commands.c

/*
* commands.c - commands without an address
*	... also handles the  :w  command, which can contain an address
*
*
*  Entry point:
*
*	int simp_cmd(n, c)
*	int n;
*	char c;
*		If the count n, character c and, in some cases, characters that
*		follow c constitute one of the commands listed below, then the
*		command is performed and 1 is returned.  Otherwise, 0 is returned.
*
*	The commands recognized by simp_cmd() are:
*
*	a	- append characters after the cursor location
*	A	- append characters at the end of the current line
*	C	- change the remainder of the line (same as c$)
*	D	- delete the remainder of the line (same as d$)
*	i	- insert characters at the cursor location
*	J	- join two lines together
*	m	- mark the current position
*	o	- insert lines below the current line
*	O	- insert lines above the current line
*	p	- put the contents of the yank buffer below the current line
*	P	- put the contents of the yank buffer above the current line
*	q	- quit; don't save the modifications
*	r<char>	- replace the current character by <char>
*	s	- substitute for the current character (same as c<space>)
*	u	- undo the most recent buffer-change command
*	<n>x	- delete n characters (same as <n>d<space>)
*	ZZ	- save the modifications and quit
*	?	- tell the current position in the file
*	.	- redo the most recent buffer-change command
*	*	- iterate the last search-change pair
*	:e	- edit another file
*	:r	- read a file; place its contents below the current line
*	:R	- read a file; place its contents above the current line
*	:w	- write a range of lines to a file
*
*
* External procedures calls:
*
*	address(n, c, op)				.. file address.c
*	int n;
*	char c, op;
*		Set the buffer's cursor according to the count n,
*		the cursor movement command c and the operation op.
*
*	b_delete(first, last)				.. file Bman.c
*	int first, last;
*		Delete a range of buffer lines.
*
*	b_free()					.. file Bman.c
*		Free all temporary buffer storage.
*
*	b_getcur(line_ptr, pos_ptr)			.. file Bman.c
*	int *line_ptr, *pos_ptr;
*		Return the line and position of the cursor.
*
*	b_getmark(line_ptr, pos_ptr)			.. file Bman.c
*	int *line_ptr, *pos_ptr;
*		Return the line and position of the mark.
*
*	b_gets(k, s)					.. file Bman.c
*	int k;
*	char s[];
*		Copy the k-th buffer line to s.
*
*	int b_insert(k, s)				.. file Bman.c
*	int k;
*	char s[];
*		Insert s into the buffer as line k; tell if successful.
*
*	int b_modified()				.. file Bman.c
*		Tell if buffer contents differ from the external file.
*
*	b_setcur(line, pos)				.. file Bman.c
*	int line, pos;
*		Set the cursor to the indicated location.
*
*	b_setline(line)					.. file Bman.c
*	int line;
*		Set the cursor to line's first nonwhite character.
*
*	b_setmark(line, pos)				.. file Bman.c
*	int line, pos;
*		Mark the indicated location.
*
*	int b_size()					.. file Bman.c
*		Return the number of lines currently in the buffer.
*
*	b_unmod()					.. file Bman.c
*		Record that buffer contents match the external file.
*
*	do_insert()					.. file operator.c
*		Read characters from keyboard; insert them in buffer.
*
*	do_put(way)					.. file operator.c
*	int way;
*		Put the yank buffer on the indicated side of the current line.
*
*	k_donext(command)				.. file keyboard.c
*	char *command;
*		Arrange for the given editor command to be executed next.
*
*	k_finish()					.. file keyboard.c
*		Close down the keyboard manager.
*
*	int k_getch()					.. file keyboard.c
*		Return the next character of the command.
*
*	k_redo()					.. file keyboard.c
*		Redo the most recent buffer-change command.
*
*	s_finish()					.. file Sman.c
*		Shut down the display module.
*
*	char *s_getmsg(msg)				.. file Sman.c
*	char *msg;
*		Print msg; return the user's reply,
*
*	int s_ismsg()					.. file Sman.c
*		Tell if an error message is pending.
*
*	s_putmsg(msg)					.. file Sman.c
*	char *msg;
*		Print the message on the last row.
*
*	s_refresh()					.. file Sman.c
*		Bring the display up to date with the buffer.
*
*	s_savemsg(msg, val)				.. file Sman.c
*	char *msg;
*	int val;
*		Format msg and save it for the next screen refreshing.
*
*	undo()						.. file Bman.c
*		Undo the most recent buffer-change command.
*/

