我给你举个例子方便快速理吵隐如解：
TLV 是 tag , length 和 value 的缩写.一个基本的数据元就包括上面三个域. Tag 唯一标识该数据元, length 是 value 域的长度. Value就是数据本身了. 举升启个例子, 下面是一个tlv格式的AID（应用标识符）字节串” 9F0607A0000000031010 ”, 其中 9F06 是tag, 07 是长度, A0000000031010 就是AID本身的值了.
对于程序编写人员来说，如果有类似上面这样的一串TLV编码的字节串从卡片传过来, 怎么样从中提取我们想要的数据. 这就牵扯出TLV解码的问题了
TLV一种可变格式，TLV的意思就是：Type类型， Lenght长度，携困Value值；
Type和Length的长度固定，一般那是2、4个字节；
Value的长度有Length指定；
解析方法：
1.读取type 转换为ntohl、ntohs转换为主机字节序得到类型；指针偏移+2或4
2.读取lenght，转换为ntohl、ntohs转换为主机字节序得到长度；指针偏移+2或4
3.根据得到的长度读取value，指针偏移+Length；
TLV编码就是指先对Tag编码，再对Length编码，最后对Value编码。
有点长，慢慢看吧Begin VB.Form frmMain
Caption = "Form1"
ClientHeight= 3090
ClientLeft = 60
ClientTop = 450
ClientWidth = 4680
LinkTopic = "Form1"
ScaleHeight = 3090
ScaleWidth = 4680
StartUpPosition = 3 '窗口缺省
Begin VB.CommandButton Command1
Caption = "Command1"
Height = 975
Left= 1320
TabIndex= 0
Top = 1080
Width = 2415
End
End
Attribute VB_Name = "frmMain"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Option Explicit
Private Const MEM_RELEASE = &H8000
Private Const LVM_FIRST = &H1000
Private Const LVM_GETHEADER = LVM_FIRST + 31
Private Const LVM_GETITEMCOUNT = (LVM_FIRST + 4)
Private Const LVM_GETITEM = (LVM_FIRST + 5)
Private Const LVM_GETSTRINGWIDTH = (LVM_FIRST + 17)
Private Const LVM_GETCOLUMN = (LVM_FIRST + 25)
Private Const LVM_GETITEMTEXT = (LVM_FIRST + 45)
Private Const HDM_FIRST = &H1200
Private Const HDM_GETITEMCOUNT = (HDM_FIRST + 0)
Private Const HDM_ORDERTOINDEX = (HDM_FIRST + 15)
Private Const PROCESS_QUERY_INFORMATION = 1024
Private Const PROCESS_VM_OPERATION = &H8
Private Const PROCESS_VM_READ = &H10
Private Const PROCESS_VM_WRITE = &H20
Private Const STANDARD_RIGHTS_REQUIRED = &HF0000
Private Const MAX_LVMSTRING As Long = 255
Private Const MEM_COMMIT = &H1000
Private Const PAGE_READWRITE = &H4
Private Const LVIF_TEXT As Long = &H1
Private Const LVM_GETCOLUMNCOUNT = &HF11B
Private Type LV_ITEMA
mask As Long
iItemAs Long
iSubItem As Long
stateAs Long
stateMaskAs Long
pszText As Long
cchTextMax As Long
iImage As Long
lParam As Long
iIndent As Long
End Type
Private Declare Function OpenProcess Lib "kernel32" (ByVal dwDesiredAccess As Long, ByVal bInheritHandle As Long, ByVal dwProcId As Long) As Long
Private Declare Function VirtualAllocEx Lib "kernel32" (ByVal hProcess As Long, ByVal lpAddress As Long, ByVal dwSize As Long, ByVal flAllocationType As Long, ByVal flProtect As Long) As Long
Private Declare Function VirtualFreeEx Lib "kernel32" (ByVal hProcess As Long, ByVal lpAddress As Long, ByVal dwSize As Long, ByVal dwFreeType As Long) As Long
Private Declare Function WriteProcessMemory Lib "kernel32" (ByVal hProcess As Long, ByVal lpBaseAddress As Any, ByRef lpBuffer As Any, ByVal nSize As Long, lpNumberOfBytesWritten As Long) As Long
