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[taler-exchange] branch master updated: fix rounding, extend test
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From: |
gnunet |
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Subject: |
[taler-exchange] branch master updated: fix rounding, extend test |
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Date: |
Sun, 19 Jan 2020 20:11:34 +0100 |
This is an automated email from the git hooks/post-receive script.
grothoff pushed a commit to branch master
in repository exchange.
The following commit(s) were added to refs/heads/master by this push:
new 600592db fix rounding, extend test
600592db is described below
commit 600592dbf6aced50a92cced8ab9d773d06f0f4f4
Author: Christian Grothoff <address@hidden>
AuthorDate: Sun Jan 19 20:11:32 2020 +0100
fix rounding, extend test
---
src/include/taler_amount_lib.h | 29 +++++++-------
src/util/amount.c | 87 ++++++++++++++++++++++++++++--------------
src/util/test_amount.c | 37 +++++++++++++-----
3 files changed, 102 insertions(+), 51 deletions(-)
diff --git a/src/include/taler_amount_lib.h b/src/include/taler_amount_lib.h
index 6e2a5f58..e3f39cbb 100644
--- a/src/include/taler_amount_lib.h
+++ b/src/include/taler_amount_lib.h
@@ -116,7 +116,7 @@ struct TALER_Amount
* Parse denomination description, in the format "T:V.F".
*
* @param str denomination description
- * @param denom denomination to write the result to
+ * @param[out] denom denomination to write the result to
* @return #GNUNET_OK if the string is a valid denomination specification,
* #GNUNET_SYSERR if it is invalid.
*/
@@ -129,7 +129,7 @@ TALER_string_to_amount (const char *str,
* Parse denomination description, in the format "T:V.F".
*
* @param str denomination description
- * @param denom denomination to write the result to, in NBO
+ * @param[out] denom denomination to write the result to, in NBO
* @return #GNUNET_OK if the string is a valid denomination specification,
* #GNUNET_SYSERR if it is invalid.
*/
@@ -142,7 +142,7 @@ TALER_string_to_amount_nbo (const char *str,
* Get the value of "zero" in a particular currency.
*
* @param cur currency description
- * @param denom denomination to write the result to
+ * @param[out] denom denomination to write the result to
* @return #GNUNET_OK if @a cur is a valid currency specification,
* #GNUNET_SYSERR if it is invalid.
*/
@@ -164,7 +164,7 @@ TALER_amount_is_valid (const struct TALER_Amount *amount);
/**
* Convert amount from host to network representation.
*
- * @param res where to store amount in network representation
+ * @param[out] res where to store amount in network representation
* @param d amount in host representation
*/
void
@@ -175,7 +175,7 @@ TALER_amount_hton (struct TALER_AmountNBO *res,
/**
* Convert amount from network to host representation.
*
- * @param res where to store amount in host representation
+ * @param[out] res where to store amount in host representation
* @param dn amount in network representation
*/
void
@@ -232,7 +232,7 @@ TALER_amount_cmp_currency_nbo (const struct TALER_AmountNBO
*a1,
/**
* Perform saturating subtraction of amounts.
*
- * @param diff where to store (@a a1 - @a a2), or invalid if @a a2 > @a a1
+ * @param[out] diff where to store (@a a1 - @a a2), or invalid if @a a2 > @a a1
* @param a1 amount to subtract from
* @param a2 amount to subtract
* @return #GNUNET_OK if the subtraction worked,
@@ -249,7 +249,7 @@ TALER_amount_subtract (struct TALER_Amount *diff,
/**
* Perform addition of amounts.
*
- * @param sum where to store @a a1 + @a a2, set to "invalid" on overflow
+ * @param[out] sum where to store @a a1 + @a a2, set to "invalid" on overflow
* @param a1 first amount to add
* @param a2 second amount to add
* @return #GNUNET_OK if the addition worked,
@@ -262,10 +262,10 @@ TALER_amount_add (struct TALER_Amount *sum,
/**
- * Divide an amount by a float. Note that this function
+ * Divide an amount by a @ divisor. Note that this function
* may introduce a rounding error!
