Add float_to_binary and binary_to_float

9 files changed, 325 insertions, 155 deletions

diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index 36d606130f..06fefa8efb 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -300,6 +300,18 @@
       </desc>
     </func>
     <func>
+      <name name="binary_to_float" arity="1"/>
+      <fsummary>Convert from text representation to a float</fsummary>
+      <desc>
+        <p>Returns the float whose text representation is <c><anno>Binary</anno></c>.</p>
+        <pre>
+> <input>binary_to_float(&lt;&lt;"2.2017764e+0">>).</input>
+2.2017764</pre>
+        <p>Failure: <c>badarg</c> if <c><anno>Binary</anno></c> contains a bad
+          representation of a float.</p>
+      </desc>
+    </func>
+    <func>
       <name name="binary_to_integer" arity="1"/>
       <fsummary>Convert from text representation to an integer</fsummary>
       <desc>
@@ -987,26 +999,38 @@ true
       </desc>
     </func>
     <func>
-      <name name="float_to_list" arity="1"/>
+      <name name="float_to_binary" arity="1"/>
       <fsummary>Text representation of a float</fsummary>
       <desc>
-        <p>Returns a string which corresponds to the text
-          representation of <c><anno>Float</anno></c>.</p>
+        <p>The same as <c>float_to_binary(<anno>Float</anno>,[{scientific,20}])</c>.</p>
+      </desc>
+    </func>
+    <func>
+      <name name="float_to_binary" arity="2"/>
+      <fsummary>Text representation of a float formatted using given options</fsummary>
+      <desc>
+        <p>Returns a binary which corresponds to the text
+          representation of <c><anno>Float</anno></c> using fixed decimal 
+	  point formatting. The <c><anno>Options</anno></c> behave in the same
+	  way as <seealso marker="#float_to_list/2">float_to_list/2</seealso>.
+	</p>
         <pre>
-> <input>float_to_list(7.0).</input>
-"7.00000000000000000000e+00"</pre>
+> <input>float_to_binary(7.12, [{decimals, 4}]).</input>
+&lt;&lt;"7.1200">>
+> <input>float_to_binary(7.12, [{decimals, 4}, compact]).</input>
+&lt;&lt;"7.12">></pre>
+      </desc>
+    </func>
+    <func>
+      <name name="float_to_list" arity="1"/>
+      <fsummary>Text representation of a float</fsummary>
+      <desc>
+	<p>The same as <c>float_to_list(<anno>Float</anno>,[{scientific,20}])</c>.</p>
       </desc>
     </func>
     <func>
-      <name>float_to_list(Float, Options) -> string()</name>
+      <name name="float_to_list" arity="2"/>
       <fsummary>Text representation of a float formatted using given options</fsummary>
-      <type>
-        <v>Float = float()</v>
-        <v>Options = [Option]</v>
-        <v>Option = {decimals, Decimals::0..253} |
-                    {scientific, Decimals::0..249} |
-                    compact</v>
-      </type>
       <desc>
         <p>Returns a string which corresponds to the text
           representation of <c>Float</c> using fixed decimal point formatting.
@@ -1019,7 +1043,8 @@ true
           only meaningful together with the <c>decimals</c> option). When
           <c>scientific</c> option is provided, the float will be formatted using
           scientific notation with <c>Decimals</c> digits of precision. If
-          <c>Options</c> is <c>[]</c> the function behaves like <c>float_to_list/1</c>.
+          <c>Options</c> is <c>[]</c> the function behaves like 
+	  <c><seealso marker="#float_to_list/1">float_to_list/1</seealso></c>.
           </p>
         <pre>
 > <input>float_to_list(7.12, [{decimals, 4}]).</input>
diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index a596068527..5adcf6d5c7 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -39,6 +39,7 @@
 #include "erl_thr_progress.h"
 #define ERTS_PTAB_WANT_BIF_IMPL__
 #include "erl_ptab.h"
+#include "erl_bits.h"
 
 static Export* flush_monitor_message_trap = NULL;
 static Export* set_cpu_topology_trap = NULL;
@@ -2955,29 +2956,9 @@ BIF_RETTYPE list_to_integer_2(BIF_ALIST_2)
 
 /**********************************************************************/
 
-/* convert a float to a list of ascii characters */
+static int do_float_to_charbuf(Process *p, Eterm efloat, Eterm list, 
+			char *fbuf, int sizeof_fbuf) {
 
