1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157

use crate::*;
use rs_alloc::*;

pub struct MemoryStreamWriter {
    data    : Vec<u8>,
    cursor  : usize,
}

impl MemoryStreamWriter {
    pub fn new() -> Self {
        Self { data: Vec::new(), cursor: 0 }
    }

    pub fn data(&self) -> &Vec<u8> { &self.data }
    pub fn data_mut(&mut self) -> &mut Vec<u8> { &mut self.data }
}

impl Drop for MemoryStreamWriter {
    fn drop(&mut self) {}
}

impl Stream for MemoryStreamWriter {
    fn tell(&self) -> usize { self.cursor }
    fn size(&self) -> usize { self.data.len() }
}

impl StreamWriter for MemoryStreamWriter {
    fn write(&mut self, buff: &[u8]) -> Result<usize, ()> {
        let available   = self.data.len() - self.cursor;
        let remaining   = if buff.len() < available { 0 } else { buff.len() - available };
        let first       = usize::min(available, buff.len());

        for i in 0..first {
            self.data[self.cursor + i] = buff[i];
        }
        for i in 0..remaining {
            self.data.push(buff[first + i]);
        }
        self.cursor += buff.len();
        Ok(buff.len())
    }
}

impl StreamSeek for MemoryStreamWriter {
    fn seek(&mut self, cursor: usize) -> Result<usize, ()> {
        if self.data.len() < cursor {
            self.cursor = self.data.len();
        } else {
            self.cursor = cursor;
        }
        Ok(self.cursor)
    }
}

pub struct MemoryStreamReader {
    data    : Vec<u8>,
    cursor  : usize,
}

impl MemoryStreamReader {
    pub fn from(src: &[u8]) -> Self {
        let mut v = Vec::new();
        v.append(src);
        Self { data : v, cursor: 0 }
    }
}

impl Stream for MemoryStreamReader {
    fn tell(&self) -> usize { self.cursor }
    fn size(&self) -> usize { self.data.len() }
}

impl Drop for MemoryStreamReader {
    fn drop(&mut self) {}
}

impl StreamReader for MemoryStreamReader {
    fn is_eof(&self) -> bool { self.cursor == self.data.len() }
    fn read(&mut self, buff: &mut [u8]) -> Result<usize, ()> {
        let read_len =
            if buff.len() > self.data.len() - self.cursor {
                self.data.len() - self.cursor
            } else {
                buff.len()
            };
        for c in 0..read_len {
            buff[c] = self.data[self.cursor + c];
        }
        self.cursor += read_len;
        Ok(read_len)
    }
}

impl StreamSeek for MemoryStreamReader {
    fn seek(&mut self, cursor: usize) -> Result<usize, ()> {
        if self.data.len() < cursor {
            self.cursor = self.data.len();
        } else {
            self.cursor = cursor;
        }
        Ok(self.cursor)
    }
}

///////////////////////////////////////////////////////////////////////////////
#[cfg(test)]
mod tests {
    use super::*;
    #[test]
    fn test_memory_write_stream() {
        let mut msw = MemoryStreamWriter::new();
        let string = "hello world".as_bytes();
        assert!(msw.write(string) == Result::Ok(11));
        assert!(msw.tell() == 11);
        assert!(msw.size() == 11);
        let data = msw.data().as_slice();
        assert!(data.len() == 11);
        for i in 0..string.len() {
            assert!(data[i] == string[i]);
        }
        assert!(msw.seek(5) == Result::Ok(5));
        assert!(msw.write("1234".as_bytes()) == Result::Ok(4));
        assert!(msw.tell() == 9);
        let string = "hello1234ld".as_bytes();
        let data = msw.data().as_slice();
        assert!(data.len() == 11);
        for i in 0..string.len() {
            assert!(data[i] == string[i]);
        }
        assert!(msw.seek(14) == Result::Ok(11));
    }

    #[test]
    fn test_memory_read_stream() {
        let mut msr = MemoryStreamReader::from("hello world".as_bytes());
        assert!(msr.tell() == 0);
        assert!(msr.size() == 11);
        let string = "hello world".as_bytes();
        let mut buff = [0u8; 11];
        assert!(msr.read(&mut buff) == Result::Ok(11));
        for i in 0..string.len() {
            assert!(buff[i] == string[i]);
        }
        assert!(msr.seek(5) == Result::Ok(5));

        let mut buff = [0u8; 4];
        assert!(msr.read(&mut buff) == Result::Ok(4));
        assert!(msr.tell() == 9);
        let string = " wor".as_bytes();
        for i in 0..string.len() {
            assert!(buff[i] == string[i]);
        }
        assert!(msr.seek(14) == Result::Ok(11));

        assert!("0.1234".parse::<f32>().unwrap() == 0.1234_f32);
    }
}