*
- * @param result where to store @a dividend / @a divisor
+ * @param[out] result where to store @a dividend / @a divisor
* @param dividend amount to divide
* @param divisor by what to divide, must be positive
*/
@@ -278,7 +278,7 @@ TALER_amount_divide (struct TALER_Amount *result,
/**
* Normalize the given amount.
*
- * @param amount amount to normalize
+ * @param[in,out] amount amount to normalize
* @return #GNUNET_OK if normalization worked
* #GNUNET_NO if value was already normalized
* #GNUNET_SYSERR if value was invalid or could not be normalized
@@ -312,13 +312,14 @@ TALER_amount2s (const struct TALER_Amount *amount);
/**
* Round the amount to something that can be transferred on the wire.
* The rounding mode is specified via the smallest transferable unit,
- * which must only have a fractional part.
+ * which must only have a fractional part *or* only a value (either
+ * of the two must be zero!).
*
* @param[in,out] amount amount to round down
- * @param[in] round_unit unit that should be rounded down to,
- * the value part of this amount must be zero
+ * @param[in] round_unit unit that should be rounded down to, and
+ * either value part or the faction must be zero (but not both)
* @return #GNUNET_OK on success, #GNUNET_NO if rounding was unnecessary,
- * #GNUNET_SYSERR if the amount or currency was invalid
+ * #GNUNET_SYSERR if the amount or currency or @a round_unit was
invalid
*/
int
TALER_amount_round_down (struct TALER_Amount *amount,
diff --git a/src/util/amount.c b/src/util/amount.c
index c1142b07..a9b41ba7 100644
--- a/src/util/amount.c
+++ b/src/util/amount.c
@@ -53,7 +53,7 @@ invalidate (struct TALER_Amount *a)
* Parse money amount description, in the format "A:B.C".
*
* @param str amount description
- * @param denom amount to write the result to
+ * @param[out] denom amount to write the result to
* @return #GNUNET_OK if the string is a valid amount specification,
* #GNUNET_SYSERR if it is invalid.
*/
@@ -189,7 +189,7 @@ TALER_string_to_amount (const char *str,
* Parse denomination description, in the format "T:V.F".
*
* @param str denomination description
- * @param denom denomination to write the result to, in NBO
+ * @param[out] denom denomination to write the result to, in NBO
* @return #GNUNET_OK if the string is a valid denomination specification,
* #GNUNET_SYSERR if it is invalid.
*/
@@ -213,7 +213,7 @@ TALER_string_to_amount_nbo (const char *str,
* Convert amount from host to network representation.
*
* @param res where to store amount in network representation
- * @param d amount in host representation
+ * @param[out] d amount in host representation
*/
void
TALER_amount_hton (struct TALER_AmountNBO *res,
@@ -232,7 +232,7 @@ TALER_amount_hton (struct TALER_AmountNBO *res,
/**
* Convert amount from network to host representation.
*
- * @param res where to store amount in host representation
+ * @param[out] res where to store amount in host representation
* @param dn amount in network representation
*/
void
@@ -253,7 +253,7 @@ TALER_amount_ntoh (struct TALER_Amount *res,
* Get the value of "zero" in a particular currency.
*
* @param cur currency description
- * @param denom denomination to write the result to
+ * @param[out] denom denomination to write the result to
* @return #GNUNET_OK if @a cur is a valid currency specification,
* #GNUNET_SYSERR if it is invalid.
*/
@@ -370,7 +370,8 @@ TALER_amount_cmp (const struct TALER_Amount *a1,
struct TALER_Amount n2;
GNUNET_assert (GNUNET_YES ==
- TALER_amount_cmp_currency (a1, a2));
+ TALER_amount_cmp_currency (a1,
+ a2));
n1 = *a1;
n2 = *a2;
GNUNET_assert (GNUNET_SYSERR !=
@@ -394,7 +395,7 @@ TALER_amount_cmp (const struct TALER_Amount *a1,
/**
* Perform saturating subtraction of amounts.
