treerack/context.go

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package treerack
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import (
"io"
"unicode"
)
type context struct {
reader io.RuneReader
offset int
readOffset int
readErr error
eof bool
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store *store
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tokens []rune
match bool
node *Node
isExcluded [][]int
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}
func newContext(r io.RuneReader) *context {
return &context{
reader: r,
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store: &store{},
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}
}
func (c *context) read() bool {
if c.eof || c.readErr != nil {
return false
}
t, n, err := c.reader.ReadRune()
if err != nil {
if err == io.EOF {
if n == 0 {
c.eof = true
return false
}
} else {
c.readErr = err
return false
}
}
c.readOffset++
if t == unicode.ReplacementChar {
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c.readErr = ErrInvalidUnicodeCharacter
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return false
}
c.tokens = append(c.tokens, t)
return true
}
func (c *context) token() (rune, bool) {
if c.offset == c.readOffset {
if !c.read() {
return 0, false
}
}
if len(c.tokens) <= c.offset {
println(len(c.tokens), c.offset)
}
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return c.tokens[c.offset], true
}
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func (c *context) excluded(offset int, id int) bool {
if len(c.isExcluded) <= id {
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return false
}
for i := range c.isExcluded[id] {
if c.isExcluded[id][i] == offset {
return true
}
}
return false
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}
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func (c *context) exclude(offset int, id int) {
if len(c.isExcluded) <= id {
if cap(c.isExcluded) > id {
c.isExcluded = c.isExcluded[:id+1]
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} else {
c.isExcluded = c.isExcluded[:cap(c.isExcluded)]
for i := cap(c.isExcluded); i <= id; i++ {
c.isExcluded = append(c.isExcluded, nil)
}
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}
}
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for i := range c.isExcluded[id] {
if c.isExcluded[id][i] == -1 {
c.isExcluded[id][i] = offset
return
}
}
c.isExcluded[id] = append(c.isExcluded[id], offset)
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}
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func (c *context) include(offset int, id int) {
for i := range c.isExcluded[id] {
if c.isExcluded[id][i] == offset {
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// c.isExcluded[id] = append(c.isExcluded[id][:i], c.isExcluded[id][i+1:]...)
c.isExcluded[id][i] = -1
break
}
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}
}
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func (c *context) fromStore(id int) bool {
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to, m, ok := c.store.getMatch(c.offset, id)
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if !ok {
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return false
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}
if m {
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c.success(to)
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} else {
c.fail(c.offset)
}
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return true
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}
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func (c *context) success(to int) {
c.offset = to
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c.match = true
}
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func (c *context) fail(offset int) {
c.offset = offset
c.match = false
}
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func (c *context) finalize(root parser) error {
rootID := root.nodeID()
to, match, found := c.store.getMatch(0, rootID)
if !found || !match || to < c.readOffset {
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return ErrUnexpectedCharacter
}
if !c.eof {
c.read()
if !c.eof {
if c.readErr != nil {
return c.readErr
}
return ErrUnexpectedCharacter
}
}
return nil
}