Merge pull request #55 from goriy/example_realloc_fix

small fix of jsondump example for cases of realloc failures

1 files changed, 17 insertions, 4 deletions

diff --git a/example/jsondump.c b/example/jsondump.c
index 3490bbf49..7be628772 100644
--- a/example/jsondump.c
+++ b/example/jsondump.c
@@ -4,6 +4,21 @@
 #include <errno.h>
 #include "../jsmn.h"
 
+/* Function realloc_it() is a wrapper function for standart realloc()
+ * with one difference - it frees old memory pointer in case of realloc
+ * failure. Thus, DO NOT use old data pointer in anyway after call to
+ * realloc_it(). If your code has some kind of fallback algorithm if
+ * memory can't be re-allocated - use standart realloc() instead.
+ */
+static inline void *realloc_it(void *ptrmem, size_t size) {
+	void *p = realloc(ptrmem, size);
+	if (!p)  {
+		free (ptrmem);
+		fprintf(stderr, "realloc(): errno=%d\n", errno);
+	}
+	return p;
+}
+
 /*
  * An example of reading JSON from stdin and printing its content to stdout.
  * The output looks like YAML, but I'm not sure if it's really compatible.
@@ -82,9 +97,8 @@ int main() {
 			}
 		}
 
-		js = realloc(js, jslen + r + 1);
+		js = realloc_it(js, jslen + r + 1);
 		if (js == NULL) {
-			fprintf(stderr, "realloc(): errno=%d\n", errno);
 			return 3;
 		}
 		strncpy(js + jslen, buf, r);
@@ -95,9 +109,8 @@ again:
 		if (r < 0) {
 			if (r == JSMN_ERROR_NOMEM) {
 				tokcount = tokcount * 2;
-				tok = realloc(tok, sizeof(*tok) * tokcount);
+				tok = realloc_it(tok, sizeof(*tok) * tokcount);
 				if (tok == NULL) {
-					fprintf(stderr, "realloc(): errno=%d\n", errno);
 					return 3;
 				}
 				goto again;