Integers need to be converted to a byte array of defined endianness to be reliably and consistently saved and transmitted, and converted back to be accurately received and read. The goal is to be as portable as possible, while maintaining concise and fast code.

#ifndef LE_h
#define LE_h
#include <stdint.h>
inline static uint16_t le16(const uint8_t b[static 2]) {
    return b[0]|(uint16_t)b[1]<<8;
}
inline static uint32_t le32(const uint8_t b[static 4]) {
    return le16(b)|(uint32_t)le16(b+2)<<16;
}
inline static uint64_t le64(const uint8_t b[static 8]) {
    return le32(b)|(uint64_t)le32(b+4)<<32;
}
inline static void le16b(uint8_t b[static 2], const uint16_t n) {
    b[0] = n;
    b[1] = n>>8;
}
inline static void le32b(uint8_t b[static 4], const uint32_t n) {
    le16b(b, n);
    le16b(b+2, n>>16);
}
inline static void le64b(uint8_t b[static 8], const uint64_t n) {
    le32b(b, n);
    le32b(b+4, n>>32);
}
#endif /* LE_h */