oga/ext/c/lexer.rl

126 lines
3.3 KiB
Ragel

#include "lexer.h"
/*
The following two macros allow the Ragel grammar to use generic function calls
without relying on the setup of the C or Java lexer. Using these macros we can
also pass along `self` to the callback functions without having to hard-code
this in to the Ragel grammar.
In the C lexer we don't need the `data` variable (since this is pulled in based
on `ts` and `te`) so the macro ignores this argument.
*/
#define callback(name, data, encoding, start, stop) \
liboga_xml_lexer_callback(self, name, encoding, start, stop);
#define callback_simple(name) \
liboga_xml_lexer_callback_simple(self, name);
#define oga_ivar_get(owner, name) \
rb_ivar_get(owner, rb_intern(name))
#define oga_ivar_set(owner, name, value) \
rb_ivar_set(owner, rb_intern(name), value)
#define advance_line(amount) \
rb_funcall(self, rb_intern("advance_line"), 1, INT2NUM(amount));
%%machine c_lexer;
/**
* Calls a method defined in the Ruby side of the lexer. The String value is
* created based on the values of `ts` and `te` and uses the encoding specified
* in `encoding`.
*
* @example
* rb_encoding *encoding = rb_enc_get(...);
* liboga_xml_lexer_callback(self, "on_string", encoding, ts, te);
*/
void liboga_xml_lexer_callback(
VALUE self,
const char *name,
rb_encoding *encoding,
const char *ts,
const char *te
)
{
VALUE value = rb_enc_str_new(ts, te - ts, encoding);
VALUE method = rb_intern(name);
rb_funcall(self, method, 1, value);
}
/**
* Calls a method defined in the Ruby side of the lexer without passing it any
* arguments.
*
* @example
* liboga_xml_lexer_callback_simple(self, "on_cdata_start");
*/
void liboga_xml_lexer_callback_simple(VALUE self, const char *name)
{
VALUE method = rb_intern(name);
rb_funcall(self, method, 0);
}
%% write data;
/**
* Lexes the String specifies as the method argument. Token values have the
* same encoding as the input value.
*
* This method keeps track of an internal state using the instance variables
* `@act` and `@cs`.
*/
VALUE oga_xml_lexer_advance(VALUE self, VALUE data_block)
{
/* Make sure that all data passed back to Ruby has the proper encoding. */
rb_encoding *encoding = rb_enc_get(data_block);
char *data_str_val = StringValueCStr(data_block);
const char *p = data_str_val;
const char *pe = data_str_val + strlen(data_str_val);
const char *eof = pe;
const char *ts = 0;
const char *te = 0;
const char *mark = 0;
int act = NUM2INT(oga_ivar_get(self, "@act"));
int cs = NUM2INT(oga_ivar_get(self, "@cs"));
int lines = 0;
%% write exec;
oga_ivar_set(self, "@act", INT2NUM(act));
oga_ivar_set(self, "@cs", INT2NUM(cs));
return Qnil;
}
/**
* Resets the internal state of the lexer.
*/
VALUE oga_xml_lexer_reset(VALUE self)
{
oga_ivar_set(self, "@act", INT2NUM(0));
oga_ivar_set(self, "@cs", INT2NUM(c_lexer_start));
return Qnil;
}
%%{
include base_lexer "base_lexer.rl";
}%%
void Init_liboga_xml_lexer()
{
VALUE mOga = rb_const_get(rb_cObject, rb_intern("Oga"));
VALUE mXML = rb_const_get(mOga, rb_intern("XML"));
VALUE cLexer = rb_define_class_under(mXML, "Lexer", rb_cObject);
rb_define_method(cLexer, "advance_native", oga_xml_lexer_advance, 1);
rb_define_method(cLexer, "reset_native", oga_xml_lexer_reset, 0);
}