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rts-transput.c

     
 //! @file rts-transput.c
 //! @author J. Marcel van der Veer
 
 //! @section Copyright
 //!
 //! This file is part of Algol68G - an Algol 68 compiler-interpreter.
 //! Copyright 2001-2025 J. Marcel van der Veer [algol68g@xs4all.nl].
 
 //! @section License
 //!
 //! This program is free software; you can redistribute it and/or modify it 
 //! under the terms of the GNU General Public License as published by the 
 //! Free Software Foundation; either version 3 of the License, or 
 //! (at your option) any later version.
 //!
 //! This program is distributed in the hope that it will be useful, but 
 //! WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 //! or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 
 //! more details. You should have received a copy of the GNU General Public 
 //! License along with this program. If not, see [http://www.gnu.org/licenses/].
 
 //! @section Synopsis 
 //!
 //! Transput routines.
 
 #include "a68g.h"
 #include "a68g-genie.h"
 #include "a68g-prelude.h"
 #include "a68g-transput.h"
 
 // Transput - General routines and unformatted transput.
 // But Eeyore wasn't listening. He was taking the balloon out, and putting
 // it back again, as happy as could be ... Winnie the Pooh, A.A. Milne.
 // - Revised Report on the Algorithmic Language Algol 68.
 
 // File table handling 
 // In a table we record opened files.
 // When execution ends, unclosed files are closed, and temps are removed.
 // This keeps /tmp free of spurious files :-)
 
 //! @brief Init a file entry.
 
 void init_file_entry (int k)
 {
   if (k >= 0 && k < MAX_OPEN_FILES) {
     FILE_ENTRY *fe = &(A68 (file_entries)[k]);
     POS (fe) = NO_NODE;
     IS_OPEN (fe) = A68_FALSE;
     IS_TMP (fe) = A68_FALSE;
     FD (fe) = A68_NO_FILE;
     IDF (fe) = nil_ref;
   }
 }
 
 //! @brief Initialise file entry table.
 
 void init_file_entries (void)
 {
   for (int k = 0; k < MAX_OPEN_FILES; k++) {
     init_file_entry (k);
   }
 }
 
 //! @brief Store file for later closing when not explicitly closed.
 
 int store_file_entry (NODE_T * p, FILE_T fd, char *idf, BOOL_T is_tmp)
 {
   for (int k = 0; k < MAX_OPEN_FILES; k++) {
     FILE_ENTRY *fe = &(A68 (file_entries)[k]);
     if (!IS_OPEN (fe)) {
       int len = 1 + (int) strlen (idf);
       POS (fe) = p;
       IS_OPEN (fe) = A68_TRUE;
       IS_TMP (fe) = is_tmp;
       FD (fe) = fd;
       IDF (fe) = heap_generator (p, M_C_STRING, len);
       BLOCK_GC_HANDLE (&(IDF (fe)));
       a68_bufcpy (DEREF (char, &IDF (fe)), idf, len);
       return k;
     }
   }
   diagnostic (A68_RUNTIME_ERROR, p, ERROR_TOO_MANY_OPEN_FILES);
   exit_genie (p, A68_RUNTIME_ERROR);
   return -1;
 }
 
 //! @brief Close file and delete temp file.
 
 void close_file_entry (NODE_T * p, int k)
 {
   if (k >= 0 && k < MAX_OPEN_FILES) {
     FILE_ENTRY *fe = &(A68 (file_entries)[k]);
     if (IS_OPEN (fe)) {
 // Close the file.
       if (FD (fe) != A68_NO_FILE && close (FD (fe)) == -1) {
         init_file_entry (k);
         diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_CLOSE);
         exit_genie (p, A68_RUNTIME_ERROR);
       }
       IS_OPEN (fe) = A68_FALSE;
     }
   }
 }
 
 //! @brief Close file and delete temp file.
 
 void free_file_entry (NODE_T * p, int k)
 {
   close_file_entry (p, k);
   if (k >= 0 && k < MAX_OPEN_FILES) {
     FILE_ENTRY *fe = &(A68 (file_entries)[k]);
     if (IS_OPEN (fe)) {
 // Attempt to remove a temp file, but ignore failure.
       if (FD (fe) != A68_NO_FILE && IS_TMP (fe)) {
         if (!IS_NIL (IDF (fe))) {
           char *filename;
           CHECK_INIT (p, INITIALISED (&(IDF (fe))), M_ROWS);
           filename = DEREF (char, &IDF (fe));
           if (filename != NO_TEXT) {
             (void) remove (filename);
           }
         }
       }
 // Restore the fields.
       if (!IS_NIL (IDF (fe))) {
         UNBLOCK_GC_HANDLE (&(IDF (fe)));
       }
       init_file_entry (k);
     }
   }
 }
 
 //! @brief Close all files and delete all temp files.
 
 void free_file_entries (void)
 {
   for (int k = 0; k < MAX_OPEN_FILES; k++) {
     free_file_entry (NO_NODE, k);
   }
 }
 
 // Strings in transput are of arbitrary size. For this, we have transput buffers.
 // A transput buffer is a REF STRUCT (INT size, index, STRING buffer).
 // It is in the heap, but cannot be gc'ed. If it is too small, we give up on
 // it and make a larger one.
 
 A68_REF ref_transput_buffer[MAX_TRANSPUT_BUFFER];
 
 //! @brief Set max number of chars in a transput buffer.
 
 void set_transput_buffer_size (int n, int size)
 {
   A68_INT *k = (A68_INT *) (ADDRESS (&ref_transput_buffer[n]));
   STATUS (k) = INIT_MASK;
   VALUE (k) = size;
 }
 
 //! @brief Set char index for transput buffer.
 
 void set_transput_buffer_index (int n, int cindex)
 {
   A68_INT *k = (A68_INT *) (ADDRESS (&ref_transput_buffer[n]) + SIZE (M_INT));
   STATUS (k) = INIT_MASK;
   VALUE (k) = cindex;
 }
 
 //! @brief Get max number of chars in a transput buffer.
 
 int get_transput_buffer_size (int n)
 {
   A68_INT *k = (A68_INT *) (ADDRESS (&ref_transput_buffer[n]));
   return VALUE (k);
 }
 
 //! @brief Get char index for transput buffer.
 
 int get_transput_buffer_index (int n)
 {
   A68_INT *k = (A68_INT *) (ADDRESS (&ref_transput_buffer[n]) + SIZE (M_INT));
   return VALUE (k);
 }
 
 //! @brief Get char[] from transput buffer.
 
 char *get_transput_buffer (int n)
 {
   return (char *) (ADDRESS (&ref_transput_buffer[n]) + 2 * SIZE (M_INT));
 }
 
 //! @brief Mark transput buffer as no longer in use.
 
 void unblock_transput_buffer (int n)
 {
   set_transput_buffer_index (n, -1);
 }
 
 //! @brief Find first unused transput buffer (for opening a file).
 
 int get_unblocked_transput_buffer (NODE_T * p)
 {
   for (int k = FIXED_TRANSPUT_BUFFERS; k < MAX_TRANSPUT_BUFFER; k++) {
     if (get_transput_buffer_index (k) == -1) {
       return k;
     }
   }
 // Oops!
   diagnostic (A68_RUNTIME_ERROR, p, ERROR_TOO_MANY_OPEN_FILES);
   exit_genie (p, A68_RUNTIME_ERROR);
   return -1;
 }
 
 //! @brief Empty contents of transput buffer.
 
