简单的算法代码：
#include <iostream>
#include <string>
std::string::size_type GetLengthWithUTF(std::string &sValue);
int main()
{
std::string sTestValueUTF8 = "\xD0\xB6\xD0\xB6\xD0\xB6";
std::string sTestValueASCII = "\x67\x67\x67";
std::string sTestValueMIX = "\x67\x67\x67\xD0\xB6\xD0\xB6\xD0\xB6";
std::string::size_type iFuncResult = 0;
std::cout << "=========== START TEST ==========\n\n";
std::cout << "+TEST UTF8 STRING\n";
std::cout << "+----+Bytes of string (sTestValueUTF8.length()) = " << sTestValueUTF8.length() << "\n";
iFuncResult = GetLengthWithUTF(sTestValueUTF8);
std::cout << "+----+Function result (GetLengthWithUTF(\"" << sTestValueUTF8 << "\")) = " << iFuncResult<< "\n\n";
std::cout << "+TEST ASCII STRING\n";
std::cout << "+----+Bytes of string (sTestValueASCII.length()) = " << sTestValueASCII.length() << "\n";
iFuncResult = GetLengthWithUTF(sTestValueASCII);
std::cout << "+----+Function result (GetLengthWithUTF(\"" << sTestValueASCII << "\")) = " << iFuncResult<< "\n\n";
std::cout << "+TEST MIX STRING\n";
std::cout << "+----+Bytes of string (sTestValueMIX.length()) = " << sTestValueMIX.length() << "\n";
iFuncResult = GetLengthWithUTF(sTestValueMIX);
std::cout << "+----+Function result (GetLengthWithUTF(\"" << sTestValueMIX << "\")) = " << iFuncResult<< "\n\n";
std::cout << "\n=========== END TEST ==========\n\n";
}
std::string::size_type GetLengthWithUTF(std::string &sValue)
{
std::cout << " +----+START GetLengthWithUTF\n";
std::cout << " +Input string is: " << sValue << "\n";
std::string::size_type i;
std::cout << " +Start cycle\n";
int iCountUTF8characters = 0;
for (i = 0; i < sValue.length(); i++)
{
std::cout << " +----+Iteration N " << i << "\n";
std::cout << " +Current character is: " << sValue[i] << ", integer value = " << (int)sValue[i] << "\n";
if (sValue[i] > 127)
{
iCountUTF8characters++;
std::cout << " +----+If statement (sValue[i] > 127) is true, value of iCountUTF8characters is: " << iCountUTF8characters << "\n";
}
else
{
std::cout << " +----+If statement (sValue[i] > 127) is false.\n";
}
}
std::cout << " +End cycle\n";
iCountUTF8characters = iCountUTF8characters / 2;
std::cout << " +Return sValue.length() - (iCountUTF8characters / 2) ---> " << sValue.length() << " - (" << iCountUTF8characters << " / 2) = " << (sValue.length() - (std::string::size_type)iCountUTF8characters) <<"\n";
std::cout << " +----+ASCIID GetLengthWithUTF\n";
return (sValue.length() - (std::string::size_type)iCountUTF8characters);
}
控制台编译命令：
AIX 6
g++ -o test test.cpp
RHEL Server 6.7圣地亚哥
g++ -o test test.cpp
Microsoft Windows v10.0.14393
cl /EHsc test.cpp
结果：
AIX 6
=========== START TEST ==========
+TEST UTF8 STRING
+----+Bytes of string (sTestValueUTF8.length()) = 6
+----+START GetLengthWithUTF
+Input string is: жжж
+Start cycle
+----+Iteration N 0
+Current character is: Ь integer value = 208
+----+If statement (sValue[i] > 127) is true, value of iCountUTF8characters is: 1
+----+Iteration N 1
+Current character is: ֬ integer value = 182
+----+If statement (sValue[i] > 127) is true, value of iCountUTF8characters is: 2
+----+Iteration N 2
+Current character is: Ь integer value = 208
+----+If statement (sValue[i] > 127) is true, value of iCountUTF8characters is: 3
+----+Iteration N 3
+Current character is: ֬ integer value = 182
+----+If statement (sValue[i] > 127) is true, value of iCountUTF8characters is: 4
+----+Iteration N 4
+Current character is: Ь integer value = 208
+----+If statement (sValue[i] > 127) is true, value of iCountUTF8characters is: 5
+----+Iteration N 5
+Current character is: ֬ integer value = 182
+----+If statement (sValue[i] > 127) is true, value of iCountUTF8characters is: 6
+End cycle
+Return sValue.length() - (iCountUTF8characters / 2) ---> 6 - (3 / 2) = 3
+----+ASCIID GetLengthWithUTF
+----+Function result (GetLengthWithUTF("жжж")) = 3
+TEST ASCII STRING
+----+Bytes of string (sTestValueASCII.length()) = 3
+----+START GetLengthWithUTF
+Input string is: ggg
+Start cycle
+----+Iteration N 0
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 1
