Merge pull request #476 from katef/kate/xstrndup

Add xstrndup

include/adt/xalloc.h

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2017 Katherine Flavel
+ * Copyright 2008-2024 Katherine Flavel
  *
  * See LICENCE for the full copyright terms.
  */
@@ -8,21 +8,22 @@
 #define XALLOC_H
 
 /*
- * Duplicate a string. Returns NULL on error.
+ * These functions are for CLI use only; they exit on error
  */
+
 char *
 xstrdup(const char *s);
 
-/*
- * The following functions are for CLI use only; they exit on error
- */
+char *
+xstrndup(const char *s, size_t n);
 
 void *
 xmalloc(size_t sz);
 
 void *
 xcalloc(size_t count, size_t sz);
 
+/* equivalent to free(p) when sz is 0, returns NULL */
 void *
 xrealloc(void *p, size_t sz);
 

src/adt/xalloc.c

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2017 Katherine Flavel
+ * Copyright 2008-2024 Katherine Flavel
  *
  * See LICENCE for the full copyright terms.
  */
@@ -24,6 +24,19 @@ xstrdup(const char *s)
 	return strcpy(new, s);
 }
 
+char *
+xstrndup(const char *s, size_t n)
+{
+	char *new;
+
+	new = malloc(n);
+	if (new == NULL) {
+		return NULL;
+	}
+
+	return memcpy(new, s, n);
+}
+
 void *
 xmalloc(size_t sz)
 {
@@ -57,11 +70,8 @@ xrealloc(void *p, size_t sz)
 {
 	void *q;
 
-	/* This is legal and frees p, but confusing; use free() instead */
-	assert(sz != 0);
-
 	q = realloc(p, sz);
-	if (q == NULL) {
+	if (sz > 0 && q == NULL) {
 		perror("realloc");
 		abort();
 	}

src/libfsm/parser.act

@@ -241,11 +241,8 @@
 	@};
 
 	IDENT: () -> (s :string) = @{
+		/* XXX: don't exit in library code */
 		@s = xstrdup(lex_state->buf.a);
-		if (@s == NULL) {
-			perror("xstrdup");
-			exit(EXIT_FAILURE);
-		}
 	@};
 
 %actions%
@@ -288,11 +285,8 @@
 				exit(EXIT_FAILURE);
 			}
 
+			/* XXX: don't exit in library code */
 			new->id = xstrdup(@n);
-			if (new->id == NULL) {
-				perror("xstrdup");
-				exit(EXIT_FAILURE);
-			}
 
 			if (!fsm_addstate(fsm, &@s)) {
 				perror("fsm_addstate");