 void reset_transput_buffer (int n)
 {
   set_transput_buffer_index (n, 0);
   (get_transput_buffer (n))[0] = NULL_CHAR;
 }
 
 //! @brief Initialise transput buffers before use.
 
 void init_transput_buffers (NODE_T * p)
 {
   for (int k = 0; k < MAX_TRANSPUT_BUFFER; k++) {
     ref_transput_buffer[k] = heap_generator (p, M_ROWS, 2 * SIZE (M_INT) + TRANSPUT_BUFFER_SIZE);
     BLOCK_GC_HANDLE (&ref_transput_buffer[k]);
     set_transput_buffer_size (k, TRANSPUT_BUFFER_SIZE);
     reset_transput_buffer (k);
   }
 // Last buffers are available for FILE values.
   for (int k = FIXED_TRANSPUT_BUFFERS; k < MAX_TRANSPUT_BUFFER; k++) {
     unblock_transput_buffer (k);
   }
 }
 
 //! @brief Make a transput buffer larger.
 
 void enlarge_transput_buffer (NODE_T * p, int k, int size)
 {
   int n = get_transput_buffer_index (k);
   char *sb_1 = get_transput_buffer (k), *sb_2;
   UNBLOCK_GC_HANDLE (&ref_transput_buffer[k]);
   ref_transput_buffer[k] = heap_generator (p, M_ROWS, 2 * SIZE (M_INT) + size);
   BLOCK_GC_HANDLE (&ref_transput_buffer[k]);
   set_transput_buffer_size (k, size);
   set_transput_buffer_index (k, n);
   sb_2 = get_transput_buffer (k);
   a68_bufcpy (sb_2, sb_1, size);
 }
 
 //! @brief Add char to transput buffer; if the buffer is full, make it larger.
 
 void plusab_transput_buffer (NODE_T * p, int k, char ch)
 {
   char *sb = get_transput_buffer (k);
   int size = get_transput_buffer_size (k);
   int n = get_transput_buffer_index (k);
   if (n == size - 2) {
     enlarge_transput_buffer (p, k, 10 * size);
     plusab_transput_buffer (p, k, ch);
   } else {
     sb[n] = ch;
     sb[n + 1] = NULL_CHAR;
     set_transput_buffer_index (k, n + 1);
   }
 }
 
 //! @brief Add char to transput buffer at the head; if the buffer is full, make it larger.
 
 void plusto_transput_buffer (NODE_T * p, char ch, int k)
 {
   char *sb = get_transput_buffer (k);
   int size = get_transput_buffer_size (k);
   int n = get_transput_buffer_index (k);
   if (n == size - 2) {
     enlarge_transput_buffer (p, k, 10 * size);
     plusto_transput_buffer (p, ch, k);
   } else {
     MOVE (&sb[1], &sb[0], (unt) size);
     sb[0] = ch;
     sb[n + 1] = NULL_CHAR;
     set_transput_buffer_index (k, n + 1);
   }
 }
 
 //! @brief Add chars to transput buffer.
 
 void add_chars_transput_buffer (NODE_T * p, int k, int N, char *ch)
 {
   for (int j = 0; j < N; j++) {
     plusab_transput_buffer (p, k, ch[j]);
   }
 }
 
 //! @brief Add char[] to transput buffer.
 
 void add_string_transput_buffer (NODE_T * p, int k, char *ch)
 {
   for (; ch[0] != NULL_CHAR; ch++) {
     plusab_transput_buffer (p, k, ch[0]);
   }
 }
 
 //! @brief Add A68 string to transput buffer.
 
 void add_a_string_transput_buffer (NODE_T * p, int k, BYTE_T * ref)
 {
   A68_REF row = *(A68_REF *) ref;
   CHECK_INIT (p, INITIALISED (&row), M_ROWS);
   A68_ARRAY *arr; A68_TUPLE *tup;
   GET_DESCRIPTOR (arr, tup, &row);
   if (ROW_SIZE (tup) > 0) {
     BYTE_T *base_address = DEREF (BYTE_T, &ARRAY (arr));
     for (int i = LWB (tup); i <= UPB (tup); i++) {
       int addr = INDEX_1_DIM (arr, tup, i);
       A68_CHAR *ch = (A68_CHAR *) & (base_address[addr]);
       CHECK_INIT (p, INITIALISED (ch), M_CHAR);
       plusab_transput_buffer (p, k, (char) VALUE (ch));
     }
   }
 }
 
 //! @brief Pop A68 string and add to buffer.
 
 void add_string_from_stack_transput_buffer (NODE_T * p, int k)
 {
   DECREMENT_STACK_POINTER (p, A68_REF_SIZE);
   add_a_string_transput_buffer (p, k, STACK_TOP);
 }
 
 //! @brief Pop first character from transput buffer.
 
 char pop_char_transput_buffer (int k)
 {
   char *sb = get_transput_buffer (k);
   int n = get_transput_buffer_index (k);
   if (n <= 0) {
     return NULL_CHAR;
   } else {
     char ch = sb[0];
     MOVE (&sb[0], &sb[1], n);
     set_transput_buffer_index (k, n - 1);
     return ch;
   }
 }
 
 //! @brief Add C string to A68 string.
 
 void add_c_string_to_a_string (NODE_T * p, A68_REF ref_str, char *s)
 {
   int len_2 = (int) strlen (s);
 // left part.
   CHECK_REF (p, ref_str, M_REF_STRING);
   A68_REF a = *DEREF (A68_REF, &ref_str);
   CHECK_INIT (p, INITIALISED (&a), M_STRING);
   A68_ARRAY *arr_1; A68_TUPLE *tup_1;
   GET_DESCRIPTOR (arr_1, tup_1, &a);
   int len_1 = ROW_SIZE (tup_1);
 // Sum string.
   A68_REF c = heap_generator (p, M_STRING, DESCRIPTOR_SIZE (1));
   A68_REF d = heap_generator_2 (p, M_STRING, len_1 + len_2, SIZE (M_CHAR));
 // Calculate again since garbage collector might have moved data.
 // Todo: GC should not move volatile data.
   GET_DESCRIPTOR (arr_1, tup_1, &a);
 // Make descriptor of new string.
   A68_ARRAY *arr_3; A68_TUPLE *tup_3;
   GET_DESCRIPTOR (arr_3, tup_3, &c);
   DIM (arr_3) = 1;
   MOID (arr_3) = M_CHAR;
   ELEM_SIZE (arr_3) = SIZE (M_CHAR);
   SLICE_OFFSET (arr_3) = 0;
   FIELD_OFFSET (arr_3) = 0;
   ARRAY (arr_3) = d;
   LWB (tup_3) = 1;
   UPB (tup_3) = len_1 + len_2;
   SHIFT (tup_3) = LWB (tup_3);
   SPAN (tup_3) = 1;
 // add strings.
   BYTE_T *b_1 = (ROW_SIZE (tup_1) > 0 ? DEREF (BYTE_T, &ARRAY (arr_1)) : NO_BYTE);
   BYTE_T *b_3 = DEREF (BYTE_T, &ARRAY (arr_3));
   int u = 0;
   for (int v = LWB (tup_1); v <= UPB (tup_1); v++) {
     MOVE ((BYTE_T *) & b_3[u], (BYTE_T *) & b_1[INDEX_1_DIM (arr_1, tup_1, v)], SIZE (M_CHAR));
     u += SIZE (M_CHAR);
   }
   for (int v = 0; v < len_2; v++) {
     A68_CHAR ch;
     STATUS (&ch) = INIT_MASK;
     VALUE (&ch) = s[v];
     MOVE ((BYTE_T *) & b_3[u], (BYTE_T *) & ch, SIZE (M_CHAR));
     u += SIZE (M_CHAR);
   }
   *DEREF (A68_REF, &ref_str) = c;
 }
 
 //! @brief Purge buffer for file.
 
 void write_purge_buffer (NODE_T * p, A68_REF ref_file, int k)
 {
   A68_FILE *file = FILE_DEREF (&ref_file);
   if (IS_NIL (STRING (file))) {
     if (!(FD (file) == A68_STDOUT && A68 (halt_typing))) {
       WRITE (FD (file), get_transput_buffer (k));
     }
   } else {
     add_c_string_to_a_string (p, STRING (file), get_transput_buffer (k));
   }
   reset_transput_buffer (k);
 }
 
 // Routines that involve the A68 expression stack.
 
