bzip2file stream for reading

tests/.gitignore

@@ -1,2 +1,5 @@
 nimcache
-ziptests
+ziptests
+zlibtests
+gziptests
+bzip2tests

tests/bzip2tests.nim

@@ -0,0 +1,18 @@
+import os, ../zip/bzip2files
+
+proc readAllAndClose(f: Stream): string =
+  doAssert(not f.isNil, "error opening stream")
+  shallowCopy result, f.readAll()
+  f.close()
+
+const path = currentSourcePath().splitPath().head
+
+proc main() =
+  # reference text data
+  let text = newFileStream(path / "files/gzipfiletest.txt").readAllAndClose()
+  # reference BZIP2 archive (made with bzip2: stable 1.0.6 on OSX)
+  let arch_bz2 = newBz2FileStream(path / "files/gzipfiletest.txt.bz2").readAllAndClose()
+
+  doAssert(arch_bz2 == text)
+
+main()

zip.nimble

@@ -11,8 +11,13 @@ skipDirs = @["tests"]
 
 requires "nim >= 0.10.0"
 
+when defined(nimdistros):
+  import distros
+  foreignDep "bzip2"
+
 task tests, "Run lib tests":
   withDir "tests":
     exec "nim c -r ziptests"
     exec "nim c -r zlibtests"
     exec "nim c -r gziptests"
+    exec "nim c -r bzip2tests"

zip/bzip2.nim

@@ -0,0 +1,25 @@
+when defined(windows):
+  const libbz2 = "bzip2.dll"
+elif defined(macosx):
+  const libbz2 = "libbz2.dylib"
+else:
+  const libbz2 = "libbz2.so.1"
+
+type
+  Pbytef* = cstring
+  Bz2File* = pointer
+
+proc bz2libVersion*(): cstring {.cdecl, dynlib: libbz2,
+  importc: "BZ2_bzlibVersion".}
+
+proc bz2open*(path: cstring, mode: cstring): Bz2File {.cdecl, dynlib: libbz2,
+  importc: "BZ2_bzopen".}
+
+proc bz2read*(thefile: Bz2File, buf: pointer, length: int): int32 {.cdecl,
+  dynlib: libbz2, importc: "BZ2_bzread".}
+
+proc bz2close*(thefile: Bz2File): int32 {.cdecl, dynlib: libbz2,
+  importc: "BZ2_bzclose".}
+
+proc bz2error*(thefile: Bz2File, errnum: var int32): Pbytef {.cdecl,
+  dynlib: libbz2, importc: "BZ2_bzerror".}

zip/bzip2files.nim

@@ -0,0 +1,37 @@
+import os
+import bzip2
+import streams
+export streams
+
+## This module implements a bzip2file stream for reading.
+
+type
+  Bz2FileStream* = ref object of Stream
+    mode: FileMode
+    f: Bz2File
+
+proc fsClose(s: Stream) =
+  if not Bz2FileStream(s).f.isNil:
+    discard bz2close(Bz2FileStream(s).f)
+    Bz2FileStream(s).f = nil
+
+proc fsReadData(s: Stream, buffer: pointer, bufLen: int): int =
+  result = bz2read(Bz2FileStream(s).f, buffer, bufLen).int
+  if result == -1:
+    raise newException(IOError, "cannot read from stream!")
+
+proc newBz2FileStream*(filename: string, mode=fmRead): Bz2FileStream =
+  ## Opens a Bz2file as a file stream. `mode` can only be ``fmRead``.
+  new(result)
+  case mode
+  of fmRead: result.f = bz2open(filename, "rb")
+  else: raise newException(IOError, "unsupported file mode '" & $mode &
+                          "' for Bz2FileStream!")
+  if result.f.isNil:
+    let err = osLastError()
+    if err != OSErrorCode(0'i32):
+      raiseOSError(err)
+
+  result.mode = mode
+  result.closeImpl = fsClose
+  result.readDataImpl = fsReadData