update sproto (#1720)

Co-authored-by: zixun <lb151450@alibaba-inc.com>

lualib-src/sproto/README.md

@@ -104,7 +104,7 @@ local sprotocore = require "sproto.core" -- optional
 * `sproto.new(spbin)` creates a sproto object by a schema binary string (generates by parser).
 * `sprotocore.newproto(spbin)` creates a sproto c object by a schema binary string (generates by parser).
 * `sproto.sharenew(spbin)` share a sproto object from a sproto c object (generates by sprotocore.newproto).
-* `sproto.parse(schema)` creares a sproto object by a schema text string (by calling parser.parse)
+* `sproto.parse(schema)` creates a sproto object by a schema text string (by calling parser.parse)
 * `sproto:exist_type(typename)` detect whether a type exist in sproto object.
 * `sproto:encode(typename, luatable)` encodes a lua table with typename into a binary string.
 * `sproto:decode(typename, blob [,sz])` decodes a binary string generated by sproto.encode with typename. If blob is a lightuserdata (C ptr), sz (integer) is needed.
@@ -217,7 +217,7 @@ Types
 * **string** : string
 * **binary** : binary string (it's a sub type of string)
 * **integer** : integer, the max length of an integer is signed 64bit. It can be a fixed-point number with specified precision.
-* **double** : double, floating-point number.
+* **double** : double precision floating-point number, satisfy [the IEEE 754 standard](https://en.wikipedia.org/wiki/Double-precision_floating-point_format).
 * **boolean** : true or false
 
 You can add * before the typename to declare an array.
@@ -230,7 +230,7 @@ User defined type can be any name in alphanumeric characters except the build-in
 
 * Where are double or real types?
 
-I have been using Google protocol buffers for many years in many projects, and I found the real types were seldom used. If you really need it, you can use string to serialize the double numbers. When you need decimal, you can specify the fixed-point presision.
+I have been using Google protocol buffers for many years in many projects, and I found the real types were seldom used. If you really need it, you can use string to serialize the double numbers. When you need decimal, you can specify the fixed-point precision.
 
 **NOTE** : `double` is supported now.
 
@@ -263,6 +263,7 @@ For integer array, an additional byte (4 or 8) to indicate the value is 32bit or
 Read the examples below to see more details.
 
 Notice: If the tag is not declared in schema, the decoder will simply ignore the field for protocol version compatibility.
+Notice more: all examples are tested in `test_wire_protocol.lua`, update `test_wire_protocol.lua` when update examples.
 
 ```
 .Person {
@@ -277,6 +278,9 @@ Notice: If the tag is not declared in schema, the decoder will simply ignore the
 	bools 1 : *boolean
 	number 2 : integer
 	bignumber 3 : integer
+ 	double 4 : double
+ 	doubles 5 : *double
+ 	fpn 6 : integer(2)
 }
 ```
 
@@ -405,6 +409,39 @@ A0 86 01 00 (100000, 32bit integer)
 00 1C F4 AB FD FF FF FF (-10000000000, 64bit integer)
 ```
 
+Example 7:
+```
+data {
+    double = 0.01171875,
+    doubles = {0.01171875, 23, 4}
+}
+
+03 00 (fn = 3)
+07 00 (skip id = 3)
+00 00 (id = 4, value in data part)
+00 00 (id = 5, value in data part)
+
+08 00 00 00 (sizeof number, data part)
+00 00 00 00 00 00 88 3f (0.01171875, 64bit double)
+
+19 00 00 00 (sizeof doubles)
+08 (sizeof double)
+00 00 00 00 00 00 88 3f (0.01171875, 64bit double)
+00 00 00 00 00 00 37 40 (23, 64bit double)
+00 00 00 00 00 00 10 40 (4, 64bit double)
+```
+
+Example 8:
+```
+data {
+    fpn = 1.82,
+}
+
+02 00 (fn = 2)
+0b 00 (skip id = 5)
+6e 01 (id = 6, value = 0x16e/2 - 1 = 182)
+```
+
 0 Packing
 =======
 

lualib-src/sproto/lsproto.c

@@ -84,14 +84,16 @@ lua_seti(lua_State *L, int index, lua_Integer n) {
 #if defined(SPROTO_WEAK_TYPE)
 static int64_t
 tointegerx (lua_State *L, int idx, int *isnum) {
-	int64_t v;
-	if (lua_isnumber(L, idx)) {
-		v = (int64_t)(round(lua_tonumber(L, idx)));
-		if (isnum) *isnum = 1;
-		return v;
-	} else {
-		return lua_tointegerx(L, idx, isnum);
+	int _isnum = 0;
+	int64_t v = lua_tointegerx(L, idx, &_isnum);
+	if (!_isnum){
+		double num = lua_tonumberx(L, idx, &_isnum);
+		if(_isnum) {
+			v = (int64_t)llround(num);
+		}
 	}
+	if(isnum) *isnum = _isnum;
+	return v;
 }
 
 static int
@@ -613,7 +615,7 @@ getbuffer(lua_State *L, int index, size_t *sz) {
 /*
 	lightuserdata sproto_type
 	string source	/  (lightuserdata , integer)
-	return table
+	return table, sz(decoded bytes)
  */
 static int
 ldecode(lua_State *L) {

lualib-src/sproto/sproto.c

@@ -898,7 +898,7 @@ encode_array(sproto_callback cb, struct sproto_arg *args, uint8_t *data, int siz
 		buffer = encode_integer_array(cb,args,buffer,size, &noarray);
 		if (buffer == NULL)
 			return -1;
-	
+
 		if (noarray) {
 			return 0;
 		}
@@ -1088,26 +1088,33 @@ expand64(uint32_t v) {
 	return value;
 }
 
+static int
+decode_empty_array(sproto_callback cb, struct sproto_arg *args) {
+	// It's empty array, call cb with index == -1 to create the empty array.
+	args->index = -1;
+	args->value = NULL;
+	args->length = 0;
+	return cb(args);
+}
+
 static int
 decode_array(sproto_callback cb, struct sproto_arg *args, uint8_t * stream) {
 	uint32_t sz = todword(stream);
 	int type = args->type;
 	int i;
 	if (sz == 0) {
-		// It's empty array, call cb with index == -1 to create the empty array.
-		args->index = -1;
-		args->value = NULL;
-		args->length = 0;
-		cb(args);
-		return 0;
-	}	
+		return decode_empty_array(cb, args);
+	}
 	stream += SIZEOF_LENGTH;
 	switch (type) {
 	case SPROTO_TDOUBLE:
 	case SPROTO_TINTEGER: {
+		if (--sz == 0) {
+			// An empty array but with a len prefix
+			return decode_empty_array(cb, args);
+		}
 		int len = *stream;
 		++stream;
-		--sz;
 		if (len == SIZEOF_INT32) {
 			if (sz % SIZEOF_INT32 != 0)
 				return -1;