64 lines
2.0 KiB
Plaintext
64 lines
2.0 KiB
Plaintext
// json_scan_guard.hako — JsonScanGuardBox
|
|
// Responsibility: escape-aware JSON scanning with step budget (Fail-Fast)
|
|
|
|
using selfhost.shared.json.core.string_scan as StringScanBox
|
|
|
|
static box JsonScanGuardBox {
|
|
// Seek the end index (inclusive) of an object starting at `start` (must be '{').
|
|
// Returns: end index or -1 on failure/budget exceeded.
|
|
seek_obj_end(text, start, budget) {
|
|
if text == null { return -1 }
|
|
if start < 0 || start >= text.length() { return -1 }
|
|
if text.substring(start, start+1) != "{" { return -1 }
|
|
local n = text.length()
|
|
local depth = 0
|
|
local i = start
|
|
local steps = 0
|
|
loop (i < n) {
|
|
if steps >= budget { return -1 }
|
|
steps = steps + 1
|
|
local ch = StringScanBox.read_char(text, i)
|
|
if ch == "\\" { i = i + 2 continue }
|
|
if ch == "\"" {
|
|
// jump to end quote (escape-aware)
|
|
local j = StringScanBox.find_quote(text, i+1)
|
|
if j < 0 { return -1 }
|
|
i = j + 1
|
|
continue
|
|
}
|
|
if ch == "{" { depth = depth + 1 }
|
|
if ch == "}" { depth = depth - 1 if depth == 0 { return i } }
|
|
i = i + 1
|
|
}
|
|
return -1
|
|
}
|
|
|
|
// Seek the end index (inclusive) of an array starting at `start` (must be '[').
|
|
// Returns: end index or -1 on failure/budget exceeded.
|
|
seek_array_end(text, start, budget) {
|
|
if text == null { return -1 }
|
|
if start < 0 || start >= text.length() { return -1 }
|
|
if text.substring(start, start+1) != "[" { return -1 }
|
|
local n = text.length()
|
|
local depth = 0
|
|
local i = start
|
|
local steps = 0
|
|
loop (i < n) {
|
|
if steps >= budget { return -1 }
|
|
steps = steps + 1
|
|
local ch = StringScanBox.read_char(text, i)
|
|
if ch == "\\" { i = i + 2 continue }
|
|
if ch == "\"" {
|
|
local j = StringScanBox.find_quote(text, i+1)
|
|
if j < 0 { return -1 }
|
|
i = j + 1
|
|
continue
|
|
}
|
|
if ch == "[" { depth = depth + 1 }
|
|
if ch == "]" { depth = depth - 1 if depth == 0 { return i } }
|
|
i = i + 1
|
|
}
|
|
return -1
|
|
}
|
|
}
|