Correct display of amounts with keep_precision

Fixes #167 / 1D275740-D1A6-42B7-BDE4-F2F85E30CE8E

3 files changed, 217 insertions, 14 deletions

diff --git a/src/amount.cc b/src/amount.cc
index 1cba92f8..9b7c3676 100644
--- a/src/amount.cc
+++ b/src/amount.cc
@@ -47,6 +47,8 @@ static mpz_t  temp;
 static mpq_t  tempq;
 static mpfr_t tempf;
 static mpfr_t tempfb;
+static mpfr_t tempfnum;
+static mpfr_t tempfden;
 #endif
 
 struct amount_t::bigint_t : public supports_flags<>
@@ -111,7 +113,7 @@ bool amount_t::is_initialized = false;
 namespace {
   void stream_out_mpq(std::ostream&	            out,
 		      mpq_t		            quant,
-		      amount_t::precision_t         prec,
+		      amount_t::precision_t         precision,
 		      int                           zeros_prec = -1,
 		      const optional<commodity_t&>& comm       = none)
   {
@@ -125,17 +127,39 @@ namespace {
 
       // Convert the rational number to a floating-point, extending the
       // floating-point to a large enough size to get a precise answer.
-      const std::size_t bits = (mpz_sizeinbase(mpq_numref(quant), 2) +
-				mpz_sizeinbase(mpq_denref(quant), 2));
-      mpfr_set_prec(tempfb, bits + amount_t::extend_by_digits*8);
-      mpfr_set_q(tempfb, quant, GMP_RNDN);
 
-      if (mpfr_asprintf(&buf, "%.*Rf", prec, tempfb) < 0)
+      mp_prec_t num_prec = mpz_sizeinbase(mpq_numref(quant), 2);
+      num_prec += amount_t::extend_by_digits*64;
+      if (num_prec < MPFR_PREC_MIN)
+	num_prec = MPFR_PREC_MIN;
+      DEBUG("amount.convert", "num prec = " << num_prec);
+
+      mpfr_set_prec(tempfnum, num_prec);
+      mpfr_set_z(tempfnum, mpq_numref(quant), GMP_RNDN);
+
+      mp_prec_t den_prec = mpz_sizeinbase(mpq_denref(quant), 2);
+      den_prec += amount_t::extend_by_digits*64;
+      if (den_prec < MPFR_PREC_MIN)
+	den_prec = MPFR_PREC_MIN;
+      DEBUG("amount.convert", "den prec = " << den_prec);
+
+      mpfr_set_prec(tempfden, den_prec);
+      mpfr_set_z(tempfden, mpq_denref(quant), GMP_RNDN);
+
+      mpfr_set_prec(tempfb, num_prec + den_prec);
+      mpfr_div(tempfb, tempfnum, tempfden, GMP_RNDN);
+
+      char bigbuf[4096];
+      mpfr_sprintf(bigbuf, "%.RNf", tempfb);
+      DEBUG("amount.convert", "num/den = " << bigbuf);
+
+      if (mpfr_asprintf(&buf, "%.*RNf", precision, tempfb) < 0)
 	throw_(amount_error,
 	       _("Cannot output amount to a floating-point representation"));
 	
-      DEBUG("amount.convert",
-	    "mpfr_print = " << buf << " (precision " << prec << ")");
+      DEBUG("amount.convert", "mpfr_print = " << buf
+	    << " (precision " << precision
+	    << ", zeros_prec " << zeros_prec << ")");
 
       if (zeros_prec >= 0) {
 	string::size_type index = std::strlen(buf);
@@ -211,6 +235,8 @@ void amount_t::initialize()
     mpq_init(tempq);
     mpfr_init(tempf);
     mpfr_init(tempfb);
+    mpfr_init(tempfnum);
+    mpfr_init(tempfden);
 
     commodity_pool_t::current_pool.reset(new commodity_pool_t);
 
@@ -238,6 +264,8 @@ void amount_t::shutdown()
     mpq_clear(tempq);
     mpfr_clear(tempf);
     mpfr_clear(tempfb);
+    mpfr_clear(tempfnum);
+    mpfr_clear(tempfden);
 
     commodity_pool_t::current_pool.reset();
 
