diff options
Diffstat (limited to 'walk/read.go')
| -rw-r--r-- | walk/read.go | 494 |
1 files changed, 7 insertions, 487 deletions
diff --git a/walk/read.go b/walk/read.go index bedb856..f25109c 100644 --- a/walk/read.go +++ b/walk/read.go @@ -1,491 +1,11 @@ package walk -import ( - "bufio" - "math" - "strings" - "strconv" - "fmt" -) - -type ReadAction int -const ( - ActionReadValue ReadAction = iota - ActionAppendPath - ActionPopPath - ActionIncrementPath - ActionAppendPathNull -) - -type JSONInStructure int -const ( - JSONInMap JSONInStructure = iota - JSONInArray -) - -type JSONInState int -const ( - JSONInValueEnd JSONInState = iota - JSONInValue - JSONInValueStart - JSONInString - JSONInKey -) - -type JSONIn struct { - path []Atom - reader *bufio.Reader - structure []JSONInStructure - state JSONInState - readBuffer []Atom - readIndex int - readBufferCapacity int - actionBuffer []ReadAction - actionIndex int -} - -func NewJSONIn(reader *bufio.Reader) JSONIn { - return JSONIn { - path: make([]Atom, 0, 256), - reader: reader, - structure: []JSONInStructure{}, - state: JSONInValueStart, - readBuffer: make([]Atom, 0, 256), - readIndex: 0, - readBufferCapacity: 256, - actionBuffer: make([]ReadAction, 0, 256), - actionIndex: 0, - } -} - -func isWhitespace(r rune) bool { - for _, ws := range " \t\r\n" { - if r == ws { - return true - } - } - return false -} - -func isNumberRune(r rune) bool { - return '0' <= r && r <= '9' || r == '.' -} - -func (in *JSONIn) popPath() { - if len(in.path) == 0 { - panic("Tried to pop from empty path") - } - finalAtom := in.path[len(in.path) - 1] - if finalAtom.Typ != AtomStringTerminal { - in.path = in.path[:len(in.path) - 1] - return - } - i := len(in.path) - 2 - for { - if i < 0 { - panic("Missing string begin in path") - } - if in.path[i].Typ == AtomStringTerminal { - break - } - i-- - } - in.path = in.path[:i] -} - -func (in *JSONIn) nextNonWsRune() (rune, error) { - for { - r, _, err := in.reader.ReadRune() - if err != nil { - return 0, err - } - if !isWhitespace(r) { - return r, nil - } - } -} - -func (in *JSONIn) requireString(criteria string) { - for _, r := range criteria { - in.require(r) - } +type StredReader interface { + Read() (WalkItem, error) + AssertDone() } -func (in *JSONIn) require(criterion rune) { - r, _, err := in.reader.ReadRune() - if err != nil { - panic("Error while reading required rune: " + err.Error()) - } - if r != criterion { - panic("Required rune not read") - } -} - -// Returns the first full value of a list of atoms and also a boolean to indicate if there isn't a value at the beginning -func firstValue(atoms []Atom) ([]Atom, bool) { - if len(atoms) == 0 { - return nil, true - } - if atoms[0].Typ != AtomStringTerminal { - return atoms[0:1], false - } - i := 1 - for { - if i == len(atoms) { - return nil, true - } - if atoms[i].Typ == AtomStringTerminal { - return atoms[0:i+1], false - } - i++ - } -} - -func (in *JSONIn) readValue() []Atom { - try: - value, incomplete := firstValue(in.readBuffer[in.readIndex:]) - if incomplete { - if in.readIndex == 0 { - newReadBuffer := make([]Atom, len(in.readBuffer), in.readBufferCapacity * 2) - in.readBufferCapacity *= 2 - copy(newReadBuffer, in.readBuffer) - in.readBuffer = newReadBuffer - in.fillReadBuffer() - goto try - } - copy(in.readBuffer, in.readBuffer[in.readIndex:]) - in.readBuffer = in.readBuffer[:len(in.readBuffer) - in.readIndex] - in.readIndex = 0 - copy(in.actionBuffer, in.actionBuffer[in.actionIndex:]) - in.actionBuffer = in.actionBuffer[:len(in.actionBuffer) - in.actionIndex] - in.actionIndex = 0 - in.fillReadBuffer() - goto try - } - in.readIndex += len(value) - return value -} - -func (in *JSONIn) Read() (WalkItem, error) { - for { - if in.actionIndex == len(in.actionBuffer) { - in.actionIndex = 0 - in.readIndex = 0 - in.actionBuffer = in.actionBuffer[:0] - in.readBuffer = in.readBuffer[:0] - err := in.fillReadBuffer() - if len(in.actionBuffer) == 0 { - return WalkItem{}, err - } - } - action := in.actionBuffer[in.actionIndex] - in.actionIndex++ - switch action { - case ActionReadValue: - value := in.readValue() - return WalkItem { - Value: value, - Path: in.path, - }, nil - case ActionAppendPath: - value := in.readValue() - in.path = append(in.path, value...) - case ActionAppendPathNull: - in.path = append(in.path, NewAtomNull()) - case ActionPopPath: - in.popPath() - case ActionIncrementPath: - prevIndex := in.path[len(in.path) - 1] - if prevIndex.Typ == AtomNull { - prevIndex.Typ = AtomNumber - prevIndex.data = math.Float64bits(0) - } else if prevIndex.Typ == AtomNumber { - prevIndex.data = math.Float64bits(math.Float64frombits(prevIndex.data) + 1) - } else { - panic("Invalid index in array input. Type: " + fmt.Sprintf("%v", prevIndex.Typ)) - } - in.path[len(in.path) - 1] = prevIndex - default: - panic("Invalid ReadAction") - } - } -} - -func (in *JSONIn) AssertDone() { - if len(in.structure) != 0 || in.state != JSONInValueEnd || in.readIndex < len(in.readBuffer) { - panic("Input ended on incomplete JSON root") - } -} - -func (in *JSONIn) pushReadBuffer(atom Atom) bool { - in.readBuffer = append(in.readBuffer, atom) - return len(in.readBuffer) == in.readBufferCapacity -} - -func (in *JSONIn) pushActionBuffer(action ReadAction) { - in.actionBuffer = append(in.actionBuffer, action) -} - -// Appends to the readBuffer until it has reached capacity -// Also appends to the actionBuffer as needed -func (in *JSONIn) fillReadBuffer() error { - switch in.state { - case JSONInValueStart: - goto valueStart - case JSONInValue: - goto value - case JSONInValueEnd: - goto valueEnd - case JSONInString: - goto string - case JSONInKey: - goto key - default: - panic("Invalid JSONInState") - } - valueStart: { - if len(in.structure) == 0 { - goto value - } - innermost := in.structure[len(in.structure) - 1] - switch innermost { - case JSONInMap: - goto mapValue - case JSONInArray: - goto arrayValue - default: - panic("Invalid JSONInStructure") - } - } - value: { - r, err := in.nextNonWsRune() - if err != nil { - panic("Missing value in JSON") - } - switch r { - case 'n': - in.requireString("ull") - in.pushActionBuffer(ActionReadValue) - if in.pushReadBuffer(NewAtomNull()) { - in.state = JSONInValueEnd - return nil - } - goto valueEnd - case 'f': - in.requireString("alse") - in.pushActionBuffer(ActionReadValue) - if in.pushReadBuffer(NewAtomBool(false)) { - in.state = JSONInValueEnd - return nil - } - goto valueEnd - case 't': - in.requireString("rue") - in.pushActionBuffer(ActionReadValue) - if in.pushReadBuffer(NewAtomBool(true)) { - in.state = JSONInValueEnd - return nil - } - goto valueEnd - case '"': - in.pushActionBuffer(ActionReadValue) - if in.pushReadBuffer(NewAtomStringTerminal()) { - in.state = JSONInString - return nil - } - goto string - case '{': - in.structure = append(in.structure, JSONInMap) - in.pushActionBuffer(ActionReadValue) - in.pushActionBuffer(ActionAppendPathNull) - if in.pushReadBuffer(NewAtomTerminal(MapBegin)) { - in.state = JSONInValueStart - return nil - } - goto mapValue - case '[': - in.structure = append(in.structure, JSONInArray) - in.pushActionBuffer(ActionReadValue) - in.pushActionBuffer(ActionAppendPathNull) - if in.pushReadBuffer(NewAtomTerminal(ArrayBegin)) { - in.state = JSONInValueStart - return nil - } - goto arrayValue - } - if isNumberRune(r) { - var builder strings.Builder - builder.WriteRune(r) - for { - r, _, err = in.reader.ReadRune() - if err != nil { - break - } - if !isNumberRune(r) { - in.reader.UnreadRune() - break - } - builder.WriteRune(r) - } - number, parseError := strconv.ParseFloat(builder.String(), 64) - if parseError != nil { - panic("Invalid number") - } - in.pushActionBuffer(ActionReadValue) - if in.pushReadBuffer(NewAtomNumber(number)) { - in.state = JSONInValueEnd - return nil - } - goto valueEnd - } - panic("Invalid JSON value starting with: " + string(r)) - } - string: { - r, _, err := in.reader.ReadRune() - if err != nil { - panic("Missing closing terminal in string input: " + err.Error()) - } - if r == '"' { - if in.pushReadBuffer(NewAtomStringTerminal()) { - in.state = JSONInValueEnd - return nil - } - goto valueEnd - } - if r == '\\' { - r, _, err = in.reader.ReadRune() - if err != nil { - panic("Missing rune after \\") - } - if in.pushReadBuffer(NewAtomStringRune(r)) { - in.state = JSONInString - return nil - } - goto string - } - if in.pushReadBuffer(NewAtomStringRune(r)) { - in.state = JSONInString - return nil - } - goto string - } - key: { - var full bool - for { - r, _, err := in.reader.ReadRune() - if err != nil { - panic("Missing closing terminal in string input: " + err.Error()) - } - if r == '"' { - full = in.pushReadBuffer(NewAtomStringTerminal()) - break - } - if r == '\\' { - r, _, err = in.reader.ReadRune() - if err != nil { - panic("Missing rune after \\") - } - if in.pushReadBuffer(NewAtomStringRune(r)) { - in.state = JSONInKey - return nil - } - continue - } - if in.pushReadBuffer(NewAtomStringRune(r)) { - in.state = JSONInKey - return nil - } - continue - } - r, err := in.nextNonWsRune() - if err != nil { - panic("Expected : got: " + err.Error()) - } - if r != ':' { - panic("Expected : after key") - } - if full { - in.state = JSONInValue - return nil - } - goto value - } - valueEnd: { - r, err := in.nextNonWsRune() - if err != nil { - in.state = JSONInValueEnd - return err - } - if len(in.structure) == 0 { - panic("More input after root JSON object ends") - } - innermost := in.structure[len(in.structure) - 1] - if innermost == JSONInMap && r == '}' { - in.structure = in.structure[:len(in.structure) - 1] - in.pushActionBuffer(ActionPopPath) - in.pushActionBuffer(ActionReadValue) - if in.pushReadBuffer(NewAtomTerminal(MapEnd)) { - in.state = JSONInValueEnd - return nil - } - goto valueEnd - } else if innermost == JSONInArray && r == ']' { - in.structure = in.structure[:len(in.structure) - 1] - in.pushActionBuffer(ActionPopPath) - in.pushActionBuffer(ActionReadValue) - if in.pushReadBuffer(NewAtomTerminal(ArrayEnd)) { - in.state = JSONInValueEnd - return nil - } - goto valueEnd - } - if r != ',' { - panic("Expected , after JSON value, found: \"" + string(r) + "\"") - } - goto valueStart - } - mapValue: { - in.pushActionBuffer(ActionPopPath) - r, err := in.nextNonWsRune() - if err != nil { - panic("Missing value inside object") - } - if r == '}' { - in.structure = in.structure[:len(in.structure) - 1] - in.pushActionBuffer(ActionReadValue) - if in.pushReadBuffer(NewAtomTerminal(MapEnd)) { - in.state = JSONInValueEnd - return nil - } - goto valueEnd - } - if r != '"' { - panic("Expected key found something else") - } - in.pushActionBuffer(ActionAppendPath) - if in.pushReadBuffer(NewAtomStringTerminal()) { - in.state = JSONInKey - return nil - } - goto key - } - arrayValue: { - r, err := in.nextNonWsRune() - if err != nil { - panic("Missing value inside array") - } - if r == ']' { - in.structure = in.structure[:len(in.structure) - 1] - in.pushActionBuffer(ActionPopPath) - in.pushActionBuffer(ActionReadValue) - if in.pushReadBuffer(NewAtomTerminal(ArrayEnd)) { - in.state = JSONInValueEnd - return nil - } - goto valueEnd - } - in.reader.UnreadRune() - in.pushActionBuffer(ActionIncrementPath) - goto value - } -} +type StredWriter interface { + Write(WalkItem) error + AssertDone() +}
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