Fix byte swapping in ms3_detect() for v3 records for big-endian systems. Fixes #120

Author: chad-earthscope

ChangeLog

@@ -1,3 +1,6 @@
+2025.303:
+  - Fix byte swapping in ms3_detect() for v3 records for big-endian systems.
+
 2025.298: v3.1.10
   - Add MSF_SPLITISVERSION flag to control using the splitversion value as the
   version instead the record publication version for mstl3_addmsr() and variants.

parseutils.c

@@ -203,10 +203,19 @@ ms3_detect (const char *record, uint64_t recbuflen, uint8_t *formatversion)
 
     *formatversion = 3;
 
+    /* Check to see if byte swapping is needed, v3 is little-endian */
+    swapflag = (ms_bigendianhost()) ? 1 : 0;
+
     memcpy (&sidlength, pMS3FSDH_SIDLENGTH (record), sizeof (uint8_t));
     memcpy (&extralength, pMS3FSDH_EXTRALENGTH (record), sizeof (uint16_t));
     memcpy (&datalength, pMS3FSDH_DATALENGTH (record), sizeof (uint32_t));
 
+    if (swapflag)
+    {
+      ms_gswap2 (&extralength);
+      ms_gswap4 (&datalength);
+    }
+
     reclen = MS3FSDH_LENGTH /* Length of fixed portion of header */
              + sidlength    /* Length of source identifier */
              + extralength  /* Length of extra headers */