Line data    Source code

       1             : /*
       2             :  * jdcoefct.h
       3             :  *
       4             :  * This file was part of the Independent JPEG Group's software:
       5             :  * Copyright (C) 1994-1997, Thomas G. Lane.
       6             :  * libjpeg-turbo Modifications:
       7             :  * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
       8             :  * For conditions of distribution and use, see the accompanying README.ijg
       9             :  * file.
      10             :  */
      11             : 
      12             : #define JPEG_INTERNALS
      13             : #include "jpeglib.h"
      14             : 
      15             : 
      16             : /* Block smoothing is only applicable for progressive JPEG, so: */
      17             : #ifndef D_PROGRESSIVE_SUPPORTED
      18             : #undef BLOCK_SMOOTHING_SUPPORTED
      19             : #endif
      20             : 
      21             : 
      22             : /* Private buffer controller object */
      23             : 
      24             : typedef struct {
      25             :   struct jpeg_d_coef_controller pub; /* public fields */
      26             : 
      27             :   /* These variables keep track of the current location of the input side. */
      28             :   /* cinfo->input_iMCU_row is also used for this. */
      29             :   JDIMENSION MCU_ctr;           /* counts MCUs processed in current row */
      30             :   int MCU_vert_offset;          /* counts MCU rows within iMCU row */
      31             :   int MCU_rows_per_iMCU_row;    /* number of such rows needed */
      32             : 
      33             :   /* The output side's location is represented by cinfo->output_iMCU_row. */
      34             : 
      35             :   /* In single-pass modes, it's sufficient to buffer just one MCU.
      36             :    * We allocate a workspace of D_MAX_BLOCKS_IN_MCU coefficient blocks,
      37             :    * and let the entropy decoder write into that workspace each time.
      38             :    * In multi-pass modes, this array points to the current MCU's blocks
      39             :    * within the virtual arrays; it is used only by the input side.
      40             :    */
      41             :   JBLOCKROW MCU_buffer[D_MAX_BLOCKS_IN_MCU];
      42             : 
      43             :   /* Temporary workspace for one MCU */
      44             :   JCOEF *workspace;
      45             : 
      46             : #ifdef D_MULTISCAN_FILES_SUPPORTED
      47             :   /* In multi-pass modes, we need a virtual block array for each component. */
      48             :   jvirt_barray_ptr whole_image[MAX_COMPONENTS];
      49             : #endif
      50             : 
      51             : #ifdef BLOCK_SMOOTHING_SUPPORTED
      52             :   /* When doing block smoothing, we latch coefficient Al values here */
      53             :   int *coef_bits_latch;
      54             : #define SAVED_COEFS  6          /* we save coef_bits[0..5] */
      55             : #endif
      56             : } my_coef_controller;
      57             : 
      58             : typedef my_coef_controller *my_coef_ptr;
      59             : 
      60             : 
      61             : LOCAL(void)
      62           0 : start_iMCU_row (j_decompress_ptr cinfo)
      63             : /* Reset within-iMCU-row counters for a new row (input side) */
      64             : {
      65           0 :   my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
      66             : 
      67             :   /* In an interleaved scan, an MCU row is the same as an iMCU row.
      68             :    * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
      69             :    * But at the bottom of the image, process only what's left.
      70             :    */
      71           0 :   if (cinfo->comps_in_scan > 1) {
      72           0 :     coef->MCU_rows_per_iMCU_row = 1;
      73             :   } else {
      74           0 :     if (cinfo->input_iMCU_row < (cinfo->total_iMCU_rows-1))
      75           0 :       coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
      76             :     else
      77           0 :       coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
      78             :   }
      79             : 
      80           0 :   coef->MCU_ctr = 0;
      81           0 :   coef->MCU_vert_offset = 0;
      82           0 : }