test/test_seek.py

   1 """Test seeking on files.
   2 """
   3
   4 import io
   5
   6 import pytest
   7
   8 import rarfile
   9
  10 ARC = "test/files/seektest.rar"
  11
  12 _WHENCE = 0
  13
  14
  15 def do_seek(f, pos, lim, size=None):
  16     global _WHENCE
  17     ofs = pos * 4
  18     fsize = lim * 4
  19
  20     if ofs < 0:
  21         exp = 0
  22     elif ofs > fsize:
  23         exp = fsize
  24     else:
  25         exp = ofs
  26
  27     if size:
  28         cur = f.tell()
  29         if _WHENCE == 0:
  30             f.seek(ofs, _WHENCE)
  31         elif _WHENCE == 1:
  32             f.seek(ofs - cur, _WHENCE)
  33         else:
  34             assert _WHENCE == 2
  35             f.seek(ofs - size, _WHENCE)
  36         _WHENCE = (_WHENCE + 1) % 3
  37     else:
  38         f.seek(ofs)
  39
  40     got = f.tell()
  41
  42     assert got == exp
  43     ln = f.read(4)
  44     if got == fsize and ln:
  45         raise ValueError("unexpected read")
  46     if not ln and got < fsize:
  47         raise ValueError("unexpected read failure")
  48     if ln:
  49         spos = int(ln)
  50         assert spos * 4 == got
  51
  52
  53 def run_seek(rf, fn):
  54     inf = rf.getinfo(fn)
  55     cnt = int(inf.file_size / 4)
  56     f = rf.open(fn)
  57
  58     with pytest.raises(ValueError):
  59         f.seek(0, -1)
  60     with pytest.raises(ValueError):
  61         f.seek(0, 3)
  62
  63     do_seek(f, int(cnt / 2), cnt)
  64     do_seek(f, 0, cnt)
  65
  66     for i in range(int(cnt / 2)):
  67         do_seek(f, i * 2, cnt, inf.file_size)
  68
  69     for i in range(cnt):
  70         do_seek(f, i * 2 - int(cnt / 2), cnt, inf.file_size)
  71
  72     for i in range(cnt + 10):
  73         do_seek(f, cnt - i - 5, cnt, inf.file_size)
  74
  75     f.close()
  76
  77
  78 def run_arc(arc, desc):
  79     files = ["stest1.txt", "stest2.txt"]
  80     rf = rarfile.RarFile(arc)
  81     for fn in files:
  82         run_seek(rf, fn)
  83
  84
  85 def test_seek_filename():
  86     run_arc(ARC, "fn")
  87
  88
  89 def test_seek_bytesio():
  90     # filelike: io.BytesIO, io.open()
  91     with open(ARC, "rb") as f:
  92         data = f.read()
  93     run_arc(io.BytesIO(data), "io.BytesIO")
  94
  95
  96 def test_seek_open():
  97     # filelike: file()
  98     with open(ARC, "rb") as f:
  99         run_arc(f, "open")
 100
 101
 102 def test_seek_ioopen():
 103     # filelike: io.open()
 104     with io.open(ARC, "rb") as f:
 105         run_arc(f, "io.open")
 106