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 2
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+End cycle
+Return sValue.length() - (iCountUTF8characters / 2) ---> 3 - (0 / 2) = 3
+----+ASCIID GetLengthWithUTF
+----+Function result (GetLengthWithUTF("ggg")) = 3
+TEST MIX STRING
+----+Bytes of string (sTestValueMIX.length()) = 9
+----+START GetLengthWithUTF
+Input string is: gggжжж
+Start cycle
+----+Iteration N 0
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 1
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 2
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 3
+Current character is: Ь integer value = 208
+----+If statement (sValue[i] > 127) is true, value of iCountUTF8characters is: 1
+----+Iteration N 4
+Current character is: ֬ integer value = 182
+----+If statement (sValue[i] > 127) is true, value of iCountUTF8characters is: 2
+----+Iteration N 5
+Current character is: Ь integer value = 208
+----+If statement (sValue[i] > 127) is true, value of iCountUTF8characters is: 3
+----+Iteration N 6
+Current character is: ֬ integer value = 182
+----+If statement (sValue[i] > 127) is true, value of iCountUTF8characters is: 4
+----+Iteration N 7
+Current character is: Ь integer value = 208
+----+If statement (sValue[i] > 127) is true, value of iCountUTF8characters is: 5
+----+Iteration N 8
+Current character is: ֬ integer value = 182
+----+If statement (sValue[i] > 127) is true, value of iCountUTF8characters is: 6
+End cycle
+Return sValue.length() - (iCountUTF8characters / 2) ---> 9 - (3 / 2) = 6
+----+ASCIID GetLengthWithUTF
+----+Function result (GetLengthWithUTF("gggжжж")) = 6
=========== END TEST ==========
RHEL Server 6.7圣地亚哥
=========== START TEST ==========
+TEST UTF8 STRING
+----+Bytes of string (sTestValueUTF8.length()) = 6
+----+START GetLengthWithUTF
+Input string is: жжж
+Start cycle
+----+Iteration N 0
+Current character is: Ь integer value = -48
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 1
+Current character is: ֬ integer value = -74
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 2
+Current character is: Ь integer value = -48
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 3
+Current character is: ֬ integer value = -74
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 4
+Current character is: Ь integer value = -48
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 5
+Current character is: ֬ integer value = -74
+----+If statement (sValue[i] > 127) is false.
+End cycle
+Return sValue.length() - (iCountUTF8characters / 2) ---> 6 - (0 / 2) = 6
+----+ASCIID GetLengthWithUTF
+----+Function result (GetLengthWithUTF("жжж")) = 6
+TEST ASCII STRING
+----+Bytes of string (sTestValueASCII.length()) = 3
+----+START GetLengthWithUTF
+Input string is: ggg
+Start cycle
+----+Iteration N 0
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 1
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 2
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+End cycle
+Return sValue.length() - (iCountUTF8characters / 2) ---> 3 - (0 / 2) = 3
+----+ASCIID GetLengthWithUTF
+----+Function result (GetLengthWithUTF("ggg")) = 3
+TEST MIX STRING
+----+Bytes of string (sTestValueMIX.length()) = 9
+----+START GetLengthWithUTF
+Input string is: gggжжж
+Start cycle
+----+Iteration N 0
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 1
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 2
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 3
+Current character is: Ь integer value = -48
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 4
+Current character is: ֬ integer value = -74
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 5
+Current character is: Ь integer value = -48
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 6
+Current character is: ֬ integer value = -74
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 7
+Current character is: Ь integer value = -48
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 8
+Current character is: ֬ integer value = -74
+----+If statement (sValue[i] > 127) is false.
