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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#include <cstdlib>
#include <cstdio>
enum Token {
EOF_SYMBOL,
LEFT_ANGLE,
RIGHT_ANGLE,
ANY,
};
static int current_char;
static int yytoken;
static bool in_tag = false;
bool parseXmlStream();
bool parseTagOrWord();
bool parseTagName();
inline int nextToken()
{
current_char = fgetc(stdin);
if (current_char == EOF) {
return (yytoken = EOF_SYMBOL);
} else if (current_char == '<') {
in_tag = true;
return (yytoken = LEFT_ANGLE);
} else if (in_tag && current_char == '>') {
in_tag = false;
return (yytoken = RIGHT_ANGLE);
}
return (yytoken = ANY);
}
bool parse()
{
nextToken();
return parseXmlStream();
}
bool parseXmlStream()
{
while (parseTagOrWord())
;
return true;
}
bool parseTagOrWord()
{
if (yytoken == LEFT_ANGLE) {
nextToken();
if (! parseTagName())
return false;
if (yytoken != RIGHT_ANGLE)
return false;
nextToken();
fprintf (stderr, "*** found a tag\n");
} else if (yytoken == ANY) {
nextToken();
} else {
return false;
}
return true;
}
bool parseTagName()
{
while (yytoken == ANY)
nextToken();
return true;
}
int main()
{
if (parse())
printf("OK\n");
else
printf("KO\n");
}