/*# proc: grp4decomp - CCITT Group 4 decompresses an image.# proc:*//*********************************************************************  File Name:  grp4decomp.c					    **  Modified:   Darlene E. Frederick				    **              Michael D. Garris                                    **  Date:       January 25, 1990				    	    **  Package:    CCITT4 compression routines			    **				   				    **  Contents:   ccitt4_decompress()				    **	       read_compressed_file_into_memory()		    **	       control_decompression()				    **	       prepare_to_decompress()				    **	       set_up_first_and_last_changing_elements_d()	    **	       prepare_to_decompress_next_line()		    **	       set_up_first_line_d()				    **	       crash_d()					    * ********************************************************************/#include <grp4deco.h>#ifdef TIME#include <sys/time.h>#endif#define NOALLOC 0#define ALLOC 1int decomp_alloc_flag;int decomp_write_init_flag;int decomp_read_init_flag;static char 	*all_white,                *output_area,		*all_black;				#ifdef TIMEstruct timeval  t1, t2;struct timezone tz;#endif/********************************************************************* grp4decomp is the main routine of this file.  It does pre-        ** liminary setup, calls routines, and does final processing.        *********************************************************************//*********************************************************************  Arguments							    **  ---------							    **	Passed in:         					    **		   indata - buffer containing the compressed data.  **		   inbytes - the number of bytes in indata.         **  		   width - Width in pixels of uncompressed data.    **  		   height - Number of lines of uncompressed data.   **	Returned:          					    **		   outdata - buffer containing the decompressed data**		   outbytes - the number of bytes in outdata.       *********************************************************************/grp4decomp(indata,inbytes,width,height,outdata,outbytes)unsigned char *indata, *outdata;int inbytes, width, height, *outbytes;{struct compressed_descriptor 	compressed;struct decompressed_descriptor  decompressed;	compressed.pixels_per_line = width;	compressed.number_of_lines = height;	compressed.length_in_bytes = inbytes;        compressed.data = (char *)indata;        decomp_alloc_flag = NOALLOC;        decomp_write_init_flag = True;        decomp_read_init_flag = True;	read_compressed_file_into_memory(&compressed);	decompressed.data = (char *)outdata;	control_decompression( &compressed, &decompressed );	*outbytes =         (decompressed.pixels_per_line >> 3) * decompressed.number_of_lines;}/***************************** control_decompression **************************		calls the functions that decompress the compressed file			*****************************************************************************//*********************************************************************  Arguments							    **  ---------							    **	Passed in:						    **		   compressed - structure containing the # of       **			        pixels per line, the number of      **				lines, and the compressed data.     **	Returned:						    **		   decompressed - structure containing the # of     **			          pixels per line, the number of    **				  lines, and the compressed data.   *********************************************************************/void control_decompression( compressed, decompressed )struct compressed_descriptor *compressed;struct decompressed_descriptor *decompressed;{struct parameters  sole_parameters;struct parameters *params = &sole_parameters;#ifdef TIME  SHORT i;	tz.tz_minuteswest = 0;	tz.tz_dsttime = 0;	gettimeofday(&t1, &tz);#endif	prepare_to_decompress( compressed, decompressed, params );	while(decompress_line( params ) != EOFB )  	      prepare_to_decompress_next_line( params );        /* memory deallocation added by Michael D. Garris 2/23/90 */        free(params->reference_line);        free(params->coding_line);        free(all_white);        free(all_black);#ifdef TIME	gettimeofday(&t2, &tz);	printf("\ntime difference: %ld:%ld\n", t2.tv_sec - t1.tv_sec,	t2.tv_usec - t1.tv_usec);	for(i=0; i<5; i++) printf("%c",'\07');#endif}/************************ read_compressed_file_into_memory *********************			allocates memory for the compressed image     					*****************************************************************************//*********************************************************************  Arguments							    **  ---------							    **	Passed in:						    **		   compressed - structure containing the # of       **			        pixels per line, the number of      **				lines, and the compressed data.     **	Returned:						    **		   compressed - structure containing the # of       **			          pixels per line, the number of    **				  lines, and the compressed data.   *********************************************************************/void read_compressed_file_into_memory(compressed)struct compressed_descriptor *compressed;{     if(decomp_alloc_flag){ 	if((compressed->data = (char *)calloc(compressed->length_in_bytes, sizeof(char))) == NULL) { 	    printf("\nCannot allocate enough memory for compressed file.\n"); 	    exit(1); 	}     }     else        if(compressed->data == NULL){           printf("\nNo memory allocated for input data!\n");           exit(1);        }} /* end read_compressed_file_into_memory() */	 			/*************************** prepare_to_decompress ****************************			initializes variables in preperation for decompression					*****************************************************************************//*********************************************************************  Arguments							    **  ---------							    **	Passed in:						    **		   compressed - structure containing the # of       **			        pixels per line, the number of      **				lines, and the compressed data.     **	Returned:						    **		   decompressed - structure containing the # of     **			          pixels per line, the number of    **				  lines, and the compressed data.   **		   params - structure storing information needed    **			    for comparison and other tasks.         *********************************************************************/void prepare_to_decompress( compressed, decompressed, params )struct compressed_descriptor 	*compressed;struct decompressed_descriptor  *decompressed;struct parameters *params;{		params->max_pixel = compressed->pixels_per_line;	decompressed->pixels_per_line = compressed->pixels_per_line;	decompressed->number_of_lines = compressed->number_of_lines;		set_up_first_line_d( params );	prepare_to_read_bits( compressed->data );        if(decomp_alloc_flag){           decompressed->data = (char *)calloc(            compressed->pixels_per_line *compressed->number_of_lines /Pixels_per_byte, 	   sizeof(char) );        }        else           if(decompressed->data == NULL){              printf("\nNo memory allocated for decompressed data!\n");              exit(1);           }	prepare_to_write_bits_d( decompressed->data, 	 (compressed->pixels_per_line / Pixels_per_byte) );				} /* end decompress() *//******************************* set_up_first_line_d ***************************		initializes variables in preperation for decompressing the first line					******************************************************************************//*********************************************************************  Arguments							    **  ---------							    **	Passed in:						    **		   params - structure storing information needed    **			    for comparison and other tasks.         **	Returned:						    **		   params - structure storing information needed    **			    for comparison and other tasks.         *********************************************************************/void set_up_first_line_d( params )struct parameters *params;{	params->reference_line = 	 (SHORT *)malloc( (params->max_pixel + Extra_positions) * sizeof(SHORT) );	params->coding_line = 	 (SHORT *)malloc( (params->max_pixel + Extra_positions) * sizeof(SHORT) );		*(params->reference_line + 0) = Invalid;			*(params->reference_line + 1) = params->max_pixel;	*(params->reference_line + 2) = params->max_pixel;	*(params->reference_line + 3) = params->max_pixel;		/* initialize first changing element on coding line (a0 = -1) */	*(params->coding_line) = Invalid;		params->index = 0;} /* end set_up_first_line_d() *//******************* set_up_first_and_last_changing_elements_d *****************		initializes the first and last changing elements in the coding line						******************************************************************************//*********************************************************************  Arguments							    **  ---------							    **	Passed in:						    **		   params - structure storing information needed    **			    for comparison and other tasks.         **	Returned:						    **		   params - structure storing information needed    **			    for comparison and other tasks.         *********************************************************************/void set_up_first_and_last_changing_elements_d(params)struct parameters *params;{	*(params->coding_line) = Invalid;		/*	 * set up the imaginary first changing pixel with an illegal value.	 */	 	*(params->coding_line + ++params->index) = params->max_pixel;	*(params->coding_line + ++params->index) = params->max_pixel;	*(params->coding_line + ++params->index) = params->max_pixel;		/* 	 * set up three changing pixels at the end of the line, all of which	 * contain the end-of-line flag "max_pixel."  It is necessary to create	 * three of these flags because the changing elements a0 - b2 are sometimes	 * advanced by more than one element at a time (and therefore could skip	 * over a single flag).	 */}/*********************** prepare_to_decompress_next_line *********************		initializes variables in preperation for decompressing another line				******************************************************************************//*********************************************************************  Arguments							    **  ---------							    **	Passed in:						    **		   params - structure storing information needed    **			    for comparison and other tasks.         **	Returned:						    **		   params - structure storing information needed    **			    for comparison and other tasks.         *********************************************************************/void prepare_to_decompress_next_line( params )struct parameters *params;{		set_up_first_and_last_changing_elements_d( params );	swap_the_reference_and_coding_lines( params );	params->index = 0;} /* end prepare_to_decompress_next_line() */ /******************** swap_the_reference_and_coding_lines ********************		 	      swaps the reference and coding lines				*****************************************************************************//*********************************************************************  Arguments							    **  ---------							    **	Passed in:						    **		   params - structure storing information needed    **			    for comparison and other tasks.         **	Returned:						    **		   params - structure storing information needed    **			    for comparison and other tasks.         *