Private Declare Function ReadProcessMemory Lib "kernel32" (ByVal hProcess As Long, ByVal lpBaseAddress As Any, ByRef lpBuffer As Any, ByVal nSize As Long, lpNumberOfBytesWritten As Long) As Long
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByRef lParam As Any) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
Private Declare Function GetCurrentProcessId Lib "kernel32" () As Long
Private Function GetListViewTextArray(ByVal hWindow As Long, ByVal ProcessID As Long) As String()
Dim result As Long
Dim myItem() As LV_ITEMA
Dim pHandle As Long
Dim pStrBufferMemoryAs Long
Dim pMyItemMemory As Long
Dim strBuffer() As Byte
Dim index As Long
Dim tmpString As String
Dim strLength As Long
Dim i As Integer, sum As Integer, j As Integer, hCount As Long
Dim strArr() As String, itemString As String
hCount = SendMessage(hWindow, LVM_GETHEADER, 0, 0)
If hCount >0 Then
hCount = SendMessage(hCount, HDM_GETITEMCOUNT, 0, 0)
Else
hCount = 0
End If
ReDim strBuffer(MAX_LVMSTRING)
pHandle = OpenProcess(PROCESS_VM_OPERATION Or PROCESS_VM_READ Or PROCESS_VM_WRITE, False, ProcessID)
ReDim myItem(hCount)
For j = 0 To SendMessage(hWindow, LVM_GETITEMCOUNT, 0, 0) - 1
For i = 0 To hCount
pStrBufferMemory = VirtualAllocEx(pHandle, 0, MAX_LVMSTRING, MEM_COMMIT, PAGE_READWRITE)
myItem(i).mask = LVIF_TEXT
myItem(i).iSubItem = i
myItem(i).pszText = pStrBufferMemory
myItem(i).cchTextMax = MAX_LVMSTRING
pMyItemMemory = VirtualAllocEx(pHandle, 0, Len(myItem(i)), MEM_COMMIT, PAGE_READWRITE)
result = WriteProcessMemory(pHandle, pMyItemMemory, myItem(i), Len(myItem(i)), 0)
result = SendMessage(hWindow, LVM_GETITEMTEXT, j, ByVal pMyItemMemory)
If result = 0 Then
result = VirtualFreeEx(pHandle, pStrBufferMemory, 0, MEM_RELEASE)
result = VirtualFreeEx(pHandle, pMyItemMemory, 0, MEM_RELEASE)
Exit For
End If
result = ReadProcessMemory(pHandle, pStrBufferMemory, strBuffer(0), MAX_LVMSTRING, 0)
result = ReadProcessMemory(pHandle, pMyItemMemory, myItem(i), Len(myItem(i)), 0)
tmpString = StrConv(strBuffer, vbUnicode)
tmpString = Left(tmpString, InStr(tmpString, vbNullChar) - 1)
itemString = itemString &tmpString &","
result = VirtualFreeEx(pHandle, pStrBufferMemory, 0, MEM_RELEASE)
result = VirtualFreeEx(pHandle, pMyItemMemory, 0, MEM_RELEASE)
Next
ReDim Preserve strArr(0 To sum)
strArr(j) = Left(itemString, Len(itemString) - 1)
sum = sum + 1
itemString = ""
Next
result = CloseHandle(pHandle)
GetListViewTextArray = strArr
End Function
Private Sub Command1_Click()
Dim itemStr() As String, i As Integer
itemStr = GetListViewTextArray(frmListView.lvTest.hwnd, GetCurrentProcessId)
For i = 0 To UBound(itemStr)
MsgBox itemStr(i)
Next
