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/* This file is part of the SvarCOM project and is published under the terms
* of the MIT license.
*
* Copyright (C) 2021-2022 Mateusz Viste
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
/*
* goto label
*
* if label does not exist in the currently processed batch file, then a error
* "Label not found" is displayed and the batch file is aborted. Any parent
* batches are ALSO aborted. Same behavior if called without any parameter.
*
* if called outside of a batch file, this command has no effect (and does not
* display any error, even when called without any argument).
*
* it reacts to /? by outputing its help screen
*
* only 1st argument is processed, any extra arguments are ignored (even /?).
*
* Labels can be written as:
* :LABEL
* :LABEL
* : LABEL
*
* A label can also be followed by one or more space or tabs, followed by
* anything. The label is parsed only to the first space, tab, end of line or
* end of file. Hence this would be perfectly ok:
*
* :LABEL this is a comment
*
* Labels are searched in the batch file from top to bottom and first match
* is jumped to. Matching labels is case-insensitive (ie. LABEL == LaBeL)
*/
static void goto_close_dos_handle(unsigned short fhandle) {
_asm {
push bx
mov ah, 0x3e
mov bx, fhandle
int 0x21
pop bx
}
}
static enum cmd_result cmd_goto(struct cmd_funcparam *p) {
char *buff = NULL;
const char *label;
unsigned short bufflen = 0;
unsigned short fhandle = 0;
unsigned short doserr = 0;
unsigned short batname_seg;
unsigned short batname_off;
unsigned char eof_reached = 0;
unsigned short i;
/* help? reacts only to /? being passed as FIRST argument */
if ((p->argc > 0) && imatch(p->argv[0], "/?")) {
nls_outputnl(17,0); /* "Directs batch processing to a labelled line in the batch program." */
outputnl("");
nls_outputnl(17,1); /* "GOTO LABEL" */
outputnl("");
nls_outputnl(17,2); /* "LABEL specifies a text string used in the batch program as a label." */
outputnl("");
nls_outputnl(17,3); /* "A label is on a line by itself and must be preceded by a colon." */
return(CMD_OK);
}
/* not inside a batch file? not given any argument? then do nothing */
if ((p->rmod->bat == NULL) || (p->argc == 0)) return(CMD_OK);
/* label is in first arg */
label = p->argv[0];
/* open batch file (read-only) */
batname_seg = FP_SEG(p->rmod->bat->fname);
batname_off = FP_OFF(p->rmod->bat->fname);
_asm {
push bx
push dx
mov ax, batname_seg
push ds /* save ds */
mov ds, ax
mov dx, batname_off
mov ax, 0x3d00
int 0x21 /* handle in ax on success */
pop ds
jnc OPEN_SUCCESS
mov doserr, ax
OPEN_SUCCESS:
mov fhandle, ax /* save file handle */
pop dx
pop bx
}
/* file open failed? */
if (doserr != 0) {
nls_outputnl_doserr(doserr);
return(CMD_FAIL);
}
/* reset the rmod bat counter since I will scan all lines from top to bottom */
p->rmod->bat->nextline = 0; /* remember this is a byte offset, not a line number */
/* read bat file line by line until label is found or EOF */
for (;;) {
/* move any existing data to the start of the buffer */
if (bufflen > 0) memmove(p->BUFFER, buff, bufflen);
buff = p->BUFFER; /* assumption: must be big enough to hold 2 sectors (2 * 512) */
/* if buffer has less than 512b then load it with another sector (unless eof) */
if ((eof_reached == 0) && (bufflen < 512)) {
/* load 512b of data into buffer */
_asm {
push ax
push bx
push cx
push dx
pushf
mov ah, 0x3f /* read from file handle */
mov bx, fhandle /* file handle where to read from */
mov cx, 512 /* read 512 bytes (one sector) */
mov dx, buff /* target buffer */
add dx, bufflen /* data must follow existing pending data */
int 0x21 /* CF clear on success and AX=number of bytes read */
/* error? */
jnc READ_OK
mov doserr, ax
READ_OK:
add bufflen, ax
/* set eof if amount of bytes read is shorter than cx */
cmp ax, cx
je EOF_NOT_REACHED
mov eof_reached, byte ptr 1
EOF_NOT_REACHED:
popf
pop dx
pop cx
pop bx
pop ax
}
/* on error close the file and quit */
if (doserr != 0) {
goto_close_dos_handle(fhandle);
nls_outputnl_doserr(doserr);
return(CMD_FAIL);
}
}
/* advance buffer to first non-space/non-tab/non-CR/non-LF */
while (bufflen > 0) {
if ((*buff != ' ') && (*buff != '\t') && (*buff != '\r') && (*buff != '\n')) break;
bufflen--;
buff++;
p->rmod->bat->nextline++;
}
/* if the line does not start with a colon, then jump to next line */
if ((bufflen > 0) && (*buff != ':')) {
while ((bufflen > 0) && (*buff != '\n')) {
bufflen--;
buff++;
p->rmod->bat->nextline++;
}
}
/* refill buffer if needed */
if ((bufflen < 512) && (eof_reached == 0)) continue;
/* eof? */
if (bufflen == 0) break;
/* skip the colon */
if (*buff == ':') {
bufflen--;
buff++;
p->rmod->bat->nextline++;
}
/* skip any leading white spaces (space or tab) */
while (bufflen > 0) {
if ((*buff != ' ') && (*buff != '\t')) break;
bufflen--;
buff++;
p->rmod->bat->nextline++;
}
/* read the in-file label and compare it with what's in the label buff */
for (i = 0;; i++) {
/* if end of label then check if it is also end of in-file label (ends with space, tab, \r or \n) */
if ((i == bufflen) || (buff[i] == ' ') || (buff[i] == '\t') || (buff[i] == '\r') || (buff[i] == '\n')) {
if (label[i] == 0) {
/* match found -> close file, skip to end of line and quit */
while (bufflen > 0) {
bufflen--;
buff++;
p->rmod->bat->nextline++;
if (*buff == '\n') break;
}
goto_close_dos_handle(fhandle);
return(CMD_OK);
}
break;
}
/* end of label = mismatch */
if (label[i] == 0) break;
/* case-insensitive comparison */
if ((label[i] & 0xDF) != (buff[i] & 0xDF)) break;
}
/* no match, move forward to end of line and repeat */
while ((bufflen > 0) && (*buff != '\n')) {
bufflen--;
buff++;
p->rmod->bat->nextline++;
}
}
/* close the batch file handle */
goto_close_dos_handle(fhandle);
/* label not found, display error message and abort all batch scripts */
nls_outputnl(17, 10); /* "Label not found" */
rmod_free_bat_llist(p->rmod);
/* restore echo flag as it was before running the (first) bat file */
p->rmod->flags &= ~FLAG_ECHOFLAG;
if (p->rmod->flags & FLAG_ECHO_BEFORE_BAT) p->rmod->flags |= FLAG_ECHOFLAG;
return(CMD_FAIL);
}