 //! @brief Allocate a temporary string on the stack.
 
 char *stack_string (NODE_T * p, int size)
 {
   char *new_str = (char *) STACK_TOP;
   INCREMENT_STACK_POINTER (p, size);
   if (A68_SP > A68 (expr_stack_limit)) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_STACK_OVERFLOW);
     exit_genie (p, A68_RUNTIME_ERROR);
   }
   FILL (new_str, NULL_CHAR, size);
   return new_str;
 }
 
 // Transput basic RTS routines.
 
 //! @brief REF FILE standin
 
 void genie_stand_in (NODE_T * p)
 {
   PUSH_REF (p, A68 (stand_in));
 }
 
 //! @brief REF FILE standout
 
 void genie_stand_out (NODE_T * p)
 {
   PUSH_REF (p, A68 (stand_out));
 }
 
 //! @brief REF FILE standback
 
 void genie_stand_back (NODE_T * p)
 {
   PUSH_REF (p, A68 (stand_back));
 }
 
 //! @brief REF FILE standerror
 
 void genie_stand_error (NODE_T * p)
 {
   PUSH_REF (p, A68 (stand_error));
 }
 
 //! @brief CHAR error char
 
 void genie_error_char (NODE_T * p)
 {
   PUSH_VALUE (p, ERROR_CHAR, A68_CHAR);
 }
 
 //! @brief CHAR exp char
 
 void genie_exp_char (NODE_T * p)
 {
   PUSH_VALUE (p, EXPONENT_CHAR, A68_CHAR);
 }
 
 //! @brief CHAR flip char
 
 void genie_flip_char (NODE_T * p)
 {
   PUSH_VALUE (p, FLIP_CHAR, A68_CHAR);
 }
 
 //! @brief CHAR flop char
 
 void genie_flop_char (NODE_T * p)
 {
   PUSH_VALUE (p, FLOP_CHAR, A68_CHAR);
 }
 
 //! @brief CHAR null char
 
 void genie_null_char (NODE_T * p)
 {
   PUSH_VALUE (p, NULL_CHAR, A68_CHAR);
 }
 
 //! @brief CHAR blank
 
 void genie_blank_char (NODE_T * p)
 {
   PUSH_VALUE (p, BLANK_CHAR, A68_CHAR);
 }
 
 //! @brief CHAR newline char
 
 void genie_newline_char (NODE_T * p)
 {
   PUSH_VALUE (p, NEWLINE_CHAR, A68_CHAR);
 }
 
 //! @brief CHAR formfeed char
 
 void genie_formfeed_char (NODE_T * p)
 {
   PUSH_VALUE (p, FORMFEED_CHAR, A68_CHAR);
 }
 
 //! @brief CHAR tab char
 
 void genie_tab_char (NODE_T * p)
 {
   PUSH_VALUE (p, TAB_CHAR, A68_CHAR);
 }
 
 //! @brief CHANNEL standin channel
 
 void genie_stand_in_channel (NODE_T * p)
 {
   PUSH_OBJECT (p, A68 (stand_in_channel), A68_CHANNEL);
 }
 
 //! @brief CHANNEL standout channel
 
 void genie_stand_out_channel (NODE_T * p)
 {
   PUSH_OBJECT (p, A68 (stand_out_channel), A68_CHANNEL);
 }
 
 //! @brief CHANNEL stand draw channel
 
 void genie_stand_draw_channel (NODE_T * p)
 {
   PUSH_OBJECT (p, A68 (stand_draw_channel), A68_CHANNEL);
 }
 
 //! @brief CHANNEL standback channel
 
 void genie_stand_back_channel (NODE_T * p)
 {
   PUSH_OBJECT (p, A68 (stand_back_channel), A68_CHANNEL);
 }
 
 //! @brief CHANNEL standerror channel
 
 void genie_stand_error_channel (NODE_T * p)
 {
   PUSH_OBJECT (p, A68 (stand_error_channel), A68_CHANNEL);
 }
 
 //! @brief PROC STRING program idf
 
 void genie_program_idf (NODE_T * p)
 {
   PUSH_REF (p, c_to_a_string (p, FILE_SOURCE_NAME (&A68_JOB), DEFAULT_WIDTH));
 }
 
 // FILE and CHANNEL initialisations.
 
 //! @brief Set_default_event_procedure.
 
 void set_default_event_procedure (A68_PROCEDURE * z)
 {
   STATUS (z) = INIT_MASK;
   NODE (&(BODY (z))) = NO_NODE;
   ENVIRON (z) = 0;
 }
 
 //! @brief Initialise channel.
 
 void init_channel (A68_CHANNEL * chan, BOOL_T r, BOOL_T s, BOOL_T g, BOOL_T p, BOOL_T b, BOOL_T d)
 {
   STATUS (chan) = INIT_MASK;
   RESET (chan) = r;
   SET (chan) = s;
   GET (chan) = g;
   PUT (chan) = p;
   BIN (chan) = b;
   DRAW (chan) = d;
   COMPRESS (chan) = A68_TRUE;
 }
 
 //! @brief Set default event handlers.
 
 void set_default_event_procedures (A68_FILE * f)
 {
   set_default_event_procedure (&(FILE_END_MENDED (f)));
   set_default_event_procedure (&(PAGE_END_MENDED (f)));
   set_default_event_procedure (&(LINE_END_MENDED (f)));
   set_default_event_procedure (&(VALUE_ERROR_MENDED (f)));
   set_default_event_procedure (&(OPEN_ERROR_MENDED (f)));
   set_default_event_procedure (&(TRANSPUT_ERROR_MENDED (f)));
   set_default_event_procedure (&(FORMAT_END_MENDED (f)));
   set_default_event_procedure (&(FORMAT_ERROR_MENDED (f)));
 }
 
 //! @brief Set up a REF FILE object.
 