-BIF_RETTYPE float_to_list_1(BIF_ALIST_1)
-{
-     int i;
-     Uint need;
-     Eterm* hp;
-     FloatDef f;
-     char fbuf[30];
-     
-     /* check the arguments */
-     if (is_not_float(BIF_ARG_1))
-	 BIF_ERROR(BIF_P, BADARG);
-     GET_DOUBLE(BIF_ARG_1, f);
-     if ((i = sys_double_to_chars(f.fd, fbuf, sizeof(fbuf))) <= 0)
-	 BIF_ERROR(BIF_P, EXC_INTERNAL_ERROR);
-     need = i*2;
-     hp = HAlloc(BIF_P, need);
-     BIF_RET(buf_to_intlist(&hp, fbuf, i, NIL));
-}
-
-BIF_RETTYPE float_to_list_2(BIF_ALIST_2)
-{
     const static int arity_two = make_arityval(2);
     int decimals = SYS_DEFAULT_FLOAT_DECIMALS;
     int compact = 0;
@@ -2986,16 +2967,11 @@ BIF_RETTYPE float_to_list_2(BIF_ALIST_2)
         FMT_FIXED,
         FMT_SCIENTIFIC
     } fmt_type = FMT_LEGACY;
-    Eterm list = BIF_ARG_2;
     Eterm arg;
-    int i;
-    Uint need;
-    Eterm* hp;
     FloatDef f;
-    char fbuf[256];
 
     /* check the arguments */
-    if (is_not_float(BIF_ARG_1))
+    if (is_not_float(efloat))
         goto badarg;
 
     for(; is_list(list); list = CDR(list_val(list))) {
@@ -3023,22 +2999,64 @@ BIF_RETTYPE float_to_list_2(BIF_ALIST_2)
         goto badarg;
     }
 
-    GET_DOUBLE(BIF_ARG_1, f);
+    GET_DOUBLE(efloat, f);
 
     if (fmt_type == FMT_FIXED) {
-        if ((i = sys_double_to_chars_fast(f.fd, fbuf, sizeof(fbuf),
-                decimals, compact)) <= 0)
-            goto badarg;
+        return sys_double_to_chars_fast(f.fd, fbuf, sizeof_fbuf,
+                decimals, compact);
     } else {
-        if ((i = sys_double_to_chars_ext(f.fd, fbuf, sizeof(fbuf), decimals)) <= 0)
-            goto badarg;
+        return sys_double_to_chars_ext(f.fd, fbuf, sizeof_fbuf, decimals);
     }
 
-    need = i*2;
-    hp = HAlloc(BIF_P, need);
-    BIF_RET(buf_to_intlist(&hp, fbuf, i, NIL));
 badarg:
+    return -1;
+}
+
+/* convert a float to a list of ascii characters */
+
+static BIF_RETTYPE do_float_to_list(Process *BIF_P, Eterm arg, Eterm opts) {
+  int used;
+  Eterm* hp;
+  char fbuf[256];
+  
+  if ((used = do_float_to_charbuf(BIF_P,arg,opts,fbuf,sizeof(fbuf))) <= 0) {
     BIF_ERROR(BIF_P, BADARG);
+  }
+  hp = HAlloc(BIF_P, (Uint)used*2);
+  BIF_RET(buf_to_intlist(&hp, fbuf, (Uint)used, NIL));
+}
+  
+
+BIF_RETTYPE float_to_list_1(BIF_ALIST_1)
+{
+  return do_float_to_list(BIF_P,BIF_ARG_1,NIL);
+}
+
+BIF_RETTYPE float_to_list_2(BIF_ALIST_2)
+{
+  return do_float_to_list(BIF_P,BIF_ARG_1,BIF_ARG_2);
+}
+
+/* convert a float to a binary of ascii characters */
+
+static BIF_RETTYPE do_float_to_binary(Process *BIF_P, Eterm arg, Eterm opts) {
+  int used;
+  char fbuf[256];
+  
+  if ((used = do_float_to_charbuf(BIF_P,arg,opts,fbuf,sizeof(fbuf))) <= 0) {
+    BIF_ERROR(BIF_P, BADARG);
+  }
+  BIF_RET(new_binary(BIF_P, (byte*)fbuf, (Uint)used));
+}
+
+BIF_RETTYPE float_to_binary_1(BIF_ALIST_1)
+{
+  return do_float_to_binary(BIF_P,BIF_ARG_1,NIL);
+}
+
+BIF_RETTYPE float_to_binary_2(BIF_ALIST_2)
+{
+  return do_float_to_binary(BIF_P,BIF_ARG_1,BIF_ARG_2);
 }
 
 /**********************************************************************/
@@ -3223,36 +3241,101 @@ BIF_RETTYPE string_to_float_1(BIF_ALIST_1)
     BIF_RET(tup);
 }
 
