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authorJohn Högberg <[email protected]>2018-02-13 12:34:08 +0100
committerJohn Högberg <[email protected]>2018-02-15 17:00:05 +0100
commit13497e652a9b9495fbefd52396620bfccc6d7a7c (patch)
tree3bf4c2e5b1505c4a61b145c15cb26cf1159f3994 /erts
parent45f2c76f3f4f83e82d6475536e488d4efa724a91 (diff)
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Handle unaligned binaries in erlang:iolist_to_iovec/1
A binary is a binary as long as its size in bits is evenly divisible by 8, regardless of whether it has a bit offset or not.
Diffstat (limited to 'erts')
-rw-r--r--erts/emulator/beam/erl_io_queue.c31
-rw-r--r--erts/emulator/test/iovec_SUITE.erl21
2 files changed, 42 insertions, 10 deletions
diff --git a/erts/emulator/beam/erl_io_queue.c b/erts/emulator/beam/erl_io_queue.c
index 190ba6bbb9..990c0c1cac 100644
--- a/erts/emulator/beam/erl_io_queue.c
+++ b/erts/emulator/beam/erl_io_queue.c
@@ -801,12 +801,11 @@ static Eterm iol2v_make_sub_bin(iol2v_state_t *state, Eterm bin_term,
ERTS_GET_REAL_BIN(bin_term, orig_pb_term,
byte_offset, bit_offset, bit_size);
- (void)bit_offset;
- (void)bit_size;
+ ASSERT(bit_size == 0);
sb->thing_word = HEADER_SUB_BIN;
+ sb->bitoffs = bit_offset;
sb->bitsize = 0;
- sb->bitoffs = 0;
sb->orig = orig_pb_term;
sb->is_writable = 0;
@@ -984,7 +983,7 @@ static int iol2v_append_binary(iol2v_state_t *state, Eterm bin_term) {
parent_header = binary_val(parent_binary);
binary_size = binary_size(bin_term);
- if (bit_offset != 0 || bit_size != 0) {
+ if (bit_size != 0) {
return 0;
} else if (binary_size == 0) {
state->bytereds_spent += 1;
@@ -1026,8 +1025,16 @@ static int iol2v_append_binary(iol2v_state_t *state, Eterm bin_term) {
* then just copy it into the accumulator. */
iol2v_expand_acc(state, binary_size);
- sys_memcpy(&(state->acc)->orig_bytes[state->acc_size],
- binary_data, binary_size);
+ if (ERTS_LIKELY(bit_offset == 0)) {
+ sys_memcpy(&(state->acc)->orig_bytes[state->acc_size],
+ binary_data, binary_size);
+ } else {
+ ASSERT(binary_size <= ERTS_UWORD_MAX / 8);
+
+ erts_copy_bits(binary_data, bit_offset, 1,
+ (byte*)&(state->acc)->orig_bytes[state->acc_size], 0, 1,
+ binary_size * 8);
+ }
state->acc_size += binary_size;
} else {
@@ -1038,8 +1045,16 @@ static int iol2v_append_binary(iol2v_state_t *state, Eterm bin_term) {
iol2v_expand_acc(state, spill);
- sys_memcpy(&(state->acc)->orig_bytes[state->acc_size],
- binary_data, spill);
+ if (ERTS_LIKELY(bit_offset == 0)) {
+ sys_memcpy(&(state->acc)->orig_bytes[state->acc_size],
+ binary_data, spill);
+ } else {
+ ASSERT(binary_size <= ERTS_UWORD_MAX / 8);
+
+ erts_copy_bits(binary_data, bit_offset, 1,
+ (byte*)&(state->acc)->orig_bytes[state->acc_size], 0, 1,
+ spill * 8);
+ }
state->acc_size += spill;
diff --git a/erts/emulator/test/iovec_SUITE.erl b/erts/emulator/test/iovec_SUITE.erl
index baf1174a14..76adbe4b5e 100644
--- a/erts/emulator/test/iovec_SUITE.erl
+++ b/erts/emulator/test/iovec_SUITE.erl
@@ -25,7 +25,7 @@
-export([integer_lists/1, binary_lists/1, empty_lists/1, empty_binary_lists/1,
mixed_lists/1, improper_lists/1, illegal_lists/1, cons_bomb/1,
sub_binary_lists/1, iolist_to_iovec_idempotence/1,
- iolist_to_iovec_correctness/1]).
+ iolist_to_iovec_correctness/1, unaligned_sub_binaries/1]).
-include_lib("common_test/include/ct.hrl").
@@ -36,7 +36,8 @@ suite() ->
all() ->
[integer_lists, binary_lists, empty_lists, empty_binary_lists, mixed_lists,
sub_binary_lists, illegal_lists, improper_lists, cons_bomb,
- iolist_to_iovec_idempotence, iolist_to_iovec_correctness].
+ iolist_to_iovec_idempotence, iolist_to_iovec_correctness,
+ unaligned_sub_binaries].
init_per_suite(Config) ->
Config.
@@ -123,6 +124,15 @@ iolist_to_iovec_correctness(Config) when is_list(Config) ->
true = is_iolist_equal(Optimized, Variations),
ok.
+unaligned_sub_binaries(Config) when is_list(Config) ->
+ UnalignedBins = [gen_unaligned_binary(I) || I <- lists:seq(32, 4 bsl 10, 512)],
+ UnalignedVariations = gen_variations(UnalignedBins),
+
+ Optimized = erlang:iolist_to_iovec(UnalignedVariations),
+
+ true = is_iolist_equal(Optimized, UnalignedVariations),
+ ok.
+
illegality_test(Fun, Variations) ->
[{'EXIT',{badarg, _}} = (catch Fun(Variation)) || Variation <- Variations],
ok.
@@ -138,6 +148,13 @@ equivalence_test(Fun, [Head | _] = Variations) ->
is_iolist_equal(A, B) ->
iolist_to_binary(A) =:= iolist_to_binary(B).
+gen_unaligned_binary(Size) ->
+ Bin0 = << <<I>> || I <- lists:seq(1, Size) >>,
+ <<0:3,Bin:Size/binary,31:5>> = id(<<0:3,Bin0/binary,31:5>>),
+ Bin.
+
+id(I) -> I.
+
%% Generates a bunch of lists whose contents will be equal to Base repeated a
%% few times. The lists only differ by their structure, so their reduction to
%% a simpler format should yield the same result.