 void init_file (NODE_T * p, A68_REF * ref_file, A68_CHANNEL c, FILE_T s, BOOL_T rm, BOOL_T wm, BOOL_T cm, char *env)
 {
   char *filename = (env == NO_TEXT ? NO_TEXT : getenv (env));
   *ref_file = heap_generator (p, M_REF_FILE, SIZE (M_FILE));
   BLOCK_GC_HANDLE (ref_file);
   A68_FILE *f = FILE_DEREF (ref_file);
   STATUS (f) = INIT_MASK;
   TERMINATOR (f) = nil_ref;
   CHANNEL (f) = c;
   if (filename != NO_TEXT && strlen (filename) > 0) {
     int len = 1 + (int) strlen (filename);
     IDENTIFICATION (f) = heap_generator (p, M_C_STRING, len);
     BLOCK_GC_HANDLE (&(IDENTIFICATION (f)));
     a68_bufcpy (DEREF (char, &IDENTIFICATION (f)), filename, len);
     FD (f) = A68_NO_FILE;
     READ_MOOD (f) = A68_FALSE;
     WRITE_MOOD (f) = A68_FALSE;
     CHAR_MOOD (f) = A68_FALSE;
     DRAW_MOOD (f) = A68_FALSE;
   } else {
     IDENTIFICATION (f) = nil_ref;
     FD (f) = s;
     READ_MOOD (f) = rm;
     WRITE_MOOD (f) = wm;
     CHAR_MOOD (f) = cm;
     DRAW_MOOD (f) = A68_FALSE;
   }
   TRANSPUT_BUFFER (f) = get_unblocked_transput_buffer (p);
   reset_transput_buffer (TRANSPUT_BUFFER (f));
   END_OF_FILE (f) = A68_FALSE;
   TMP_FILE (f) = A68_FALSE;
   OPENED (f) = A68_TRUE;
   OPEN_EXCLUSIVE (f) = A68_FALSE;
   FORMAT (f) = nil_format;
   STRING (f) = nil_ref;
   STRPOS (f) = 0;
   FILE_ENTRY (f) = -1;
   set_default_event_procedures (f);
 }
 
 //! @brief Initialise the transput RTL.
 
 void genie_init_transput (NODE_T * p)
 {
   init_transput_buffers (p);
 // Channels.
   init_channel (&(A68 (stand_in_channel)), A68_FALSE, A68_FALSE, A68_TRUE, A68_FALSE, A68_FALSE, A68_FALSE);
   init_channel (&(A68 (stand_out_channel)), A68_FALSE, A68_FALSE, A68_FALSE, A68_TRUE, A68_FALSE, A68_FALSE);
   init_channel (&(A68 (stand_back_channel)), A68_TRUE, A68_TRUE, A68_TRUE, A68_TRUE, A68_TRUE, A68_FALSE);
   init_channel (&(A68 (stand_error_channel)), A68_FALSE, A68_FALSE, A68_FALSE, A68_TRUE, A68_FALSE, A68_FALSE);
   init_channel (&(A68 (associate_channel)), A68_TRUE, A68_TRUE, A68_TRUE, A68_TRUE, A68_TRUE, A68_FALSE);
   init_channel (&(A68 (skip_channel)), A68_FALSE, A68_FALSE, A68_FALSE, A68_FALSE, A68_FALSE, A68_FALSE);
 #if defined (HAVE_GNU_PLOTUTILS)
   init_channel (&(A68 (stand_draw_channel)), A68_FALSE, A68_FALSE, A68_FALSE, A68_FALSE, A68_FALSE, A68_TRUE);
 #else
   init_channel (&(A68 (stand_draw_channel)), A68_FALSE, A68_FALSE, A68_FALSE, A68_FALSE, A68_FALSE, A68_TRUE);
 #endif
 // Files.
   init_file (p, &(A68 (stand_in)), A68 (stand_in_channel), A68_STDIN, A68_TRUE, A68_FALSE, A68_TRUE, "A68_STANDIN");
   init_file (p, &(A68 (stand_out)), A68 (stand_out_channel), A68_STDOUT, A68_FALSE, A68_TRUE, A68_TRUE, "A68_STANDOUT");
   init_file (p, &(A68 (stand_back)), A68 (stand_back_channel), A68_NO_FILE, A68_FALSE, A68_FALSE, A68_FALSE, NO_TEXT);
   init_file (p, &(A68 (stand_error)), A68 (stand_error_channel), A68_STDERR, A68_FALSE, A68_TRUE, A68_TRUE, "A68_STANDERROR");
   init_file (p, &(A68 (skip_file)), A68 (skip_channel), A68_NO_FILE, A68_FALSE, A68_FALSE, A68_FALSE, NO_TEXT);
 }
 
 //! @brief PROC (REF FILE) STRING idf
 
 void genie_idf (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   ref_file = *(A68_REF *) STACK_TOP;
   A68_REF ref_filename = IDENTIFICATION (FILE_DEREF (&ref_file));
   CHECK_REF (p, ref_filename, M_ROWS);
   char *filename = DEREF (char, &ref_filename);
   PUSH_REF (p, c_to_a_string (p, filename, DEFAULT_WIDTH));
 }
 
 //! @brief PROC (REF FILE) STRING term
 
 void genie_term (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   ref_file = *(A68_REF *) STACK_TOP;
   A68_REF ref_term = TERMINATOR (FILE_DEREF (&ref_file));
   CHECK_REF (p, ref_term, M_ROWS);
   char *term = DEREF (char, &ref_term);
   PUSH_REF (p, c_to_a_string (p, term, DEFAULT_WIDTH));
 }
 
 //! @brief PROC (REF FILE, STRING) VOID make term
 
 void genie_make_term (NODE_T * p)
 {
   A68_REF ref_file, str;
   POP_REF (p, &str);
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   ref_file = *(A68_REF *) STACK_TOP;
   A68_FILE *file = FILE_DEREF (&ref_file);
 // Don't check initialisation so we can "make term" before opening.
   int size = a68_string_size (p, str);
   if (INITIALISED (&(TERMINATOR (file))) && !IS_NIL (TERMINATOR (file))) {
     UNBLOCK_GC_HANDLE (&(TERMINATOR (file)));
   }
   TERMINATOR (file) = heap_generator (p, M_C_STRING, 1 + size);
   BLOCK_GC_HANDLE (&(TERMINATOR (file)));
   ASSERT (a_to_c_string (p, DEREF (char, &TERMINATOR (file)), str) != NO_TEXT);
 }
 
 //! @brief PROC (REF FILE) BOOL put possible
 
 void genie_put_possible (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   PUSH_VALUE (p, PUT (&CHANNEL (file)), A68_BOOL);
 }
 
 //! @brief PROC (REF FILE) BOOL get possible
 
 void genie_get_possible (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   PUSH_VALUE (p, GET (&CHANNEL (file)), A68_BOOL);
 }
 
 //! @brief PROC (REF FILE) BOOL bin possible
 
 void genie_bin_possible (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   PUSH_VALUE (p, BIN (&CHANNEL (file)), A68_BOOL);
 }
 
 //! @brief PROC (REF FILE) BOOL set possible
 
 void genie_set_possible (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   PUSH_VALUE (p, SET (&CHANNEL (file)), A68_BOOL);
 }
 
 //! @brief PROC (REF FILE) BOOL reidf possible
 
 void genie_reidf_possible (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   PUSH_VALUE (p, A68_FALSE, A68_BOOL);
 }
 
 //! @brief PROC (REF FILE) BOOL reset possible
 
 void genie_reset_possible (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   PUSH_VALUE (p, RESET (&CHANNEL (file)), A68_BOOL);
 }
 
 //! @brief PROC (REF FILE) BOOL compressible
 
 void genie_compressible (NODE_T * p)
 {
   A68_REF ref_file;
   A68_FILE *file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   PUSH_VALUE (p, COMPRESS (&CHANNEL (file)), A68_BOOL);
 }
 
 //! @brief PROC (REF FILE) BOOL draw possible
 
 void genie_draw_possible (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   PUSH_VALUE (p, DRAW (&CHANNEL (file)), A68_BOOL);
 }
 
