jdmainct.h (2679B)
1 /* 2 * jdmainct.h 3 * 4 * This file was part of the Independent JPEG Group's software: 5 * Copyright (C) 1994-1996, Thomas G. Lane. 6 * libjpeg-turbo Modifications: 7 * Copyright (C) 2022, D. R. Commander. 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 #include "jpegapicomp.h" 15 #include "jsamplecomp.h" 16 17 18 #if BITS_IN_JSAMPLE != 16 || defined(D_LOSSLESS_SUPPORTED) 19 20 /* Private buffer controller object */ 21 22 typedef struct { 23 struct jpeg_d_main_controller pub; /* public fields */ 24 25 /* Pointer to allocated workspace (M or M+2 row groups). */ 26 _JSAMPARRAY buffer[MAX_COMPONENTS]; 27 28 boolean buffer_full; /* Have we gotten an iMCU row from decoder? */ 29 JDIMENSION rowgroup_ctr; /* counts row groups output to postprocessor */ 30 31 /* Remaining fields are only used in the context case. */ 32 33 /* These are the master pointers to the funny-order pointer lists. */ 34 _JSAMPIMAGE xbuffer[2]; /* pointers to weird pointer lists */ 35 36 int whichptr; /* indicates which pointer set is now in use */ 37 int context_state; /* process_data state machine status */ 38 JDIMENSION rowgroups_avail; /* row groups available to postprocessor */ 39 JDIMENSION iMCU_row_ctr; /* counts iMCU rows to detect image top/bot */ 40 } my_main_controller; 41 42 typedef my_main_controller *my_main_ptr; 43 44 45 /* context_state values: */ 46 #define CTX_PREPARE_FOR_IMCU 0 /* need to prepare for MCU row */ 47 #define CTX_PROCESS_IMCU 1 /* feeding iMCU to postprocessor */ 48 #define CTX_POSTPONED_ROW 2 /* feeding postponed row group */ 49 50 51 LOCAL(void) 52 set_wraparound_pointers(j_decompress_ptr cinfo) 53 /* Set up the "wraparound" pointers at top and bottom of the pointer lists. 54 * This changes the pointer list state from top-of-image to the normal state. 55 */ 56 { 57 my_main_ptr main_ptr = (my_main_ptr)cinfo->main; 58 int ci, i, rgroup; 59 int M = cinfo->_min_DCT_scaled_size; 60 jpeg_component_info *compptr; 61 _JSAMPARRAY xbuf0, xbuf1; 62 63 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 64 ci++, compptr++) { 65 rgroup = (compptr->v_samp_factor * compptr->_DCT_scaled_size) / 66 cinfo->_min_DCT_scaled_size; /* height of a row group of component */ 67 xbuf0 = main_ptr->xbuffer[0][ci]; 68 xbuf1 = main_ptr->xbuffer[1][ci]; 69 for (i = 0; i < rgroup; i++) { 70 xbuf0[i - rgroup] = xbuf0[rgroup * (M + 1) + i]; 71 xbuf1[i - rgroup] = xbuf1[rgroup * (M + 1) + i]; 72 xbuf0[rgroup * (M + 2) + i] = xbuf0[i]; 73 xbuf1[rgroup * (M + 2) + i] = xbuf1[i]; 74 } 75 } 76 } 77 78 #endif /* BITS_IN_JSAMPLE != 16 || defined(D_LOSSLESS_SUPPORTED) */