End Sub
Private Sub Form_Load()
frmListView.Show
End Sub
VERSION 5.00
Object = "{831FDD16-0C5C-11D2-A9FC-0000F8754DA1}#2.0#0""MSCOMCTL.OCX"
Begin VB.Form frmListView
Caption = "测试窗体"
ClientHeight= 5730
ClientLeft = 60
ClientTop = 450
ClientWidth = 7425
LinkTopic = "Form2"
ScaleHeight = 5730
ScaleWidth = 7425
StartUpPosition = 3 '窗口缺省
Begin MSComctlLib.ListView lvTest
Height = 4695
Left= 360
TabIndex= 0
Top = 480
Width = 6495
_ExtentX= 11456
_ExtentY= 8281
View= 3
LabelWrap = -1 'True
HideSelection = -1 'True
_Version= 393217
ForeColor = -2147483640
BackColor = -2147483643
BorderStyle = 1
Appearance = 1
NumItems= 0
End
End
Attribute VB_Name = "frmListView"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Private Sub Form_Load()
With lvTest
.ColumnHeaders.Add , , "序号"
.ColumnHeaders.Add , , "名称"
.ColumnHeaders.Add , , "性别"
.ColumnHeaders.Add , , "年龄"
End With
AddToListview "陈辉", "男", "24"
AddToListview "张三", "男", "22"
AddToListview "李四", "女", "20"
AddToListview "王二", "男", "31"
AddToListview "麻子", "女", "18"
End Sub
Private Sub AddToListview(ByVal sName As String, sSex As String, ByVal sAge As String)
Dim item As ListItem
Set item = lvTest.ListItems.Add(, , CStr(lvTest.ListItems.Count + 1))
item.SubItems(1) = sName
item.SubItems(2) = sSex
item.SubItems(3) = sAge
End Sub
//09/10/24//lcd1602显示时间 日期 星期 温度
//通过按键校时：K10--小时，K11--分钟，K12--秒（归零），K13-星期，BR1--年，RB2--月，RB3--日。
//芯片要求：PIC16F877A
#include<pic.h> //包含单片机内部资源预定义
__CONFIG(0x1832)
//芯片配置字，看门狗关，上电延时开，掉电检测关，低压编程关，加密，4M晶体HS振迅侍荡
#define i_o RB4 //定义DS1302的数据口
#define sclk RB0 //定义DS1302的时钟口
#define rst RB5 //定义DS1302的复位口
#define rsRA1 //1602
#define rwRA2
#define e RA3
# define DQ RA0//定义18B20数据端口
unsigned char TLV=0//采集到的温度高8位
unsigned char THV=0//采集到的温度低8位
unsigned char bai
unsigned char shi //整数十位
unsigned char ge//整数个位
unsigned char shifen//十分位
float temp
void display()
//定义读取时间和日期存放表格
char table1[7]
//定义0-9的显示代码
const char table2[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90}
unsigned char rx_data,read_data,count,sec,min,hour,day,mon,week,year,time
//----------------------------------------------
//ds18b20部分
//------------------------------------------------
//延时含帆函数
void delay1(unsigned int x)
{
unsigned int i
for(i=xi>0i--)
}
//------------------------------------------------
//延时函数
void delay2(char x,char y)
{
char z
do{
z=y
do{}while(--z)
}while(--x)
}
//其指令时间为：7+（3*（Y-1）+7）*（X-1）谈昌雹如果再加上函数调用的call 指令、页面设定、传递参数花掉的7 个指令。
//则是：14+（3*（Y-1）+7）*（X-1）。
//***************************************
//初始化ds18b20
void ds18b20_init()
{
char presence=1
while(presence)
{
TRISA0=0 //主机拉至低电平
DQ=0
delay2(2,99) //延时503us
TRISA0=1 //释放总线等电阻拉高总线,并保持15~60us
delay2(2,8) //延时70us
if(DQ==1) presence=1//没有接收到应答信号，继续复位
