#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <assert.h>
#include <inttypes.h>

typedef unsigned int uint_t;

class RawReader
{
	static const uint_t RBUF_SIZE = 8192;
	char rbuf[RBUF_SIZE];

	char *rlim, *rpos;
	int rrlen, reof;

	char* read_more(char *rpos)
	{
		int l, s, t;
		char *p;

		if (reof)
			return rpos;

		l = rrlen - (rpos - rbuf);
		if (rpos != rbuf)
			memmove(rbuf, rpos, l);
		rpos = rbuf;
		p = rbuf + l;
		t = sizeof(rbuf) - l;
		s = read(0, p, t);
		if (s < 0)
			s = 0;
		rrlen = l + s;
		rlim = rpos + rrlen;
		if (s <= 0) {
			reof = 1;
		}

		return rpos;
	}

 public:
	void init(void)
	{
		rrlen = 0;
		reof = 0;
		rlim = rbuf;
		rpos = rbuf;
	}

	inline int rnextf() { return *rpos++; }

	inline int rnext()
	{
		if (rlim - rpos <= 0)
			rpos = read_more(rpos);
		return (rlim - rpos > 0) ? rnextf() : -1;
	}

	inline uint32_t getu32()
	{
		if (rlim - rpos < 12)
			rpos = read_more(rpos);

		uint32_t v;
		do {
			v = rnextf() - '0';
		} while (v >= 10);

		uint32_t res = v;

		for (;;) {
			v = rnextf() - '0';
			if (v >= 10)
				break;
			res = res * 10 + v;
		}

		return res;
	}

};

Raw Reader with uint32_t parsing

C++