Improve error handling when reading extra fields.

Based on Issue #509.

Author: dillof

THANKS

@@ -46,6 +46,7 @@ David Demelier <demelier.david@gmail.com>
 Dean Ellis <dellis1972@googlemail.com>
 Declan Moran
 Del Merritt <del@alum.mit.edu>
+Deng XingJing
 Devin Davila <daviladsoftware@gmail.com>
 Dmytro Rybachenko <atmoliton@gmail.com>
 Dylan T. <dktapps@pmmp.io>

src/diff_output.c

@@ -91,20 +91,25 @@ diff_output_data(diff_output_t *output, int side, const zip_uint8_t *data, zip_u
         return;
     }
 
-    offset = 0;
-    for (i = 0; i < data_length; i++) {
-        hexdata[offset++] = (i == 0 ? '<' : ' ');
-
-        if (i >= MAX_BYTES) {
-            snprintf(hexdata + offset, sizeof(hexdata) - offset, "...");
-            break;
-        }
-        snprintf(hexdata + offset, sizeof(hexdata) - offset, "%02x", data[i]);
-        offset += 2;
+    if (data == NULL) {
+        strcpy(hexdata, "<no data>");
     }
+    else {
+        offset = 0;
+        for (i = 0; i < data_length; i++) {
+            hexdata[offset++] = (i == 0 ? '<' : ' ');
+
+            if (i >= MAX_BYTES) {
+                snprintf(hexdata + offset, sizeof(hexdata) - offset, "...");
+                break;
+            }
+            snprintf(hexdata + offset, sizeof(hexdata) - offset, "%02x", data[i]);
+            offset += 2;
+        }
 
-    hexdata[offset++] = '>';
-    hexdata[offset] = '\0';
+        hexdata[offset++] = '>';
+        hexdata[offset] = '\0';
+    }
 
     va_start(ap, fmt);
     vsnprintf(prefix, sizeof(prefix), fmt, ap);

src/zipcmp.c

@@ -672,21 +672,19 @@ ef_read(zip_t *za, zip_uint64_t idx, struct entry *e) {
 
     e->n_extra_fields = (zip_uint16_t)(n_local + n_central);
 
-    if ((e->extra_fields = (struct ef *)malloc(sizeof(e->extra_fields[0]) * e->n_extra_fields)) == NULL)
-        return -1;
+    if ((e->extra_fields = (struct ef *)malloc(sizeof(e->extra_fields[0]) * e->n_extra_fields)) == NULL) {
+        fprintf(stderr, "%s: malloc failure\n", progname);
+        exit(1);
+    }
 
     for (i = 0; i < n_local; i++) {
         e->extra_fields[i].name = e->name;
         e->extra_fields[i].data = zip_file_extra_field_get(za, idx, i, &e->extra_fields[i].id, &e->extra_fields[i].size, ZIP_FL_LOCAL);
-        if (e->extra_fields[i].data == NULL)
-            return -1;
         e->extra_fields[i].flags = ZIP_FL_LOCAL;
     }
     for (; i < e->n_extra_fields; i++) {
         e->extra_fields[i].name = e->name;
         e->extra_fields[i].data = zip_file_extra_field_get(za, idx, (zip_uint16_t)(i - n_local), &e->extra_fields[i].id, &e->extra_fields[i].size, ZIP_FL_CENTRAL);
-        if (e->extra_fields[i].data == NULL)
-            return -1;
         e->extra_fields[i].flags = ZIP_FL_CENTRAL;
     }
 
@@ -723,6 +721,8 @@ ef_order(const void *ap, const void *bp) {
         return a->id - b->id;
     if (a->size != b->size)
         return a->size - b->size;
+    if (a->data == NULL || b->data == NULL)
+        return a->data == b->data ? 0 : (a->data == NULL ? -1 : 1);
     return memcmp(a->data, b->data, a->size);
 }