68 lines
1.5 KiB
C++
68 lines
1.5 KiB
C++
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#include "StringHelper.hpp"
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namespace YYCC::StringHelper {
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bool Printf(std::string& strl, const char* format, ...) {
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va_list argptr;
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va_start(argptr, format);
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bool ret = VPrintf(strl, format, argptr);
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va_end(argptr);
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return ret;
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}
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bool VPrintf(std::string& strl, const char* format, va_list argptr) {
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va_list args1;
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va_copy(args1, argptr);
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va_list args2;
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va_copy(args2, argptr);
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// the return value is desired char count without NULL terminal.
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// minus number means error
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int count = std::vsnprintf(nullptr, 0, format, args1);
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if (count < 0) {
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// invalid length returned by vsnprintf.
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return false;
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}
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va_end(args1);
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// resize std::string to desired count.
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// and pass its length + 1 to std::vsnprintf,
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// because std::vsnprintf only can write "buf_size - 1" chars with a trailing NULL.
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// however std::vsnprintf already have a trailing NULL, so we plus 1 for it.
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strl.resize(count);
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int write_result = std::vsnprintf(strl.data(), strl.size() + 1, format, args2);
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va_end(args2);
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if (write_result < 0 || write_result > count) {
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// invalid write result in vsnprintf.
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return false;
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}
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return true;
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}
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std::string Printf(const char* format, ...) {
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std::string ret;
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va_list argptr;
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va_start(argptr, format);
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VPrintf(ret, format, argptr);
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va_end(argptr);
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return ret;
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}
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std::string VPrintf(const char* format, va_list argptr) {
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std::string ret;
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va_list argcpy;
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va_copy(argcpy, argptr);
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VPrintf(ret, format, argcpy);
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va_end(argcpy);
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return ret;
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}
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}
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