 //! @brief PROC (REF FILE, STRING, CHANNEL) INT open
 
 void genie_open (NODE_T * p)
 {
   A68_CHANNEL channel;
   POP_OBJECT (p, &channel, A68_CHANNEL);
   A68_REF ref_iden;
   POP_REF (p, &ref_iden);
   CHECK_REF (p, ref_iden, M_REF_STRING);
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   STATUS (file) = INIT_MASK;
   FILE_ENTRY (file) = -1;
   CHANNEL (file) = channel;
   OPENED (file) = A68_TRUE;
   OPEN_EXCLUSIVE (file) = A68_FALSE;
   READ_MOOD (file) = A68_FALSE;
   WRITE_MOOD (file) = A68_FALSE;
   CHAR_MOOD (file) = A68_FALSE;
   DRAW_MOOD (file) = A68_FALSE;
   TMP_FILE (file) = A68_FALSE;
   int size = a68_string_size (p, ref_iden);
   if (INITIALISED (&(IDENTIFICATION (file))) && !IS_NIL (IDENTIFICATION (file))) {
     UNBLOCK_GC_HANDLE (&(IDENTIFICATION (file)));
   }
   IDENTIFICATION (file) = heap_generator (p, M_C_STRING, 1 + size);
   BLOCK_GC_HANDLE (&(IDENTIFICATION (file)));
   ASSERT (a_to_c_string (p, DEREF (char, &IDENTIFICATION (file)), ref_iden) != NO_TEXT);
   TERMINATOR (file) = nil_ref;
   FORMAT (file) = nil_format;
   FD (file) = A68_NO_FILE;
   if (INITIALISED (&(STRING (file))) && !IS_NIL (STRING (file))) {
     UNBLOCK_GC_HANDLE (DEREF (A68_REF, &STRING (file)));
   }
   STRING (file) = nil_ref;
   STRPOS (file) = 0;
   DEVICE_MADE (&DEVICE (file)) = A68_FALSE;
   STREAM (&DEVICE (file)) = NO_STREAM;
   set_default_event_procedures (file);
   {
     struct stat status;
     if (stat (DEREF (char, &IDENTIFICATION (file)), &status) == 0) {
       PUSH_VALUE (p, (S_ISREG (ST_MODE (&status)) != 0 ? 0 : 1), A68_INT);
     } else {
       PUSH_VALUE (p, 1, A68_INT);
     }
     errno = 0;
   }
 }
 
 //! @brief PROC (REF FILE, STRING, CHANNEL) INT establish
 
 void genie_establish (NODE_T * p)
 {
   A68_CHANNEL channel;
   POP_OBJECT (p, &channel, A68_CHANNEL);
   A68_REF ref_iden;
   POP_REF (p, &ref_iden);
   CHECK_REF (p, ref_iden, M_REF_STRING);
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   STATUS (file) = INIT_MASK;
   FILE_ENTRY (file) = -1;
   CHANNEL (file) = channel;
   OPENED (file) = A68_TRUE;
   OPEN_EXCLUSIVE (file) = A68_TRUE;
   READ_MOOD (file) = A68_FALSE;
   WRITE_MOOD (file) = A68_FALSE;
   CHAR_MOOD (file) = A68_FALSE;
   DRAW_MOOD (file) = A68_FALSE;
   TMP_FILE (file) = A68_FALSE;
   if (!PUT (&CHANNEL (file))) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_CHANNEL_DOES_NOT_ALLOW, "putting");
     exit_genie (p, A68_RUNTIME_ERROR);
   }
   int size = a68_string_size (p, ref_iden);
   if (INITIALISED (&(IDENTIFICATION (file))) && !IS_NIL (IDENTIFICATION (file))) {
     UNBLOCK_GC_HANDLE (&(IDENTIFICATION (file)));
   }
   IDENTIFICATION (file) = heap_generator (p, M_C_STRING, 1 + size);
   BLOCK_GC_HANDLE (&(IDENTIFICATION (file)));
   ASSERT (a_to_c_string (p, DEREF (char, &IDENTIFICATION (file)), ref_iden) != NO_TEXT);
   TERMINATOR (file) = nil_ref;
   FORMAT (file) = nil_format;
   FD (file) = A68_NO_FILE;
   if (INITIALISED (&(STRING (file))) && !IS_NIL (STRING (file))) {
     UNBLOCK_GC_HANDLE (DEREF (A68_REF, &STRING (file)));
   }
   STRING (file) = nil_ref;
   STRPOS (file) = 0;
   DEVICE_MADE (&DEVICE (file)) = A68_FALSE;
   STREAM (&DEVICE (file)) = NO_STREAM;
   set_default_event_procedures (file);
   PUSH_VALUE (p, 0, A68_INT);
 }
 
 //! @brief PROC (REF FILE, CHANNEL) INT create
 
 void genie_create (NODE_T * p)
 {
   A68_CHANNEL channel;
   POP_OBJECT (p, &channel, A68_CHANNEL);
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   STATUS (file) = INIT_MASK;
   FILE_ENTRY (file) = -1;
   CHANNEL (file) = channel;
   OPENED (file) = A68_TRUE;
   OPEN_EXCLUSIVE (file) = A68_FALSE;
   READ_MOOD (file) = A68_FALSE;
   WRITE_MOOD (file) = A68_FALSE;
   CHAR_MOOD (file) = A68_FALSE;
   DRAW_MOOD (file) = A68_FALSE;
   TMP_FILE (file) = A68_TRUE;
   if (INITIALISED (&(IDENTIFICATION (file))) && !IS_NIL (IDENTIFICATION (file))) {
     UNBLOCK_GC_HANDLE (&(IDENTIFICATION (file)));
   }
   IDENTIFICATION (file) = nil_ref;
   TERMINATOR (file) = nil_ref;
   FORMAT (file) = nil_format;
   FD (file) = A68_NO_FILE;
   if (INITIALISED (&(STRING (file))) && !IS_NIL (STRING (file))) {
     UNBLOCK_GC_HANDLE (DEREF (A68_REF, &STRING (file)));
   }
   STRING (file) = nil_ref;
   STRPOS (file) = 0;
   DEVICE_MADE (&DEVICE (file)) = A68_FALSE;
   STREAM (&DEVICE (file)) = NO_STREAM;
   set_default_event_procedures (file);
   PUSH_VALUE (p, 0, A68_INT);
 }
 
 //! @brief PROC (REF FILE, REF STRING) VOID associate
 
 void genie_associate (NODE_T * p)
 {
   A68_REF ref_string;
   POP_REF (p, &ref_string);
   CHECK_REF (p, ref_string, M_REF_STRING);
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   if (IS_IN_HEAP (&ref_file) && !IS_IN_HEAP (&ref_string)) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_SCOPE_DYNAMIC_1, M_REF_STRING);
     exit_genie (p, A68_RUNTIME_ERROR);
   } else if (IS_IN_FRAME (&ref_file) && IS_IN_FRAME (&ref_string)) {
     if (REF_SCOPE (&ref_string) > REF_SCOPE (&ref_file)) {
       diagnostic (A68_RUNTIME_ERROR, p, ERROR_SCOPE_DYNAMIC_1, M_REF_STRING);
       exit_genie (p, A68_RUNTIME_ERROR);
     }
   }
   A68_FILE *file = FILE_DEREF (&ref_file);
   STATUS (file) = INIT_MASK;
   FILE_ENTRY (file) = -1;
   CHANNEL (file) = A68 (associate_channel);
   OPENED (file) = A68_TRUE;
   OPEN_EXCLUSIVE (file) = A68_FALSE;
   READ_MOOD (file) = A68_FALSE;
   WRITE_MOOD (file) = A68_FALSE;
   CHAR_MOOD (file) = A68_FALSE;
   DRAW_MOOD (file) = A68_FALSE;
   TMP_FILE (file) = A68_FALSE;
   if (INITIALISED (&(IDENTIFICATION (file))) && !IS_NIL (IDENTIFICATION (file))) {
     UNBLOCK_GC_HANDLE (&(IDENTIFICATION (file)));
   }
   IDENTIFICATION (file) = nil_ref;
   TERMINATOR (file) = nil_ref;
   FORMAT (file) = nil_format;
   FD (file) = A68_NO_FILE;
   if (INITIALISED (&(STRING (file))) && !IS_NIL (STRING (file))) {
     UNBLOCK_GC_HANDLE (DEREF (A68_REF, &STRING (file)));
   }
   STRING (file) = ref_string;
   BLOCK_GC_HANDLE ((A68_REF *) (&(STRING (file))));
   STRPOS (file) = 0;
   DEVICE_MADE (&DEVICE (file)) = A68_FALSE;
   STREAM (&DEVICE (file)) = NO_STREAM;
   set_default_event_procedures (file);
 }
 
