cangrepp

commit 4e5eeccd8049accf5604efad12cd2a9f11a1df2d
parent 1c5d537e98f90c9b479d772c65c39bcbebe14685
Author: olikru <olikru@tkruger.se>
Date:   Mon,  6 May 2024 22:03:38 +0200

context for pierre

Diffstat:
M
Makefile
 | 
2
+-
M
pierre.c
 | 
20
++++++++++++++++----
M
pierre.h
 | 
12
+++++++++++-
M
test_angrepp.c
 | 
7
++++++-
M
tools/pierre.c
 | 
6
+++++-

5 files changed, 39 insertions(+), 8 deletions(-)
diff --git a/Makefile b/Makefile
@@ -1,6 +1,6 @@
 .SUFFIXES: .c .o .so
 CC=clang
-CFLAGS+=-std=c99 -pedantic -Wall -Werror -Wstrict-prototypes
+CFLAGS+=-std=c11 -pedantic -Wall -Werror -Wstrict-prototypes
 CFLAGS+=-Wmissing-prototypes -Wmissing-declarations -Wshadow
 CFLAGS+=-Wpointer-arith -Wcast-qual -Wsign-compare
 CFLAGS+=-O2 -g
diff --git a/pierre.c b/pierre.c
@@ -1,4 +1,5 @@
 #include <fmpz.h>
+#include <fmpz_vec.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -6,7 +7,19 @@
 #include "pierre.h"
 
 void
-fermat_factor(fmpz_t r, fmpz_t n, size_t limit)
+fermat_ctx_init(fermat_ctx *ctx)
+{
+  ctx->zs = _fmpz_vec_init(FERMAT_CTX_NZS);
+}
+
+void
+fermat_ctx_clear(fermat_ctx *ctx)
+{
+  _fmpz_vec_clear(ctx->zs, FERMAT_CTX_NZS);
+}
+
+void
+fermat_factor(fermat_ctx *ctx, fmpz_t r, fmpz_t n, size_t limit)
 {
   size_t i;
   uint64_t inc = 1;
@@ -24,13 +37,12 @@ fermat_factor(fmpz_t r, fmpz_t n, size_t limit)
   }
 
   if (found) {
-    fmpz_t tmp;
-    fmpz_init_set(tmp, n);
+    fmpz_t tmp = {ctx->zs[0]};
+    fmpz_set(tmp, n);
     fmpz_sub(tmp, r, n); // tmp = b^2
     fmpz_sqrt(tmp, tmp); // tmp = b
     fmpz_sqrt(r, r);     // r = a
     fmpz_add(r, r, tmp);
-    fmpz_clear(tmp);
   } else {
     fmpz_set_ui(r, 0);
   }
diff --git a/pierre.h b/pierre.h
@@ -1,6 +1,15 @@
 #ifndef _PIERRE_H_
 #define _PIERRE_H_
 
+#define FERMAT_CTX_NZS 1
+
+typedef struct __fermat_ctx {
+  fmpz* zs;
+} fermat_ctx;
+
+void fermat_ctx_init(fermat_ctx *ctx);
+void fermat_ctx_clear(fermat_ctx *ctx);
+
 /**
  * Fermat factorisation of an integer.
  *
@@ -10,10 +19,11 @@
  * is a perfect square for some i in [1, limit]. If no factor is found
  * it sets res to 0.
  *
+ * @param ctx   fermat factoring context
  * @param res   the output fmpz_t
  * @param n     the number to attempt to Fermat factorise
  * @param limit iteration limit bound
  */
-void fermat_factor(fmpz_t r, fmpz_t n, size_t limit);
+void fermat_factor(fermat_ctx *ctx, fmpz_t r, fmpz_t n, size_t limit);
 
 #endif
diff --git a/test_angrepp.c b/test_angrepp.c
@@ -41,15 +41,20 @@ static void
 test_pierre_factor(void)
 {
   fmpz_t n, r;
+  fermat_ctx ctx;
+
+  fermat_ctx_init(&ctx);
   fmpz_init(n);
   fmpz_init(r);
+
   fmpz_set_str(n, "13957163057215389251", 10);
 
-  fermat_factor(r, n, 200);
+  fermat_factor(&ctx, r, n, 200);
 
   assert(fmpz_divisible(n, r));
   assert(fmpz_cmp_ui(r, 1) > 0);
 
+  fermat_ctx_clear(&ctx);
   fmpz_clear(n);
   fmpz_clear(r);
 }
diff --git a/tools/pierre.c b/tools/pierre.c
@@ -12,15 +12,19 @@ int
 main(void)
 {
   fmpz_t read, factor;
+  fermat_ctx ctx;
+
+  fermat_ctx_init(&ctx);
   fmpz_init(factor);
   fmpz_init(read);
 
   while (read_next_hex_fmpz(read) == 0) {
-    fermat_factor(factor, read, DEFAULT_LIMIT);
+    fermat_factor(&ctx, factor, read, DEFAULT_LIMIT);
     fmpz_print(factor);
     printf("\n");
   }
 
+  fermat_ctx_clear(&ctx);
   fmpz_clear(factor);
   fmpz_clear(read);