

METHODDEF(int) consume_markers(j_decompress_ptr cinfo);

/*

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

 */

LOCAL(void)

initial_setup(j_decompress_ptr cinfo)

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

{

  int ci;

  jpeg_component_info *compptr;

  int data_unit = cinfo->master->lossless ? 1 : DCTSIZE;

  /* 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);

  /* Lossy JPEG images must have 8 or 12 bits per sample.  Lossless JPEG images

   * can have 2 to 16 bits per sample.

   */

#ifdef D_LOSSLESS_SUPPORTED

  if (cinfo->master->lossless) {

    if (cinfo->data_precision < 2 || cinfo->data_precision > 16)

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

  } else

#endif

  {

    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);

  }

#if JPEG_LIB_VERSION >= 80

  cinfo->block_size = data_unit;

  cinfo->natural_order = jpeg_natural_order;

  cinfo->lim_Se = DCTSIZE2 - 1;

#endif

  /* We initialize DCT_scaled_size and min_DCT_scaled_size to DCTSIZE in lossy

   * mode.  In the full decompressor, this will be overridden by jdmaster.c;

   * but in the transcoder, jdmaster.c is not used, so we must do it here.

   */

#if JPEG_LIB_VERSION >= 70

  cinfo->min_DCT_h_scaled_size = cinfo->min_DCT_v_scaled_size = data_unit;

#else

  cinfo->min_DCT_scaled_size = data_unit;

#endif

  /* Compute dimensions of components */

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

       ci++, compptr++) {

#if JPEG_LIB_VERSION >= 70

    compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = data_unit;

#else

    compptr->DCT_scaled_size = data_unit;

#endif

    /* Size in data units */

    compptr->width_in_blocks = (JDIMENSION)

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

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

    compptr->height_in_blocks = (JDIMENSION)

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

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

    /* Set the first and last MCU columns to decompress from multi-scan images.

     * By default, decompress all of the MCU columns.

     */

    cinfo->master->first_MCU_col[ci] = 0;

    cinfo->master->last_MCU_col[ci] = compptr->width_in_blocks - 1;

    /* 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 * data_unit));

  /* 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;

  int data_unit = cinfo->master->lossless ? 1 : DCTSIZE;

  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 data unit per MCU */

    compptr->MCU_width = 1;

    compptr->MCU_height = 1;

    compptr->MCU_blocks = 1;

    compptr->MCU_sample_width = compptr->_DCT_scaled_size;

    compptr->last_col_width = 1;

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

     * as the number of data unit 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 * data_unit));

    cinfo->MCU_rows_in_scan = (JDIMENSION)

      jdiv_round_up((long)cinfo->image_height,

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

    cinfo->blocks_in_MCU = 0;

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

      compptr = cinfo->cur_comp_info[ci];

      /* Sampling factors give # of data units 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_scaled_size;

      /* Figure number of non-dummy data units 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.

 * Rec. ITU-T T.81 | ISO/IEC 10918-1 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));

    memcpy(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);

  if (!cinfo->master->lossless)

    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 or difference controller after it's read

 * all the expected data of the scan.

 */

METHODDEF(void)

finish_input_pass(j_decompress_ptr 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 or difference controller's consume_data routine, depending on

 * whether we are reading a compressed data segment or inter-segment 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;

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

  switch (val) {

  case JPEG_REACHED_SOS:        /* Found SOS */

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

      initial_setup(cinfo);

      inputctl->inheaders = FALSE;

      /* 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! */

      start_input_pass(cinfo);

    }

    break;

  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;

    }

    break;

  case JPEG_SUSPENDED:

    break;

  }

  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 = TRUE;

  /* 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 = (struct jpeg_input_controller *)inputctl;

  /* 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 = TRUE;

}