645 lines
13 KiB
Go
645 lines
13 KiB
Go
// Package gjson provides searching for json strings.
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package gjson
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import "strconv"
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// Type is Result type
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type Type byte
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const (
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// Null is a null json value
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Null Type = iota
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// False is a json false boolean
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False
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// Number is json number
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Number
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// String is a json string
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String
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// True is a json true boolean
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True
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// JSON is a raw block of JSON
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JSON
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)
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// Result represents a json value that is returned from Get().
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type Result struct {
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// Type is the json type
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Type Type
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// Raw is the raw json
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Raw string
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// Str is the json string
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Str string
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// Num is the json number
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Num float64
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}
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// String returns a string representation of the value.
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func (t Result) String() string {
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switch t.Type {
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default:
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return "null"
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case False:
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return "false"
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case Number:
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return strconv.FormatFloat(t.Num, 'f', -1, 64)
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case String:
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return t.Str
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case JSON:
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return t.Raw
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case True:
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return "true"
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}
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}
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// Exists returns true if value exists.
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//
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// if gjson.Get(json, "name.last").Exists(){
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// println("value exists")
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// }
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func (t Result) Exists() bool {
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return t.Type != Null || len(t.Raw) != 0
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}
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// Value returns one of these types:
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//
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// bool, for JSON booleans
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// float64, for JSON numbers
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// Number, for JSON numbers
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// string, for JSON string literals
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// nil, for JSON null
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//
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func (t Result) Value() interface{} {
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switch t.Type {
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default:
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return nil
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case False:
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return false
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case Number:
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return t.Num
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case String:
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return t.Str
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case JSON:
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return t.Raw
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case True:
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return true
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}
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}
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type part struct {
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wild bool
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key string
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}
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type frame struct {
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key string
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count int
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stype byte
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}
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// Get searches json for the specified path.
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// A path is in dot syntax, such as "name.last" or "age".
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// This function expects that the json is well-formed, and does not validate.
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// Invalid json will not panic, but it may return back unexpected results.
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// When the value is found it's returned immediately.
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//
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// A path is a series of keys seperated by a dot.
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// A key may contain special wildcard characters '*' and '?'.
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// To access an array value use the index as the key.
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// To get the number of elements in an array use the '#' character.
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// The dot and wildcard character can be escaped with '\'.
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//
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// {
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// "name": {"first": "Tom", "last": "Anderson"},
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// "age":37,
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// "children": ["Sara","Alex","Jack"]
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// }
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// "name.last" >> "Anderson"
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// "age" >> 37
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// "children.#" >> 3
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// "children.1" >> "Alex"
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// "child*.2" >> "Jack"
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// "c?ildren.0" >> "Sara"
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//
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func Get(json string, path string) Result {
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var s int
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var wild bool
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var parts = make([]part, 0, 4)
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// do nothing when no path specified
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if len(path) == 0 {
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return Result{} // nothing
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}
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// parse the path. just split on the dot
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for i := 0; i < len(path); i++ {
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next_part:
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if path[i] == '\\' {
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// go into escape mode
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epart := []byte(path[s:i])
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i++
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if i < len(path) {
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epart = append(epart, path[i])
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i++
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for ; i < len(path); i++ {
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if path[i] == '\\' {
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i++
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if i < len(path) {
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epart = append(epart, path[i])
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}
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continue
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} else if path[i] == '.' {
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parts = append(parts, part{wild: wild, key: string(epart)})
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if wild {
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wild = false
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}
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s = i + 1
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i++
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goto next_part
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} else if path[i] == '*' || path[i] == '?' {
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wild = true
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}
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epart = append(epart, path[i])
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}
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}
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parts = append(parts, part{wild: wild, key: string(epart)})
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goto end_parts
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} else if path[i] == '.' {
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parts = append(parts, part{wild: wild, key: path[s:i]})
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if wild {
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wild = false
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}
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s = i + 1
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} else if path[i] == '*' || path[i] == '?' {
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wild = true
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}
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}
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parts = append(parts, part{wild: wild, key: path[s:]})
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end_parts:
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var i, depth int
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var squashed string
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var f frame
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var matched bool
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var stack = make([]frame, 0, 4)
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depth = 1
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// look for first delimiter
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for ; i < len(json); i++ {
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if json[i] > ' ' {
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if json[i] == '{' {
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f.stype = '{'
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} else if json[i] == '[' {
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f.stype = '['
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} else {
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// not a valid type
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return Result{}
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}
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i++
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break
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}
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}
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stack = append(stack, f)
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// search for key
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read_key:
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if f.stype == '[' {
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f.key = strconv.FormatInt(int64(f.count), 10)
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f.count++
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} else {
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for ; i < len(json); i++ {
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if json[i] == '"' {
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//read to end of key
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i++
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// readstr
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// the first double-quote has already been read
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s = i
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for ; i < len(json); i++ {
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if json[i] == '"' {
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f.key = json[s:i]
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i++
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break
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}
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if json[i] == '\\' {
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i++
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for ; i < len(json); i++ {
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if json[i] == '"' {
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// look for an escaped slash
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if json[i-1] == '\\' {
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n := 0
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for j := i - 2; j > s-1; j-- {
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if json[j] != '\\' {
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break
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}
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n++
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}
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if n%2 == 0 {
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continue
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}
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}
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break
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}
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}
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f.key = unescape(json[s:i])
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i++
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break
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}
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}
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break
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}
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}
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}
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// end readstr
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// we have a brand new key.