@@ -556,12 +584,10 @@ amount_t::precision_t amount_t::display_precision() const
 
   commodity_t& comm(commodity());
 
-  if (! comm || keep_precision())
-    return quantity->prec;
-  else if (comm.precision() != quantity->prec)
+  if (comm && ! keep_precision())
     return comm.precision();
   else
-    return quantity->prec;
+    return comm ? std::max(quantity->prec, comm.precision()) : quantity->prec;
 }
 
 void amount_t::in_place_negate()
@@ -643,7 +669,7 @@ void amount_t::in_place_floor()
   _dup();
 
   std::ostringstream out;
-  stream_out_mpq(out, MP(quantity), 0);
+  stream_out_mpq(out, MP(quantity), precision_t(0));
 
   mpq_set_str(MP(quantity), out.str().c_str(), 10);
 }
diff --git a/test/regress/1D275740.test b/test/regress/1D275740.test
new file mode 100644
index 00000000..72eb1769
--- /dev/null
+++ b/test/regress/1D275740.test
@@ -0,0 +1,177 @@
+print
+<<<
+D 1.200,40 €
+
+1999/11/01 * Achat
+   Actif:SSB      125 STK
+   Actif:SSB            -1672,42 $
+
+1999/11/04 * Vente
+   Actif:SSB        -125 STK
+   Dépense:SSB:Commissions       55,07 $
+   Actif:SSB             1821,54 $
+
+2001/05/01 * Vente
+   Actif:SSEA       -188,7974 STK @ 14,200 $
+   Dépense:SSEA:Commissions       19,60 $
+   Actif:SSEA          2661,32 $
+
+2001/12/21 * Achat
+   Actif:LPG                  7,34316 AMD @ 200,340 €
+   Actif:LPG                    -1471,13 €
+
+2002/12/31 * Réinv. des dividendes
+   Actif:LPG                0,03032 AMD @ 135,060 €
+   Revenu:Dividende:AMD       -4,10 €
+
+2003/12/31 * Réinv. des dividendes
+   Actif:LPG                0,02356 AMD @ 147,830 €
+   Revenu:Dividende:AMD       -3,48 €
+
+2004/02/17 * Vente
+   Actif:LPG                  -7,39704 AMD @ 148,860 €
+   Actif:LPG                     1101,12 €
+
+2005/12/31 * Réinv. des dividendes
+   Actif:LPG                0,87704 LAPD @ 22,680 €
+   Revenu:Dividende:LAPD      -19,89 €
+
+2006/06/30 * Achat
+   Actif:CPE                   54,7328 PM @ 33,200 €
+   Actif:CPE                     -1817,13 €
+
+2006/06/30 * Achat
+   Actif:CPE                   13,8913 PM @ 33,200 €
+   Actif:CPE                      -461,19 €
+
+2007/04/01 Achat
+   Actif:SV               0,2087 CE @ 622,900 €
+   Actif:BC                           -130,00 €
+
+2007/12/27 Vente
+   Actif:SV               -0,2086 EA @ 183,800 €
+   Actif:SV                      38,34 €
+
+2008/01/01 Achat
+   Actif:SV               0,1757 CE @ 739,900 €
+   Actif:BC                           -130,00 €
+
+2008/02/01 Achat
+   Actif:SV               3,1863 EA @ 163,200 €
+   Actif:BC                           -520,00 €
+
+2008/05/01 Achat
+   Actif:SV               0,2599 CE @ 654,100 €
+   Actif:BC                           -170,00 €
+
+2008/10/30 Vente
+   Actif:SV                 -0,0405 CD @ 155,800 €
+   Actif:SV                       6,31 €
+
+2008/12/31 Vente
+   Actif:SV                 -0,0357 MFE @ 259,100 €
+   Actif:SV                       9,25 €
+
+2009/06/29 Vente
+   Actif:SV                 -0,0786 CD @ 155,600 €
+   Actif:SV                      12,23 €
+
+2009/07/30 Vente
+   Actif:SV                 -0,0417 MFE @ 321,100 €
+   Actif:SV                      13,39 €
+
+2009/08/01 Achat
+   Actif:SV                 1,0204 MFE @ 333,200 €
+   Actif:BC                           -340,00 €
+
+2009/09/29 Vente
+   Actif:SV                 -0,0415 MFE @ 358,800 €
+   Actif:SV                      14,89 €
+>>>1
+1999/11/01 * Achat
