Fix a segmentation violation when zep isn't given a file to edit.

zep.c

@@ -1,24 +1,17 @@
 /* zep.c,  Zep Emacs, Public Domain, Hugh Barney, 2017, Derived from: Anthony's Editor January 93 */
-
 #include <stdlib.h>
-#include <stdarg.h>
 #include <assert.h>
 #include <curses.h>
 #include <stdio.h>
-#include <sys/types.h>
+#include <fcntl.h>
 #include <sys/stat.h>
-#include <sys/ioctl.h>
 #include <ctype.h>
-#include <limits.h>
 #include <string.h>
 #include <unistd.h>
-#include <termios.h>
 
 #define E_NAME          "zep"
-#define E_VERSION       "v1.3"
+#define E_VERSION       "v1.6"
 #define E_LABEL         "Zep:"
-
-#define B_MODIFIED	0x01		/* modified buffer */
 #define MSGLINE         (LINES-1)
 #define CHUNK           8096L
 #define K_BUFFER_LENGTH 256
@@ -52,15 +45,14 @@ typedef struct buffer_t
 	int b_row;                /* cursor row */
 	int b_col;                /* cursor col */
 	char b_fname[MAX_FNAME + 1]; /* filename */
-	char b_flags;             /* buffer flags */
+	char b_modified;          /* was modified */
 } buffer_t;
 
 /*
- * Some compilers define size_t as a unsigned 16 bit number while
+ * Some compilers define size_t as a unsigned 16 bit number while point_t and
- * point_t and off_t might be defined as a signed 32 bit number.  
+ * off_t might be defined as a signed 32 bit number. malloc(), realloc(),
- * malloc(), realloc(), fread(), and fwrite() take size_t parameters,
+ * fread(), and fwrite() take size_t parameters, which means there will be some
- * which means there will be some size limits because size_t is too
+ * size limits because size_t is too small of a type.
- * small of a type.
  */
 #define MAX_SIZE_T      ((unsigned long) (size_t) ~0)
 
@@ -68,7 +60,6 @@ int done;
 char_t *input;
 int msgflag;
 char msgline[TEMPBUF];
-char temp[TEMPBUF];
 keymap_t *key_return;
 keymap_t *key_map;
 buffer_t *curbp;
@@ -80,11 +71,11 @@ buffer_t* new_buffer()
 {
 	buffer_t *bp = (buffer_t *)malloc(sizeof(buffer_t));
 	assert(bp != NULL);
-
 	bp->b_point = 0;
+	bp->b_mark = NOMARK;
 	bp->b_page = 0;
 	bp->b_epage = 0;
-	bp->b_flags = 0;
+	bp->b_modified = 0;
 	bp->b_buf = NULL;
 	bp->b_ebuf = NULL;
 	bp->b_gap = NULL;
@@ -97,21 +88,20 @@ buffer_t* new_buffer()
 
 void fatal(char *msg)
 {
-	move(LINES-1, 0);
-	refresh();
 	noraw();
 	endwin();
 	printf("\n" E_NAME " " E_VERSION ": %s\n", msg);
 	exit(1);
 }
 
-void msg(char *msg, ...)
+int msg(char *msg, ...)
 {
 	va_list args;
 	va_start(args, msg);
 	(void)vsprintf(msgline, msg, args);
 	va_end(args);
 	msgflag = TRUE;
+	return FALSE;
 }
 
 /* Given a buffer offset, convert it to a pointer into the buffer */
@@ -133,11 +123,9 @@ int growgap(buffer_t *bp, point_t n)
 {
 	char_t *new;
 	point_t buflen, newlen, xgap, xegap;
-		
 	assert(bp->b_buf <= bp->b_gap);
 	assert(bp->b_gap <= bp->b_egap);
 	assert(bp->b_egap <= bp->b_ebuf);
-
 	xgap = bp->b_gap - bp->b_buf;
 	xegap = bp->b_egap - bp->b_buf;
 	buflen = bp->b_ebuf - bp->b_buf;
@@ -147,24 +135,16 @@ int growgap(buffer_t *bp, point_t n)
 	newlen = buflen + n * sizeof (char_t);
 