 //! @brief PROC (REF FILE) VOID close
 
 void genie_close (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   if (!OPENED (file) || (!READ_MOOD (file) && !WRITE_MOOD (file) && !DRAW_MOOD (file))) {
     return;
   }
   DEVICE_MADE (&DEVICE (file)) = A68_FALSE;
 #if defined (HAVE_GNU_PLOTUTILS)
   if (DEVICE_OPENED (&DEVICE (file))) {
     ASSERT (close_device (p, file) == A68_TRUE);
     STREAM (&DEVICE (file)) = NO_STREAM;
     return;
   }
 #endif
   FD (file) = A68_NO_FILE;
   OPENED (file) = A68_FALSE;
   unblock_transput_buffer (TRANSPUT_BUFFER (file));
   set_default_event_procedures (file);
   free_file_entry (p, FILE_ENTRY (file));
 }
 
 //! @brief PROC (REF FILE) VOID lock
 
 void genie_lock (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   if (!OPENED (file) || (!READ_MOOD (file) && !WRITE_MOOD (file) && !DRAW_MOOD (file))) {
     return;
   }
   DEVICE_MADE (&DEVICE (file)) = A68_FALSE;
 #if defined (HAVE_GNU_PLOTUTILS)
   if (DEVICE_OPENED (&DEVICE (file))) {
     ASSERT (close_device (p, file) == A68_TRUE);
     STREAM (&DEVICE (file)) = NO_STREAM;
     return;
   }
 #endif
 #if defined (BUILD_UNIX)
   errno = 0;
   ASSERT (fchmod (FD (file), (mode_t) 0x0) != -1);
 #endif
   if (FD (file) != A68_NO_FILE && close (FD (file)) == -1) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_LOCK);
     exit_genie (p, A68_RUNTIME_ERROR);
   } else {
     FD (file) = A68_NO_FILE;
     OPENED (file) = A68_FALSE;
     unblock_transput_buffer (TRANSPUT_BUFFER (file));
     set_default_event_procedures (file);
   }
   free_file_entry (p, FILE_ENTRY (file));
 }
 
 //! @brief PROC (REF FILE) VOID erase
 
 void genie_erase (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   if (!OPENED (file) || (!READ_MOOD (file) && !WRITE_MOOD (file) && !DRAW_MOOD (file))) {
     return;
   }
   DEVICE_MADE (&DEVICE (file)) = A68_FALSE;
 #if defined (HAVE_GNU_PLOTUTILS)
   if (DEVICE_OPENED (&DEVICE (file))) {
     ASSERT (close_device (p, file) == A68_TRUE);
     STREAM (&DEVICE (file)) = NO_STREAM;
     return;
   }
 #endif
   if (FD (file) != A68_NO_FILE && close (FD (file)) == -1) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_SCRATCH);
     exit_genie (p, A68_RUNTIME_ERROR);
   } else {
     unblock_transput_buffer (TRANSPUT_BUFFER (file));
     set_default_event_procedures (file);
   }
 // Remove the file.
   if (!IS_NIL (IDENTIFICATION (file))) {
     char *filename;
     CHECK_INIT (p, INITIALISED (&(IDENTIFICATION (file))), M_ROWS);
     filename = DEREF (char, &IDENTIFICATION (file));
     if (remove (filename) != 0) {
       diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_SCRATCH);
       exit_genie (p, A68_RUNTIME_ERROR);
     }
     UNBLOCK_GC_HANDLE (&(IDENTIFICATION (file)));
     IDENTIFICATION (file) = nil_ref;
   }
   init_file_entry (FILE_ENTRY (file));
 }
 
 //! @brief PROC (REF FILE) VOID backspace
 
 void genie_backspace (NODE_T * p)
 {
   ADDR_T pop_sp = A68_SP;
   PUSH_VALUE (p, -1, A68_INT);
   genie_set (p);
   A68_SP = pop_sp;
 }
 
 //! @brief PROC (REF FILE, INT) INT set
 
 void genie_set (NODE_T * p)
 {
   A68_INT pos;
   POP_OBJECT (p, &pos, A68_INT);
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   if (!OPENED (file)) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_NOT_OPEN);
     exit_genie (p, A68_RUNTIME_ERROR);
   }
   if (!SET (&CHANNEL (file))) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_CANT_SET);
     exit_genie (p, A68_RUNTIME_ERROR);
   }
   if (!IS_NIL (STRING (file))) {
     A68_REF z = *DEREF (A68_REF, &STRING (file));
     int size;
 // Circumvent buffering problems.
     STRPOS (file) -= get_transput_buffer_index (TRANSPUT_BUFFER (file));
     ASSERT (STRPOS (file) > 0);
     reset_transput_buffer (TRANSPUT_BUFFER (file));
 // Now set.
     CHECK_INT_ADDITION (p, STRPOS (file), VALUE (&pos));
     STRPOS (file) += VALUE (&pos);
     A68_ARRAY *arr; A68_TUPLE *tup;
     GET_DESCRIPTOR (arr, tup, &z);
     size = ROW_SIZE (tup);
     if (size <= 0 || STRPOS (file) < 0 || STRPOS (file) >= size) {
       A68_BOOL res;
       on_event_handler (p, FILE_END_MENDED (FILE_DEREF (&ref_file)), ref_file);
       POP_OBJECT (p, &res, A68_BOOL);
       if (VALUE (&res) == A68_FALSE) {
         diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_ENDED);
         exit_genie (p, A68_RUNTIME_ERROR);
       }
     }
     PUSH_VALUE (p, STRPOS (file), A68_INT);
   } else if (FD (file) == A68_NO_FILE) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_RESET);
     exit_genie (p, A68_RUNTIME_ERROR);
   } else {
     errno = 0;
     __off_t curpos = lseek (FD (file), 0, SEEK_CUR);
     __off_t maxpos = lseek (FD (file), 0, SEEK_END);
 // Circumvent buffering problems.
     int reserve = get_transput_buffer_index (TRANSPUT_BUFFER (file));
     curpos -= (__off_t) reserve;
     __off_t res = lseek (FD (file), -reserve, SEEK_CUR);
     ASSERT (res != -1 && errno == 0);
     reset_transput_buffer (TRANSPUT_BUFFER (file));
 // Now set.
     CHECK_INT_ADDITION (p, curpos, VALUE (&pos));
     curpos += VALUE (&pos);
     if (curpos < 0 || curpos >= maxpos) {
       A68_BOOL ret;
       on_event_handler (p, FILE_END_MENDED (FILE_DEREF (&ref_file)), ref_file);
       POP_OBJECT (p, &ret, A68_BOOL);
       if (VALUE (&ret) == A68_FALSE) {
         diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_ENDED);
         exit_genie (p, A68_RUNTIME_ERROR);
       }
       PUSH_VALUE (p, (int) lseek (FD (file), 0, SEEK_CUR), A68_INT);
     } else {
       res = lseek (FD (file), curpos, SEEK_SET);
       if (res == -1 || errno != 0) {
         diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_SET);
         exit_genie (p, A68_RUNTIME_ERROR);
       }
       PUSH_VALUE (p, (int) res, A68_INT);
     }
   }
 }
 