+static BIF_RETTYPE do_charbuf_to_float(Process *BIF_P,char *buf) {
+  FloatDef f;
+  Eterm res;
+  Eterm* hp;
+
+  if (sys_chars_to_double(buf, &f.fd) != 0)
+    BIF_ERROR(BIF_P, BADARG);
+
+  hp = HAlloc(BIF_P, FLOAT_SIZE_OBJECT);
+  res = make_float(hp);
+  PUT_DOUBLE(f, hp);
+  BIF_RET(res);
+
+}
 
 BIF_RETTYPE list_to_float_1(BIF_ALIST_1)
 {
     int i;
-    FloatDef f;
     Eterm res;
-    Eterm* hp;
     char *buf = NULL;
 
     i = list_length(BIF_ARG_1);
-    if (i < 0) {
-    badarg:
-	if (buf)
-	    erts_free(ERTS_ALC_T_TMP, (void *) buf);
-	BIF_ERROR(BIF_P, BADARG);
-    }
-
+    if (i < 0)
+      BIF_ERROR(BIF_P, BADARG);
+    
     buf = (char *) erts_alloc(ERTS_ALC_T_TMP, i + 1);
     
     if (intlist_to_buf(BIF_ARG_1, buf, i) < 0)
-	goto badarg;
+      goto list_to_float_1_error;
     buf[i] = '\0';		/* null terminal */
+    
+    if ((res = do_charbuf_to_float(BIF_P,buf)) == THE_NON_VALUE)
+      goto list_to_float_1_error;
+    
+    erts_free(ERTS_ALC_T_TMP, (void *) buf);
+    BIF_RET(res);
+    
+ list_to_float_1_error:
+    erts_free(ERTS_ALC_T_TMP, (void *) buf);
+    BIF_ERROR(BIF_P, BADARG);
+
+}
+
+BIF_RETTYPE binary_to_float_1(BIF_ALIST_1)
+{
+    Eterm res;
+    Eterm binary = BIF_ARG_1;
+    Sint size;
+    byte* bytes, *buf;
+    Eterm* real_bin;
+    Uint offs = 0;
+    Uint bit_offs = 0;
+
+    if (is_not_binary(binary) || (size = binary_size(binary)) == 0)
+      BIF_ERROR(BIF_P, BADARG);
+
+    /* 
+     *  Unfortunately we have to copy the binary because we have to insert
+     *  the '\0' at the end of the binary for strtod to work 
+     *  (there is no nstrtod :( )
+     */
+
+    buf = erts_alloc(ERTS_ALC_T_TMP, size + 1);
+
+    real_bin = binary_val(binary);
+    if (*real_bin == HEADER_SUB_BIN) {
+	ErlSubBin* sb = (ErlSubBin *) real_bin;
+	if (sb->bitsize) {
+	    goto binary_to_float_1_error;
+	}
+	offs = sb->offs;
+	bit_offs = sb->bitoffs;
+	real_bin = binary_val(sb->orig);
+    } 
+    if (*real_bin == HEADER_PROC_BIN) {
+	bytes = ((ProcBin *) real_bin)->bytes + offs;
+    } else {
+	bytes = (byte *)(&(((ErlHeapBin *) real_bin)->data)) + offs;
+    }
+    if (bit_offs)
+      erts_copy_bits(bytes, bit_offs, 1, buf, 0, 1, size*8);
+    else
+      memcpy(buf, bytes, size);
+    
+    buf[size] = '\0';
+    
+    if ((res = do_charbuf_to_float(BIF_P,(char*)buf)) == THE_NON_VALUE)
+	goto binary_to_float_1_error;
 
-    if (sys_chars_to_double(buf, &f.fd) != 0)
-	goto badarg;
-    hp = HAlloc(BIF_P, FLOAT_SIZE_OBJECT);
-    res = make_float(hp);
-    PUT_DOUBLE(f, hp);
     erts_free(ERTS_ALC_T_TMP, (void *) buf);
     BIF_RET(res);
+
+ binary_to_float_1_error:
+    erts_free(ERTS_ALC_T_TMP, (void *) buf);
+    BIF_ERROR(BIF_P, BADARG);
 }
 
 /**********************************************************************/
diff --git a/erts/emulator/beam/bif.tab b/erts/emulator/beam/bif.tab
index aa6105de73..b74dc5c3fe 100644
--- a/erts/emulator/beam/bif.tab
+++ b/erts/emulator/beam/bif.tab
@@ -565,6 +565,9 @@ bif erlang:binary_to_integer/1
 bif erlang:binary_to_integer/2
 bif erlang:integer_to_binary/1
 bif erlang:list_to_integer/2
+bif erlang:float_to_binary/1
+bif erlang:float_to_binary/2
+bif erlang:binary_to_float/1
 