+    Actif:SSB                           125,0000 STK @ 13,37936 $
+    Actif:SSB                             -1672,42 $
+
+1999/11/04 * Vente
+    Actif:SSB                           -125,0000 STK @ 15,01288 $
+    Dépense:SSB:Commissions                  55,07 $
+    Actif:SSB                              1821,54 $
+
+2001/05/01 * Vente
+    Actif:SSEA                          -188,7974 STK @ 14,20 $
+    Dépense:SSEA:Commissions                 19,60 $
+    Actif:SSEA                             2661,32 $
+
+2001/12/21 * Achat
+    Actif:LPG                            7,34316 AMD @ 200,34 €
+    Actif:LPG                            -1.471,13 €
+
+2002/12/31 * Réinv. des dividendes
+    Actif:LPG                            0,03032 AMD @ 135,06 €
+    Revenu:Dividende:AMD                     -4,10 €
+
+2003/12/31 * Réinv. des dividendes
+    Actif:LPG                            0,02356 AMD @ 147,83 €
+    Revenu:Dividende:AMD                     -3,48 €
+
+2004/02/17 * Vente
+    Actif:LPG                           -7,39704 AMD @ 148,86 €
+    Actif:LPG                             1.101,12 €
+
+2005/12/31 * Réinv. des dividendes
+    Actif:LPG                           0,87704 LAPD @ 22,68 €
+    Revenu:Dividende:LAPD                   -19,89 €
+
+2006/06/30 * Achat
+    Actif:CPE                             54,7328 PM @ 33,20 €
+    Actif:CPE                            -1.817,13 €
+
+2006/06/30 * Achat
+    Actif:CPE                             13,8913 PM @ 33,20 €
+    Actif:CPE                              -461,19 €
+
+2007/04/01 Achat
+    Actif:SV                               0,2087 CE @ 622,90 €
+    Actif:BC                               -130,00 €
+
+2007/12/27 Vente
+    Actif:SV                              -0,2086 EA @ 183,80 €
+    Actif:SV                                 38,34 €
+
+2008/01/01 Achat
+    Actif:SV                               0,1757 CE @ 739,90 €
+    Actif:BC                               -130,00 €
+
+2008/02/01 Achat
+    Actif:SV                               3,1863 EA @ 163,20 €
+    Actif:BC                               -520,00 €
+
+2008/05/01 Achat
+    Actif:SV                               0,2599 CE @ 654,10 €
+    Actif:BC                               -170,00 €
+
+2008/10/30 Vente
+    Actif:SV                              -0,0405 CD @ 155,80 €
+    Actif:SV                                  6,31 €
+
+2008/12/31 Vente
+    Actif:SV                             -0,0357 MFE @ 259,10 €
+    Actif:SV                                  9,25 €
+
+2009/06/29 Vente
+    Actif:SV                              -0,0786 CD @ 155,60 €
+    Actif:SV                                 12,23 €
+
+2009/07/30 Vente
+    Actif:SV                             -0,0417 MFE @ 321,10 €
+    Actif:SV                                 13,39 €
+
+2009/08/01 Achat
+    Actif:SV                              1,0204 MFE @ 333,20 €
+    Actif:BC                               -340,00 €
+
+2009/09/29 Vente
+    Actif:SV                             -0,0415 MFE @ 358,80 €
+    Actif:SV                                 14,89 €
+>>>2
+=== 0
diff --git a/test/regress/2E3496BD.test b/test/regress/2E3496BD.test
index cb105f08..466464b3 100644
--- a/test/regress/2E3496BD.test
+++ b/test/regress/2E3496BD.test
@@ -15,6 +15,6 @@ While balancing transaction from "$FILE", lines 3-5:
 Unbalanced remainder is:
           100.00 USD
 Amount to balance against:
-         1,600.0 USD
+        1,600.00 USD
 Error: Transaction does not balance
 === 1