tedit.c

来自「Software Development in C: A Practical A」· C语言 代码 · 共 112 行

#include "Tbuffer.h"
#include <stdio.h>


#define CONTROL_D (char)4
#define CONTROL_U (char)21

#define MAX_DISPLAY_LINES 25



#define ClearScreen()									\
		{												\
			int i;										\
														\
			for (i=0;i<MAX_DISPLAY_LINES;i++)			\
			{											\
				printf("\n");							\
			}											\
		}


int main()
{
	text_buffer buffer;
	text_string tempString;
	int i,j,top;
	char tempChar;
	const int LINES_PER_SCREENFUL = 20;
	const int LINES_TO_SCROLL_PER_PAGE = LINES_PER_SCREENFUL -1;

	// Fill the text buffer.
	for (i=0,tempChar='A';i<TEXT_BUFFER_LENGTH;i++)
	{
		// Initialize each row.
		TextStringInitString(buffer[i]);

		// Fill the row with characters.
		for (j=0;j<TEXT_STRING_MAX_LENGTH-1;j++)
		{
			// Put the character in the buffer.
			TextStringAppendCharacter(buffer[i],tempChar++);
			if (tempChar>'z')
			{
				tempChar = 'A';
			}
		}
	}

	// While the user does not want to quit...
	for (tempChar = ' ',top=0;
		 (tempChar!='Q') && (tempChar!='q');
		 scanf("%c",&tempChar))
	{
		if (tempChar!='\n')
		{
			switch (tempChar)
			{
				// If the user typed ^D...
				case CONTROL_D:
					/* Adjust the top display line downward one 
					screefull. */
					top += LINES_TO_SCROLL_PER_PAGE;
				break;

				// If the user typed ^U...
				case CONTROL_U:
					/* Adjust the top display line upward one 
					screefull. */
					top -= LINES_TO_SCROLL_PER_PAGE;
				break;
				
				default: 
					/*Warning the wrong input */
					printf("%c", (char)7); 
				break;
				
			}

			// If the top line is before beginning of the buffer...
			if (top<0)
			{
				// Adjust it.
				top = 0;
			}
			// Else if the user scrolled too far toward the end...
			else if (top > TEXT_BUFFER_LENGTH-LINES_PER_SCREENFUL)
			{
				// Adjust the top line
				top = TEXT_BUFFER_LENGTH-LINES_PER_SCREENFUL;
			}

			// Print the contents of the buffer
			ClearScreen();
			for (i=0;
				 (i<LINES_PER_SCREENFUL) && (top+i<TEXT_BUFFER_LENGTH);
				 i++)
			{
				/* Print the buffer line number and the display line
				number. */
				printf("%d,%d:  ",top+i,i);
				TextBufferGetRow(buffer,top+i,tempString);
				TextStringPrintString(tempString);
				printf("\n");
			}

			// Print a prompt for the user.
			printf("Enter a command >>>");

		}
	}
}