ics - unfolder.go

     1  package ics
     2  
     3  import (
     4  	"bytes"
     5  	"io"
     6  )
     7  
     8  type unfolder struct {
     9  	r      io.Reader
    10  	bufLen int
    11  	buf    [2]byte
    12  }
    13  
    14  func (u *unfolder) Read(p []byte) (int, error) {
    15  	var (
    16  		m, n int
    17  		err  error
    18  	)
    19  	q := p
    20  	if u.bufLen > 0 {
    21  		n = copy(p, u.buf[:u.bufLen])
    22  		if n > 0 {
    23  			u.buf[0] = u.buf[1]
    24  			u.bufLen -= n
    25  			p = p[n:]
    26  			m += n
    27  		}
    28  	}
    29  	for len(p) > 0 && err == nil {
    30  		n, err = u.r.Read(p)
    31  		m += n
    32  		p = p[:n]
    33  		var toRead int
    34  		for {
    35  			pos := bytes.Index(p, eol[:])
    36  			if pos == -1 {
    37  				break
    38  			}
    39  			copy(p[pos:], p[pos+3:])
    40  			p = p[pos:]
    41  			toRead += 3
    42  		}
    43  		p = p[len(p)-toRead:]
    44  		m -= toRead
    45  	}
    46  	q = q[:m]
    47  	for err == nil {
    48  		if lq := len(q); lq > 0 && q[lq-1] == '\r' {
    49  			u.bufLen, err = u.r.Read(u.buf[:])
    50  			if u.bufLen < 2 {
    51  				break
    52  			}
    53  			if u.buf[0] == '\n' && u.buf[1] == ' ' {
    54  				m--
    55  				if err == nil {
    56  					n, err = u.r.Read(q[lq-1:])
    57  					m += n
    58  					u.bufLen = 0
    59  				}
    60  			} else {
    61  				break
    62  			}
    63  		} else if lq > 1 && q[lq-2] == '\r' && q[lq-1] == '\n' {
    64  			u.bufLen, err = u.r.Read(u.buf[:1])
    65  			if u.bufLen < 1 {
    66  				break
    67  			}
    68  			if u.buf[0] == ' ' {
    69  				m -= 2
    70  				if err == nil {
    71  					n, err = u.Read(q[lq-2:])
    72  					m += n
    73  					u.bufLen = 0
    74  				}
    75  			} else {
    76  				break
    77  			}
    78  		} else {
    79  			break
    80  		}
    81  	}
    82  	return m, err
    83  }