From 95c53611976a9f494ff96725822dcf6533e1f498 Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 22 Jan 2014 23:47:33 +0900
Subject: [PATCH] rewrite min/max/gcd/lcm with C

---
 piclib/built-in.scm |  35 +-----------
 src/number.c        | 136 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 138 insertions(+), 33 deletions(-)

diff --git a/piclib/built-in.scm b/piclib/built-in.scm
index 9d4bcf00..711cca48 100644
--- a/piclib/built-in.scm
+++ b/piclib/built-in.scm
@@ -361,18 +361,6 @@
 
 ;;; 6.2. Numbers
 
-(define (min x . args)
-  (let loop ((pivot x) (rest args))
-    (if (null? rest)
-	pivot
-	(loop (if (< pivot (car rest)) pivot (car rest)) (cdr rest)))))
-
-(define (max x . args)
-  (let loop ((pivot x) (rest args))
-    (if (null? rest)
-	pivot
-	(loop (if (> pivot (car rest)) pivot (car rest)) (cdr rest)))))
-
 (define (floor/ n m)
   (values (floor-quotient n m)
 	  (floor-remainder n m)))
@@ -388,27 +376,8 @@
   (let ((n (exact (floor (sqrt k)))))
     (values n (- k (square n)))))
 
-(define (gcd n m)
-  (if (negative? n)
-      (set! n (- n)))
-  (if (negative? m)
-      (set! m (- m)))
-  (if (> n m)
-      ((lambda (tmp)
-	 (set! n m)
-	 (set! m tmp))
-       n))
-  (if (zero? n)
-      m
-      (gcd (floor-remainder m n) n)))
-
-(define (lcm n m)
-  (/ (* n m) (gcd n m)))
-
-(export min max
-        floor/ truncate/
-        exact-integer-sqrt
-        gcd lcm)
+(export floor/ truncate/
+        exact-integer-sqrt)
 
 ;;; 6.3 Booleans
 
diff --git a/src/number.c b/src/number.c
index 0adcbdbc..321bab31 100644
--- a/src/number.c
+++ b/src/number.c
@@ -4,9 +4,28 @@
 
 #include <math.h>
 #include <limits.h>
+#include <stdlib.h>
 
 #include "picrin.h"
 
+static int
+gcd(int a, int b)
+{
+  if (a > b)
+    return gcd(b, a);
+  if (a < 0)
+    return gcd(-a, b);
+  if (a > 0)
+    return gcd(b % a, a);
+  return b;
+}
+
+static int
+lcm(int a, int b)
+{
+  return abs(a * b) / gcd(a, b);
+}
+
 static pic_value
 pic_number_real_p(pic_state *pic)
 {
@@ -183,6 +202,62 @@ pic_number_even_p(pic_state *pic)
   return pic_bool_value(i % 2 == 0);
 }
 
+static pic_value
+pic_number_max(pic_state *pic)
+{
+  size_t argc;
+  pic_value *argv;
+  int i;
+  double f;
+  bool e = true;
+
+  pic_get_args(pic, "*", &argc, &argv);
+
+  f = -INFINITY;
+  for (i = 0; i < argc; ++i) {
+    if (pic_int_p(argv[i])) {
+      f = fmax(f, pic_int(argv[i]));
+    }
+    else if (pic_float_p(argv[i])) {
+      e = false;
+      f = fmax(f, pic_float(argv[i]));
+    }
+    else {
+      pic_error(pic, "min: number required");
+    }
+  }
+
+  return e ? pic_int_value(f) : pic_float_value(f);
+}
+
+static pic_value
+pic_number_min(pic_state *pic)
+{
+  size_t argc;
+  pic_value *argv;
+  int i;
+  double f;
+  bool e = true;
+
+  pic_get_args(pic, "*", &argc, &argv);
+
+  f = INFINITY;
+  for (i = 0; i < argc; ++i) {
+    if (pic_int_p(argv[i])) {
+      f = fmin(f, pic_int(argv[i]));
+    }
+    else if (pic_float_p(argv[i])) {
+      e = false;
+      f = fmin(f, pic_float(argv[i]));
+    }
+    else {
+      pic_error(pic, "min: number required");
+    }
+  }
+
+  return e ? pic_int_value(f) : pic_float_value(f);
+}
+
 #define DEFINE_ARITH_OP(op, name, unit)                         \
   static pic_value                                              \
   pic_number_##name(pic_state *pic)                             \
@@ -333,6 +408,58 @@ pic_number_trunc_remainder(pic_state *pic)
   }
 }
 
+static pic_value
+pic_number_gcd(pic_state *pic)
+{
+  size_t argc;
+  pic_value *args;
+  int r;
+  bool e = true;
+
+  pic_get_args(pic, "*", &argc, &args);
+
+  r = 0;
+  while (argc-- > 0) {
+    if (pic_int_p(args[argc])) {
+      r = gcd(r, pic_int(args[argc]));
+    }
+    else if (pic_float_p(args[argc])) {
+      e = false;
+      r = gcd(r, pic_float(args[argc]));
+    }
+    else {
+      pic_error(pic, "gcd: number required");
+    }
+  }
+  return e ? pic_int_value(r) : pic_float_value(r);
+}
+
+static pic_value
+pic_number_lcm(pic_state *pic)
+{
+  size_t argc;
+  pic_value *args;
+  int r;
+  bool e = true;
+
+  pic_get_args(pic, "*", &argc, &args);
+
+  r = 1;
+  while (argc-- > 0) {
+    if (pic_int_p(args[argc])) {
+      r = lcm(r, pic_int(args[argc]));
+    }
+    else if (pic_float_p(args[argc])) {
+      e = false;
+      r = lcm(r, pic_float(args[argc]));
+    }
+    else {
+      pic_error(pic, "lcm: number required");
+    }
+  }
+  return e ? pic_int_value(r) : pic_float_value(r);
+}
+
 static pic_value
 pic_number_floor(pic_state *pic)
 {
@@ -581,6 +708,11 @@ pic_init_number(pic_state *pic)
   pic_defun(pic, "negative?", pic_number_negative_p);
   pic_defun(pic, "odd?", pic_number_odd_p);
   pic_defun(pic, "even?", pic_number_even_p);
+  pic_gc_arena_restore(pic, ai);
+
+  pic_defun(pic, "min", pic_number_min);
+  pic_defun(pic, "max", pic_number_max);
+  pic_gc_arena_restore(pic, ai);
 
   pic_defun(pic, "+", pic_number_add);
   pic_defun(pic, "-", pic_number_sub);
@@ -595,6 +727,10 @@ pic_init_number(pic_state *pic)
   pic_defun(pic, "truncate-remainder", pic_number_trunc_remainder);
   pic_gc_arena_restore(pic, ai);
 
+  pic_defun(pic, "gcd", pic_number_gcd);
+  pic_defun(pic, "lcm", pic_number_lcm);
+  pic_gc_arena_restore(pic, ai);
+
   pic_defun(pic, "floor", pic_number_floor);
   pic_defun(pic, "ceiling", pic_number_ceil);
   pic_defun(pic, "truncate", pic_number_trunc);