*
- * @param diff where to store (@a a1 - @a a2), or invalid if @a a2 > @a a1
+ * @param[out] diff where to store (@a a1 - @a a2), or invalid if @a a2 > @a a1
* @param a1 amount to subtract from
* @param a2 amount to subtract
* @return #GNUNET_OK if the subtraction worked,
@@ -411,11 +412,14 @@ TALER_amount_subtract (struct TALER_Amount *diff,
struct TALER_Amount n2;
if (GNUNET_YES !=
- TALER_amount_cmp_currency (a1, a2))
+ TALER_amount_cmp_currency (a1,
+ a2))
{
invalidate (diff);
return GNUNET_SYSERR;
}
+ /* make local copies to avoid aliasing problems between
+ diff and a1/a2 */
n1 = *a1;
n2 = *a2;
if ( (GNUNET_SYSERR == TALER_amount_normalize (&n1)) ||
@@ -457,7 +461,7 @@ TALER_amount_subtract (struct TALER_Amount *diff,
/**
* Perform addition of amounts.
*
- * @param sum where to store @a a1 + @a a2, set to "invalid" on overflow
+ * @param[out] sum where to store @a a1 + @a a2, set to "invalid" on overflow
* @param a1 first amount to add
* @param a2 second amount to add
* @return #GNUNET_OK if the addition worked,
@@ -478,6 +482,8 @@ TALER_amount_add (struct TALER_Amount *sum,
invalidate (sum);
return GNUNET_SYSERR;
}
+ /* make local copies to avoid aliasing problems between
+ diff and a1/a2 */
n1 = *a1;
n2 = *a2;
if ( (GNUNET_SYSERR == TALER_amount_normalize (&n1)) ||
@@ -519,7 +525,7 @@ TALER_amount_add (struct TALER_Amount *sum,
/**
* Normalize the given amount.
*
- * @param amount amount to normalize
+ * @param[in,out] amount amount to normalize
* @return #GNUNET_OK if normalization worked
* #GNUNET_NO if value was already normalized
* #GNUNET_SYSERR if value was invalid or could not be normalized
@@ -622,6 +628,7 @@ TALER_amount_to_string (const struct TALER_Amount *amount)
const char *
TALER_amount2s (const struct TALER_Amount *amount)
{
+ /* 12 is sufficient for a uint32_t value in decimal; 3 is for ":.\0" */
static char result[TALER_AMOUNT_FRAC_LEN + TALER_CURRENCY_LEN + 3 + 12];
struct TALER_Amount norm;
@@ -656,10 +663,10 @@ TALER_amount2s (const struct TALER_Amount *amount)
/**
- * Divide an amount by a float. Note that this function
+ * Divide an amount by a @a divisor. Note that this function
* may introduce a rounding error!
*
- * @param result where to store @a dividend / @a divisor
+ * @param[out] result where to store @a dividend / @a divisor
* @param dividend amount to divide
* @param divisor by what to divide, must be positive
*/
@@ -670,45 +677,69 @@ TALER_amount_divide (struct TALER_Amount *result,
{
uint64_t modr;
- GNUNET_assert (0 != divisor);
+ GNUNET_assert (0 != divisor); /* division by zero is discouraged */
*result = *dividend;
+ /* in case @a dividend was not yet normalized */
+ GNUNET_assert (GNUNET_SYSERR !=
+ TALER_amount_normalize (result));
if (1 == divisor)
return;
modr = result->value % divisor;
result->value /= divisor;
- /* modr is a 32-bit value, so we can safely multiply by (<32-bit) base and
add fraction! */
+ /* modr fits into 32 bits, so we can safely multiply by (<32-bit) base and
add fraction! */
modr = (modr * TALER_AMOUNT_FRAC_BASE) + result->fraction;
- GNUNET_assert (modr < TALER_AMOUNT_FRAC_BASE * divisor);
result->fraction = (uint32_t) (modr / divisor);
+ /* 'fraction' could now be larger than #TALER_AMOUNT_FRAC_BASE, so we must
normalize */
+ TALER_amount_normalize (result);
}
/**
* Round the amount to something that can be transferred on the wire.
* The rounding mode is specified via the smallest transferable unit,
- * which must only have a fractional part.
+ * which must only have a fractional part *or* only a value (either
+ * of the two must be zero!).
+ *
+ * If the @a round_unit given is zero, we do nothing and return #GNUNET_NO.