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// is it the key that we are looking for?
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if parts[depth-1].wild {
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// it's a wildcard path element
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matched = wildcardMatch(f.key, parts[depth-1].key)
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} else {
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matched = parts[depth-1].key == f.key
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}
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// read to the value token
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// there's likely a colon here, but who cares. just burn past it.
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var val string
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var vc byte
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for ; i < len(json); i++ {
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if json[i] < '"' { // control character
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continue
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}
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if json[i] < '-' { // string
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i++
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// we read the val below
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vc = '"'
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goto proc_val
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}
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if json[i] < '[' { // number
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if json[i] == ':' {
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continue
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}
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vc = '0'
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s = i
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i++
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// look for characters that cannot be in a number
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for ; i < len(json); i++ {
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switch json[i] {
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default:
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continue
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case ' ', '\t', '\r', '\n', ',', ']', '}':
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}
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break
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}
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val = json[s:i]
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goto proc_val
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}
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if json[i] < ']' { // '['
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i++
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vc = '['
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goto proc_delim
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}
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if json[i] < 'u' { // true, false, null
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vc = json[i]
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s = i
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i++
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for ; i < len(json); i++ {
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// let's pick up any character. it doesn't matter.
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if json[i] < 'a' || json[i] > 'z' {
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break
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}
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}
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val = json[s:i]
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goto proc_val
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}
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// must be an open objet
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i++
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vc = '{'
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goto proc_delim
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}
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// sanity check before we move on
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if i >= len(json) {
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return Result{}
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}
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proc_delim:
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if (matched && depth == len(parts)) || !matched {
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// -- BEGIN SQUASH -- //
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// squash the value, ignoring all nested arrays and objects.
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s = i - 1
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// the first '[' or '{' has already been read
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depth := 1
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for ; i < len(json); i++ {
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if json[i] >= '"' && json[i] <= '}' {
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if json[i] == '{' || json[i] == '[' {
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depth++
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} else if json[i] == '}' || json[i] == ']' {
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depth--
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if depth == 0 {
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i++
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break
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}
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} else if json[i] == '"' {
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i++
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s2 := i
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for ; i < len(json); i++ {
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if json[i] == '"' {
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// look for an escaped slash
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if json[i-1] == '\\' {
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n := 0
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for j := i - 2; j > s2-1; j-- {
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if json[j] != '\\' {
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break
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}
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n++
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}
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if n%2 == 0 {
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continue
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}
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}
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break
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}
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}
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if i == len(json) {
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break
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}
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}
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}
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}
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squashed = json[s:i]
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// -- END SQUASH -- //
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}
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// process the value
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proc_val:
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if matched {
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// hit, that's good!
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if depth == len(parts) {
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var value Result
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value.Raw = val
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switch vc {
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case '{', '[':
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value.Raw = squashed
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value.Type = JSON
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case 'n':
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value.Type = Null
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case 't':
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value.Type = True
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case 'f':
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value.Type = False
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case '"':
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value.Type = String
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// readstr
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// the val has not been read yet
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// the first double-quote has already been read
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s = i
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for ; i < len(json); i++ {
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if json[i] == '"' {
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value.Str = json[s:i]
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i++
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break
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}
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if json[i] == '\\' {
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i++
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for ; i < len(json); i++ {
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if json[i] == '"' {
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// look for an escaped slash
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if json[i-1] == '\\' {
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n := 0
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for j := i - 2; j > s-1; j-- {
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if json[j] != '\\' {
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break
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}
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n++
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}
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if n%2 == 0 {
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continue
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}
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}
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break
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}
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}
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value.Str = unescape(json[s:i])
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i++
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break
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}
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}
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// end readstr
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case '0':
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value.Type = Number
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value.Num, _ = strconv.ParseFloat(val, 64)
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}
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return value
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//} else if vc != '{' {
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// can only deep search objects
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// return Result{}
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} else {
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f.stype = vc
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stack = append(stack, f)
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depth++
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goto read_key
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}
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}
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if vc == '"' {
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// readstr
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// the val has not been read yet. we can read and throw away.
