Qt下QByteArray的使用

今天遇到一个问题，想要实现一种功能：在QLineEdit中书写16进制字符串比如 00 01 ff，然后保存为16进制转换后的字节形式到内存中，然后在文件中进行查找字符串匹配，后来发现QByteArray QByteArray::fromHex(const QByteArray & hexEncoded)函数可以实现这个功能。

QByteArray QByteArray::fromHex(const QByteArray & hexEncoded)
Returns a decoded copy of the hex encoded array hexEncoded. Input is not checked for validity; invalid characters in the input are skipped, enabling the decoding process to continue with subsequent characters.

For example:

QByteArray text = QByteArray::fromHex("517420697320677265617421");
text.data();            // returns "Qt is great!"

---

对于字符串匹配查找方面，我用的是泛型函数库algorithm中的search函数：
具体用法请到:http://www.cplusplus.com中查询，这里只给出例子:

// search algorithm example
#include      // std::cout
#include     // std::search
#include        // std::vector

bool mypredicate (int i, int j) {
  return (i==j);
}

int main () {
  std::vector<int> haystack;

  // set some values:        haystack: 10 20 30 40 50 60 70 80 90
  for (int i=1; i<10; i++) haystack.push_back(i*10);

  // using default comparison:
  int needle1[] = {40,50,60,70};
  std::vector<int>::iterator it;
  it = std::search (haystack.begin(), haystack.end(), needle1, needle1+4);

  if (it!=haystack.end())
    std::cout << "needle1 found at position " << (it-haystack.begin()) << '\n';
  else
    std::cout << "needle1 not found\n";

  // using predicate comparison:
  int needle2[] = {20,30,50};
  it = std::search (haystack.begin(), haystack.end(), needle2, needle2+3, mypredicate);

  if (it!=haystack.end())
    std::cout << "needle2 found at position " << (it-haystack.begin()) << '\n';
  else
    std::cout << "needle2 not found\n";

  return 0;
}

Output:
needle1 found at position 3
needle2 not found