#include <stdlib.h>
#include <string.h>

#include "s.h"

extern void b_getcur(), b_gets(), b_setcur(), s_refresh(), do_insert();
extern void k_donext(), s_savemsg(), b_delete(), b_setmark();
extern void do_put(), s_putmsg(), b_free(), k_finish(), s_finish();
extern void undo(), k_redo(), adjust(), b_getmark(), address();
extern void b_newcmd(), b_unmod(), b_setline();
extern int b_size(), b_modified(), k_getch(), s_ismsg(), strsame(), b_insert();
static void do_star(), do_io(), do_write(), write_lines();
static int do_read();

static char cur_file[MAXTEXT];	/* remembers name of the current file */

int simp_cmd(n, c)
int n;
char c;
{
	int cur_line, cur_pos, i;
	char *t, text1[MAXTEXT], text2[MAXTEXT]; 

	b_getcur(&cur_line, &cur_pos);
	switch (c) {
		case 'a':
			b_gets(cur_line, text1);
			if (text1[0] != '\0') {	/* unless the line is empty */
				b_setcur(cur_line, cur_pos+1);
				s_refresh();
			}
			do_insert();
			break;
		case 'A':
			b_gets(cur_line, text1);
			b_setcur(cur_line, strlen(text1));
			s_refresh();
			do_insert();
			break;
		case 'C':
			k_donext("c$");
			break;
		case 'D':
			k_donext("d$");
			break;
		case 'i':
			do_insert();
			break;
		case 'J':
			if (cur_line >= b_size()) {
				UNKNOWN;
				break;
			}
			b_gets(cur_line, text1);
			i = strlen(text1); 
			/* put a space between the two lines */
			text1[i] = ' ';
			b_gets(cur_line + 1, text2);
			/* strip leading white characters from second line */
			for (t = text2; isspace(*t); ++t)
				;
			if (i + 1 + strlen(t) >= MAXTEXT-1) {
				s_savemsg("Line length exceeds %d.", MAXTEXT);
				break;
			}
			strcpy(text1 + i + 1, t);
			b_delete(cur_line, cur_line + 1);
			b_insert(cur_line, text1);
			b_setcur(cur_line, i);
			break;
		case 'm':
			b_setmark();
			break;
		case 'o':
			++cur_line;
			/* no break statement; fall into ... */
		case 'O':
			b_insert(cur_line, "");
			b_setcur(cur_line, 0);
			s_refresh();
			do_insert();
			break;
		case 'p':
			do_put(1);
			break;
		case 'P':
			do_put(-1);
			break;
		case 'q':
			if (b_modified()) {
				s_putmsg("Discard? ");
				if (k_getch() != 'y') {
					UNKNOWN;
					break;
				}
			}
			if (s_ismsg())
				s_refresh();
			b_free();
			k_finish();
			s_finish();
			exit(0);
		case 'r':
			sprintf(text1, "c %c%c", k_getch(), ESCAPE);
			k_donext(text1);	/* c<space><char><esc> */
			break;
		case 's':
			k_donext("c ");		/* c<space> */
			break;
		case 'u':
			undo();
			break;
		case 'x':
			if (n == 0)	/* set default */
				n = 1;
			sprintf(text1, "%dd ", n);
			k_donext(text1);	/* <n>d<space> */
			break;
		case 'Z':
			if (k_getch() != 'Z') {
				UNKNOWN;
				break;
			}
			if (b_modified()) {
				sprintf(text1, ":w%cq", CR);
				k_donext(text1);	/* :w<return>q */
			} else
				k_donext("q");
			break;
		case '?':
			sprintf(text1, "%s: %sline %d of %d", cur_file,
				(b_modified()) ? "[Modified] " : "",
				cur_line, b_size());
			s_savemsg(text1, 0);
			break;
		case '.':
			k_redo();
			break;
		case '*':
			do_star();
			break;
		case ':':
			do_io();
			break;
		case '#':
			adjust(n);
			break;
		default:
			return(0);
	}
	return(1);
}

