emailler/drivers/vic20filteredinput.s

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.export get_filtered_input
.export filter_text
.export filter_ip
.export filter_dns
.export filter_url
.export filter_number
.import get_key
.include "zeropage.inc"
.include "../inc/common.inc"
allowed_ptr = ptr1
.code
; cribbed from http://codebase64.org/doku.php?id=base:robust_string_input
; ======================================================================
; Input a string and store it in GOTINPUT, terminated with a null byte.
; AX is a pointer to the allowed list of characters, null-terminated.
; set AX to $0000 for no filter on input
; max # of chars in y returns num of chars entered in y.
; ======================================================================
; Main entry
get_filtered_input:
sty MAXCHARS
stax temp_allowed
; Zero characters received.
lda #$00
sta INPUT_Y
; Wait for a character.
@input_get:
jsr get_key
sta LASTCHAR
cmp #$14 ; Delete
beq @delete
cmp #$0d ; Return
beq @input_done
; End reached?
lda INPUT_Y
cmp MAXCHARS
beq @input_get
; Check the allowed list of characters.
ldax temp_allowed
stax allowed_ptr ; Since we are reusing this zero page, it may not stil be the same value since last time!
ldy #$00
lda allowed_ptr+1 ; Was the input filter point nul?
beq @input_ok
@check_allowed:
lda (allowed_ptr),y ; Overwritten
beq @input_get ; Reached end of list (0)
cmp LASTCHAR
beq @input_ok ; Match found
; Not end or match, keep checking
iny
jmp @check_allowed
@input_ok:
lda LASTCHAR ; Get the char back
ldy INPUT_Y
sta GOTINPUT,y ; Add it to string
jsr $ffd2 ; Print it
inc INPUT_Y ; Next character
; Not yet.
jmp @input_get
@input_done:
ldy INPUT_Y
beq @no_input
lda #$00
sta GOTINPUT,y ; Zero-terminate
clc
ldax #GOTINPUT
rts
@no_input:
sec
rts
; Delete last character.
@delete:
; First, check if we're at the beginning. If so, just exit.
lda INPUT_Y
bne @delete_ok
jmp @input_get
; At least one character entered.
@delete_ok:
; Move pointer back.
dec INPUT_Y
; Store a zero over top of last character, just in case no other characters are entered.
ldy INPUT_Y
lda #$00
sta GOTINPUT,y
; Print the delete char
lda #$14
jsr $ffd2
; Wait for next char
jmp @input_get
; =================================================
; Some example filters
; =================================================
filter_text:
.byte ",!#'()* "
filter_url:
.byte ":/%&?+$"
filter_dns:
.byte "-ABCDEFGHIJKLMNOPQRSTUVWXYZ"
filter_ip:
.byte "."
filter_number:
.byte "1234567890",0
.bss
temp_allowed: .res 2
MAXCHARS: .res 1
LASTCHAR: .res 1
INPUT_Y: .res 1
GOTINPUT: .res 40
; -- LICENSE FOR vic20filteredinput.s --
; The contents of this file are subject to the Mozilla Public License
; Version 1.1 (the "License"); you may not use this file except in
; compliance with the License. You may obtain a copy of the License at
; http://www.mozilla.org/MPL/
;
; Software distributed under the License is distributed on an "AS IS"
; basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
; License for the specific language governing rights and limitations
; under the License.
;
; The Original Code is ip65.
;
; The Initial Developer of the Original Code is Jonno Downes,
; jonno@jamtronix.com.
; Portions created by the Initial Developer are Copyright (C) 2009
; Jonno Downes. All Rights Reserved.
; -- LICENSE END --