Files
CSE4303H4/helper.cpp
Zheyuan Wu 4627f0db5c init
2026-03-02 21:18:02 -06:00

61 lines
1.4 KiB
C++

// load environment variables from .env file
#include <fstream>
#include <cstdlib>
#include <string>
#include <cstring>
void load_env(char const* path)
{
std::ifstream f(path);
std::string line;
while (std::getline(f, line))
{
if (line.empty() || line[0] == '#')
continue;
auto pos = line.find('=');
if (pos == std::string::npos)
continue;
std::string key = line.substr(0, pos);
std::string val = line.substr(pos + 1);
#ifdef _WIN32
_putenv_s(key.c_str(), val.c_str());
#else
setenv(key.c_str(), val.c_str(), 1);
#endif
}
}
// hex to byte helper function
int hex_to_bytes_upper(const char *hex, unsigned char *out, size_t out_size)
{
size_t i = 0;
while (hex[0] && hex[1])
{
if (i >= out_size)
return -1;
unsigned char h = hex[0];
unsigned char l = hex[1];
int hi = (h <= '9') ? (h - '0') : (h - 'A' + 10);
int lo = (l <= '9') ? (l - '0') : (l - 'A' + 10);
// minimal sanity check
if (hi < 0 || hi > 15 || lo < 0 || lo > 15)
return -1;
out[i++] = (unsigned char)((hi << 4) | lo);
hex += 2;
}
return (int)i;
}
char * byte_to_hex(unsigned char *bytes, size_t len)
{
char *hex = new char[len * 2 + 1];
for (size_t i = 0; i < len; i++)
{
sprintf(hex + i * 2, "%02X", bytes[i]);
}
hex[len * 2] = '\0';
return hex;
}