Ensure that encoded doubles have a decimal point

Numbers like 1.0 were being encoded as <<"1">> which can lead to a bit
of confusion. This merely checks if a decimial point exists and if not
it appends ".0" to the value.

c_src/encoder.c

@@ -385,15 +385,34 @@ enc_long(Encoder* e, ErlNifSInt64 val)
 static inline int
 enc_double(Encoder* e, double val)
 {
+    char* start;
+    size_t len;
+    size_t i;
+
     if(!enc_ensure(e, 32)) {
         return 0;
     }
 
-    //snprintf(&(e->p[e->i]), 31, "%0.20g", val);
-    sprintf(&(e->p[e->i]), "%.20g", val);
-    e->i += strlen(&(e->p[e->i]));
-    e->count++;
+    start = &(e->p[e->i]);
+
+    sprintf(start, "%0.20g", val);
+    len = strlen(start);
+
+    // Check if we have a decimal point
+    for(i = 0; i < len; i++) {
+        if(start[i] == '.' || start[i] == 'e' || start[i] == 'E')
+            goto done;
+    }
+
+    if(len > 29) return 0;
+
+    // Force a decimal point
+    start[len++] = '.';
+    start[len++] = '0';
 
+done:
+    e->i += len;
+    e->count++;
     return 1;
 }
 

test/003-numbers.t

@@ -35,22 +35,22 @@ good() ->
             1234567890123456789012345012,
             <<"1234567890123456789012345012">>
         },
+        {<<"1.0">>, 1.0},
         {
             <<"0.000000000000000000000000000000000001">>,
             1.0E-36,
             <<"9.9999999999999994104e-37">>
         },
-        {<<"1.0">>, 1.0, <<"1">>},
         {<<"0.75">>, 0.75},
         {<<"2.0123456789">>, 2.0123456789, <<"2.0123456789000000455">>},
         {<<"2.4234324E24">>, 2.4234324E24, <<"2.4234323999999998107e+24">>},
         {<<"-3.1416">>, -3.1416, <<"-3.1415999999999999481">>},
-        {<<"1E4">>, 10000.0, <<"10000">>},
-        {<<"1.0E+01">>, 10.0, <<"10">>},
-        {<<"1e1">>, 10.0, <<"10">>},
-        {<<"3.0E2">>, 300.0, <<"300">>},
-        {<<"0E3">>, 0.0, <<"0">>},
-        {<<"1.5E3">>, 1500.0, <<"1500">>},
+        {<<"1E4">>, 10000.0, <<"10000.0">>},
+        {<<"1.0E+01">>, 10.0, <<"10.0">>},
+        {<<"1e1">>, 10.0, <<"10.0">>},
+        {<<"3.0E2">>, 300.0, <<"300.0">>},
+        {<<"0E3">>, 0.0, <<"0.0">>},
+        {<<"1.5E3">>, 1500.0, <<"1500.0">>},
         {<<"2.5E-1">>, 0.25, <<"0.25">>},
         {<<"-0.325E+2">>, -32.5, <<"-32.5">>}
     ].

test/005-arrays.t

@@ -17,7 +17,7 @@ good() ->
         {<<"[\t[\n]\r]">>, [[]], <<"[[]]">>},
         {<<"[\t123, \r true\n]">>, [123, true], <<"[123,true]">>},
         {<<"[1,\"foo\"]">>, [1, <<"foo">>]},
-        {<<"[11993444355.0,1]">>, [11993444355.0,1], <<"[11993444355,1]">>},
+        {<<"[11993444355.0,1]">>, [11993444355.0,1]},
         {
             <<"[\"\\u00A1\",\"\\u00FC\"]">>,
             [<<194, 161>>, <<195, 188>>],