diff options
Diffstat (limited to 'libgo/go/io/ioutil/ioutil.go')
-rw-r--r-- | libgo/go/io/ioutil/ioutil.go | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/libgo/go/io/ioutil/ioutil.go b/libgo/go/io/ioutil/ioutil.go new file mode 100644 index 000000000..fb3fdcda1 --- /dev/null +++ b/libgo/go/io/ioutil/ioutil.go @@ -0,0 +1,90 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Utility functions. + +package ioutil + +import ( + "bytes" + "io" + "os" + "sort" +) + +// ReadAll reads from r until an error or EOF and returns the data it read. +func ReadAll(r io.Reader) ([]byte, os.Error) { + var buf bytes.Buffer + _, err := io.Copy(&buf, r) + return buf.Bytes(), err +} + +// ReadFile reads the file named by filename and returns the contents. +func ReadFile(filename string) ([]byte, os.Error) { + f, err := os.Open(filename, os.O_RDONLY, 0) + if err != nil { + return nil, err + } + defer f.Close() + // It's a good but not certain bet that FileInfo will tell us exactly how much to + // read, so let's try it but be prepared for the answer to be wrong. + fi, err := f.Stat() + var n int64 + if err == nil && fi.Size < 2e9 { // Don't preallocate a huge buffer, just in case. + n = fi.Size + } + // Add a little extra in case Size is zero, and to avoid another allocation after + // Read has filled the buffer. + n += bytes.MinRead + // Pre-allocate the correct size of buffer, then set its size to zero. The + // Buffer will read into the allocated space cheaply. If the size was wrong, + // we'll either waste some space off the end or reallocate as needed, but + // in the overwhelmingly common case we'll get it just right. + buf := bytes.NewBuffer(make([]byte, 0, n)) + _, err = buf.ReadFrom(f) + return buf.Bytes(), err +} + +// WriteFile writes data to a file named by filename. +// If the file does not exist, WriteFile creates it with permissions perm; +// otherwise WriteFile truncates it before writing. +func WriteFile(filename string, data []byte, perm uint32) os.Error { + f, err := os.Open(filename, os.O_WRONLY|os.O_CREAT|os.O_TRUNC, perm) + if err != nil { + return err + } + n, err := f.Write(data) + f.Close() + if err == nil && n < len(data) { + err = io.ErrShortWrite + } + return err +} + +// A dirList implements sort.Interface. +type fileInfoList []*os.FileInfo + +func (f fileInfoList) Len() int { return len(f) } +func (f fileInfoList) Less(i, j int) bool { return f[i].Name < f[j].Name } +func (f fileInfoList) Swap(i, j int) { f[i], f[j] = f[j], f[i] } + +// ReadDir reads the directory named by dirname and returns +// a list of sorted directory entries. +func ReadDir(dirname string) ([]*os.FileInfo, os.Error) { + f, err := os.Open(dirname, os.O_RDONLY, 0) + if err != nil { + return nil, err + } + list, err := f.Readdir(-1) + f.Close() + if err != nil { + return nil, err + } + fi := make(fileInfoList, len(list)) + for i := range list { + fi[i] = &list[i] + } + sort.Sort(fi) + return fi, nil +} |