Refactor bigint functions and add remaining helpers

A second variant of the mpz-based iterator is added, and both functions
are moved into a new 'mpz' module, removing 'iterations' and the common
pszip.h header.

These iterators have been updated to have all (de)allocation performed
externally as to reduce overhead / boost performance.  Related helper
functions have also been added to this module.

Signed-off-by: Malfurious <m@lfurio.us>

1 files changed, 22 insertions, 0 deletions

diff --git a/mpz.h b/mpz.h
new file mode 100644
index 0000000..ef41ec6
--- /dev/null
+++ b/mpz.h
@@ -0,0 +1,22 @@
+#pragma once
+
+#include <gmp.h>
+#include <stddef.h>
+
+/* This struct contains the instance data used by the iterators.  Allocation is
+ * performed at a single point to reduce run-time overhead.
+ *
+ * 'current' contains the iterator's current value.  The rest of the members are
+ * temporary variables.  See the appropriate memory management functions for
+ * this type. */
+struct pszip_mpz_state
+{
+    mpz_t current, a, b, c, d;
+};
+
+void pszip_mpz_state_init(struct pszip_mpz_state *mpzs, size_t popcnt, size_t size);
+void pszip_mpz_state_clear(struct pszip_mpz_state *mpzs);
+void pszip_mpz_init_data(mpz_t n, const void *data, size_t size);
+
+void pszip_mpz_iterate_bithack01(struct pszip_mpz_state *mpzs);
+void pszip_mpz_iterate_bithack02(struct pszip_mpz_state *mpzs);