/*
?*?Copyright???2001-2011?Stéphane?Raimbault?
?*
?*?This?library?is?free?software;?you?can?redistribute?it?and/or
?*?modify?it?under?the?terms?of?the?GNU?Lesser?General?Public
?*?License?as?published?by?the?Free?Software?Foundation;?either
?*?version?2.1?of?the?License?or?（at?your?option）?any?later?version.
?*
?*?This?library?is?distributed?in?the?hope?that?it?will?be?useful
?*?but?WITHOUT?ANY?WARRANTY;?without?even?the?implied?warranty?of
?*?MERCHANTABILITY?or?FITNESS?FOR?A?PARTICULAR?PURPOSE.??See?the?GNU
?*?Lesser?General?Public?License?for?more?details.
?*
?*?You?should?have?received?a?copy?of?the?GNU?Lesser?General?Public
?*?License?along?with?this?library;?if?not?write?to?the?Free?Software
?*?Foundation?Inc.?51?Franklin?Street?Fifth?Floor?Boston?MA?02110-1301?USA
?*
?*
?*?This?library?implements?the?Modbus?protocol.
?*?http://libmodbus.org/
?*/

#include?
#include?
#include?
#include?
#include?
#include?

#include?

#include?“modbus.h“
#include?“modbus-private.h“

/*?Internal?use?*/
#define?MSG_LENGTH_UNDEFINED?-1

/*?Exported?version?*/
const?unsigned?int?libmodbus_version_major?=?LIBMODBUS_VERSION_MAJOR;
const?unsigned?int?libmodbus_version_minor?=?LIBMODBUS_VERSION_MINOR;
const?unsigned?int?libmodbus_version_micro?=?LIBMODBUS_VERSION_MICRO;

/*?Max?between?RTU?and?TCP?max?adu?length?（so?TCP）?*/
#define?MAX_MESSAGE_LENGTH?260

/*?3?steps?are?used?to?parse?the?query?*/
typedef?enum?{
????_STEP_FUNCTION
????_STEP_meta
????_STEP_DATA
}?_step_t;

const?char?*modbus_strerror（int?errnum）?{
????switch?（errnum）?{
????case?EMBXILFUN:
????????return?“Illegal?function“;
????case?EMBXILADD:
????????return?“Illegal?data?address“;
????case?EMBXILVAL:
????????return?“Illegal?data?value“;
????case?EMBXSFAIL:
????????return?“Slave?device?or?server?failure“;
????case?EMBXACK:
????????return?“Acknowledge“;
????case?EMBXSBUSY:
????????return?“Slave?device?or?server?is?busy“;
????case?EMBXNACK:
????????return?“Negative?acknowledge“;
????case?EMBXMEMPAR:
????????return?“Memory?parity?error“;
????case?EMBXGPATH:
????????return?“Gateway?path?unavailable“;
????case?EMBXGTAR:
????????return?“Target?device?failed?to?respond“;
????case?EMBBADCRC:
????????return?“Invalid?CRC“;
????case?EMBBADDATA:
????????return?“Invalid?data“;
????case?EMBBADEXC:
????????return?“Invalid?exception?code“;
????case?EMBMDATA:
????????return?“Too?many?data“;
????default:
????????return?strerror（errnum）;
????}
}

void?_error_print（modbus_t?*ctx?const?char?*context）
{
????if?（ctx->debug）?{
????????fprintf（stderr?“ERROR?%s“?modbus_strerror（errno））;
????????if?（context?!=?NULL）?{
????????????fprintf（stderr?“:?%s\n“?context）;
????????}?else?{
????????????fprintf（stderr?“\n“）;
????????}
????}
}

int?_sleep_and_flush（modbus_t?*ctx）
{
#ifdef?_WIN32
????/*?usleep?doesn‘t?exist?on?Windows?*/
????Sleep（（ctx->response_timeout.tv_sec?*?1000）?+
??????????（ctx->response_timeout.tv_usec?/?10