const_string_builder.h

#pragma once
 
#include "libmicroemu/types.h"
#include <cstddef>
#include <cstdint>
#include <cstring>
#include <string_view>
 
namespace libmicroemu::internal {

class ConstStringBuilder {
public:
  ConstStringBuilder(char *buf, std::size_t buf_len) : buf_(buf), buf_len_(buf_len) {}

  ConstStringBuilder &AddString(const std::string_view &str) {
    for (std::size_t i = 0U; i < str.length(); ++i) {
      if (act_pos_ >= (buf_len_ - 1U)) { // -1 due to null termination
        return *this;
      }
      buf_[act_pos_] = str[i];
      act_pos_++;
    }
    return *this;
  }
 
  ConstStringBuilder &AddChar(char ch) {
    if (act_pos_ >= (buf_len_ - 1U)) { // -1 due to null termination
      return *this;
    }
    buf_[act_pos_] = ch;
    act_pos_++;
    return *this;
  }
  ConstStringBuilder &AddInt(i32 no) {
    if (act_pos_ >= (buf_len_ - 1U)) { // -1 due to null termination
      return *this;
    }
    std::size_t left_space = buf_len_ - static_cast<size_t>(act_pos_) -
                             1U; // -1 to have enough space for null termination
 
    act_pos_ += IntToString(&buf_[act_pos_], left_space - 1U, no);
    return *this;
  }
 
  ConstStringBuilder &AddUInt(u32 no) {
    if (act_pos_ >= (buf_len_ - 1U)) { // -1 due to null termination
      return *this;
    }
    std::size_t left_space = buf_len_ - static_cast<size_t>(act_pos_) -
                             1U; // -1 to have enough space for null termination
 
    act_pos_ += UIntToString(&buf_[act_pos_], left_space - 1U, no);
    return *this;
  }
 
  ConstStringBuilder &Terminate() {
    buf_[act_pos_] = '\0';
    return *this;
  }
 
private:
  u32 IntToString(char *buf, std::size_t len, i32 number) {
    std::size_t index = 0U;
    i32 is_negative = 0;
 
    // Überprüfen, ob die Zahl negativ ist
    if (number < 0) {
      is_negative = 1;
      number = -number;
    }
 
    do {
      if (index >= len - 1U) { // -1 for minus sign
        break;
      }
      buf[index++] = (char)((number % 10) + '0');
      number /= 10;
    } while (number > 0);
 
    // Add negative sign if needed
    if (is_negative) {
      if (index < len) {
        buf[index++] = '-';
      }
    }
    ReverseString(buf, index);
    return index;
  }

  u32 UIntToString(char *buf, std::size_t len, u32 number) {
    std::size_t index = 0U;
 
    do {
      if (index >= len) {
        break;
      }
      buf[index++] = (char)((number % 10) + '0');
      number /= 10;
    } while (number > 0);
    ReverseString(buf, index);
    return index;
  }
 
  void ReverseString(char *str, size_t len) {
    std::size_t start = 0;
    std::size_t end = len - 1;
    while (start < end) {
      char temp = str[start];
      str[start] = str[end];
      str[end] = temp;
      start++;
      end--;
    }
  }
 
  u32 act_pos_{0U};
  char *buf_;
  std::size_t buf_len_;
};
 
} // namespace libmicroemu::internal