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authorSverker Eriksson <[email protected]>2010-06-16 17:58:35 +0200
committerSverker Eriksson <[email protected]>2010-07-05 15:29:17 +0200
commite5d41874ec0d2aaf2037d10dd92091edd2405924 (patch)
tree29bd6fc639f50c35555cfbadeacaf711bef12bde /erts/emulator/beam
parentfdf51bf4a7127883705d71dab1bbd4556b28e05a (diff)
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term_to_binary use all 32 bits of INTEGER_EXT
Earlier, external format INTEGER_EXT was only produced for 28-bit signed integers. Now full 32-bit signed integers are produced as INTEGER_EXT to avoid the more costly SMALL_BIG_EXT format. Both old and new code can read 32-bit INTEGER_EXT. Also fixed integer encoding bugs in erl_interface erl_encode/erl_decode. (Thanks to Alexander Demidenko for reporting)
Diffstat (limited to 'erts/emulator/beam')
-rw-r--r--erts/emulator/beam/external.c53
1 files changed, 35 insertions, 18 deletions
diff --git a/erts/emulator/beam/external.c b/erts/emulator/beam/external.c
index f41b61d73d..466165f26f 100644
--- a/erts/emulator/beam/external.c
+++ b/erts/emulator/beam/external.c
@@ -65,11 +65,9 @@
# endif
#endif
-/*
- * For backward compatibility reasons, only encode integers that
- * fit in 28 bits (signed) using INTEGER_EXT.
+/* Does Sint fit in Sint32?
*/
-#define IS_SSMALL28(x) (((Uint) (((x) >> (28-1)) + 1)) < 2)
+#define IS_SSMALL32(x) (((Uint) (((x) >> (32-1)) + 1)) < 2)
/*
* Valid creations for nodes are 1, 2, or 3. 0 can also be sent
@@ -1571,13 +1569,15 @@ enc_term(ErtsAtomCacheMap *acmp, Eterm obj, byte* ep, Uint32 dflags)
case SMALL_DEF:
{
+ /* From R14B we no longer restrict INTEGER_EXT to 28 bits,
+ * as done earlier for backward compatibility reasons. */
Sint val = signed_val(obj);
if ((Uint)val < 256) {
*ep++ = SMALL_INTEGER_EXT;
put_int8(val, ep);
ep++;
- } else if (sizeof(Sint) == 4 || IS_SSMALL28(val)) {
+ } else if (sizeof(Sint) == 4 || IS_SSMALL32(val)) {
*ep++ = INTEGER_EXT;
put_int32(val, ep);
ep += 4;
@@ -1599,18 +1599,32 @@ enc_term(ErtsAtomCacheMap *acmp, Eterm obj, byte* ep, Uint32 dflags)
break;
case BIG_DEF:
- if ((n = big_bytes(obj)) < 256) {
- *ep++ = SMALL_BIG_EXT;
- put_int8(n, ep);
- ep += 1;
- }
- else {
- *ep++ = LARGE_BIG_EXT;
- put_int32(n, ep);
- ep += 4;
+ {
+ int sign = big_sign(obj);
+ n = big_bytes(obj);
+ if (sizeof(Sint)==4 && n<=4) {
+ Uint dig = big_digit(obj,0);
+ Sint val = sign ? -dig : dig;
+ if ((val<0) == sign) {
+ *ep++ = INTEGER_EXT;
+ put_int32(val, ep);
+ ep += 4;
+ break;
+ }
+ }
+ if (n < 256) {
+ *ep++ = SMALL_BIG_EXT;
+ put_int8(n, ep);
+ ep += 1;
+ }
+ else {
+ *ep++ = LARGE_BIG_EXT;
+ put_int32(n, ep);
+ ep += 4;
+ }
+ *ep++ = sign;
+ ep = big_to_bytes(obj, ep);
}
- *ep++ = big_sign(obj);
- ep = big_to_bytes(obj, ep);
break;
case PID_DEF:
@@ -2687,7 +2701,7 @@ encode_size_struct2(ErtsAtomCacheMap *acmp, Eterm obj, unsigned dflags)
if ((Uint)val < 256)
result += 1 + 1; /* SMALL_INTEGER_EXT */
- else if (sizeof(Sint) == 4 || IS_SSMALL28(val))
+ else if (sizeof(Sint) == 4 || IS_SSMALL32(val))
result += 1 + 4; /* INTEGER_EXT */
else {
DeclareTmpHeapNoproc(tmp_big,2);
@@ -2699,7 +2713,10 @@ encode_size_struct2(ErtsAtomCacheMap *acmp, Eterm obj, unsigned dflags)
}
break;
case BIG_DEF:
- if ((i = big_bytes(obj)) < 256)
+ i = big_bytes(obj);
+ if (sizeof(Sint)==4 && i <= 4 && (big_digit(obj,0)-big_sign(obj)) < (1<<31))
+ result += 1 + 4; /* INTEGER_EXT */
+ else if (i < 256)
result += 1 + 1 + 1 + i; /* tag,size,sign,digits */
else
result += 1 + 4 + 1 + i; /* tag,size,sign,digits */