else presence=0 //接收到应答信号
delay2(2,60) //延时430us
}
}
//*****************************************************
//写ds18b20
void ds18b20_write_byte(unsigned char code)
{
unsigned char i,k
for(i=8i>0i--)
{
k=code&0x01
TRISA0=0
DQ=0 //数据线拉低产生时间片
asm("nop")
asm("nop")
if(k) DQ=1//写1则拉高数据电平
delay1(3) //延时42us，ds18b20对数据线采样
asm("nop")
TRISA0=1 //采样结束，释放总线，拉高电平
code=code>>1
delay1(7) //延时82us
}
}
//****************************************************
//读ds18b20
unsigned char ds18b20_read_byte()
{
unsigned char i,k
for(i=8i>0i--)
{
k=k>>1
TRISA0=0
DQ=0//数据线拉低再拉高产生读时间片
asm("nop")
asm("nop")
TRISA0=1
asm("nop")
asm("nop")
if(DQ) k=k|0x80 //15us内要完成读位
delay1(6) //延时72us后释放总线
}
return (k)
}
//********************************************
//启动温度转换函数
void get_temp()
{
int i
signed int t
TRISA0=1
ds18b20_init()//复位等待从机应答
ds18b20_write_byte(0XCC) //忽略ROM匹配
ds18b20_write_byte(0X44) //发送温度转化命令
for(i=2i>0i--)
{
display() //调用多次显示函数，确保温度转换完成所需要的时间
}
ds18b20_init()//再次复位，等待从机应答
ds18b20_write_byte(0XCC) //忽略ROM匹配
ds18b20_write_byte(0XBE) //发送读温度命令
TLV=ds18b20_read_byte()//读出温度低8
THV=ds18b20_read_byte()//读出温度高8位
TRISA0=1 //释放总线
t=THV<<8
t=t|TLV
if(t<0)//负温度
{
temp=(~t+1)*0.0625*10+0.5 //负温度时，取反加1再乘以0.0625得实际温度，乘10+0.5显示小数点一位，且四舍五入
}
else
temp=t*0.0625*10+0.5 //正温度
if(t<0)
bai='-'//负温度时百位显示负号
else
bai=(const) temp/1000+0x30 //百位
shi=((const) temp%1000)/100 //十位
ge=((const) temp%1000)%100/10 //个位
shifen=((const) temp%1000)%100%10 //十分位
NOP()
}
//---------------------------------------------
//------------DS1303部分-----------------------
//---------------------------------------------
//延时程序
void delay() //延时程序
{
int i//定义整形变量
for(i=0x64i--)//延时
}
//写一个字节数据函数
void write_byte(unsigned char data)
{
int j //设置循环变量
for(j=0j<8j++) //连续写8bit
{
i_o=0 //先设置数据为0
sclk=0 //时钟信号拉低
if(data&0x01) //判断待发送的数据位是0或1
{
i_o=1 //待发送数据位是1
}
data=data>>1 //待发送的数据右移1位
sclk=1 //拉高时钟信号
}
sclk=0//写完一个字节，拉低时钟信号
}
//---------------------------------------------
//读一个字节函数
unsigned char read_byte()
{
int j //设置循环变量
TRISB4=1//设置数据口方向为输入
for(j=8j--) //连续读取8bit
{
sclk=0 //拉低时钟信号
rx_data=rx_data>>1//接收寄存器右移1位
if(i_o==1) rx_data=rx_data|0x80
sclk=1 //拉高时钟信号
}
TRISB4=0 //恢复数据口方向为输出
sclk=0 //拉低时钟信号
return(rx_data)//返回读取到的数据
}
//----------------------------------------------
//写DS1302
void write_ds1302(unsigned char addr,unsigned char code)
{
rst=0
sclk=0
rst=1
write_byte(addr)
write_byte(code)
sclk=0
rst=1
}
//-------------------------------------------
//读DS1302
void read_ds1302(unsigned char addr)
{
rst=0
sclk=0
rst=1
write_byte(addr)
read_data=read_byte()
//return read_data
}
//---------------------------------------------
//读取时间函数
void get_time()
{
int i//设置循环变量
rst=1//使能DS1302
write_byte(0xbf) //发送多字节读取命令