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// the first double-quote has already been read
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s = i
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for ; i < len(json); i++ {
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if json[i] == '"' {
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// look for an escaped slash
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if json[i-1] == '\\' {
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n := 0
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for j := i - 2; j > s-1; j-- {
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if json[j] != '\\' {
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break
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}
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n++
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}
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if n%2 == 0 {
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continue
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}
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}
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break
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}
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}
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i++
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// end readstr
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}
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// read to the comma or end of object
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for ; i < len(json); i++ {
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switch json[i] {
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case '}', ']':
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if parts[depth-1].key == "#" {
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return Result{Type: Number, Num: float64(f.count)}
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}
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// step the stack back
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depth--
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if depth == 0 {
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return Result{}
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}
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stack = stack[:len(stack)-1]
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f = stack[len(stack)-1]
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case ',':
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i++
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goto read_key
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}
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}
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return Result{}
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}
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// unescape unescapes a string
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func unescape(json string) string { //, error) {
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var str = make([]byte, 0, len(json))
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for i := 0; i < len(json); i++ {
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switch {
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default:
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str = append(str, json[i])
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case json[i] < ' ':
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return "" //, errors.New("invalid character in string")
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case json[i] == '\\':
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i++
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if i >= len(json) {
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return "" //, errors.New("invalid escape sequence")
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}
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switch json[i] {
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default:
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return "" //, errors.New("invalid escape sequence")
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case '\\':
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str = append(str, '\\')
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case '/':
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str = append(str, '/')
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case 'b':
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str = append(str, '\b')
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case 'f':
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str = append(str, '\f')
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case 'n':
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str = append(str, '\n')
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case 'r':
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str = append(str, '\r')
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case 't':
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str = append(str, '\t')
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case '"':
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str = append(str, '"')
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case 'u':
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if i+5 > len(json) {
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return "" //, errors.New("invalid escape sequence")
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}
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i++
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// extract the codepoint
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var code int
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for j := i; j < i+4; j++ {
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switch {
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default:
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return "" //, errors.New("invalid escape sequence")
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case json[j] >= '0' && json[j] <= '9':
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code += (int(json[j]) - '0') << uint(12-(j-i)*4)
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case json[j] >= 'a' && json[j] <= 'f':
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code += (int(json[j]) - 'a' + 10) << uint(12-(j-i)*4)
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case json[j] >= 'a' && json[j] <= 'f':
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code += (int(json[j]) - 'a' + 10) << uint(12-(j-i)*4)
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}
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}
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str = append(str, []byte(string(code))...)
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i += 3 // only 3 because we will increment on the for-loop
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}
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}
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}
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return string(str) //, nil
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}
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// Less return true if a token is less than another token.
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// The caseSensitive paramater is used when the tokens are Strings.
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// The order when comparing two different type is:
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//
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// Null < False < Number < String < True < JSON
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//
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func (t Result) Less(token Result, caseSensitive bool) bool {
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if t.Type < token.Type {
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return true
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}
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if t.Type > token.Type {
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return false
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}
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switch t.Type {
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default:
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return t.Raw < token.Raw
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case String:
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if caseSensitive {
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return t.Str < token.Str
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}
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return stringLessInsensitive(t.Str, token.Str)
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case Number:
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return t.Num < token.Num
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}
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}
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func stringLessInsensitive(a, b string) bool {
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for i := 0; i < len(a) && i < len(b); i++ {
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if a[i] >= 'A' && a[i] <= 'Z' {
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if b[i] >= 'A' && b[i] <= 'Z' {
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// both are uppercase, do nothing
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if a[i] < b[i] {
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return true
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} else if a[i] > b[i] {
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return false
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}
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} else {
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// a is uppercase, convert a to lowercase
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if a[i]+32 < b[i] {
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return true
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} else if a[i]+32 > b[i] {
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return false
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}
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}
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} else if b[i] >= 'A' && b[i] <= 'Z' {
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// b is uppercase, convert b to lowercase
|
|
if a[i] < b[i]+32 {
|
|
return true
|
|
} else if a[i] > b[i]+32 {
|
|
return false
|
|
}
|
|
} else {
|
|
// neither are uppercase
|
|
if a[i] < b[i] {
|
|
return true
|
|
} else if a[i] > b[i] {
|
|
return false
|
|
}
|
|
}
|
|
}
|
|
return len(a) < len(b)
|
|
}
|
|
|
|
// wilcardMatch returns true if str matches pattern. This is a very
|
|
// simple wildcard match where '*' matches on any number characters
|
|
// and '?' matches on any one character.
|
|
func wildcardMatch(str, pattern string) bool {
|
|
if pattern == "*" {
|
|
return true
|
|
}
|
|
return deepMatch(str, pattern)
|
|
}
|
|
func deepMatch(str, pattern string) bool {
|
|
for len(pattern) > 0 {
|
|
switch pattern[0] {
|
|
default:
|
|
if len(str) == 0 || str[0] != pattern[0] {
|
|
return false
|
|
}
|
|
case '?':
|
|
if len(str) == 0 {
|
|
return false
|
|
}
|
|
case '*':
|
|
return wildcardMatch(str, pattern[1:]) ||
|
|
(len(str) > 0 && wildcardMatch(str[1:], pattern))
|
|
}
|
|
str = str[1:]
|
|
pattern = pattern[1:]
|
|
}
|
|
return len(str) == 0 && len(pattern) == 0
|
|
}
|