1 files changed, 59 insertions, 0 deletions
diff --git a/vere/pkg/noun/jets/e/crc.c b/vere/pkg/noun/jets/e/crc.c
new file mode 100644
index 0000000..496b8d5
--- /dev/null
+++ b/vere/pkg/noun/jets/e/crc.c
@@ -0,0 +1,59 @@
+/// @file
+
+#include <stdio.h>
+#include <allocate.h>
+#include "zlib.h"
+
+#include "jets/w.h"
+
+#include "noun.h"
+
+u3_noun
+u3qe_crc32(u3_noun input_octs)
+{
+  u3_atom head = u3h(input_octs);
+  u3_atom tail = u3t(input_octs);
+  c3_w  tel_w = u3r_met(3, tail);
+  c3_w hed_w;
+  if ( c3n == u3r_safe_word(head, &hed_w) ) {
+    return u3m_bail(c3__fail);
+  }
+  c3_y* input;
+
+  if (c3y == u3a_is_cat(tail)) {
+    input = (c3_y*)&tail;
+  }
+  else {
+    u3a_atom* vat_u = u3a_to_ptr(tail);
+    input = (c3_y*)vat_u->buf_w;
+  }
+
+  if ( tel_w > hed_w ) {
+    return u3m_error("subtract-underflow");
+  }
+
+  c3_w led_w = hed_w - tel_w;
+  c3_w crc_w = 0;
+
+  crc_w = crc32(crc_w, input, tel_w);
+
+  while ( led_w > 0 ) {
+    c3_y byt_y = 0;
+    crc_w = crc32(crc_w, &byt_y, 1);
+    led_w--;
+  }
+
+  return u3i_word(crc_w);
+}
+
+u3_noun
+u3we_crc32(u3_noun cor)
+{
+  u3_noun a = u3r_at(u3x_sam, cor);
+
+  if ( (u3du(a) == c3y) && (u3ud(u3h(a)) == c3y) && (u3ud(u3t(a)) == c3y) ) {
+    return u3qe_crc32(a);
+  } else {
+    return u3m_bail(c3__exit);
+  }
+}