WebSVN – SvarDOS – Diff – /svarcom/trunk/cmd/goto.c

 /* This file is part of the SvarCOM project and is published under the terms
  * of the MIT license.
+ *
- * Copyright (C) 2021 Mateusz Viste
+ * 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,
  * 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.
+ * 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], "/?")) {
-    outputnl("Directs batch processing to a labelled line in the batch program.");
+    nls_outputnl(17,0); /* "Directs batch processing to a labelled line in the batch program." */
     outputnl("");
-    outputnl("GOTO LABEL");
+    nls_outputnl(17,1); /* "GOTO LABEL" */
     outputnl("");
-    outputnl("LABEL specifies a text string used in the batch program as a label.");
+    nls_outputnl(17,2); /* "LABEL specifies a text string used in the batch program as a label." */
     outputnl("");
-    outputnl("A label is on a line by itself and must be preceded by a colon.");
+    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? then do nothing */
+  /* not inside a batch file? not given any argument? then do nothing */
-  if (p->rmod->bat == NULL) return(CMD_OK);
+  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++;
-  /* TODO open batch file and read it line by line until label is found or EOF */
+      p->rmod->bat->nextline++;
+    }
-  /* TODO if label not found, display error message and abort all batch scripts */
+    /* 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);
+          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);
+}

Subversion Repositories SvarDOS

(root)/svarcom/trunk/cmd/goto.c @ 1134 – Rev 962 → 964