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author | Sverker Eriksson <sverker@erlang.org> | 2012-02-20 19:52:13 +0100 |
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committer | Sverker Eriksson <sverker@erlang.org> | 2012-02-21 12:10:40 +0100 |
commit | 75b831aa879234db6d8821a32f4c411ef6cfc6ff (patch) | |
tree | 96018e44b4915f152484a6f6a770f0c064c07fc4 /erts/emulator/beam | |
parent | 520ddbc83ec87bcec262680bd915184182e3998e (diff) | |
download | otp-75b831aa879234db6d8821a32f4c411ef6cfc6ff.tar.gz otp-75b831aa879234db6d8821a32f4c411ef6cfc6ff.tar.bz2 otp-75b831aa879234db6d8821a32f4c411ef6cfc6ff.zip |
erts: Fix bignum-bug in ETS with compressed option
A large 64-bit immediate number will be stored as SMALL_BIG_EXT by ETS
compressed format. When uncompressing, the SMALL_BIG_EXT was first
decoded as as bignum (by bytes_to_big) and then turned into a small
(by big_norm). This works for normal "binary_to_term" as
decoded_size() over-estimates the needed heap size. But for ETS no
over-estimation is done as the real term size is known and stored in
DbTerm.
Fixed by preventing bytes_to_big() from writing bignum digit when the
number is seen to fit in an immediate.
Diffstat (limited to 'erts/emulator/beam')
-rw-r--r-- | erts/emulator/beam/big.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/erts/emulator/beam/big.c b/erts/emulator/beam/big.c index 976f05c990..25ac790d81 100644 --- a/erts/emulator/beam/big.c +++ b/erts/emulator/beam/big.c @@ -1844,6 +1844,7 @@ dsize_t big_bytes(Eterm x) /* ** Load a bignum from bytes ** xsz is the number of bytes in xp +** *r is untouched if number fits in small */ Eterm bytes_to_big(byte *xp, dsize_t xsz, int xsgn, Eterm *r) { @@ -1852,7 +1853,7 @@ Eterm bytes_to_big(byte *xp, dsize_t xsz, int xsgn, Eterm *r) ErtsDigit d; int i; - while(xsz >= sizeof(ErtsDigit)) { + while(xsz > sizeof(ErtsDigit)) { d = 0; for(i = sizeof(ErtsDigit); --i >= 0;) d = (d << 8) | xp[i]; @@ -1867,11 +1868,20 @@ Eterm bytes_to_big(byte *xp, dsize_t xsz, int xsgn, Eterm *r) d = 0; for(i = xsz; --i >= 0;) d = (d << 8) | xp[i]; + if (++rsz == 1 && IS_USMALL(xsgn,d)) { + if (xsgn) d = -d; + return make_small(d); + } *rwp = d; rwp++; - rsz++; } - return big_norm(r, rsz, (short) xsgn); + if (xsgn) { + *r = make_neg_bignum_header(rsz); + } + else { + *r = make_pos_bignum_header(rsz); + } + return make_big(r); } /* |