* fstab.c: Added; wrap <fstab.h> functions: getfsent(3), getfsfile(3),

[mono.git] / support / x-struct-str.c

diff --git a/support/x-struct-str.c b/support/x-struct-str.c
new file mode 100644 (file)
index 0000000..09f1a67
--- /dev/null
+++ b/support/x-struct-str.c
@@ -0,0 +1,92 @@
+/*
+ * A helper routine to copy the strings between differing structures.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+
+#include "mph.h"
+
+#define MAX_OFFSETS 10
+
+#define str_at(p, n) (*(char**)(((char*)p)+n))
+
+char* MPH_INTERNAL
+_mph_copy_structure_strings (
+       void *to,   size_t *to_offsets, 
+       void *from, size_t *from_offsets, 
+       size_t num_strings)
+{
+       int i;
+       size_t buflen;
+       int len[MAX_OFFSETS];
+       char *buf, *cur = NULL;
+
+       g_assert (num_strings < MAX_OFFSETS);
+
+       for (i = 0; i < num_strings; ++i) {
+               str_at (to, to_offsets[i]) = NULL;
+       }
+
+       buflen = num_strings;
+       for (i = 0; i < num_strings; ++i) {
+               len[i] = strlen (str_at(from, from_offsets[i]));
+               if (len[i] < INT_MAX - buflen)
+                       buflen += len[i];
+               else
+                       len[i] = -1;
+       }
+
+       cur = buf = malloc (buflen);
+       if (buf == NULL) {
+               return NULL;
+       }
+
+       for (i = 0; i < num_strings; ++i) {
+               if (len[i] > 0) {
+                       str_at (to, to_offsets[i]) = 
+                               strcpy (cur, str_at (from, from_offsets[i]));
+                       cur += (len[i] +1);
+               }
+       }
+
+       return buf;
+}
+
+#ifdef TEST
+
+#include <stdio.h>
+
+struct foo {
+       char *a;
+       int   b;
+       char *c;
+};
+
+struct bar {
+       int    b;
+       char  *a;
+       double d;
+       char  *c;
+};
+
+int
+main ()
+{
+       /* test copying foo to bar */
+       struct foo f = {"hello", 42, "world"};
+       struct bar b;
+       size_t foo_offsets[] = {offsetof(struct foo, a), offsetof(struct foo, c)};
+       size_t bar_offsets[] = {offsetof(struct bar, a), offsetof(struct bar, c)};
+       char *buf;
+
+       buf = _mph_copy_structure_strings (&b, bar_offsets, 
+                       &f, foo_offsets, 2);
+       printf ("b.a=%s\n", b.a);
+       printf ("b.c=%s\n", b.c);
+
+       return 0;
+}
+#endif
+