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  1. /*****************************************************//**
  2.  * @brief	Prmitive hexadecimal file viewer (pipe it to 'less' or 'more'
  3.  *		to make it much less primitive... see Usage below).
  4.  * @file	hexview.c
  5.  * @version	0.1A
  6.  * @date	21 Feb, 2012
  7.  * @author 	migf1 <mig_f1@hotmail.com>
  8.  * @par Language:
  9.  *		C (ANSI C89)
  10.  * @par Usage:
  11.  *		hexview [-raw] [filename]
  12.  *		\n
  13.  *		Use -raw as the 1st command-line argument to force raw output
  14.  *		(useful for piping, e.g: hexview -raw file | less)
  15.  *
  16.  * @remark	Feel free to experiment with the values of the pre-processor
  17.  * 		constants: FMT_NCOLS, FMT_PGBREAK and FMT_POS. They affect the
  18.  *		appearance of the output.
  19.  *********************************************************
  20.  */
  21.  
  22. #include <stdio.h>
  23. #include <stdlib.h>
  24. #include <string.h>
  25. #include <ctype.h>
  26.  
  27. #define MAXINPUT	(1024+1)
  28.  
  29. #define FMT_FPOS	8		/* width in # of chars for the file-pos field */
  30. #define FMT_NCOLS	16		/* # of columns in Bytes area(no more than 16)*/
  31. #define FMT_PGBREAK	20		/* # of lines before page-break appears       */
  32.  
  33. #define pressENTER()							\
  34. do{									\
  35. 	char mYcHAr;							\
  36. 	printf( "press ENTER..." );					\
  37. 	while ( (mYcHAr=getchar()) != '\n' && mYcHAr != EOF )		\
  38. 		;							\
  39. }while(0)
  40.  
  41. typedef unsigned char Byte;
  42.  
  43. /*********************************************************//**
  44.  * Read a c-string from stdin.
  45.  *************************************************************
  46.  */
  47. char *s_read( char *s, size_t maxlen )
  48. {
  49. 	size_t len = 0U;
  50.  
  51. 	if ( !s || !fgets( s, maxlen, stdin) )
  52. 		return NULL;
  53.  
  54. 	if ( maxlen > MAXINPUT)
  55. 		maxlen = MAXINPUT;
  56.  
  57. 	if ( s[ (len=strlen(s))-1 ] == '\n')
  58. 		s[ len-1 ] = '\0';
  59.  
  60. 	return s;
  61. }
  62.  
  63. /*********************************************************//**
  64.  * Return user selection on page-breaks
  65.  *************************************************************
  66.  */
  67. char on_pagebreak(void)
  68. {
  69. 	char input[ MAXINPUT ] = {'\0'};
  70.  
  71. 	printf("--- Q to quit, ENTER to continue --- ");
  72. 	fflush( stdout );
  73.  
  74. 	if ( !fgets( input, MAXINPUT, stdin ) )
  75. 		return '\0';
  76.  
  77. 	return tolower( *input );
  78. }
  79.  
  80. /*********************************************************//**
  81.  * Display text labels and other info on the currently displayed page.
  82.  *************************************************************
  83.  */
  84. void show_header( const char *fname, unsigned long int pg )
  85. {
  86. 	unsigned short int i;
  87. 	const unsigned short totalcols = (FMT_FPOS + 1) + (3*FMT_NCOLS) + FMT_NCOLS;
  88.  
  89. 	if ( !fname || !*fname )
  90. 		return;
  91.  
  92. 	/* text labels for Bytes & Chars areas */
  93. 	printf( "%*s | page %lu\n", totalcols/2,fname, pg);
  94. 	printf( "%-*c %-*s%-*s\n", FMT_FPOS,' ', (3*FMT_NCOLS),"Bytes area", FMT_NCOLS,"Chars area" );
  95.  
  96. 	/* text label for file-position */
  97. 	printf("%-*s ", FMT_FPOS,"Pos");
  98.  
  99. 	/* hex indicies for Bytes */
  100. 	for (i=0; i < FMT_NCOLS; i++)
  101. 		printf( "%-2hX ", i);
  102.  