 #
 # Obsolete
diff --git a/erts/emulator/test/num_bif_SUITE.erl b/erts/emulator/test/num_bif_SUITE.erl
index 92ef456fe8..b92a0e2059 100644
--- a/erts/emulator/test/num_bif_SUITE.erl
+++ b/erts/emulator/test/num_bif_SUITE.erl
@@ -37,22 +37,22 @@
 
 -export([all/0, suite/0, groups/0, init_per_suite/1, end_per_suite/1, 
 	 init_per_group/2, end_per_group/2, t_abs/1, t_float/1,
-	 t_float_to_list/1, t_integer_to_string/1,
+	 t_float_to_string/1, t_integer_to_string/1,
 	 t_string_to_integer/1,
-	 t_list_to_float_safe/1, t_list_to_float_risky/1,
+	 t_string_to_float_safe/1, t_string_to_float_risky/1,
 	 t_round/1, t_trunc/1
      ]).
 
 suite() -> [{ct_hooks,[ts_install_cth]}].
 
 all() -> 
-    [t_abs, t_float, t_float_to_list, t_integer_to_string,
-     {group, t_list_to_float}, t_string_to_integer, t_round,
+    [t_abs, t_float, t_float_to_string, t_integer_to_string,
+     {group, t_string_to_float}, t_string_to_integer, t_round,
      t_trunc].
 
 groups() -> 
-    [{t_list_to_float, [],
-      [t_list_to_float_safe, t_list_to_float_risky]}].
+    [{t_string_to_float, [],
+      [t_string_to_float_safe, t_string_to_float_risky]}].
 
 init_per_suite(Config) ->
     Config.
@@ -112,111 +112,136 @@ t_float(Config) when is_list(Config) ->
     ok.
 
 
-%% Tests float_to_list/1, float_to_list/2.
-
-t_float_to_list(Config) when is_list(Config) ->
-    test_ftl("0.0e+0", 0.0),
-    test_ftl("2.5e+1", 25.0),
-    test_ftl("2.5e+0", 2.5),
-    test_ftl("2.5e-1", 0.25),
-    test_ftl("-3.5e+17", -350.0e15),
-    "1.00000000000000000000e+00"  = float_to_list(1.0),
-    "1.00000000000000000000e+00"  = float_to_list(1.0,  []),
-    "-1.00000000000000000000e+00" = float_to_list(-1.0, []),
-    "-1.00000000000000000000"     = float_to_list(-1.0, [{decimals, 20}]),
-    {'EXIT', {badarg, _}}         = (catch float_to_list(1.0,  [{decimals, -1}])),
-    {'EXIT', {badarg, _}}         = (catch float_to_list(1.0,  [{decimals, 254}])),
-    {'EXIT', {badarg, _}}         = (catch float_to_list(1.0,  [{scientific, 250}])),
-    {'EXIT', {badarg, _}}         = (catch float_to_list(1.0e+300, [{decimals, 1}])),
-    "1.0e+300"                    = float_to_list(1.0e+300, [{scientific, 1}]),
-    "1.0"                         = float_to_list(1.0, [{decimals, 249}, compact]),
-    "1"                           = float_to_list(1.0, [{decimals, 0}]),
-    "2"                           = float_to_list(1.9, [{decimals, 0}]),
-    "123456789012345680.0"        = erlang:float_to_list(
-                                        123456789012345678.0, [{decimals, 236}, compact]),
-    {'EXIT', {badarg, _}}         = (catch float_to_list(
-                                        123456789012345678.0, [{decimals, 237}])),
-    Expected = "1." ++ string:copies("0", 249) ++ "e+00",
-    Expected = float_to_list(1.0,  [{scientific, 249}, compact]),
+%% Tests float_to_list/1, float_to_list/2, float_to_binary/1, float_to_binary/2
+
+t_float_to_string(Config) when is_list(Config) ->
+    test_fts("0.00000000000000000000e+00", 0.0),
+    test_fts("2.50000000000000000000e+01", 25.0),
+    test_fts("2.50000000000000000000e+00", 2.5),
+    test_fts("2.50000000000000000000e-01", 0.25),
+    test_fts("-3.50000000000000000000e+17", -350.0e15),
+    test_fts("1.00000000000000000000e+00",1.0),
+    test_fts("1.00000000000000000000e+00",1.0,  []),
+    test_fts("-1.00000000000000000000e+00",-1.0, []),
+    test_fts("-1.00000000000000000000",-1.0, [{decimals, 20}]),
+    {'EXIT', {badarg, _}} = (catch float_to_list(1.0,  [{decimals, -1}])),
+    {'EXIT', {badarg, _}} = (catch float_to_list(1.0,  [{decimals, 254}])),
+    {'EXIT', {badarg, _}} = (catch float_to_list(1.0,  [{scientific, 250}])),
+    {'EXIT', {badarg, _}} = (catch float_to_list(1.0e+300, [{decimals, 1}])),
+    {'EXIT', {badarg, _}} = (catch float_to_binary(1.0,  [{decimals, -1}])),
+    {'EXIT', {badarg, _}} = (catch float_to_binary(1.0,  [{decimals, 254}])),
+    {'EXIT', {badarg, _}} = (catch float_to_binary(1.0,  [{scientific, 250}])),
+    {'EXIT', {badarg, _}} = (catch float_to_binary(1.0e+300, [{decimals, 1}])),
+    test_fts("1.0e+300",1.0e+300, [{scientific, 1}]),
+    test_fts("1.0",1.0,  [{decimals,   249}, compact]),
+    test_fts("1",1.0,[{decimals,0}]),
+    test_fts("2",1.9,[{decimals,0}]),
+    test_fts("123456789012345680.0",123456789012345678.0,
+	     [{decimals, 236}, compact]),
+    {'EXIT', {badarg, _}} = (catch float_to_list(
+				     123456789012345678.0, [{decimals, 237}])),
+    {'EXIT', {badarg, _}} = (catch float_to_binary(
+				     123456789012345678.0, [{decimals, 237}])),
+    test_fts("1." ++ string:copies("0", 249) ++ "e+00",
+	     1.0,  [{scientific, 249}, compact]),
 