 //! @brief PROC (REF FILE) VOID reset
 
 void genie_reset (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   if (!OPENED (file)) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_NOT_OPEN);
     exit_genie (p, A68_RUNTIME_ERROR);
   }
   if (!RESET (&CHANNEL (file))) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_CANT_RESET);
     exit_genie (p, A68_RUNTIME_ERROR);
   }
   if (IS_NIL (STRING (file))) {
     close_file_entry (p, FILE_ENTRY (file));
   } else {
     STRPOS (file) = 0;
   }
   READ_MOOD (file) = A68_FALSE;
   WRITE_MOOD (file) = A68_FALSE;
   CHAR_MOOD (file) = A68_FALSE;
   DRAW_MOOD (file) = A68_FALSE;
   FD (file) = A68_NO_FILE;
 //  set_default_event_procedures (file);.
 }
 
 //! @brief PROC (REF FILE, PROC (REF FILE) BOOL) VOID on file end
 
 void genie_on_file_end (NODE_T * p)
 {
   A68_PROCEDURE z;
   POP_PROCEDURE (p, &z);
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   FILE_END_MENDED (file) = z;
 }
 
 //! @brief PROC (REF FILE, PROC (REF FILE) BOOL) VOID on page end
 
 void genie_on_page_end (NODE_T * p)
 {
   A68_PROCEDURE z;
   POP_PROCEDURE (p, &z);
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   PAGE_END_MENDED (file) = z;
 }
 
 //! @brief PROC (REF FILE, PROC (REF FILE) BOOL) VOID on line end
 
 void genie_on_line_end (NODE_T * p)
 {
   A68_PROCEDURE z;
   POP_PROCEDURE (p, &z);
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   LINE_END_MENDED (file) = z;
 }
 
 //! @brief PROC (REF FILE, PROC (REF FILE) BOOL) VOID on format end
 
 void genie_on_format_end (NODE_T * p)
 {
   A68_PROCEDURE z;
   POP_PROCEDURE (p, &z);
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   FORMAT_END_MENDED (file) = z;
 }
 
 //! @brief PROC (REF FILE, PROC (REF FILE) BOOL) VOID on format error
 
 void genie_on_format_error (NODE_T * p)
 {
   A68_PROCEDURE z;
   POP_PROCEDURE (p, &z);
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   FORMAT_ERROR_MENDED (file) = z;
 }
 
 //! @brief PROC (REF FILE, PROC (REF FILE) BOOL) VOID on value error
 
 void genie_on_value_error (NODE_T * p)
 {
   A68_PROCEDURE z;
   POP_PROCEDURE (p, &z);
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   VALUE_ERROR_MENDED (file) = z;
 }
 
 //! @brief PROC (REF FILE, PROC (REF FILE) BOOL) VOID on open error
 
 void genie_on_open_error (NODE_T * p)
 {
   A68_PROCEDURE z;
   POP_PROCEDURE (p, &z);
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   OPEN_ERROR_MENDED (file) = z;
 }
 
 //! @brief PROC (REF FILE, PROC (REF FILE) BOOL) VOID on transput error
 
 void genie_on_transput_error (NODE_T * p)
 {
   A68_PROCEDURE z;
   POP_PROCEDURE (p, &z);
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   TRANSPUT_ERROR_MENDED (file) = z;
 }
 
 //! @brief Invoke event routine.
 
 void on_event_handler (NODE_T * p, A68_PROCEDURE z, A68_REF ref_file)
 {
   if (NODE (&(BODY (&z))) == NO_NODE) {
 // Default procedure.
     PUSH_VALUE (p, A68_FALSE, A68_BOOL);
   } else {
     ADDR_T pop_sp = A68_SP, pop_fp = A68_FP;
     PUSH_REF (p, ref_file);
     genie_call_event_routine (p, M_PROC_REF_FILE_BOOL, &z, pop_sp, pop_fp);
   }
 }
 
 //! @brief Handle end-of-file event.
 
 void end_of_file_error (NODE_T * p, A68_REF ref_file)
 {
   on_event_handler (p, FILE_END_MENDED (FILE_DEREF (&ref_file)), ref_file);
   A68_BOOL z;
   POP_OBJECT (p, &z, A68_BOOL);
   if (VALUE (&z) == A68_FALSE) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_ENDED);
     exit_genie (p, A68_RUNTIME_ERROR);
   }
 }
 
 //! @brief Handle file-open-error event.
 
 void open_error (NODE_T * p, A68_REF ref_file, char *mode)
 {
   on_event_handler (p, OPEN_ERROR_MENDED (FILE_DEREF (&ref_file)), ref_file);
   A68_BOOL z;
   POP_OBJECT (p, &z, A68_BOOL);
   if (VALUE (&z) == A68_FALSE) {
     CHECK_REF (p, ref_file, M_REF_FILE);
     A68_FILE *file = FILE_DEREF (&ref_file);
     CHECK_INIT (p, INITIALISED (file), M_FILE);
     char *filename;
     if (!IS_NIL (IDENTIFICATION (file))) {
       filename = DEREF (char, &IDENTIFICATION (FILE_DEREF (&ref_file)));
     } else {
       filename = "(missing filename)";
     }
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_CANNOT_OPEN_FOR, filename, mode);
     exit_genie (p, A68_RUNTIME_ERROR);
   }
 }
 
 //! @brief Handle value error event.
 
 void value_error (NODE_T * p, MOID_T * m, A68_REF ref_file)
 {
   A68_FILE *f = FILE_DEREF (&ref_file);
   if (END_OF_FILE (f)) {
     end_of_file_error (p, ref_file);
   } else {
     on_event_handler (p, VALUE_ERROR_MENDED (f), ref_file);
     A68_BOOL z;
     POP_OBJECT (p, &z, A68_BOOL);
     if (VALUE (&z) == A68_FALSE) {
       diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_TRANSPUT, m);
       exit_genie (p, A68_RUNTIME_ERROR);
     }
   }
 }
 
 //! @brief Handle value_error event.
 
 void value_sign_error (NODE_T * p, MOID_T * m, A68_REF ref_file)
 {
   A68_FILE *f = FILE_DEREF (&ref_file);
   if (END_OF_FILE (f)) {
     end_of_file_error (p, ref_file);
   } else {
     on_event_handler (p, VALUE_ERROR_MENDED (f), ref_file);
     A68_BOOL z;
     POP_OBJECT (p, &z, A68_BOOL);
     if (VALUE (&z) == A68_FALSE) {
       diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_TRANSPUT_SIGN, m);
       exit_genie (p, A68_RUNTIME_ERROR);
     }
   }
 }
 
 //! @brief Handle transput-error event.
 
 void transput_error (NODE_T * p, A68_REF ref_file, MOID_T * m)
 {
   on_event_handler (p, TRANSPUT_ERROR_MENDED (FILE_DEREF (&ref_file)), ref_file);
   A68_BOOL z;
   POP_OBJECT (p, &z, A68_BOOL);
   if (VALUE (&z) == A68_FALSE) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_TRANSPUT, m);
     exit_genie (p, A68_RUNTIME_ERROR);
   }
 }
 
 // Implementation of put and get.
 
