varint.c

char *enc_varint(char *dest, uint32_t source) {
  for(; source >= 0x80; dest++, source >>= 7) {
    *dest = 0x80 | (source & 0x7F);
  }
  *dest = source & 0x7F;
  return ++dest;
}

char *dec_varint(int32_t *dest, char *source) {
  for(; *(unsigned char *) source & 0x80; source++, *(uint32_t *) dest <<= 7) {
    *(uint32_t *) dest |= *source & 0x7F;
  }
  *(uint32_t *) dest |= *source & 0x7F;
  return ++source;
}