     X1 = float_to_list(1.0),
     X2 = float_to_list(1.0, [{scientific, 20}]),
     X1 = X2,
-    "1.000e+00" = float_to_list(1.0,   [{scientific, 3}]),
-    "1.000"     = float_to_list(1.0,   [{decimals, 3}]),
-    "1.0"       = float_to_list(1.0,   [{decimals, 1}]),
-    "1.0"       = float_to_list(1.0,   [{decimals, 3}, compact]),
-    "1.12"      = float_to_list(1.123, [{decimals, 2}]),
-    "1.123"     = float_to_list(1.123, [{decimals, 3}]),
-    "1.123"     = float_to_list(1.123, [{decimals, 3}, compact]),
-    "1.1230"    = float_to_list(1.123, [{decimals, 4}]),
-    "1.12300"   = float_to_list(1.123, [{decimals, 5}]),
-    "1.123"     = float_to_list(1.123, [{decimals, 5}, compact]),
-    "1.1234"    = float_to_list(1.1234,[{decimals, 6}, compact]),
-    "1.01"      = float_to_list(1.005, [{decimals, 2}]),
-    "-1.01"     = float_to_list(-1.005,[{decimals, 2}]),
-    "0.999"     = float_to_list(0.999, [{decimals, 3}]),
-    "-0.999"    = float_to_list(-0.999,[{decimals, 3}]),
-    "1.0"       = float_to_list(0.999, [{decimals, 2}, compact]),
-    "-1.0"      = float_to_list(-0.999,[{decimals, 2}, compact]),
-    "0.5"       = float_to_list(0.5,   [{decimals, 1}]),
-    "-0.5"      = float_to_list(-0.5,  [{decimals, 1}]),
+
+    Y1 = float_to_binary(1.0),
+    Y2 = float_to_binary(1.0, [{scientific, 20}]),
+    Y1 = Y2,
+
+    test_fts("1.000e+00",1.0,   [{scientific, 3}]),
+    test_fts("1.000",1.0,   [{decimals,   3}]),
+    test_fts("1.0",1.0, [{decimals, 1}]),
+    test_fts("1.0",1.0, [{decimals, 3}, compact]),
+    test_fts("1.12",1.123, [{decimals, 2}]),
+    test_fts("1.123",1.123, [{decimals, 3}]),
+    test_fts("1.123",1.123, [{decimals, 3}, compact]),
+    test_fts("1.1230",1.123, [{decimals, 4}]),
+    test_fts("1.12300",1.123, [{decimals, 5}]),
+    test_fts("1.123",1.123, [{decimals, 5}, compact]),
+    test_fts("1.1234",1.1234,[{decimals, 6}, compact]),
+    test_fts("1.01",1.005, [{decimals, 2}]),
+    test_fts("-1.01",-1.005,[{decimals, 2}]),
+    test_fts("0.999",0.999, [{decimals, 3}]),
+    test_fts("-0.999",-0.999,[{decimals, 3}]),
+    test_fts("1.0",0.999, [{decimals, 2}, compact]),
+    test_fts("-1.0",-0.999,[{decimals, 2}, compact]),
+    test_fts("0.5",0.5,   [{decimals, 1}]),
+    test_fts("-0.5",-0.5,  [{decimals, 1}]),
     "2.333333"  = erlang:float_to_list(7/3, [{decimals, 6}, compact]),
     "2.333333"  = erlang:float_to_list(7/3, [{decimals, 6}]),
-    "0.00000000000000000000e+00" = float_to_list(0.0, [compact]),
-    "0.0"       = float_to_list(0.0,   [{decimals, 10}, compact]),
-    "123000000000000000000.0"    = float_to_list(1.23e20, [{decimals,   10}, compact]),
-    "1.2300000000e+20"           = float_to_list(1.23e20, [{scientific, 10}, compact]),
-    "1.23000000000000000000e+20" = float_to_list(1.23e20, []),
+    <<"2.333333">>  = erlang:float_to_binary(7/3, [{decimals, 6}, compact]),
+    <<"2.333333">>  = erlang:float_to_binary(7/3, [{decimals, 6}]),
+    test_fts("0.00000000000000000000e+00",0.0, [compact]),
+    test_fts("0.0",0.0,   [{decimals, 10}, compact]),
+    test_fts("123000000000000000000.0",1.23e20, [{decimals,   10}, compact]),
+    test_fts("1.2300000000e+20",1.23e20, [{scientific, 10}, compact]),
+    test_fts("1.23000000000000000000e+20",1.23e20, []),
     ok.
     
