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package azblob
import (
"errors"
"fmt"
"io"
"strconv"
)
// httpRange defines a range of bytes within an HTTP resource, starting at offset and
// ending at offset+count. A zero-value httpRange indicates the entire resource. An httpRange
// which has an offset but na zero value count indicates from the offset to the resource's end.
type httpRange struct {
offset int64
count int64
}
func (r httpRange) pointers() *string {
if r.offset == 0 && r.count == CountToEnd { // Do common case first for performance
return nil // No specified range
}
endOffset := "" // if count == CountToEnd (0)
if r.count > 0 {
endOffset = strconv.FormatInt((r.offset+r.count)-1, 10)
}
dataRange := fmt.Sprintf("bytes=%v-%s", r.offset, endOffset)
return &dataRange
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
func validateSeekableStreamAt0AndGetCount(body io.ReadSeeker) (int64, error) {
if body == nil { // nil body's are "logically" seekable to 0 and are 0 bytes long
return 0, nil
}
err := validateSeekableStreamAt0(body)
if err != nil {
return 0, err
}
count, err := body.Seek(0, io.SeekEnd)
if err != nil {
return 0, errors.New("body stream must be seekable")
}
body.Seek(0, io.SeekStart)
return count, nil
}
// return an error if body is not a valid seekable stream at 0
func validateSeekableStreamAt0(body io.ReadSeeker) error {
if body == nil { // nil body's are "logically" seekable to 0
return nil
}
if pos, err := body.Seek(0, io.SeekCurrent); pos != 0 || err != nil {
// Help detect programmer error
if err != nil {
return errors.New("body stream must be seekable")
}
return errors.New("body stream must be set to position 0")
}
return nil
}
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