Documenta il formato PSB dei file Creo e aggiungi il parser di riferimento

Reverse engineering di 9253000117a.prt.35: contenitore (offset dall'ultimo
campo dell'intestazione, indice a catena), grammatica completa delle sezioni
(id progressivi dei campi, tabella "dopo X viene Y", marcatori di chiusura),
tabella dei double verificata sulla norma delle matrici, sezioni compresse e
catalogo del contenuto. Parser Python in scripts/psb/. docs/history.md
raccoglie stato, metodo e punti aperti per riprendere il lavoro.

Co-Authored-By: Claude <noreply@anthropic.com>

scripts/psb/tagmap.py

@@ -0,0 +1,47 @@
+import sys,os,math,collections,struct,glob,itertools
+sys.path.insert(0,os.path.dirname(os.path.abspath(__file__)))
+import prt,psb
+class TF(float):
+    pass
+orig=psb.P.rdbl
+def rdbl(s):
+    p0=s.p; t=s.b[p0]
+    v=orig(s)
+    if 0x49<=t<=0xdf and not isinstance(v,psb.Unk):
+        o=TF(v); o.tag=t; o.pl=bytes(s.b[p0+1:p0+7]); return o
+    return v
+psb.P.rdbl=rdbl
+OFFS=[0]+list(range(0x44,0x4d))
+def mag(tf,off):
+    return struct.unpack('>d',(0x3f75+tf.tag-off).to_bytes(2,'big')+tf.pl)[0]
+votes=collections.defaultdict(collections.Counter)
+def walk(v,name=''):
+    if isinstance(v,psb.Node):
+        for n,x in v: walk(x,n)
+    elif isinstance(v,psb.Arr):
+        for x in v: walk(x,name)
+    elif isinstance(v,list) and v and isinstance(v[0],list) and len(v) in (3,4) and len(v[0])==3 and name in ('local_sys','orient','matrix','transf_to_local'):
+        rows=v[:3]
+        if any(isinstance(c,psb.Unk) for r in rows for c in r): return
+        vecs=rows+[[rows[i][j] for i in range(3)] for j in range(3)]
+        for r in vecs:
+            tf=[c for c in r if isinstance(c,TF)]
+            if not tf or len(tf)>2: continue
+            rest=sum(c*c for c in r if not isinstance(c,TF))
+            sols=[]
+            for offs in itertools.product(OFFS,repeat=len(tf)):
+                n=rest+sum(mag(c,o)**2 for c,o in zip(tf,offs))
+                if abs(n-1)<1e-9: sols.append(offs)
+            if len(sols)==1:
+                for c,o in zip(tf,sols[0]): votes[c.tag][o]+=1
+for f in sys.argv[1:]:
+    for g in glob.glob(f):
+        try: d,secs,order=prt.load(g)
+        except Exception: continue
+        for nme in order:
+            o,l,fl=secs[nme]
+            if fl[2]!='9' or l<200: continue
+            p,root,e=psb.parse(d[o:o+l])
+            if root: walk(root[1])
+for t in sorted(votes):
+    print(hex(t), {hex(o):n for o,n in votes[t].items()}, ' -> prefix', [hex((0x3f75+t-o) | (0x8000 if o else 0)) for o in votes[t]])