-test_ftl(Expect, Float) ->
-    %% No ?line on the next line -- we want the line number from t_float_to_list.
-    Expect = remove_zeros(lists:reverse(float_to_list(Float)), []).
-
-%% Removes any non-significant zeros in a floating point number.
-%% Example: 2.500000e+01 -> 2.5e+1
-
-remove_zeros([$+, $e|Rest], [$0, X|Result]) ->
-    remove_zeros([$+, $e|Rest], [X|Result]);
-remove_zeros([$-, $e|Rest], [$0, X|Result]) ->
-    remove_zeros([$-, $e|Rest], [X|Result]);
-remove_zeros([$0, $.|Rest], [$e|Result]) ->
-    remove_zeros(Rest, [$., $0, $e|Result]);
-remove_zeros([$0|Rest], [$e|Result]) ->
-    remove_zeros(Rest, [$e|Result]);
-remove_zeros([Char|Rest], Result) ->
-    remove_zeros(Rest, [Char|Result]);
-remove_zeros([], Result) ->
-    Result.
+test_fts(Expect, Float) ->
+    Expect = float_to_list(Float),
+    BinExpect = list_to_binary(Expect),
+    BinExpect = float_to_binary(Float).
+
+test_fts(Expect, Float, Args) ->
+    Expect = float_to_list(Float,Args),
+    BinExpect = list_to_binary(Expect),
+    BinExpect = float_to_binary(Float,Args).
+
 
 %% Tests list_to_float/1.
 
-t_list_to_float_safe(Config) when is_list(Config) ->
-    0.0 = list_to_float(id("0.0")),
-    0.0 = list_to_float(id("-0.0")),
-    0.5 = list_to_float(id("0.5")),
-    -0.5 = list_to_float(id("-0.5")),
-    100.0 = list_to_float(id("1.0e2")),
-    127.5 = list_to_float(id("127.5")),
-    -199.5 = list_to_float(id("-199.5")),
+t_string_to_float_safe(Config) when is_list(Config) ->
+    test_stf(0.0,"0.0"),
+    test_stf(0.0,"-0.0"),
+    test_stf(0.5,"0.5"),
+    test_stf(-0.5,"-0.5"),
+    test_stf(100.0,"1.0e2"),
+    test_stf(127.5,"127.5"),
+    test_stf(-199.5,"-199.5"),
 
