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#ifndef __BASIC_IO_HH__
#define __BASIC_IO_HH__
// copyright (C) 2004 graydon hoare <graydon@pobox.com>
// all rights reserved.
// licensed to the public under the terms of the GNU GPL (>= 2)
// see the file COPYING for details
// this file provides parsing and printing primitives used by the higher
// level parser and printer routines for the two datatypes change_set and
// revision_set. every revision_set contains a number of change_sets, so
// their i/o routines are somewhat related.
#include <iosfwd>
#include <string>
#include <vector>
#include <map>
namespace basic_io
{
typedef enum
{
TOK_SYMBOL,
TOK_STRING,
TOK_HEX,
TOK_NONE,
} token_type;
struct
input_source
{
size_t line, col;
std::istream & in;
std::string name;
int lookahead;
char c;
input_source(std::istream & i, std::string const & nm)
: line(1), col(1), in(i), name(nm), lookahead(0), c('\0')
{}
inline void peek() { lookahead = in.peek(); }
inline void eat()
{
in.get(c);
++col;
if (c == '\n')
{
col = 1;
++line;
}
}
inline void advance() { eat(); peek(); }
void err(std::string const & s);
};
struct
tokenizer
{
input_source & in;
tokenizer(input_source & i) : in(i) {}
inline token_type get_token(std::string & val)
{
val.clear();
val.reserve(80);
in.peek();
while (true)
{
if (in.lookahead == EOF)
return TOK_NONE;
if (!std::isspace(in.lookahead))
break;
in.advance();
}
switch (in.lookahead)
{
case '"':
{
in.advance();
while (static_cast<char>(in.lookahead) != '"')
{
if (in.lookahead == EOF)
in.err("input stream ended in string");
if (static_cast<char>(in.lookahead) == '\\')
{
// possible escape: we understand escaped quotes
// and escaped backslashes. nothing else.
in.advance();
if (!(static_cast<char>(in.lookahead) == '"'
|| static_cast<char>(in.lookahead) == '\\'))
{
in.err("unrecognized character escape");
}
}
in.advance();
val += in.c;
}
if (static_cast<char>(in.lookahead) != '"')
in.err("string did not end with '\"'");
in.eat();
return basic_io::TOK_STRING;
}
case '[':
{
in.advance();
while (static_cast<char>(in.lookahead) != ']')
{
if (in.lookahead == EOF)
in.err("input stream ended in hex string");
if (!std::isxdigit(in.lookahead))
in.err("non-hex character in hex string");
in.advance();
val += in.c;
}
if (static_cast<char>(in.lookahead) != ']')
in.err("hex string did not end with ']'");
in.eat();
return basic_io::TOK_HEX;
}
default:
if (std::isalpha(in.lookahead))
{
while (std::isalnum(in.lookahead) || in.lookahead == '_')
{
in.advance();
val += in.c;
}
return basic_io::TOK_SYMBOL;
}
}
return basic_io::TOK_NONE;
}
void err(std::string const & s);
};
struct
stanza
{
stanza();
size_t indent;
std::vector<std::pair<std::string, std::string> > entries;
void push_hex_pair(std::string const & k, std::string const & v);
void push_str_pair(std::string const & k, std::string const & v);
};
struct
printer
{
bool empty_output;
std::ostream & out;
printer(std::ostream & ost);
void print_stanza(stanza const & st);
};
struct
parser
{
tokenizer & tok;
parser(tokenizer & t) : tok(t)
{
advance();
}
std::string token;
token_type ttype;
void err(std::string const & s);
std::string tt2str(token_type tt);
inline void advance()
{
ttype = tok.get_token(token);
}
inline void eat(token_type want)
{
if (ttype != want)
err("wanted "
+ tt2str(want)
+ ", got "
+ tt2str(ttype)
+ (token.empty()
? std::string("")
: (std::string(" with value ") + token)));
advance();
}
inline void str() { eat(basic_io::TOK_STRING); }
inline void sym() { eat(basic_io::TOK_SYMBOL); }
inline void hex() { eat(basic_io::TOK_HEX); }
inline void str(std::string & v) { v = token; str(); }
inline void sym(std::string & v) { v = token; sym(); }
inline void hex(std::string & v) { v = token; hex(); }
inline bool symp() { return ttype == basic_io::TOK_SYMBOL; }
inline bool symp(std::string const & val)
{
return ttype == basic_io::TOK_SYMBOL && token == val;
}
inline void esym(std::string const & val)
{
if (!(ttype == basic_io::TOK_SYMBOL && token == val))
err("wanted symbol '"
+ val +
+ "', got "
+ tt2str(ttype)
+ (token.empty()
? std::string("")
: (std::string(" with value ") + token)));
advance();
}
};
}
#endif // __BASIC_IO_HH__
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