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authorStefan Krah <skrah@bytereef.org>2012-04-10 21:11:54 (GMT)
committerStefan Krah <skrah@bytereef.org>2012-04-10 21:11:54 (GMT)
commitec766a61795a21015ba5b95c106f1c2b089b3ff0 (patch)
treec2b3369c46528a9cc35b1b6d191442ce5d80eb37 /Modules/_decimal
parent7b544ca08d6daa4d0b30aee6fab9a5f71540adaa (diff)
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1) Remove claim of an input invariant that is only true for static mpd_t.
Resizing is used _inside_ libmpdec functions, and it is permitted to change x->alloc several times while setting x->len at the end of the function. Therefore, for dynamic mpd_t x->alloc can _temporarily_ drop below x->len. Of course the final result always has x->len <= x->alloc. For static mpd_t this cannot happen, since resizing to a smaller coefficient is a no-op. 2) Remove micro optimization in mpd_switch_to_dyn(): Previously only the valid initialized part of the existing coefficient up to x->len was copied to the new dynamic memory area. Now copying does the same as realloc() and the entire old memory area is copied. The rationale for this change is that it is no longer needed to memorize the explanation given in 1).
Diffstat (limited to 'Modules/_decimal')
-rw-r--r--Modules/_decimal/libmpdec/memory.c2
-rw-r--r--Modules/_decimal/libmpdec/mpdecimal.c4
2 files changed, 2 insertions, 4 deletions
diff --git a/Modules/_decimal/libmpdec/memory.c b/Modules/_decimal/libmpdec/memory.c
index 037ba35..bf6350f 100644
--- a/Modules/_decimal/libmpdec/memory.c
+++ b/Modules/_decimal/libmpdec/memory.c
@@ -222,7 +222,7 @@ mpd_switch_to_dyn(mpd_t *result, mpd_ssize_t nwords, uint32_t *status)
return 0;
}
- memcpy(result->data, p, result->len * (sizeof *result->data));
+ memcpy(result->data, p, result->alloc * (sizeof *result->data));
result->alloc = nwords;
mpd_set_dynamic_data(result);
return 1;
diff --git a/Modules/_decimal/libmpdec/mpdecimal.c b/Modules/_decimal/libmpdec/mpdecimal.c
index b83334e..844f238 100644
--- a/Modules/_decimal/libmpdec/mpdecimal.c
+++ b/Modules/_decimal/libmpdec/mpdecimal.c
@@ -454,9 +454,7 @@ mpd_del(mpd_t *dec)
* Resize the coefficient. Existing data up to 'nwords' is left untouched.
* Return 1 on success, 0 otherwise.
*
- * Input invariants:
- * 1) MPD_MINALLOC <= result->alloc.
- * 2) 0 <= result->len <= result->alloc.
+ * Input invariant: MPD_MINALLOC <= result->alloc.
*
* Case nwords == result->alloc:
* 'result' is unchanged. Return 1.