Back out changes in #366 and introduce read_argv_int/float()

* Revert "Extend "read_argv" native"

This reverts commit aaa2934595.

This broke binary compatibility with either older, already compiled
plugins, or newly compiled plugins if you forgot to update .inc headers.

This happened because read_argv used to receive maxlen by value, and
after
this commit it receives it by reference. This causes read_argv either
to fail, or worse, to buffer overflow, resulting in a security vulnerability.

Newly introduced functionality for read_argv should be added with a new,
separate native.

* Add "read_argv_int" & "read_argv_float" natives

amxmodx/amxmodx.cpp

@@ -2460,19 +2460,36 @@ static cell AMX_NATIVE_CALL read_argv(AMX *amx, cell *params) /* 3 param */
 	int argc = params[1];
 
 	const char *value = g_fakecmd.notify ? (argc >= 0 && argc < 3 ? g_fakecmd.argv[argc] : "") : CMD_ARGV(argc);
-
-	switch (*params / sizeof(cell))
-	{
-		case 1:
-			return atoi(value);
-		case 3:
-			return set_amxstring_utf8(amx, params[2], value, strlen(value), *get_amxaddr(amx, params[3]));
-		default:
-			cell *fCell = get_amxaddr(amx, params[2]);
-			REAL fparam = static_cast<REAL>(atof(value));
-			*fCell = amx_ftoc(fparam);
-			return static_cast<int>(fparam);
+	return set_amxstring_utf8(amx, params[2], value, strlen(value), params[3]);
 }
+
+static cell AMX_NATIVE_CALL read_argv_int(AMX *amx, cell *params) /* 1 param */
+{
+	int argc = params[1];
+
+	if (argc <= 0)
+	{
+		return 0;
+	}
+
+	const char *value = g_fakecmd.notify ? (argc >= 1 && argc < 3 ? g_fakecmd.argv[argc] : "") : CMD_ARGV(argc);
+
+	return atoi(value);
+}
+
+static cell AMX_NATIVE_CALL read_argv_float(AMX *amx, cell *params) /* 1 param */
+{
+	int argc = params[1];
+
+	if (argc <= 0)
+	{
+		return 0;
+	}
+
+	const char *value = g_fakecmd.notify ? (argc >= 1 && argc < 3 ? g_fakecmd.argv[argc] : "") : CMD_ARGV(argc);
+	float flValue = atof(value);
+
+	return amx_ftoc(flValue);
 }
 
 static cell AMX_NATIVE_CALL read_args(AMX *amx, cell *params) /* 2 param */
@@ -4754,6 +4771,8 @@ AMX_NATIVE_INFO amxmodx_Natives[] =
 	{"read_argc",				read_argc},
 	{"read_args",				read_args},
 	{"read_argv",				read_argv},
+	{"read_argv_int",			read_argv_int},
+	{"read_argv_float",			read_argv_float},
 	{"read_data",				read_data},
 	{"read_datanum",			read_datanum},
 	{"read_datatype",			read_datatype},

plugins/include/amxmodx.inc

@@ -1318,32 +1318,39 @@ native get_playersnum(flag = 0);
 native get_players(players[MAX_PLAYERS], &num, const flags[] = "", const team[] = "");
 
 /**
- * Retrieves argument of client command.
+ * Retrieves argument of client command as string.
  *
  * @note Should only be used inside of the client_command() forward.
- * @note Usage examples:
- *       value = read_argv(1);
- *       read_argv(2, floatvalue);
- *       written = read_argv(3, buffer, buffersize);
  *
  * @param id        Argument index starting from 1, 0 returns the command itself
- * @param ...       Changes the native's behavior depending on how many
- *                  additional parameters are provided:
- *                     0 - Return the argument integer value directly
- *                     1 - Store the argument float value in the variable passed
- *                         as the second parameter
- *                     2 - Copy the argument string value to the buffer provided
- *                         in the second parameter, using the third as the
- *                         maximum buffer size
+ * @param output    Buffer to copy command argument to
+ * @param len       Maximum buffer size
  *
- * @return          Changes depending on how many additional parameters are
- *                  provided:
- *                     0 - Returns the argument integer value
- *                     1 - Returns the argument float value, converted
- *                         (truncated) to an integer
- *                     2 - Returns the number of cells written to the buffer
+ * @return          Number of cells written to buffer
  */
-native read_argv(id, any:...);
+native read_argv(id, output[], len);
+
+/**
+ * Retrieves argument of client command as integer value.
+ *
+ * @note Should only be used inside of the client_command() forward.
+ *
+ * @param id        Argument index starting from 1
+ *
+ * @return          Integer value
+ */
+native read_argv_int(id);
+
+/**
+ * Retrieves argument of client command as float value.
+ *
+ * @note Should only be used inside of the client_command() forward.
+ *
+ * @param id        Argument index starting from 1
+ *
+ * @return          Float value
+ */
+native Float:read_argv_float(id);
 
 /**
  * Retrieves full client command string.