tweaks: condense two comments, and rename two parameters

Also use 'while' instead of 'for'.

src/history.c

@@ -414,7 +414,7 @@ void load_poshistory(void)
 
 		/* Read and parse each line, and store the extracted data. */
 		while ((read = getline(&line, &buf_len, hisfile)) > 5) {
-			/* Decode nulls as embedded newlines. */
+			/* Decode NULs as embedded newlines. */
 			unsunder(line, read);
 
 			/* Find where the x index and line number are in the line. */
@@ -484,7 +484,7 @@ void save_poshistory(void)
 						posptr->filename, posptr->lineno, posptr->xno);
 			length = strlen(path_and_place);
 
-			/* Encode newlines in filenames as nulls. */
+			/* Encode newlines in filenames as NULs. */
 			sunder(path_and_place);
 			/* Restore the terminating newline. */
 			path_and_place[length - 1] = '\n';

src/proto.h

@@ -567,8 +567,8 @@ int digits(ssize_t n);
 #endif
 bool parse_num(const char *str, ssize_t *val);
 bool parse_line_column(const char *str, ssize_t *line, ssize_t *column);
-void unsunder(char *str, size_t true_len);
-void sunder(char *str);
+void unsunder(char *string, size_t length);
+void sunder(char *string);
 #if !defined(ENABLE_TINY) || defined(ENABLE_TABCOMP) || defined(ENABLE_BROWSER)
 void free_chararray(char **array, size_t len);
 #endif

src/utils.c

@@ -159,23 +159,24 @@ bool parse_line_column(const char *str, ssize_t *line, ssize_t *column)
 	return retval;
 }
 
-/* For non-null-terminated lines.  A line, by definition, shouldn't
- * normally have newlines in it, so encode its nulls as newlines. */
-void unsunder(char *str, size_t true_len)
+/* In the given string, recode each embedded NUL as a newline. */
+void unsunder(char *string, size_t length)
 {
-	for (; true_len > 0; true_len--, str++) {
-		if (*str == '\0')
-			*str = '\n';
+	while (length > 0) {
+		if (*string == '\0')
+			*string = '\n';
+		length--;
+		string++;
 	}
 }
 
-/* For non-null-terminated lines.  A line, by definition, shouldn't
- * normally have newlines in it, so decode its newlines as nulls. */
-void sunder(char *str)
+/* In the given string, recode each embedded newline as a NUL. */
+void sunder(char *string)
 {
-	for (; *str != '\0'; str++) {
-		if (*str == '\n')
-			*str = '\0';
+	while (*string != '\0') {
+		if (*string == '\n')
+			*string = '\0';
+		string++;
 	}
 }