Extend endianness-invariant check-summing API for continuation.

src/cdi_cksum.c

@@ -18,6 +18,27 @@ cdiCheckSum(int type, int count, const void *buffer)
   return s;
 }
 
+void
+cdiCheckSumRStart(struct cdiCheckSumState *state)
+{
+  state->sum = 0U;
+  state->len = 0;
+}
+
+void
+cdiCheckSumRAdd(struct cdiCheckSumState *state, int type, int count, const void *buffer)
+{
+  size_t elemSize = (size_t) serializeGetSizeInCore(1, type, NULL);
+  memcrc_r_eswap(&state->sum, (const unsigned char *) buffer, (size_t) count, elemSize);
+  state->len += (off_t) (elemSize * (size_t) count);
+}
+
+uint32_t
+cdiCheckSumRValue(struct cdiCheckSumState state)
+{
+  return memcrc_finish(&state.sum, state.len);
+}
+
 /*
  * Local Variables:
  * c-file-style: "Java"

src/cdi_cksum.h

@@ -3,8 +3,25 @@
 
 #include <inttypes.h>
 
+/* single checksum computation over one array */
 uint32_t cdiCheckSum(int type, int count, const void *data);
 
+/* composable check-sum computation,
+ * 0. datatype,
+ * 1. init,
+ * 2. partial, appendable computation, and
+ * 3. final checksum-computation
+ */
+struct cdiCheckSumState
+{
+  uint32_t sum;
+  off_t len;
+};
+
+void cdiCheckSumRStart(struct cdiCheckSumState *state);
+void cdiCheckSumRAdd(struct cdiCheckSumState *state, int type, int count, const void *data);
+uint32_t cdiCheckSumRValue(struct cdiCheckSumState state);
+
 #endif
 
 /*