98 lines
2.9 KiB
C++
98 lines
2.9 KiB
C++
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/*
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Copyright (C) 1993 Free Software Foundation
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This file is part of the GNU IO Library. This library is free
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software; you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2, or (at your option)
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any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this library; see the file COPYING. If not, write to the Free
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Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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As a special exception, if you link this library with files
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compiled with a GNU compiler to produce an executable, this does not cause
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the resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why
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the executable file might be covered by the GNU General Public License. */
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// Test streambuf::sputbackc
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#include <iostream.h>
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#include <stdlib.h>
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#include <string.h>
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// Read either "dog", "hound", or "hounddog".
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// If "dog" is found, return 1.
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// If "hound" is found, return 2.
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// If "hounddog" is found, return 3.
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// If non of these are found, return -1.
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void unget_string(streambuf *sb, char *str, int count)
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{
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for (str += count; -- count >= 0; )
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sb->sputbackc(*--str);
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}
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int my_scan(streambuf* sb)
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{
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char buffer[20];
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// Try reading "hounddog":
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int count;
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count = sb->sgetn(buffer, 8);
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if (count == 8 && strncmp(buffer, "hounddog", 8) == 0)
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return 3;
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// No, no "hounddog": Backup to 'fence' ...
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unget_string(sb, buffer, count);
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// ... and try reading "dog":
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count = sb->sgetn(buffer, 3);
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if (count == 3 && strncmp(buffer, "dog", 3) == 0)
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return 1;
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// No, no "dog" either: Backup to 'fence' ...
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unget_string(sb, buffer, count);
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// ... and try reading "hound":
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count = sb->sgetn(buffer, 5);
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if (count == 5 && strncmp(buffer, "hound", 5) == 0)
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return 2;
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// No, no "hound" either: Backup to 'fence' and signal failure.
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unget_string(sb, buffer, count);
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return -1;
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}
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int main(int argc, char **argv)
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{
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streambuf *sb = cin.rdbuf();
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if (argc > 1 && strncmp(argv[1], "-b", 2) == 0) {
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streambuf *ret;
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int buffer_size = atoi(&argv[1][2]);
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if (buffer_size == 0)
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ret = sb->setbuf(NULL, 0);
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else
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ret = sb->setbuf(new char[buffer_size], buffer_size);
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if (ret != sb)
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cerr << "Warning: cin.rdbuf()->setbuf failed!\n";
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}
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for (;;) {
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int code = my_scan(sb);
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int ch = sb->sbumpc();
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if (code == -1 && ch == EOF)
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break;
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int n = 0;
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while (ch != EOF && ch != '\n') {
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n++;
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ch = sb->sbumpc();
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};
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if (ch == EOF) {
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cout << "[Unexpected EOF]\n";
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break;
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}
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cout << "Code: " << code << " followed by " << n << " chars\n";
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}
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}
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