[英]Quickly convert raw data to hex string in c++
I'm reading data from a file and trying to display the raw data as 2 digit hex strings. 我正在从文件中读取数据并尝试将原始数据显示为2位十六进制字符串。
I'm using the Qt framework, specifically the QTextEdit. 我正在使用Qt框架,特别是QTextEdit。
I've tried a bunch of different approaches and have almost accomplished what I want it to do, however it has some unexpected errors I don't know anything about. 我尝试了很多不同的方法,几乎完成了我想要它做的事情,但它有一些我不知道的意外错误。
Currently this is my implementation: 目前这是我的实施:
1) Read in the data: 1)读入数据:
ifstream file (filePath, ios::in|ios::binary|ios::ate);
if (file.is_open())
{
size = file.tellg();
memblock = new char [size+1];
file.seekg(0, ios::beg);
file.read(memblock, size);
file.close();
}
2) Create a single QString that will be used (because QTextEdit requires a QString): 2)创建一个将使用的QString(因为QTextEdit需要一个QString):
QString s;
3) Loop through the array appending each successive character to the QString s. 3)循环遍历数组,将每个连续的字符附加到QString。
int count = 0;
for(i=0;i<size;i++)
{
count++;;
s.append(QString::number(memblock[i], 16).toUpper());
s.append("\t");
if (count == 16)
{
s.append("\n");
count -= 16;
}
}
Now this works fine, except when it reaches a character FF
, it appears as FFFFFFFFFFFFFFFF
现在这个工作正常,除非它到达字符
FF
,它显示为FFFFFFFFFFFFFFFF
So my main questions are: 所以我的主要问题是:
I want this implementation to be as fast as possible, so if something like sprintf could work, please let me know, as I would guess that might be faster that QString::number. 我希望这个实现尽可能快,所以如果像sprintf这样的东西可以工作,请告诉我,因为我猜想QString :: number可能会更快。
QString
can't be used for binary data. QString
不能用于二进制数据。 You should use QByteArray
instead. 你应该使用
QByteArray
。 It can be easily created from char*
buffer and can be easily converted to hex string using toHex
. 它可以很容易地从
char*
buffer创建,并且可以使用toHex
轻松转换为十六进制字符串。
QByteArray array(memblock, size);
textEdit->setText(QString(array.toHex()));
QString::number
doesn't have an overload that takes a char
, so your input is being promoted to an int
; QString::number
没有带char
的重载,所以你的输入被提升为int
; consequently you're seeing the effects of sign extension. 因此你看到了符号扩展的影响。 You should be seeing similar behavior for any input greater than
0x7F
. 您应该看到任何大于
0x7F
输入0x7F
类似的行为。
Try casting the data prior to calling the function. 在调用函数之前尝试转换数据。
s.append(QString::number(static_cast<unsigned char>(memblock[i]), 16).toUpper());
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