for(i=0i<7i++) //连续读取7个字节数据
{
table1[i]=read_byte() //调用读取1个字节数据的函数
}
rst=0 //复位DS1302
}
//DS1302初始化函数
void ds1302_init()
{
sclk=0 //拉低时钟信号
rst =0 //复位DS1302
rst=1//使能DS1302
write_ds1302(0x8e,0) //发控制命令
rst=0//复位
}
//---------------------------------------------
//设置时间函数
void set_time()
{
//定义待设置的时间： 秒、 分、 时、 日、月、星期、年、控制字
const char table[]={0x00,0x00,0x12,0x23,0x10,0x05,0x09,0x00}
int i//定义循环变量
rst=1//使能DS1302
write_byte(0xbe) //时钟多字节写命令
for(i=0i<8i++) //连续写8个字节数据
{
write_byte(table[i]) //调用写一个字节函数
}
rst=0//复位
}
//-------------------------------------------
//8位二进制数转换为十进制数
void two_to_ten(unsigned char i)
{
time=(table1[i]&0x0f)+(table1[i]>>4)*0x0a
}
//-------------------------------------------
//十进制数转换为BCD码
void ten_to_bcd(unsigned char i)
{
time=((i/0x0a)<<4)|(i%0x0a)
}
//------------------------------------------
//校时程序
void change_time()
{
if(RC0==0) //改变星期---k13
{
delay()
if(RC0==0)
{
if(count==0)
{
count=1
two_to_ten(5)
week=time
week++
if(week>=8)
{
week==1
write_ds1302(0x8A,1)
}
else
write_ds1302(0x8A,week)
}
}
}
else if(RC1==0) //秒归零--k12
{
delay()
if(RC1==0)
{
if(count==0)
{
count=1
write_ds1302(0x80,0)
}
}
}
else if(RC2==0)//改变分位--k11
{
delay()
if(RC2==0)
{
if(count==0)
{
count=1
two_to_ten(1)//BCD码转换成十进制数
min=time
min++
if(min>=60)
{
min=0
write_ds1302(0x82,min)
}
else
{
ten_to_bcd(min)//十进制数转换为BCD码存进DS1302
write_ds1302(0x82,time)
}
}
}
}
else if(RC3==0)//改变小时位--k10
{
delay()
if(RC3==0)
{
if(count==0)
{
count=1
two_to_ten(2)//BCD码转换成十进制数
hour=time
hour++
if(hour>=24)
{
hour=0
write_ds1302(0x84,hour)
}
else
{
ten_to_bcd(hour)
write_ds1302(0x84,time)
}
}
}
}
else if(RB2==0)
{
delay()
if(RB2==0)
{
if(count==0)
{
count=1
two_to_ten(4)//BCD码转换成十进制数
mon=time
mon++
if(mon>=13)
{
mon=1
write_ds1302(0x88,mon)
}
else
{
ten_to_bcd(mon)
write_ds1302(0x88,time)
}
}
}
}
else if(RB3==0)
{
delay()
if(RB3==0)
{
if(count==0)
{
count=1
two_to_ten(3)//BCD码转换成十进制数
day=time
day++
if((table1[6]%4==0)&&(table1[4]==2)&&(day>=30)) //润年2月
{
day=1
write_ds1302(0x86,day)
}
else if(((table1[6]%4)!=0)&&(table1[4]==2)&&(day>=29))//非润年的2月
{
day=1
write_ds1302(0x86,day)
}
else if(((table1[4]==1)||(table1[4]==3)||(table1[4]==5)||(table1[4]==7)||(table1[4]==8)||(table1[4]==0x10)||(table1[4]==0x12))&&(day>=32))
{
day=1
write_ds1302(0x86,day)
}
else if(((table1[4]==4)||(table1[4]==6)||(table1[4]==9)||(table1[4]==0x11))&&(day>=31))
{
day=1
write_ds1302(0x86,day)
}
else
{
ten_to_bcd(day)
write_ds1302(0x86,time)
}
}
}
}
else if(RB1==0)
{
delay()
if(RB1==0)
{
if(count==0)
{
count=1
two_to_ten(6)//BCD码转换成十进制数
year=time
year++
if(year>=16)
{
year=0x00
write_ds1302(0x8c,0)
}
else
{
ten_to_bcd(year)
write_ds1302(0x8c,time)
}
}
}
}
else
count=0
}
