variable length quantity

vlq.h

#pragma once
#include <stdint.h>
#include <array.h>

// read variable length quantity
uint32_t _vlq_read(const uint8_t *&out) {
  uint32_t val = 0;
  for (;;) {
    const uint8_t c = *(out++);
    val = (val << 7) | (c & 0x7f);
    if ((c & 0x80) == 0) {
      break;
    }
  }
  return val;
}

// write variable length quantity
void _vlq_write(uint8_t *&out, uint32_t val) {
  std::array<uint8_t, 16> data;
  int32_t i = 0;
  for (; val; ++i) {
    data[i] = val & 0x7f;
    val >>= 7;
  }
  do {
    --i;
    *(out++) = data[i] | (i ? 0x80 : 0x00);
  } while (i > 0);
}