 	if (buflen == 0) {
-		if (newlen < 0 || MAX_SIZE_T < newlen) fatal("Failed to allocate required memory.\n");
+		if (newlen < 0 || MAX_SIZE_T < newlen) fatal("Failed to allocate required memory");
 		new = (char_t*) malloc((size_t) newlen);
-		if (new == NULL) fatal("Failed to allocate required memory.\n");
+		if (new == NULL) fatal("Failed to allocate required memory");
 	} else {
-		if (newlen < 0 || MAX_SIZE_T < newlen) {
+		if (newlen < 0 || MAX_SIZE_T < newlen) return msg("Failed to allocate required memory");
-			msg("Failed to allocate required memory");
-			return (FALSE);
-		}
 		new = (char_t*) realloc(bp->b_buf, (size_t) newlen);
-		if (new == NULL) {
+		if (new == NULL) return msg("Failed to allocate required memory");
-			msg("Failed to allocate required memory");    /* Report non-fatal error. */
-			return (FALSE);
-		}
 	}
 
-	/* Relocate pointers in new buffer and append the new
+	/* Relocate pointers in new buffer and append the new extension to the end of the gap */
-	 * extension to the end of the gap.
-	 */
 	bp->b_buf = new;
 	bp->b_gap = bp->b_buf + xgap;      
 	bp->b_ebuf = bp->b_buf + buflen;
@@ -197,7 +177,6 @@ void save()
 {
 	FILE *fp;
 	point_t length;
-
 	fp = fopen(curbp->b_fname, "w");
 	if (fp == NULL) msg("Failed to open file \"%s\".", curbp->b_fname);
 	(void) movegap(curbp, (point_t) 0);
@@ -205,39 +184,25 @@ void save()
 	if (fwrite(curbp->b_egap, sizeof (char), (size_t) length, fp) != length) 
 		msg("Failed to write file \"%s\".", curbp->b_fname);
 	fclose(fp);
-	curbp->b_flags &= ~B_MODIFIED;
+	curbp->b_modified = 0;
 	msg("File \"%s\" %ld bytes saved.", curbp->b_fname, pos(curbp, curbp->b_ebuf));
 }
 
 /* reads file into buffer at point */
-int insert_file(char *fn, int modflag)
+int insert_file(char *fn)
 {
 	FILE *fp;
 	size_t len;
 	struct stat sb;
 
-	if (stat(fn, &sb) < 0) {
+	if (stat(fn, &sb) < 0) return msg("Failed to find file \"%s\".", fn);
-		msg("Failed to find file \"%s\".", fn);
+	if (MAX_SIZE_T < sb.st_size) return msg("File \"%s\" is too big to load.", fn);
-		return (FALSE);
-	}
-	if (MAX_SIZE_T < sb.st_size) {
-		msg("File \"%s\" is too big to load.", fn);
-		return (FALSE);
-	}
 	if (curbp->b_egap - curbp->b_gap < sb.st_size * sizeof (char_t) && !growgap(curbp, sb.st_size))
 		return (FALSE);
-	if ((fp = fopen(fn, "r")) == NULL) {
+	if ((fp = fopen(fn, "r")) == NULL) return msg("Failed to open file \"%s\".", fn);
-		msg("Failed to open file \"%s\".", fn);
-		return (FALSE);
-	}
 	curbp->b_point = movegap(curbp, curbp->b_point);
 	curbp->b_gap += len = fread(curbp->b_gap, sizeof (char), (size_t) sb.st_size, fp);
-
+	if (fclose(fp) != 0) return msg("Failed to close file \"%s\".", fn);
-	if (fclose(fp) != 0) {
-		msg("Failed to close file \"%s\".", fn);
-		return (FALSE);
-	}
-	curbp->b_flags &= (modflag ? B_MODIFIED : ~B_MODIFIED);
 	msg("File \"%s\" %ld bytes read.", fn, len);
 	return (TRUE);
 }
@@ -248,7 +213,6 @@ char_t *get_key(keymap_t *keys, keymap_t **key_return)
 	int submatch;
 	static char_t buffer[K_BUFFER_LENGTH];
 	static char_t *record = buffer;
-
 	*key_return = NULL;
 
