Please explain this code for fast input.

[Knightrider29]

The code is too large, so I'm posting the link.
http://www.codechef.com/viewsolution/1553773

Please explain the code outside int main() i.e class Fastinput line-by-line, if possible or mention any website/link to go through. (:

[mutexe]

The code is too large

You might get some more replies if you ask more specific questions and maybe post some small code segments in here.

[Knightrider29]

Okay mutexe (:
Plz explain the code after defining the terms like dataOffset, buffer, uint32_t etc. (assuming that they are commonly used terms)

public:
        size_t m_dataOffset;
        FastInput() {
                        m_dataOffset = 0;
                        m_dataSize = 0;
                        m_v = 0x80000000;
                }
                uint32_t ReadNext() {
                        if (m_dataOffset == m_dataSize) {
                                int r = read(0, m_buffer, sizeof(m_buffer));
                                if (r <= 0) return m_v;
                                m_dataOffset = 0;
                                m_dataSize = 0;
                                int i = 0;
                                if (m_buffer[0] < '0') {
                                        if (m_v != 0x80000000) {
                                                m_data[m_dataSize++] = m_v;
                                                m_v = 0x80000000;
                                        }
                                        for (; (i < r) && (m_buffer[i] < '0'); ++i);
                                }
                                for (; i < r;) {
                                        if (m_buffer[i] >= '0') {
                                                m_v = m_v * 10 + m_buffer[i] - 48;
                                                ++i;
                                        } else {
                                                m_data[m_dataSize++] = m_v;
                                                m_v = 0x80000000;
                                                for (i = i + 1; (i < r) && (m_buffer[i] < '0'); ++i);
                                        }
                                }
                        }
                        return m_data[m_dataOffset++];
                }

[mutexe]

ReadNext() returns an unsigned long integer:
http://www.nongnu.org/avr-libc/user-manual/group__avr__stdint.html

it looks like it's reading data from a socket? (line 10), then it seems to be populating your m_v variable from the newly populated buffer.