super-graph/jsn/strip.go

107 lines
1.9 KiB
Go
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2019-05-13 01:27:26 +02:00
package jsn
import (
"bytes"
)
func Strip(b []byte, path [][]byte) []byte {
s, e, d := 0, 0, 0
ob := b
pi := 0
pm := false
state := expectKey
for i := 0; i < len(b); i++ {
if state == expectObjClose || state == expectListClose {
switch b[i] {
case '{', '[':
d++
case '}', ']':
d--
}
}
switch {
case state == expectKey && b[i] == '"':
state = expectKeyClose
s = i
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case state == expectKeyClose && (b[i-1] != '\\' && b[i] == '"'):
state = expectColon
if pi == len(path) {
pi = 0
}
pm = bytes.Equal(b[(s+1):i], path[pi])
if pm {
pi++
}
case state == expectColon && b[i] == ':':
state = expectValue
case state == expectValue && b[i] == '"':
state = expectString
s = i
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case state == expectString && (b[i-1] != '\\' && b[i] == '"'):
e = i
case state == expectValue && b[i] == '[':
state = expectListClose
s = i
d++
case state == expectListClose && d == 0 && b[i] == ']':
e = i
case state == expectValue && b[i] == '{':
state = expectObjClose
s = i
d++
case state == expectObjClose && d == 0 && b[i] == '}':
e = i
case state == expectValue && (b[i] >= '0' && b[i] <= '9'):
state = expectNumClose
s = i
case state == expectNumClose &&
((b[i] < '0' || b[i] > '9') &&
(b[i] != '.' && b[i] != 'e' && b[i] != 'E' && b[i] != '+' && b[i] != '-')):
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e = i - 1
case state == expectValue &&
(b[i] == 'f' || b[i] == 'F' || b[i] == 't' || b[i] == 'T'):
state = expectBoolClose
s = i
case state == expectBoolClose && (b[i] == 'e' || b[i] == 'E'):
e = i
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case state == expectValue && b[i] == 'n':
state = expectNull
case state == expectNull && b[i] == 'l':
e = i
}
if e != 0 {
if pm && (b[s] == '[' || b[s] == '{') {
b = b[s:(e + 1)]
i = 0
if pi == len(path) {
return b
}
}
state = expectKey
e = 0
}
}
return ob
}