Function UnsignedLeb128Size

Bcore/src/main/cpp/base/leb128.h:201–208

Returns the number of bytes needed to encode the value in unsigned LEB128.

// Returns the number of bytes needed to encode the value in unsigned LEB128.
static inline uint32_t UnsignedLeb128Size(uint32_t data) {
  // bits_to_encode = (data != 0) ? 32 - CLZ(x) : 1  // 32 - CLZ(data | 1)
  // bytes = ceil(bits_to_encode / 7.0);             // (6 + bits_to_encode) / 7
  uint32_t x = 6 + 32 - CLZ(data | 1U);
  // Division by 7 is done by (x * 37) >> 8 where 37 = ceil(256 / 7).
  // This works for 0 <= x < 256 / (7 * 37 - 256), i.e. 0 <= x <= 85.
  return (x * 37) >> 8;
}

static inline bool IsLeb128Terminator(const uint8_t* ptr) {
  return *ptr <= 0x7f;