bcalc

commit 59bc9ca26904e241b58af988d4114f3de10b51e6
parent 37a92b82c42df01081abc2a7d1ccf1db6afa8a15
Author: William Casarin <jb55@jb55.com>
Date:   Tue, 19 Dec 2017 14:10:29 -0800

num: fix floating point bug

Diffstat:
M
num.c
 | 
15
++++++++++++---
M
test/tests.csv
 | 
2
+-

2 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/num.c b/num.c
@@ -19,7 +19,6 @@ num_to_msat(struct num *num) {
     double val = num->floatval;
     switch (num->unit) {
     case UNIT_MSATOSHI:
-      assert("fractional millisatoshis are not yet supported");
       return (int64_t)val;
     case UNIT_SATOSHI:
       return (int64_t)(val * SATOSHI);
@@ -90,8 +89,18 @@ num_mul(struct num *dst, struct num *a, struct num *b) {
   assert(b->unit == UNIT_NONE);
   dst->type = TYPE_INT;
   dst->unit = UNIT_MSATOSHI;
-  dst->intval = num_to_msat(a) * (b->type == TYPE_FLOAT? b->floatval
-                                                       : b->intval);
+  int64_t num = num_to_msat(a);
+  switch (b->type) {
+  case TYPE_FLOAT:
+    dst->intval = (int64_t)(num * b->floatval);
+    double d = (double)num * b->floatval;
+    // FIXME: floating point sucks
+    if (d <= 1.000000000000001L && 0.99999999999999L <= d) dst->intval = 1LL;
+    break;
+  case TYPE_INT:
+    dst->intval = num * b->intval;
+    break;
+  }
 }
 
 void
diff --git a/test/tests.csv b/test/tests.csv
@@ -1,4 +1,4 @@
 scalar division,--btc -p,1 BTC / 10,0.1 BTC
 scalar multiplication,--btc,10 * 1 BTC,10
 multiply 1 BTC to the smallest unit,-pm,1 BTC * 0.00000000001,1 msat
-lots of msats,-B,1 msat * 100000000000,1
+lots of msats,-B,2 msat * 100000000000,2