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writebuffer.go
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writebuffer.go
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package bacc
import "io"
type writeBuffer struct {
offset int64
writer io.WriterAt
buffer [1024]byte
marker int64
}
func newWriteBuffer(writer io.WriterAt) *writeBuffer {
return &writeBuffer{offset: 0, writer: writer, marker: 0}
}
func (wb *writeBuffer) mark() {
wb.marker = wb.offset
}
func (wb *writeBuffer) writtenSinceMarker() int64 {
return wb.offset - wb.marker
}
func (wb *writeBuffer) skip(bytes int64) {
wb.offset += bytes
}
func (wb *writeBuffer) Write(p []byte) (n int, err error) {
n, err = wb.writer.WriteAt(p, wb.offset)
if err != nil {
return
}
wb.offset += int64(n)
return
}
func (wb *writeBuffer) writeUint8(value uint8) (n int, err error) {
wb.buffer[0] = value
n, err = wb.writer.WriteAt(wb.buffer[:1], wb.offset)
if err != nil {
return
}
wb.offset++
return
}
func (wb *writeBuffer) writeUint16(value uint16) (n int, err error) {
wb.buffer[0] = byte(value >> 8)
wb.buffer[1] = byte(value)
n, err = wb.writer.WriteAt(wb.buffer[:2], wb.offset)
if err != nil {
return
}
wb.offset += 2
return
}
func (wb *writeBuffer) writeUint24(value uint32) (n int, err error) {
wb.buffer[0] = byte(value >> 16)
wb.buffer[1] = byte(value >> 8)
wb.buffer[2] = byte(value)
n, err = wb.writer.WriteAt(wb.buffer[:3], wb.offset)
if err != nil {
return
}
wb.offset += 3
return
}
func (wb *writeBuffer) writeUint32(value uint32) (n int, err error) {
wb.buffer[0] = byte(value >> 24)
wb.buffer[1] = byte(value >> 16)
wb.buffer[2] = byte(value >> 8)
wb.buffer[3] = byte(value)
n, err = wb.writer.WriteAt(wb.buffer[:4], wb.offset)
if err != nil {
return
}
wb.offset += 4
return
}
func (wb *writeBuffer) writeUint64(value uint64) (n int, err error) {
wb.buffer[0] = byte(value >> 56)
wb.buffer[1] = byte(value >> 48)
wb.buffer[2] = byte(value >> 40)
wb.buffer[3] = byte(value >> 32)
wb.buffer[4] = byte(value >> 24)
wb.buffer[5] = byte(value >> 16)
wb.buffer[6] = byte(value >> 8)
wb.buffer[7] = byte(value)
n, err = wb.writer.WriteAt(wb.buffer[:8], wb.offset)
if err != nil {
return
}
wb.offset += 8
return
}
func (wb *writeBuffer) writeUtf8(value string) (n int, err error) {
data := []byte(value)
wb.buffer[0] = 0x00
written := 0
n, err = wb.writer.WriteAt(data, wb.offset)
if err != nil {
return
}
written += n
wb.offset += int64(len(data))
wb.writer.WriteAt(wb.buffer[:1], wb.offset)
if err != nil {
return
}
written += n
n = written
wb.offset++
return
}