 //! @brief Get next char from file.
 
 int char_scanner (A68_FILE * f)
 {
   if (get_transput_buffer_index (TRANSPUT_BUFFER (f)) > 0) {
 // There are buffered characters.
     END_OF_FILE (f) = A68_FALSE;
     return pop_char_transput_buffer (TRANSPUT_BUFFER (f));
   } else if (IS_NIL (STRING (f))) {
 // Fetch next CHAR from the FILE.
     char ch;
     ssize_t chars_read = io_read_conv (FD (f), &ch, 1);
     if (chars_read == 1) {
       END_OF_FILE (f) = A68_FALSE;
       return ch;
     } else {
       END_OF_FILE (f) = A68_TRUE;
       return EOF_CHAR;
     }
   } else {
 // File is associated with a STRING. Give next CHAR. 
 // When we're outside the STRING give EOF_CHAR. 
     A68_REF z = *DEREF (A68_REF, &STRING (f)); A68_ARRAY *arr; A68_TUPLE *tup;
     GET_DESCRIPTOR (arr, tup, &z);
     int k = STRPOS (f) + LWB (tup);
     if (ROW_SIZE (tup) <= 0 || k < LWB (tup) || k > UPB (tup)) {
       END_OF_FILE (f) = A68_TRUE;
       return EOF_CHAR;
     } else {
       BYTE_T *base = DEREF (BYTE_T, &ARRAY (arr));
       A68_CHAR *ch = (A68_CHAR *) & (base[INDEX_1_DIM (arr, tup, k)]);
       STRPOS (f)++;
       return VALUE (ch);
     }
   }
 }
 
 //! @brief Push back look-ahead character to file.
 
 void unchar_scanner (NODE_T * p, A68_FILE * f, char ch)
 {
   END_OF_FILE (f) = A68_FALSE;
   plusab_transput_buffer (p, TRANSPUT_BUFFER (f), ch);
 }
 
 //! @brief PROC (REF FILE) BOOL eof
 
 void genie_eof (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   if (!OPENED (file)) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_NOT_OPEN);
     exit_genie (p, A68_RUNTIME_ERROR);
   }
   if (DRAW_MOOD (file)) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_WRONG_MOOD, "draw");
     exit_genie (p, A68_RUNTIME_ERROR);
   }
   if (WRITE_MOOD (file)) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_WRONG_MOOD, "write");
     exit_genie (p, A68_RUNTIME_ERROR);
   } else if (READ_MOOD (file)) {
     int ch = char_scanner (file);
     PUSH_VALUE (p, (BOOL_T) ((ch == EOF_CHAR || END_OF_FILE (file)) ? A68_TRUE : A68_FALSE), A68_BOOL);
     unchar_scanner (p, file, (char) ch);
   } else {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_WRONG_MOOD, "undetermined");
     exit_genie (p, A68_RUNTIME_ERROR);
   }
 }
 
 //! @brief PROC (REF FILE) BOOL eoln
 
 void genie_eoln (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   if (!OPENED (file)) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_NOT_OPEN);
     exit_genie (p, A68_RUNTIME_ERROR);
   }
   if (DRAW_MOOD (file)) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_WRONG_MOOD, "draw");
     exit_genie (p, A68_RUNTIME_ERROR);
   }
   if (WRITE_MOOD (file)) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_WRONG_MOOD, "write");
     exit_genie (p, A68_RUNTIME_ERROR);
   } else if (READ_MOOD (file)) {
     int ch = char_scanner (file);
     if (END_OF_FILE (file)) {
       end_of_file_error (p, ref_file);
     }
     PUSH_VALUE (p, (BOOL_T) (ch == NEWLINE_CHAR ? A68_TRUE : A68_FALSE), A68_BOOL);
     unchar_scanner (p, file, (char) ch);
   } else {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_WRONG_MOOD, "undetermined");
     exit_genie (p, A68_RUNTIME_ERROR);
   }
 }
 
 //! @brief PROC (REF FILE) VOID new line
 
 void genie_new_line (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   if (!OPENED (file)) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_NOT_OPEN);
     exit_genie (p, A68_RUNTIME_ERROR);
   }
   if (DRAW_MOOD (file)) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_WRONG_MOOD, "draw");
     exit_genie (p, A68_RUNTIME_ERROR);
   }
   if (WRITE_MOOD (file)) {
     on_event_handler (p, LINE_END_MENDED (file), ref_file);
     if (IS_NIL (STRING (file))) {
       WRITE (FD (file), NEWLINE_STRING);
     } else {
       add_c_string_to_a_string (p, STRING (file), NEWLINE_STRING);
     }
   } else if (READ_MOOD (file)) {
     BOOL_T siga = A68_TRUE;
     while (siga) {
       int ch;
       if (END_OF_FILE (file)) {
         end_of_file_error (p, ref_file);
       }
       ch = char_scanner (file);
       siga = (BOOL_T) ((ch != NEWLINE_CHAR) && (ch != EOF_CHAR) && !END_OF_FILE (file));
     }
   } else {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_WRONG_MOOD, "undetermined");
     exit_genie (p, A68_RUNTIME_ERROR);
   }
 }
 
 //! @brief PROC (REF FILE) VOID new page
 
 void genie_new_page (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   if (!OPENED (file)) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_NOT_OPEN);
     exit_genie (p, A68_RUNTIME_ERROR);
   }
   if (DRAW_MOOD (file)) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_WRONG_MOOD, "draw");
     exit_genie (p, A68_RUNTIME_ERROR);
   }
   if (WRITE_MOOD (file)) {
     on_event_handler (p, PAGE_END_MENDED (file), ref_file);
     if (IS_NIL (STRING (file))) {
       WRITE (FD (file), "\f");
     } else {
       add_c_string_to_a_string (p, STRING (file), "\f");
     }
   } else if (READ_MOOD (file)) {
     BOOL_T siga = A68_TRUE;
     while (siga) {
       if (END_OF_FILE (file)) {
         end_of_file_error (p, ref_file);
       }
       int ch = char_scanner (file);
       siga = (BOOL_T) ((ch != FORMFEED_CHAR) && (ch != EOF_CHAR) && !END_OF_FILE (file));
     }
   } else {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_WRONG_MOOD, "undetermined");
     exit_genie (p, A68_RUNTIME_ERROR);
   }
 }
 
 //! @brief PROC (REF FILE) VOID space
 
 void genie_space (NODE_T * p)
 {
   A68_REF ref_file;
   POP_REF (p, &ref_file);
   CHECK_REF (p, ref_file, M_REF_FILE);
   A68_FILE *file = FILE_DEREF (&ref_file);
   CHECK_INIT (p, INITIALISED (file), M_FILE);
   if (!OPENED (file)) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_NOT_OPEN);
     exit_genie (p, A68_RUNTIME_ERROR);
   }
   if (DRAW_MOOD (file)) {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_WRONG_MOOD, "draw");
     exit_genie (p, A68_RUNTIME_ERROR);
   }
   if (WRITE_MOOD (file)) {
     WRITE (FD (file), " ");
   } else if (READ_MOOD (file)) {
     if (!END_OF_FILE (file)) {
       (void) char_scanner (file);
     }
   } else {
     diagnostic (A68_RUNTIME_ERROR, p, ERROR_FILE_WRONG_MOOD, "undetermined");
     exit_genie (p, A68_RUNTIME_ERROR);
   }
 }
     

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