/*
--------------------  the star command  --------------------
* Entry point:
*
*	do_star()
*		From the minimum of the current and marked lines, alternate
*		between n and redo commands until the maximum of the two lines
*		is reached.  The marked line defaults to the last buffer line.
*/

#define STAR_MAX  50	/* limits the number of n and redo commands */

static void do_star()
{
	static int all_lines, doing_star = 0, iterations, start_line = 0,
		   start_pos;
	int cur_line, cur_pos, done, mark_line, mark_pos, old_line, old_pos;

	if (!b_modified()) {
		UNKNOWN;
		return;
	}
	if (s_ismsg()) {  /* an error message is waiting; don't continue */
		doing_star = 0;
		if (start_line == 0)
			UNKNOWN;
		else
			b_setcur(start_line, start_pos);
		return;
	}
	if (!doing_star) {	/* initialize for this star command */
		doing_star = 1;
		iterations = 0;
		b_getcur(&start_line, &start_pos);
		b_getmark(&mark_line, &mark_pos);
		if (mark_line > 0 && mark_line < start_line) {
			/* guarantee that cursor precedes mark */
			b_setmark();
			b_setcur(mark_line, mark_pos);
			b_getcur(&start_line, &start_pos);
			b_getmark(&mark_line, &mark_pos);
		}
		if (mark_line == 0 || mark_line == b_size() || start_line == b_size())
			all_lines = 1;
		else {
			all_lines = 0;
			/* move mark to the following line */
			b_setcur(mark_line+1, 0);
			b_setmark();
			b_setcur(start_line, start_pos);
		}
	}
	/* execute an n command */
	b_getcur(&old_line, &old_pos);
	address(0, 'n', ' ');
	b_getcur(&cur_line, &cur_pos);
	b_getmark(&mark_line, &mark_pos);
	/* done if past mark or if the search fails */
	done = (((!all_lines && cur_line >= mark_line) ||
		(cur_line < old_line) ||
		(cur_line == old_line)) && (cur_pos <= old_pos));
	if (!done && ++iterations <= STAR_MAX)
		/* execute a redo command then return to this procedure */
		k_donext(".*");
	else {
		if (done)
			if (iterations == 1)
				s_savemsg("1 change", 0);
			else
				s_savemsg("%d changes", iterations);
		else
			s_savemsg("%d changes; type '*' to continue.", STAR_MAX);
		doing_star = 0;
		b_setcur(start_line, start_pos);
	}
}

/*
--------------------  I/O commands  --------------------
*
*  Entry point:
*
*	do_io();
*		Read the part of an edit command after ':', then execute it.
*
*/

static void do_io()
{
	int cur_line, cur_pos, size;
	char *file, *s_getmsg(), msg[80], *reply;

	/* get the remainder of the command */
	reply = s_getmsg(":");
	b_getcur(&cur_line, &cur_pos);
	
	/* write commands contain an address; treat them as a special case */
	if (*reply == 'w') {
		do_write(reply+1);
		b_setcur(cur_line, cur_pos);
		return;
	}

	/* find the start of the file name */
	for (file = reply+1; *file == ' '; ++file)
		;
	if (*file == '\0')
		file = cur_file;	/* default: use the current file name */
	switch (*reply) {
		case 'e':
			if (b_modified()) {
				s_putmsg("Discard? ");
				if (k_getch() != 'y')
					break;
			}
			if (file != cur_file)
				strcpy(cur_file, file);	/* remember name */
			b_delete(1, b_size());
			b_newcmd();	/* so the :e command cannot be undone */
			if ((size = do_read(file, 1)) > 0) {
				sprintf(msg, "%s: %d lines", file, size);
				s_savemsg(msg, 0);
			} else {
				if (size == -1) {
					sprintf(msg, "%s is a new file", file);
					s_savemsg(msg, 0);
				}
				b_insert(1, "");
				b_setcur(1, 0);
			}
			/* record that buffer contents match external file */
			b_unmod();
			break;
		case 'r':
			++cur_line;
			/* no break statement; fall into ... */
		case 'R':
			if ((size = do_read(file, cur_line)) > 5)
				s_savemsg("%d lines read", size);
			else if (size == -1) {
				sprintf(msg, "Cannot read %s.", file);
				s_savemsg(msg, 0);
			}
			break;
		default:
			UNKNOWN;
			break;
	}
}

