From c9b3681ce26a30c47a312c3eeeea4f7655e94354 Mon Sep 17 00:00:00 2001
From: Leo C <erbl259-lmu@yahoo.de>
Date: Mon, 15 Aug 2016 14:09:02 +0200
Subject: [PATCH] read_symfile: Check symbols for valid characters.

---
 ddt180.z80 | 105 ++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 76 insertions(+), 29 deletions(-)

diff --git a/ddt180.z80 b/ddt180.z80
index 5275297..50d500e 100644
--- a/ddt180.z80
+++ b/ddt180.z80
@@ -516,9 +516,7 @@ skipbl0:
 	inc de
 skipbl:
 	ld a,(de)
-	cp ' '
-	jr z,skipbl0
-	cp TAB
+	call test_whitespace
 	jr z,skipbl0
 	or a
 	ret
@@ -3137,64 +3135,62 @@ rs_2:
 	call	read_hexbyte	; symval L
 	ld	l,a
 	add	hl,de
-	push	hl		; symval
 	call	read_byte
 	cp	' '
 	jr	z,rs_4
-	pop	hl		; discard symval
 rs_3:	call	read_byte
 	cp	' '
-	jr	c,rs_2
-	jr	rs_3
+	jr	nc,rs_3
+	jr	rs_2
 
-rs_4:	ld	hl,(BDOS+1)	;
-	ld	d,0		; setup symlen
-rs_5:	dec	hl		;
+rs_4:
+	push	hl		; symval
+	ld	hl,(BDOS+1)	;
+	ld	b,0		; setup symlen
+rs_5:
+	dec	hl		;
 	call	read_byte	; next char of symbol name
-	cp	TAB		; symbol term?
-	jr	z,rs_6		;
-	cp	CR		;
-	jr	z,rs_6		;
-	cp	'!'		; TODO: check for valid symbol char instead
-	jr	c,error3	;
+	call	test_sym_char	; valid char?
+	jr	nz,rs_6
 	ld	(hl),a		;
-	inc	d		; symlen++
-	ld	a,d		;
+	inc	b		; symlen++
+	ld	a,b		;
 	cp	10h+1		;
 	jr	c,rs_5		;
 error3:
 	jp	ERROR		;
 
-rs_6:	push	de		; symlen
-	push	hl		;
+rs_6:
+	call	test_symterm_ch
+	jr	nz,error3
+
+	push	bc		; symlen
 	ex	de,hl		;
 	ld	hl,(BDOS+1)	;
 	inc	hl		;
-	ld	e,(hl)		;
+	ld	c,(hl)		;
 	inc	hl		;
-	ld	d,(hl)		;
-	pop	hl		;
-	ld	(hl),d		;
+	ld	b,(hl)		;
+	ex	de,hl
+	ld	(hl),b		;
 	dec	hl		;
-	ld	(hl),e		;
+	ld	(hl),c		;
 	dec	hl		;
 	ld	(hl),0c3h	;
 
 	ld	de,(max_load)	;
 	call	cp_hl_de	;
 	jr	c,error3	;
-
 	ld	de,(reg_sp)	;
 	call	cp_hl_de	;
 	jr	nc,rs_61	;
 	ld	(reg_sp),hl	;
 rs_61:
-
 	ld	de,(BDOS+1)	;
 	ld	(BDOS+1),hl	;
 	ex	de,hl		;
-	pop	af		;
-	ld	(hl),a		; symlen
+	pop	af		; symlen
+	ld	(hl),a		;
 	inc	hl		;
 	pop	de		; symval
 	ld	(hl),e		;
@@ -3207,6 +3203,57 @@ rs_61:
 	jp	rs_1		;
 
 
+; test for valid character for symbols
+; return z if valid
+
+test_sym_char:
+	cp	'$'
+	ret	z
+	cp	'%'
+	ret	z
+	cp	'.'
+	ret	z
+	cp	'_'
+	ret	z
+	call	test_alphanum
+	ret	c		; cy == 1 --> z == 0
+	cp	a		; return z
+	ret
+
+
+; check if char is in [0..9,?,@,A..Z,a..z]
+; return cy if invalid
+; return nc if valid alfanumeric char
+
+test_alphanum:
+	cp	'z'+1
+	ccf
+	ret	c
+	cp	'a'
+	ret	nc
+	cp	'Z'+1
+	ccf
+	ret	c
+	cp	'?'
+	ret	nc
+test_numeral:
+	cp	'9'+1
+	ccf
+	ret	c
+	cp	'0'
+	ret
+
+test_symterm_ch:
+	cp	CR
+	ret	z
+	cp	LF
+	ret	z
+test_whitespace:
+	cp	' '
+	ret	z
+	cp	TAB
+	ret
+
 p_max_high0:
 	call assert_eol
 p_max_high:
-- 
2.39.2