code wiki / _hdl_build / _pe_png.nx
_pe_png.nx source
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1// AUTHORED BY THE NISHI BUILDER (pattern: WIRE_TLV v3 le/pad/trail) -- [type][len][body][trail] wire walk, no Claude logic
2import "nx_syscalls.nx"
3func _pe_png_rdbe(b: *u8, off: i64, w: i64) -> i64 { var v: i64 = 0; var i: i64 = 0; while i < w { v = (v << 8) | (b[off + i] & 0xff); i = i + 1 } return v }
4func _pe_png_count(b: *u8, n: i64) -> i64 {
5 var off: i64 = 0
6 var c: i64 = 0
7 while off < n {
8 if off + 8 > n { return 0 - 1 }
9 let l: i64 = _pe_png_rdbe(b, off + 0, 4)
10 if off + 12 + l > n { return 0 - 1 }
11 off = off + 12 + l
12 c = c + 1
13 }
14 return c
15}
16func _pe_png_find(b: *u8, n: i64, t: i64) -> i64 {
17 var off: i64 = 0
18 while off < n {
19 if off + 8 > n { return 0 - 2 }
20 let ty: i64 = _pe_png_rdbe(b, off + 4, 4)
21 let l: i64 = _pe_png_rdbe(b, off + 0, 4)
22 if off + 12 + l > n { return 0 - 2 }
23 if ty == t { return off + 8 }
24 off = off + 12 + l
25 }
26 return 0 - 1
27}