+End cycle
+Return sValue.length() - (iCountUTF8characters / 2) ---> 9 - (0 / 2) = 9
+----+ASCIID GetLengthWithUTF
+----+Function result (GetLengthWithUTF("gggжжж")) = 9
=========== END TEST ==========
Microsoft Windows v10.0.14393
=========== START TEST ==========
+TEST UTF8 STRING
+----+Bytes of string (sTestValueUTF8.length()) = 6
+----+START GetLengthWithUTF
+Input string is: жжж
+Start cycle
+----+Iteration N 0
+Current character is: Ь integer value = -48
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 1
+Current character is: ֬ integer value = -74
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 2
+Current character is: Ь integer value = -48
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 3
+Current character is: ֬ integer value = -74
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 4
+Current character is: Ь integer value = -48
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 5
+Current character is: ֬ integer value = -74
+----+If statement (sValue[i] > 127) is false.
+End cycle
+Return sValue.length() - (iCountUTF8characters / 2) ---> 6 - (0 / 2) = 6
+----+ASCIID GetLengthWithUTF
+----+Function result (GetLengthWithUTF("жжж")) = 6
+TEST ASCII STRING
+----+Bytes of string (sTestValueASCII.length()) = 3
+----+START GetLengthWithUTF
+Input string is: ggg
+Start cycle
+----+Iteration N 0
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 1
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 2
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+End cycle
+Return sValue.length() - (iCountUTF8characters / 2) ---> 3 - (0 / 2) = 3
+----+ASCIID GetLengthWithUTF
+----+Function result (GetLengthWithUTF("ggg")) = 3
+TEST MIX STRING
+----+Bytes of string (sTestValueMIX.length()) = 9
+----+START GetLengthWithUTF
+Input string is: gggжжж
+Start cycle
+----+Iteration N 0
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 1
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 2
+Current character is: g, integer value = 103
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 3
+Current character is: Ь integer value = -48
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 4
+Current character is: ֬ integer value = -74
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 5
+Current character is: Ь integer value = -48
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 6
+Current character is: ֬ integer value = -74
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 7
+Current character is: Ь integer value = -48
+----+If statement (sValue[i] > 127) is false.
+----+Iteration N 8
+Current character is: ֬ integer value = -74
+----+If statement (sValue[i] > 127) is false.
+End cycle
+Return sValue.length() - (iCountUTF8characters / 2) ---> 9 - (0 / 2) = 9
+----+ASCIID GetLengthWithUTF
+----+Function result (GetLengthWithUTF("gggжжж")) = 9
=========== END TEST ==========
该算法必须计算字符串中的字符数.从测试结果可以看出,它仅在AIX下可以正常工作.
如果有人帮助我理解这种荒谬的算法在不同操作系统上的行为,我将感到非常高兴.该算法是在OS AIX下创建的.从AIX迁移到LINUX之后,发现它存在问题,我进行了更广泛的测试,您所看到的结果.我的主要问题是该死的算法在AIX下如何工作.我无法以任何逻辑的方式解释它.
解决方法:
看起来这两种系统在处理字符符号的方式上有所不同,这是标准所允许的.您的AIX编译器将char视为无符号,而其他两个系统将其视为有符号.
在具有无符号字符的系统上,条件sValue [i]> 127的表现完全符合人们的预期.但是,相同的表达式在带有签名字符的系统上永远不会成功.
这就是为什么对于代码为128及以上的字符会得到负数的原因.例如,当208被视为单字节有符号值时,它变为-48.
您可以通过强制转换为无符号的或通过使用位掩码检查八位来解决此问题：
if (sValue[i] & 128) {
... // MSB is set
}