 	/* if recorded bytes remain, return next recorded byte. */
@@ -256,19 +220,16 @@ char_t *get_key(keymap_t *keys, keymap_t **key_return)
 		*key_return = NULL;
 		return record++;
 	}
-	/* reset record buffer. */
+	
-	record = buffer;
+	record = buffer; /* reset record buffer. */
-
 	do {
 		assert(K_BUFFER_LENGTH > record - buffer);
-		/* read and record one byte. */
+		*record++ = (unsigned)getch(); /* read and record one byte. */
-		*record++ = (unsigned)getch();
 		*record = '\0';
 
 		/* if recorded bytes match any multi-byte sequence... */
 		for (k = keys, submatch = 0; k->key_bytes != NULL; ++k) {
 			char_t *p, *q;
-
 			for (p = buffer, q = (char_t *)k->key_bytes; *p == *q; ++p, ++q) {
 			        /* an exact match */
 				if (*q == '\0' && *p == '\0') {
@@ -279,9 +240,7 @@ char_t *get_key(keymap_t *keys, keymap_t **key_return)
 				}
 			}
 			/* record bytes match part of a command sequence */
-			if (*p == '\0' && *q != '\0') {
+			if (*p == '\0' && *q != '\0') submatch = 1;
-				submatch = 1;
-			}
 		}
 	} while (submatch);
 	/* nothing matched, return recorded bytes. */
@@ -310,7 +269,7 @@ point_t segstart(buffer_t *bp, point_t start, point_t finish)
 		p = ptr(bp, scan);
 		if (*p == '\n') {
 			c = 0;
-			start = scan+1;
+			start = scan + 1;
 		} else if (COLS <= c) {
 			c = 0;
 			start = scan;
@@ -330,11 +289,9 @@ point_t segnext(buffer_t *bp, point_t start, point_t finish)
 	point_t scan = segstart(bp, start, finish);
 	for (;;) {
 		p = ptr(bp, scan);
-		if (bp->b_ebuf <= p || COLS <= c)
+		if (bp->b_ebuf <= p || COLS <= c) break;
-			break;
 		++scan;
-		if (*p == '\n')
+		if (*p == '\n') break;
-			break;
 		c += *p == '\t' ? 8 - (c & 7) : 1;
 	}
 	return (p < bp->b_ebuf ? scan : pos(bp, bp->b_ebuf));
@@ -353,10 +310,7 @@ point_t upup(buffer_t *bp, point_t off)
 }
 
 /* Move down one screen line */
-point_t dndn(buffer_t *bp, point_t off)
+point_t dndn(buffer_t *bp, point_t off) { return (segnext(bp, lnstart(bp,off), off)); }
-{
-	return (segnext(bp, lnstart(bp,off), off));
-}
 
 /* Return the offset of a column on the specified line */
 point_t lncolumn(buffer_t *bp, point_t offset, int column)
@@ -373,14 +327,14 @@ point_t lncolumn(buffer_t *bp, point_t offset, int column)
 void modeline(buffer_t *bp)
 {
 	int i;
+	char temp[TEMPBUF];
 	char mch;
 	
 	standout();
 	move(bp->w_top + bp->w_rows, 0);
-	mch = ((bp->b_flags & B_MODIFIED) ? '*' : '=');
+	mch = bp->b_modified ? '*' : '=';
 	sprintf(temp, "=%c " E_LABEL " == %s ", mch, bp->b_fname);
 	addstr(temp);
-
 	for (i = strlen(temp) + 1; i <= COLS; i++)
 		addch('=');
 	standend();
@@ -450,8 +404,7 @@ void display()
 		}
 		if (*p == '\n' || COLS <= j) {
 			j -= COLS;
-			if (j < 0)
+			if (j < 0) j = 0;
-				j = 0;
 			++i;
 		}
 		++bp->b_epage;
@@ -509,7 +462,7 @@ void insert()
 	curbp->b_point = movegap(curbp, curbp->b_point);
 	*curbp->b_gap++ = *input == '\r' ? '\n' : *input;
 	curbp->b_point = pos(curbp, curbp->b_egap);
-	curbp->b_flags |= B_MODIFIED;
+	curbp->b_modified = 1;
 }
 
