103 lines
2.2 KiB
Go
103 lines
2.2 KiB
Go
// Copyright (c) 2024-2026 Celestino Amoroso (celestino.amoroso@gmail.com).
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// All rights reserved.
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// builtin-os-file.go
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package expr
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import (
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"git.portale-stac.it/go-pkg/expr/file"
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"git.portale-stac.it/go-pkg/expr/kern"
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)
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const fileByteIteratorType = "fileByteIterator"
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type fileFileByteIterator struct {
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fileIterBase
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b byte
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}
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func newFileByteIterator(r *file.Reader, autoClose bool) *fileFileByteIterator {
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return &fileFileByteIterator{
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fileIterBase: fileIterBase{reader: r, index: -1, count: 0, autoClose: autoClose},
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b: 0}
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}
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func (it *fileFileByteIterator) TypeName() string {
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return fileByteIteratorType
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}
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func (it *fileFileByteIterator) String() string {
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return it.repr(fileByteIteratorType)
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}
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func (it *fileFileByteIterator) Next() (item any, err error) { // must return io.EOF after the last item
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if it.b, err = it.reader.ReadByte(); err == nil {
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it.increment()
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item = it.b
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} else if it.autoClose {
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it.Clean()
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}
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return
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}
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func (it *fileFileByteIterator) Current() (item any, err error) {
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item = it.b
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return
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}
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func (it *fileFileByteIterator) Reset() (err error) {
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if err = it.reader.Reset(); err == nil {
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it.reset()
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it.b = 0
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}
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return
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}
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func (it *fileFileByteIterator) Clean() (err error) {
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if it.reader.Valid() {
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if err = it.reader.GetFile().Close(); err == nil {
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it.reader = nil
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}
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}
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it.reset()
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it.b = 0
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return
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}
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func (it *fileFileByteIterator) CallOperation(name string, args map[string]any) (v any, err error) {
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switch name {
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case kern.NextName:
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v, err = it.Next()
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case kern.ResetName:
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err = it.Reset()
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case kern.CleanName:
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err = it.Clean()
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case kern.IndexName:
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v = int64(it.Index())
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case kern.CurrentName:
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v, err = it.Current()
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case kern.CountName:
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v = it.count
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default:
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err = kern.ErrNoOperation(name)
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}
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return
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}
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func fileByteIteratorFunc(ctx kern.ExprContext, name string, args map[string]any) (result any, err error) {
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var handle *file.Reader
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var invalidFileHandle any
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var autoClose bool
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if handle, invalidFileHandle, autoClose, err = initFileHandle(ctx, name, args); err == nil {
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if handle != nil {
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result = newFileByteIterator(handle, autoClose)
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}
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}
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if err == nil && (handle == nil || invalidFileHandle != nil) {
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err = errInvalidFileHandle(name, invalidFileHandle)
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}
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return
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}
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