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 /*

  * jdinput.c

  *

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

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

  * libjpeg-turbo Modifications:

  * Copyright (C) 2010, D. R. Commander.

  * 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 jdphuff.c.

  */

 #define JPEG_INTERNALS

 #include "jinclude.h"

 #include "jpeglib.h"

 #include "jpegcomp.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 JPP((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;

   /* 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);

   /* For now, precision must match compiled-in value... */

   if (cinfo->data_precision != BITS_IN_JSAMPLE)

     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 = DCTSIZE;

     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 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 = DCTSIZE;

 #else

   cinfo->min_DCT_scaled_size = DCTSIZE;

 #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 = DCTSIZE;

 #else

     compptr->DCT_scaled_size = DCTSIZE;

 #endif

     /* 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 * DCTSIZE));

     compptr->height_in_blocks = (JDIMENSION)

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

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

     /* 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*DCTSIZE));

   /* 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_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*DCTSIZE));

     cinfo->MCU_rows_in_scan = (JDIMENSION)

       jdiv_round_up((long) cinfo->image_height,

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

     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_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->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.

  */

 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;

 }