     {'EXIT',{badarg,_}} = (catch list_to_float(id("0"))),
     {'EXIT',{badarg,_}} = (catch list_to_float(id("0..0"))),
     {'EXIT',{badarg,_}} = (catch list_to_float(id("0e12"))),
     {'EXIT',{badarg,_}} = (catch list_to_float(id("--0.0"))),
+    {'EXIT',{badarg,_}} = (catch binary_to_float(id(<<"0">>))),
+    {'EXIT',{badarg,_}} = (catch binary_to_float(id(<<"0..0">>))),
+    {'EXIT',{badarg,_}} = (catch binary_to_float(id(<<"0e12">>))),
+    {'EXIT',{badarg,_}} = (catch binary_to_float(id(<<"--0.0">>))),
+
+    UBin = <<0:3,(id(<<"0.0">>))/binary,0:5>>,
+    <<_:3,UnAlignedBin:3/binary,0:5>> = id(UBin),
+    0.0 = binary_to_float(UnAlignedBin),
+
+    ABin = <<0:8,(id(<<"1.0">>))/binary,0:8>>,
+    <<_:8,AlignedBin:3/binary,0:8>> = id(ABin),
+    1.0 = binary_to_float(AlignedBin),
 
     ok.
 
 %% This might crash the emulator...
 %% (Known to crash the Unix version of Erlang 4.4.1)
 
-t_list_to_float_risky(Config) when is_list(Config) ->
+t_string_to_float_risky(Config) when is_list(Config) ->
     Many_Ones = lists:duplicate(25000, id($1)),
     id(list_to_float("2."++Many_Ones)),
     {'EXIT', {badarg, _}} = (catch list_to_float("2"++Many_Ones)),
+
+    id(binary_to_float(list_to_binary("2."++Many_Ones))),
+    {'EXIT', {badarg, _}} = (catch binary_to_float(
+				     list_to_binary("2"++Many_Ones))),
     ok.
 
+test_stf(Expect,List) ->
+    Expect = list_to_float(List),
+    Bin = list_to_binary(List),
+    Expect = binary_to_float(Bin).
+
 %% Tests round/1.
 
 t_round(Config) when is_list(Config) ->
diff --git a/erts/preloaded/src/erlang.erl b/erts/preloaded/src/erlang.erl
index 744527aeff..8e4a471a82 100644
--- a/erts/preloaded/src/erlang.erl
+++ b/erts/preloaded/src/erlang.erl
@@ -74,7 +74,7 @@
 
 -export([adler32/1, adler32/2, adler32_combine/3, append_element/2]).
 -export([atom_to_binary/2, atom_to_list/1, binary_part/2, binary_part/3]).
--export([binary_to_atom/2, binary_to_existing_atom/2]).
+-export([binary_to_atom/2, binary_to_existing_atom/2, binary_to_float/1]).
 -export([binary_to_integer/1,binary_to_integer/2]).
 -export([binary_to_list/1]).
 -export([binary_to_list/3, binary_to_term/1, binary_to_term/2]).
@@ -87,7 +87,8 @@
 -export([display_nl/0, display_string/1, dist_exit/3, erase/0, erase/1]).
 -export([error/1, error/2, exit/1, exit/2, external_size/1]).
 -export([external_size/2, finish_after_on_load/2, finish_loading/1, float/1]).
--export([float_to_list/1, float_to_list/2]).
+-export([float_to_binary/1, float_to_binary/2,
+	 float_to_list/1, float_to_list/2]).
 -export([fun_info/2, fun_to_list/1, function_exported/3]).
 -export([garbage_collect/0, garbage_collect/1]).
 -export([garbage_collect_message_area/0, get/0, get/1, get_keys/1]).
@@ -322,6 +323,12 @@ binary_to_atom(_Binary, _Encoding) ->
 binary_to_existing_atom(_Binary, _Encoding) ->
     erlang:nif_error(undefined).
 
+%% binary_to_float/1
+-spec binary_to_float(Binary) -> float() when
+      Binary :: binary().
+binary_to_float(_Binary) ->
+    erlang:nif_error(undefined).
+
 %% binary_to_integer/1
 -spec binary_to_integer(Binary) -> integer() when
       Binary :: binary().
@@ -724,6 +731,22 @@ finish_after_on_load(_P1, _P2) ->
 float(_Number) ->
     erlang:nif_error(undefined).
 
