mirror of
https://github.com/Binject/debug
synced 2026-06-08 10:28:33 +00:00
Brad Fitzpatrick
ae710b60a7
This is a subset of https://golang.org/cl/20022 with only the copyright header lines, so the next CL will be smaller and more reviewable. Go policy has been single space after periods in comments for some time. The copyright header template at: https://golang.org/doc/contribute.html#copyright also uses a single space. Make them all consistent. Change-Id: Icc26c6b8495c3820da6b171ca96a74701b4a01b0 Reviewed-on: https://go-review.googlesource.com/20111 Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
109 lines
2.1 KiB
Go
109 lines
2.1 KiB
Go
// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package elf
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import (
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"io"
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"os"
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)
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// errorReader returns error from all operations.
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type errorReader struct {
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error
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}
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func (r errorReader) Read(p []byte) (n int, err error) {
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return 0, r.error
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}
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func (r errorReader) ReadAt(p []byte, off int64) (n int, err error) {
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return 0, r.error
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}
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func (r errorReader) Seek(offset int64, whence int) (int64, error) {
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return 0, r.error
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}
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func (r errorReader) Close() error {
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return r.error
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}
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// readSeekerFromReader converts an io.Reader into an io.ReadSeeker.
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// In general Seek may not be efficient, but it is optimized for
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// common cases such as seeking to the end to find the length of the
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// data.
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type readSeekerFromReader struct {
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reset func() (io.Reader, error)
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r io.Reader
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size int64
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offset int64
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}
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func (r *readSeekerFromReader) start() {
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x, err := r.reset()
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if err != nil {
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r.r = errorReader{err}
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} else {
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r.r = x
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}
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r.offset = 0
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}
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func (r *readSeekerFromReader) Read(p []byte) (n int, err error) {
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if r.r == nil {
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r.start()
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}
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n, err = r.r.Read(p)
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r.offset += int64(n)
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return n, err
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}
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func (r *readSeekerFromReader) Seek(offset int64, whence int) (int64, error) {
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var newOffset int64
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switch whence {
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case 0:
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newOffset = offset
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case 1:
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newOffset = r.offset + offset
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case 2:
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newOffset = r.size + offset
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default:
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return 0, os.ErrInvalid
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}
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switch {
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case newOffset == r.offset:
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return newOffset, nil
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case newOffset < 0, newOffset > r.size:
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return 0, os.ErrInvalid
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case newOffset == 0:
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r.r = nil
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case newOffset == r.size:
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r.r = errorReader{io.EOF}
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default:
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if newOffset < r.offset {
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// Restart at the beginning.
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r.start()
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}
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// Read until we reach offset.
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var buf [512]byte
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for r.offset < newOffset {
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b := buf[:]
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if newOffset-r.offset < int64(len(buf)) {
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b = buf[:newOffset-r.offset]
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}
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if _, err := r.Read(b); err != nil {
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return 0, err
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}
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}
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}
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r.offset = newOffset
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return r.offset, nil
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}
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