//=========================================================================
#define PROGRAMMER "BAHN, William"
#define PROG_CODE  "wbah"
#define COURSE     "ECE-1021"
#define YEAR       (2004)
#define TERM       "Spring"
#define SECTION    (0)
#define ASSIGNMENT "Example Program"
#define REVISION   (0)
#define TITLE      "File Dump Program"
#define SUBTITLE   "Last Modified on 08 MAR 04"
#define EMAIL      "wbahn@eas.uccs.edu"
#define FILENAME   "filedump.c"
//=========================================================================

// PROBLEM:
//
// Write a program that displays the contents of a file byte-by-byte.
// Both the byte's value (in Hex) and the ASCII character (if it is
// printable) should be displayed. Non-printable ASCII codes should be
// displayed as a period (.).
//
// PSEUDOCODE:
//
// 1) TASK: Get the file name
// 2) TASK: Open and verify the file
// 3) TASK: Display Contents of File
// 3.1) TASK: Display Header
// 3.2) TASK: Display File Contents 16 bytes at a time
// 4) TASK: Display Total Byte Count

//== INCLUDE FILES ========================================================
#include <stdio.h>  // EOF, fopen(), fclose(), feof(), printf(), fgets()
#include <string.h> // strncpy()
#include <ctype.h>  // isprint()

//== MACRO DEFINITIONS ===================================================
#define MAXSTRLEN (81)
#define MAXMARKS  (60)

//== FUNCTION PROTOTYPES ==================================================
void PrintHeader(void);
char *stripCR(char *s);
long int DumpFile(FILE *fp);
void DumpHeader(void);
long int DumpBody(FILE *fp);

//== MAIN FUNCTION ========================================================
int main(int argc, char *argv[])
{
	char filename[MAXSTRLEN];
	FILE *fp;
	long int bytes;

	PrintHeader();

	//------------------------------------------------------------------
	// 1) TASK: Get the file name
	//------------------------------------------------------------------
	// Check for file name on command line, get from user if not found
	if(argc < 2)
	{
		printf("Enter filename: ");
		fgets(filename, MAXSTRLEN, stdin);
		stripCR(filename);
	}
	else
	{
		strncpy(filename, argv[1], MAXSTRLEN);
	}

	//------------------------------------------------------------------
	// 2) TASK: Open and verify the file
	//------------------------------------------------------------------
	// Open file for reading (in binary mode)
	printf("Attempting to open file: <%s>\n", filename);

	fp = fopen(filename, "rb");

	if(NULL == fp)
	{
		printf("Failed to open file for reading - abort!\n");
		return(1);
	}

	//------------------------------------------------------------------
	// 3) TASK: Display Contents of File
	//------------------------------------------------------------------
	printf("\nFile Contents:\n\n");
	bytes = DumpFile(fp);
	fclose(fp);

	//------------------------------------------------------------------
	// 4) TASK: Display Total Byte Count
	//------------------------------------------------------------------
	printf("\nTotal bytes: %li\n", bytes);

	return(0);
}

//== SUPPORT FUNCTIONS ====================================================

void PrintHeader(void)
{
	printf("========================================"
			 "=======================================\n");
	printf("Course....... %s-%i (%s %i)\n", COURSE, SECTION, TERM, YEAR);
	printf("Programmer... %s (%s)\n", PROGRAMMER, PROG_CODE);
	printf("Assignment... %s (Rev %i) (Source Code in %s)\n",
		ASSIGNMENT, REVISION, FILENAME);
	printf("Description.. %s\n", TITLE);
	printf("              %s\n", SUBTITLE);
	printf("========================================"
			 "=======================================\n");

	return;
}

char *stripCR(char *s)
{
	char *a;

	a = s;

	do
	{
		switch(*a)
		{
			case '\n':
			case '\f':
				*a = '\0';
		}
	} while('\0' != *(a++));

	return(s);
}

long int DumpFile(FILE *fp)
{
	long int bytes;

	bytes = 0;

	// 1) TASK: Display Header
	DumpHeader();

	// 2) TASK: Display File Contents 16 bytes at a time
	bytes = DumpBody(fp);

	return(bytes);
}

void DumpHeader(void)
{
	int i;

	// 1) TASK: Display Header
	// 1.1) Print column headings
	printf("   BLOCK   ");
	for(i = 0; i < 16; i++)
	{
		printf("%c", (!(i%4))? '|' : ' ');
		printf("% 2X", i);
	}

	printf("|  ");
	for(i = 0; i < 16; i++)
	{
		printf("%1X", i);
	}
	printf("\n");

	// 1.2) Print dividing line
	printf("===========");
	for(i = 0; i < 16; i++)
	{
		printf("%c", (!(i%4))? '|' : ' ');
		printf("==");
	}

	printf("|  ");
	for(i = 0; i < 16; i++)
	{
		printf("=");
	}
	printf("\n");
	return;
}

long int DumpBody(FILE *fp)
{
	int i;
	long int bytes;
	int c[16];

	bytes = 0;

	// 2) TASK: Display File Contents 16 bytes at a time

	// Initialize counter variables
	bytes = 0;

	// Loop until end of file is reached - FYI: EOF may occur within a line.
	while(!feof(fp))
	{
		//-------------------------------------------------------------
		// Print Byte Values
		//-------------------------------------------------------------

		// Print the byte count of the start of the line 0000:000 format
		printf(" %04lX:%04lX ", ((bytes>>16)&0x000FFFF), bytes&0x000FFFF);

		// Read 16 bytes from file and display
		for(i = 0; i < 16; i++)
		{
			// Print vertical dividing line every four bytes
			printf("%c", (!(i%4))? '|' : ' ');

			// Fetch and print next byte's value
			c[i] = fgetc(fp);
			if(EOF == c[i]) // End-of-file reached in middle of 16-byte group
			{
				// indicate EOF by ".." instead of value
				printf("..");
				c[i] = 0;
			}
			else
			{
				// print value and increment byte count
				printf("%02X", c[i]);
				bytes++;
			}
		}

		//-------------------------------------------------------------
		// Print ASCII symbols
		//-------------------------------------------------------------

		// Separator between value printout and ASCII printout
		printf("|  ");

		// Print the ASCII codes for the 16 bytes that were read
		for(i = 0; i < 16; i++)
		{
			printf("%c", ( isprint(c[i])? c[i] : '.' ) );
		}
		// Close line and increment line counter
		printf("\n");
	}

	return(bytes);
}