*
* @param[in,out] amount amount to round down
- * @param[in] round_unit unit that should be rounded down to,
- * the value part of this amount must be zero
+ * @param[in] round_unit unit that should be rounded down to, and
+ * either value part or the faction must be zero
* @return #GNUNET_OK on success, #GNUNET_NO if rounding was unnecessary,
- * #GNUNET_SYSERR if the amount or currency was invalid
+ * #GNUNET_SYSERR if the amount or currency or @a round_unit was
invalid
*/
int
TALER_amount_round_down (struct TALER_Amount *amount,
const struct TALER_Amount *round_unit)
{
- uint32_t delta;
-
- GNUNET_break (0 == round_unit->value);
+ if ( (0 != round_unit->fraction) &&
+ (0 != round_unit->value) )
+ {
+ GNUNET_break (0);
+ return GNUNET_SYSERR;
+ }
+ if ( (0 == round_unit->fraction) &&
+ (0 == round_unit->value) )
+ return GNUNET_NO; /* no rounding requested */
+ if (0 != round_unit->fraction)
+ {
+ uint32_t delta;
- if (0 == round_unit->fraction)
- return GNUNET_OK;
+ delta = amount->fraction % round_unit->fraction;
+ if (0 == delta)
+ return GNUNET_NO;
+ amount->fraction -= delta;
+ }
+ if (0 != round_unit->value)
+ {
+ uint64_t delta;
- delta = amount->fraction % round_unit->fraction;
- if (0 == delta)
- return GNUNET_NO;
- amount->fraction -= delta;
+ delta = amount->value % round_unit->value;
+ if (0 == delta)
+ return GNUNET_NO;
+ amount->value -= delta;
+ amount->fraction = 0;
+ }
return GNUNET_OK;
}
diff --git a/src/util/test_amount.c b/src/util/test_amount.c
index b5a21ebe..2fd8ce6a 100644
--- a/src/util/test_amount.c
+++ b/src/util/test_amount.c
@@ -236,24 +236,25 @@ main (int argc,
GNUNET_assert (1 == a2.fraction);
/* test rounding #1 */
-
GNUNET_assert (GNUNET_OK ==
TALER_string_to_amount ("EUR:0.01",
&r));
-
GNUNET_assert (GNUNET_OK ==
TALER_string_to_amount ("EUR:4.001",
&a1));
GNUNET_assert (GNUNET_OK ==
TALER_string_to_amount ("EUR:4",
&a2));
-
- GNUNET_assert (GNUNET_OK == TALER_amount_round_down (&a1, &r));
- GNUNET_assert (GNUNET_NO == TALER_amount_round_down (&a1, &r));
- GNUNET_assert (0 == TALER_amount_cmp (&a1, &a2));
+ GNUNET_assert (GNUNET_OK ==
+ TALER_amount_round_down (&a1,
+ &r));
+ GNUNET_assert (GNUNET_NO ==
+ TALER_amount_round_down (&a1,
+ &r));
+ GNUNET_assert (0 == TALER_amount_cmp (&a1,
+ &a2));
/* test rounding #2 */
-
GNUNET_assert (GNUNET_OK ==
TALER_string_to_amount ("EUR:0.001",
&r));
@@ -264,9 +265,27 @@ main (int argc,
GNUNET_assert (GNUNET_OK ==
TALER_string_to_amount ("EUR:4.001",
&a2));
- GNUNET_assert (GNUNET_NO == TALER_amount_round_down (&a1, &r));
- GNUNET_assert (0 == TALER_amount_cmp (&a1, &a2));
+ GNUNET_assert (GNUNET_NO ==
+ TALER_amount_round_down (&a1,
+ &r));
+ GNUNET_assert (0 == TALER_amount_cmp (&a1,
+ &a2));
+ /* test rounding #3 */
+ GNUNET_assert (GNUNET_OK ==
+ TALER_string_to_amount ("BTC:5",
+ &r));
+ GNUNET_assert (GNUNET_OK ==
+ TALER_string_to_amount ("BTC:12.3",
+ &a1));
+ GNUNET_assert (GNUNET_OK ==
+ TALER_string_to_amount ("BTC:10",
+ &a2));
+ GNUNET_assert (GNUNET_OK ==
+ TALER_amount_round_down (&a1,
+ &r));
+ GNUNET_assert (0 == TALER_amount_cmp (&a1,
+ &a2));
return 0;
}
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