+
+/* Returns true if FILE is an SPSS portable file,
+ false otherwise. */
+bool
+pfm_detect (FILE *file)
+{
+ unsigned char header[464];
+ char trans[256];
+ int cooked_cnt, raw_cnt;
+ int i;
+
+ cooked_cnt = raw_cnt = 0;
+ while (cooked_cnt < sizeof header)
+ {
+ int c = getc (file);
+ if (c == EOF || raw_cnt++ > 512)
+ return false;
+ else if (c != '\n' && c != '\r')
+ header[cooked_cnt++] = c;
+ }
+
+ memset (trans, 0, 256);
+ for (i = 64; i < 256; i++)
+ {
+ unsigned char c = header[i + 200];
+ if (trans[c] == 0)
+ trans[c] = portable_to_local[i];
+ }
+
+ for (i = 0; i < 8; i++)
+ if (trans[header[i + 456]] != "SPSSPORT"[i])
+ return false;
+
+ return true;
+}