//****************************************
//**************lcd1602*******************
//****************************************
//延时程序
//void delay()
// {
// unsigned char i
// for(i=100i>0i--)
// }
//****************************************
//LCD写一个字节数据
void write_lcd(unsigned char code)
{
PORTD=code
rs=1
rw=0
e=0
delay()
e=1
}
//****************************************
//lcd写命令函数
void lcd_enable(unsigned char code)
{
PORTD=code
rs=0
rw=0
e=0
delay()
e=1
}
//*****************************************
//lcd显示设置
void lcd_init()
{
lcd_enable(0x01)//清除显示
lcd_enable(0x38)//设置16X2显示，5X7点阵
lcd_enable(0x0c)//开显示，不显示光标
lcd_enable(0x06)//光标左移
}
//-------------------------------------------
//显示函数
void display()
{
//PORTD=0X80 //小时
lcd_enable(0X80)
write_lcd((table1[2]>>4)+0x30)
// PORTD=0x81
lcd_enable(0x81)
write_lcd((table1[2]&0x0f)+0x30)
// PORTD=0X82
lcd_enable(0X82)
write_lcd(':')
// PORTD=0X83 //分
lcd_enable(0X83)
write_lcd((table1[1]>>4)+0x30)
// PORTD=0x84
lcd_enable(0x84)
write_lcd((table1[1]&0x0f)+0x30)
// PORTD=0X85
lcd_enable(0X85)
write_lcd(':')
// PORTD=0X86 //秒
lcd_enable(0X86)
write_lcd((table1[0]>>4)+0x30)
// PORTD=0x87
lcd_enable(0x87)
write_lcd((table1[0]&0x0f)+0x30)
// PORTD=0X89//温度的百位
lcd_enable(0X89)
write_lcd(bai)
// PORTD=0X8a//温度的十位
lcd_enable(0X8a)
write_lcd(shi+0x30)
// PORTD=0X8b //温度的个位
lcd_enable(0X8b)
write_lcd(ge+0x30)
// PORTD=0X8c
lcd_enable(0X8c)
write_lcd('.')
// PORTD=0X8d //温度的十分位
lcd_enable(0X8d)
write_lcd(shifen+0x30)
// PORTD=0X8e //显示'C'
lcd_enable(0X8e)
write_lcd('C')
//
// PORTD=0XC0//年
lcd_enable(0XC0)
write_lcd((table1[6]>>4)+0x30)
//PORTD=0XC1
lcd_enable(0XC1)
write_lcd((table1[6]&0x0f)+0x30)
// PORTD=0XC2
lcd_enable(0XC2)
write_lcd('-')
// PORTD=0XC3 //月
lcd_enable(0XC3)
write_lcd((table1[4]>>4)+0x30)
// PORTD=0xC4
lcd_enable(0xC4)
write_lcd((table1[4]&0x0f)+0x30)
// PORTD=0XC5
lcd_enable(0XC5)
write_lcd('-')
// PORTD=0XC6 //日
lcd_enable(0XC6)
write_lcd((table1[3]>>4)+0x30)
// PORTD=0xC7
lcd_enable(0xC7)
write_lcd((table1[3]&0x0f)+0x30)
// PORTD=0XCD //星期
lcd_enable(0XCD)
write_lcd((table1[5]&0x0f)+0x30)
}
//--------------------------------------------
//引脚定义函数
void port_init()
{
TRISA=0x00//设置A口全输出
TRISD=0X00//设置D口全输出
ADCON1=0X06 //设置A口为普通I/O口
TRISB=0X0E//
OPTION=0X00 //开启B口弱上拉
PORTA=0XFF
PORTD=0XFF//先熄灭所有显示
lcd_init()
TRISC=0XEF//RC3输出，其他为输入
PORTC=0XEF
count=0
}
//----------------------------------------------
//主函数
void main()
{
port_init()//调用引脚初始化函数
read_ds1302(0x81)//查看DS1302是否起振
if(read_data&0x80) //否，则初始化DS1302
{
ds1302_init() //调用DS1302初始化函数
set_time() //调用设置时间函数
}
while(1)
{
get_time()//调用取时间函数
change_time()
get_temp() //调用温度转换函数
display() //调用显示函数
}
}
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