  103. 	/* hex indicies for Characters */
  104. 	for (i=0; i < FMT_NCOLS; i++)
  105. 		printf( "%hX", i);
  106. 	putchar('\n');
  107.  
  108. 	/* separating line */
  109. 	for (i=0; i < totalcols; i++)
  110. 		putchar('-');
  111. 	putchar('\n');
  112.  
  113.  
  114. 	return;
  115. }
  116.  
  117. /*********************************************************//**
  118.  * List the contents of a file in hex/char tabular format.
  119.  *************************************************************
  120.  */
  121. int file_hexlist( const char *fname, const unsigned short int israw )
  122. {
  123. 	Byte buffer[ FMT_NCOLS ] = {0};		/* for reading file chunks into memory*/
  124. 	unsigned long int i, row, pg;		/* byte, row and page counters        */
  125. 	FILE *fp = NULL;			/* file pointer                       */
  126.  
  127. 	if ( !fname || !*fname || NULL == (fp=fopen(fname, "rb")) )
  128. 		return 0;	/* FALSE */
  129.  
  130. 	pg = 0;
  131. 	for (i=0,row=0; !feof(fp); row++,i+=FMT_NCOLS )
  132. 	{
  133. 		unsigned int 	j;
  134. 		size_t 		n;
  135.  
  136. 		/* on page break */
  137. 		if ( !israw && row % FMT_PGBREAK == 0 ) {
  138. 			if ( row != 0 )
  139. 				if ( 'q' == on_pagebreak() )
  140. 					break;
  141. 			show_header(fname, pg+1);
  142. 			pg++;
  143. 		}
  144.  
  145. 		memset( buffer, 0, FMT_NCOLS * sizeof(Byte) );
  146. 		n = fread(buffer, sizeof(Byte), FMT_NCOLS, fp);
  147.  
  148. 		printf( "%08lX ", i);
  149.  
  150. 		for (j=0; j < n; j++)
  151. 			printf("%02hX ", buffer[j] );
  152. 		for (; j < FMT_NCOLS; j++)
  153. 			printf("   ");
  154.  
  155. 		for (j=0; j < n; j++)
  156. 			putchar( isprint(buffer[j]) ? buffer[j] : '.' );
  157. 		for (; j < FMT_NCOLS; j++)
  158. 			putchar(' ');
  159. 		putchar('\n');
  160. 	}
  161. 	putchar('\n');
  162.  
  163. 	fclose(fp);
  164. 	return 1;		/* TRUE */
  165. }
  166.  
  167. /*********************************************************//**
  168.  *
  169.  *************************************************************
  170.  */
  171. int main( int argc, char *argv[] )
  172. {
  173. 	char fname[ MAXINPUT ] = {'\0'};	/* name of the file to be viewed    */
  174. 	unsigned short int israw = 0;		/* FALSE */
  175.  
  176. 	/* parse the command line */
  177. 	if ( 1 == argc )			/* no arguments in the command line */
  178. 	{
  179. 		printf("Enter name of the file: ");
  180. 		s_read( fname, MAXINPUT );
  181. 	}
  182. 	else					/* command line contains arguments */
  183. 	{
  184. 		if ( !strcmp(argv[1], "-raw") )
  185. 			israw = 1;		/* TRUE */
  186. 		else
  187. 			strncpy( fname, argv[1], MAXINPUT-1 );
  188.  
  189. 		if ( israw && argc > 2 )
  190. 			strncpy( fname, argv[2], MAXINPUT-1 );
  191. 		else if ( israw && argc == 2  ) {
  192. 			printf("Enter name of the file: ");
  193. 			s_read( fname, MAXINPUT );
  194. 		}
  195. 	}
  196.  
  197. 	/* list the file contents */
  198. 	if ( !file_hexlist(fname, israw) ) {
  199. 		perror(NULL);
  200. 		goto exit_failure;
  201. 	}
  202.  
  203. 	if ( !israw )
  204. 		pressENTER();
  205. 	exit( EXIT_SUCCESS );
  206.  
  207. exit_failure:
  208. 	if ( !israw )
  209. 		pressENTER();
  210. 	exit( EXIT_FAILURE );
  211. }
  212.  
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https://ideone.com/ttnNJ
language:
C (gcc 8.3)
created:
13 years ago
visibility:
public

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