esp8266_milight_hub/lib/Helpers/IntParsing.h

#ifndef _INTPARSING_H
#define _INTPARSING_H

#include <Arduino.h>

template <typename T>
const T strToHex(const char* s, size_t length) {
  T value = 0;
  T base = 1;
  
  for (int i = length-1; i >= 0; i--) {
    const char c = s[i];
    
    if (c >= '0' && c <= '9') {
      value += ((c - '0') * base);
    } else if (c >= 'a' && c <= 'f') {
      value += ((c - 'a' + 10) * base);
    } else if (c >= 'A' && c <= 'F') {
      value += ((c - 'A' + 10) * base);
    } else {
      break;
    }
    
    base <<= 4;
  }
  
  return value;
}

template <typename T>
const T strToHex(const String& s) {
  return strToHex<T>(s.c_str(), s.length());
}

template <typename T>
const T parseInt(const String& s) {
  if (s.startsWith("0x")) {
    return strToHex<T>(s.substring(2));
  } else {
    return s.toInt();
  }
}

template <typename T>
void hexStrToBytes(const char* s, const size_t sLen, T* buffer, size_t maxLen) {
  int idx = 0;
  
  for (int i = 0; i < sLen && idx < maxLen; ) {
    buffer[idx++] = strToHex<T>(s+i, 2);
    i+= 2;
    
    while (i < (sLen - 1) && s[i] == ' ') {
      i++;
    }
  }
}

#endif