compact IEEE 754 double encoding in external binary format for ei

Implement the compact IEEE 754 double encoding in external binary
format for ei. Encoding for ei now always produces the NEW_FLOAT_EXT
format. Decoding and term printing handle both the old ERL_FLOAT_EXT
encoding and the new NEW_FLOAT_EXT encoding. Legacy erl_interface code
also handles the new encoding, but still produces the ERL_FLOAT_EXT
encoding by default.

Also enable the DFLAG_NEW_FLOATS distribution flag.

Reduce the number of copies of the code for encoding and decoding
doubles throughout ei and erl_interface by instead calling the ei
encoding and decoding functions wherever possible.

Restore commented-out float tests in ei_decode_SUITE and
ei_encode_SUITE in lib/erl_interface/test. Modify them to make them
match the style of other tests in the same suites.

These changes are based on an ei float patch from Serge Aleynikov
originally submitted against R12B-2 in July 2008.

1 files changed, 8 insertions, 12 deletions

diff --git a/lib/erl_interface/test/ei_encode_SUITE.erl b/lib/erl_interface/test/ei_encode_SUITE.erl
index fb790eb7c3..dd6f37e453 100644
--- a/lib/erl_interface/test/ei_encode_SUITE.erl
+++ b/lib/erl_interface/test/ei_encode_SUITE.erl
@@ -181,20 +181,14 @@ test_ei_encode_misc(Config) when is_list(Config) ->
 
     ?line <<131>>  = get_binaries(P),
 
-%    ?line {term,F} = get_term(P),
-%    ?line match_float(F, 0.0),
-%    ?line {term,F} = get_term(P),
-%    ?line match_float(F, 0.0),
+    ?line {<<70,_:8/binary>>,F0} = get_buf_and_term(P),
+    ?line true = match_float(F0, 0.0),
 
-%    ?line {term,F} = get_term(P),
-%    ?line true = match_float(F, -1.0),
-%    ?line {term,F} = get_term(P),
-%    ?line true = match_float(F, -1.0),
+    ?line {<<70,_:8/binary>>,Fn1} = get_buf_and_term(P),
+    ?line true = match_float(Fn1, -1.0),
 
-%    ?line {term,F} = get_term(P),
-%    ?line true = match_float(F, 1.0),
-%    ?line {term,F} = get_term(P),
-%    ?line true = match_float(F, 1.0),
+    ?line {<<70,_:8/binary>>,Fp1} = get_buf_and_term(P),
+    ?line true = match_float(Fp1, 1.0),
 
     ?line {<<100,0,5,"false">>,false}  = get_buf_and_term(P),
     ?line {<<100,0,4,"true">> ,true}   = get_buf_and_term(P),
@@ -310,6 +304,8 @@ get_term(P) ->
  
 %%
 
+match_float(F, Match) when is_float(F), is_float(Match), F == Match ->
+    true;
 match_float(F, Match) when is_float(F), F > Match*0.99, F < Match*1.01 ->
     true.