/*
* do_read - read a file to buffer at the indicated line;
* a returned value >= 0 tells number of lines that were read from the file
* a returned value -1 means that the file could not be opened for reading
* a returned value -2 means that the file contains nonprintable characters
*/
static int do_read(file, line)
char *file;
int line;
{
	FILE *fp, *fopen();
	int i, c;
	char text[MAXTEXT];

	if ((fp = fopen(file, "r")) == NULL)
		return(-1);
	/*
	* Read the first ten characters and check that they are printable.
	* Some C I/O packages read '\r' (<return>) characters.  Also,
	* nonprintable characters in files might be used for, e.g.,
	* printer control characters.
	*/
	for (i = 0; (c = getc(fp)) != EOF && i < 10; ++i)
		if (!isprint(c) && c != '\n' && c != '\t' ) {
			sprintf(text, "%s is not a text file", file);
			s_savemsg(text, 0);
			fclose(fp);
			return(-2);
		}
	if (i == 0) {
		sprintf(text, "%s is empty", file);
		s_savemsg(text, 0);
		fclose(fp);
		return(0);
	}

	rewind(fp);
	/* copy the file to the buffer */
	for (i = line; fgets(text, MAXTEXT, fp) != NULL; ++i) {
		text[strlen(text)-1] = '\0';	/* trim off the newline */
		if (b_insert(i, text) == 0)
			break;
	}
	fclose(fp);
	/* move to the first nonwhite character in the first line read */
	b_setline(line);
	return(i - line);
}

/* do_write - write a file according to given specifications */
static void do_write(specs)
char *specs;
{
	int cur_line, cur_pos, n, new_line, new_pos;
	char *addr, *file;


	/* special case: :w<return> writes buffer to current file */
	if (*specs == '\0') {
		write_lines(1, b_size(), cur_file);
		return;
	}
	/* special case: :w<space>file<return> writes buffer to named file */
	if (*specs == ' ') {
		for (file = specs + 1; *file == ' '; ++file)
			;
		write_lines(1, b_size(), file);
		return;
	}

	/* get the count that follows ":w" */
	n = 0;
	for (addr = specs; isdigit(*addr); ++addr)
		n = 10*n + *addr - '0';
	if (*addr == '\0') {
		UNKNOWN;
		return;
	}

	/* find and mark the end of the address */
	for (file = addr; *file != '\0' && *file != ' '; ++file)
		;
	if (*file == ' ')
		*file++ = '\0';

	b_getcur(&cur_line, &cur_pos);
	/* push the address, minus the first character, back on the input */
	k_donext(addr + 1);
	address(n, *addr, ':');
	b_getcur(&new_line, &new_pos);
	if (new_line == cur_line && new_pos == cur_pos) {
		/* the address did not make sense */
		UNKNOWN;
		return;
	}

	/* special case: :w<addr><return> writes to the current file */
	if (*file == '\0')
		file = cur_file;
			
	if (cur_line <= new_line)
		write_lines(cur_line, new_line, file);
	else
		write_lines(new_line, cur_line, file);
}

/* write_lines - write a range of lines to a file */
static void write_lines(from, to, file)
int from, to;
char *file;
{
	FILE *fopen(), *fp;
	int count = to - from + 1;
	char text[MAXTEXT-1];

	/* be cautious about overwriting files */
	if (!strsame(file, cur_file)) {
		if ((fp = fopen(file, "r")) != NULL) {
			s_putmsg("Overwrite? ");
			if (k_getch() == 'y')
				fclose(fp);
			else
				return;
		}
	} else if (from > 1 || to < b_size()) {
		s_putmsg("Write partial buffer to current file? ");
		if (k_getch() != 'y')
			return;
	}

	if ((fp = fopen(file, "w")) == NULL) {
		sprintf(text, "Cannot write %s.", file);
		s_savemsg(text, 0);
		return;
	}
	/* if entire buffer is saved, record that the user is free to quit */
	if (strsame(file, cur_file) && from == 1 && to == b_size())
		b_unmod();
	/* write the lines */
	while (from <= to) {
		b_gets(from++, text);
		fprintf(fp, "%s\n", text);
	}
	fclose(fp);
	sprintf(text, "%s: %d line%s", file, count, (count == 1) ? "" : "s");
	s_savemsg(text, 0);
}