+%% float_to_binary/1
+-spec float_to_binary(Float) -> binary() when
+      Float :: float().
+float_to_binary(_Float) ->
+    erlang:nif_error(undefined).
+
+%% float_to_binary/2
+-spec float_to_binary(Float, Options) -> binary() when
+      Float :: float(),
+      Options :: [Option],
+      Option  :: {decimals, Decimals :: 0..253} |
+                 {scientific, Decimals :: 0..249} |
+                 compact.
+float_to_binary(_Float, _Options) ->
+    erlang:nif_error(undefined).
+
 %% float_to_list/1
 -spec float_to_list(Float) -> string() when
       Float :: float().
@@ -734,8 +757,8 @@ float_to_list(_Float) ->
 -spec float_to_list(Float, Options) -> string() when
       Float :: float(),
       Options :: [Option],
-      Option  :: {decimals, non_neg_integer()} |
-                 {scientific, non_neg_integer()} |
+      Option  :: {decimals, Decimals :: 0..253} |
+                 {scientific, Decimals :: 0..249} |
                  compact.
 float_to_list(_Float, _Options) ->
     erlang:nif_error(undefined).
diff --git a/lib/compiler/src/erl_bifs.erl b/lib/compiler/src/erl_bifs.erl
index 0854ad3a3e..cc07f0b9bc 100644
--- a/lib/compiler/src/erl_bifs.erl
+++ b/lib/compiler/src/erl_bifs.erl
@@ -68,6 +68,7 @@ is_pure(erlang, atom_to_list, 1) -> true;
 is_pure(erlang, binary_part, 2) -> true;
 is_pure(erlang, binary_part, 3) -> true;
 is_pure(erlang, binary_to_atom, 2) -> true;
+is_pure(erlang, binary_to_float, 1) -> true;
 is_pure(erlang, binary_to_integer, 1) -> true;
 is_pure(erlang, binary_to_list, 1) -> true;
 is_pure(erlang, binary_to_list, 3) -> true;
@@ -76,6 +77,7 @@ is_pure(erlang, byte_size, 1) -> true;
 is_pure(erlang, element, 2) -> true;
 is_pure(erlang, float, 1) -> true;
 is_pure(erlang, float_to_list, 1) -> true;
+is_pure(erlang, float_to_binary, 1) -> true;
 is_pure(erlang, hash, 2) -> false;
 is_pure(erlang, hd, 1) -> true;
 is_pure(erlang, integer_to_binary, 1) -> true;
diff --git a/lib/stdlib/src/erl_internal.erl b/lib/stdlib/src/erl_internal.erl
index 79a06c9bec..378e629ac9 100644
--- a/lib/stdlib/src/erl_internal.erl
+++ b/lib/stdlib/src/erl_internal.erl
@@ -256,6 +256,7 @@ bif(binary_to_atom, 2) -> true;
 bif(binary_to_existing_atom, 2) -> true;
 bif(binary_to_integer, 1) -> true;
 bif(binary_to_integer, 2) -> true;
+bif(binary_to_float, 1) -> true;
 bif(binary_to_list, 1) -> true;
 bif(binary_to_list, 3) -> true;
 bif(binary_to_term, 1) -> true;
@@ -281,6 +282,8 @@ bif(exit, 2) -> true;
 bif(float, 1) -> true;
 bif(float_to_list, 1) -> true;
 bif(float_to_list, 2) -> true;
+bif(float_to_binary, 1) -> true;
+bif(float_to_binary, 2) -> true;
 bif(garbage_collect, 0) -> true;
 bif(garbage_collect, 1) -> true;
 bif(get, 0) -> true;
diff --git a/lib/tools/emacs/erlang.el b/lib/tools/emacs/erlang.el
index 5139d6f6ff..ddd22707dd 100644
--- a/lib/tools/emacs/erlang.el
+++ b/lib/tools/emacs/erlang.el
@@ -728,6 +728,7 @@ resulting regexp is surrounded by \\_< and \\_>."
       "atom_to_list"
       "binary_to_atom"
       "binary_to_existing_atom"
+      "binary_to_float"
       "binary_to_integer"
       "binary_to_list"
       "binary_to_term"
@@ -747,6 +748,7 @@ resulting regexp is surrounded by \\_< and \\_>."
       "error"
       "exit"
       "float"
+      "float_to_binary"
       "float_to_list"
       "garbage_collect"
       "get"
diff --git a/system/doc/reference_manual/data_types.xml b/system/doc/reference_manual/data_types.xml
index 1eac575df7..73ec6e2b82 100644
--- a/system/doc/reference_manual/data_types.xml
+++ b/system/doc/reference_manual/data_types.xml
@@ -397,7 +397,11 @@ hello
 14> <input>binary_to_integer(&lt;&lt;"77">>).</input>
 77
 15> <input>integer_to_binary(77).</input>
-&lt;&lt;"77">></pre>
+&lt;&lt;"77">>
+16> <input>float_to_binary(7.0).</input>
+&lt;&lt;"7.00000000000000000000e+00">>
+17> <input>binary_to_float(&lt;&lt;"7.000e+00>>").</input>
+7.0</pre>
   </section>
 </chapter>