fixed_string.hpp

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// nros-cpp: FixedString — fixed-capacity null-terminated string
// Freestanding C++14 — no exceptions, no STL required
//
// Memory layout is repr(C) compatible: identical to char[N].
// Used by codegen-generated message structs for string fields.
 
#ifndef NROS_CPP_FIXED_STRING_HPP
#define NROS_CPP_FIXED_STRING_HPP
 
#include <cstddef>
#include <string.h>
 
namespace nros {
 
template <size_t N> struct FixedString {
    char data[N];
 
    FixedString() { data[0] = '\0'; }
 
    FixedString& operator=(const char* s) {
        if (s == nullptr) {
            data[0] = '\0';
            return *this;
        }
        size_t i = 0;
        for (; i < N - 1 && s[i] != '\0'; ++i) {
            data[i] = s[i];
        }
        data[i] = '\0';
        return *this;
    }
 
    const char* c_str() const { return data; }
 
    size_t length() const {
        size_t len = 0;
        while (len < N && data[len] != '\0')
            ++len;
        return len;
    }
 
    static constexpr size_t capacity() { return N - 1; }
 
    bool operator==(const char* s) const {
        if (s == nullptr) return data[0] == '\0';
        return strncmp(data, s, N) == 0;
    }
 
    bool operator!=(const char* s) const { return !(*this == s); }
};
 
} // namespace nros
 
#endif // NROS_CPP_FIXED_STRING_HPP