 void backsp()
@@ -517,7 +470,7 @@ void backsp()
 	curbp->b_point = movegap(curbp, curbp->b_point);
 	if (curbp->b_buf < curbp->b_gap) {
 		--curbp->b_gap;
-		curbp->b_flags |= B_MODIFIED;
+		curbp->b_modified = 1;
 	}
 	curbp->b_point = pos(curbp, curbp->b_egap);
 }
@@ -527,7 +480,7 @@ void delete()
 	curbp->b_point = movegap(curbp, curbp->b_point);
 	if (curbp->b_egap < curbp->b_ebuf) {
 		curbp->b_point = pos(curbp, ++curbp->b_egap);
-		curbp->b_flags |= B_MODIFIED;
+		curbp->b_modified = 1;
 	}
 }
 
@@ -564,7 +517,7 @@ void copy_cut(int cut)
 		if (cut) {
 			curbp->b_egap += nscrap; /* if cut expand gap down */
 			curbp->b_point = pos(curbp, curbp->b_egap); /* set point to after region */
-			curbp->b_flags |= B_MODIFIED;
+			curbp->b_modified = 1;
 			msg("%ld bytes cut.", nscrap);
 		} else {
 			msg("%ld bytes copied.", nscrap);
@@ -582,7 +535,7 @@ void paste()
 		memcpy(curbp->b_gap, scrap, nscrap * sizeof (char_t));
 		curbp->b_gap += nscrap;
 		curbp->b_point = pos(curbp, curbp->b_egap);
-		curbp->b_flags |= B_MODIFIED;
+		curbp->b_modified = 1;
 	}
 }
 
@@ -607,17 +560,13 @@ point_t search_forward(buffer_t *bp, point_t start_p, char *stext)
 	point_t p,pp;
 	char* s;
 
-	if (0 == strlen(stext))
+	if (0 == strlen(stext)) return start_p;
-		return start_p;
 
 	for (p=start_p; p < end_p; p++) {
 		for (s=stext, pp=p; *s == *(ptr(bp, pp)) && *s !='\0' && pp < end_p; s++, pp++)
 			;
-
+		if (*s == '\0') return pp;
-		if (*s == '\0')
-			return pp;
 	}
-
 	return -1;
 }
 
@@ -627,7 +576,6 @@ void search()
 	int c;
 	point_t o_point = curbp->b_point;
 	point_t found;
-
 	searchtext[0] = '\0';
 	msg("Search: %s", searchtext);
 	dispmsg();
@@ -719,44 +667,36 @@ keymap_t keymap[] = {
 
 int main(int argc, char **argv)
 {
-	if (argc != 2) fatal("usage: " E_NAME " filename\n");
+	if(argc != 2)
-
+		{
+		printf("usage: %s filename\n", argv[0]);
+		exit(1);
+		}
 	initscr();	
 	raw();
 	noecho();
-	
 	curbp = new_buffer();
-	(void)insert_file(argv[1], FALSE);
+	(void)insert_file(argv[1]);
-	/* Save filename irregardless of load() success. */
+	strncpy(curbp->b_fname, argv[1], MAX_FNAME);  /* save filename regardless */
-	strncpy(curbp->b_fname, argv[1], MAX_FNAME);
 	curbp->b_fname[MAX_FNAME] = '\0'; /* force truncation */
-
 	if (!growgap(curbp, CHUNK)) fatal("Failed to allocate required memory.\n");
-
 	key_map = keymap;
 
 	while (!done) {
 		display();
 		input = get_key(key_map, &key_return);
-
 		if (key_return != NULL) {
 			(key_return->func)();
 		} else {
-			/* allow TAB and NEWLINE, any other control char is 'Not Bound' */
+			if (*input > 31 || *input == 10 || *input == 9) /* allow TAB, NEWLINE and other control char is Not Bound */
-			if (*input > 31 || *input == 10 || *input == 9)
 				insert();
-                        else {
+                        else
-				fflush(stdin);
 				msg("Not bound");
-			}
 		}
 	}
 
 	if (scrap != NULL) free(scrap);
 	if (curbp != NULL) free(curbp);
-
-	move(MSGLINE, 0);
-	refresh();
 	noraw();
 	endwin();
 	return 0;