tokenizer.c revision dee2fd54481b311ad831ac455a9192bdc0f147e3 
1
2/* Tokenizer implementation */
3
4#include "Python.h"
5#include "pgenheaders.h"
6
7#include <ctype.h>
8#include <assert.h>
9
10#include "tokenizer.h"
11#include "errcode.h"
12
13#ifndef PGEN
14#include "unicodeobject.h"
15#include "stringobject.h"
16#include "fileobject.h"
17#include "codecs.h"
18#include "abstract.h"
19#endif /* PGEN */
20
21extern char *PyOS_Readline(FILE *, FILE *, char *);
22/* Return malloc'ed string including trailing \n;
23   empty malloc'ed string for EOF;
24   NULL if interrupted */
25
26/* Don't ever change this -- it would break the portability of Python code */
27#define TABSIZE 8
28
29/* Convert a possibly signed character to a nonnegative int */
30/* XXX This assumes characters are 8 bits wide */
31#ifdef __CHAR_UNSIGNED__
32#define Py_CHARMASK(c)		(c)
33#else
34#define Py_CHARMASK(c)		((c) & 0xff)
35#endif
36
37/* Forward */
38static struct tok_state *tok_new(void);
39static int tok_nextc(struct tok_state *tok);
40static void tok_backup(struct tok_state *tok, int c);
41
42/* Token names */
43
44char *_PyParser_TokenNames[] = {
45	"ENDMARKER",
46	"NAME",
47	"NUMBER",
48	"STRING",
49	"NEWLINE",
50	"INDENT",
51	"DEDENT",
52	"LPAR",
53	"RPAR",
54	"LSQB",
55	"RSQB",
56	"COLON",
57	"COMMA",
58	"SEMI",
59	"PLUS",
60	"MINUS",
61	"STAR",
62	"SLASH",
63	"VBAR",
64	"AMPER",
65	"LESS",
66	"GREATER",
67	"EQUAL",
68	"DOT",
69	"PERCENT",
70	"BACKQUOTE",
71	"LBRACE",
72	"RBRACE",
73	"EQEQUAL",
74	"NOTEQUAL",
75	"LESSEQUAL",
76	"GREATEREQUAL",
77	"TILDE",
78	"CIRCUMFLEX",
79	"LEFTSHIFT",
80	"RIGHTSHIFT",
81	"DOUBLESTAR",
82	"PLUSEQUAL",
83	"MINEQUAL",
84	"STAREQUAL",
85	"SLASHEQUAL",
86	"PERCENTEQUAL",
87	"AMPEREQUAL",
88	"VBAREQUAL",
89	"CIRCUMFLEXEQUAL",
90	"LEFTSHIFTEQUAL",
91	"RIGHTSHIFTEQUAL",
92	"DOUBLESTAREQUAL",
93	"DOUBLESLASH",
94	"DOUBLESLASHEQUAL",
95	"AT",
96	/* This table must match the #defines in token.h! */
97	"OP",
98	"<ERRORTOKEN>",
99	"<N_TOKENS>"
100};
101
102
103/* Create and initialize a new tok_state structure */
104
105static struct tok_state *
106tok_new(void)
107{
108	struct tok_state *tok = PyMem_NEW(struct tok_state, 1);
109	if (tok == NULL)
110		return NULL;
111	tok->buf = tok->cur = tok->end = tok->inp = tok->start = NULL;
112	tok->done = E_OK;
113	tok->fp = NULL;
114	tok->tabsize = TABSIZE;
115	tok->indent = 0;
116	tok->indstack[0] = 0;
117	tok->atbol = 1;
118	tok->pendin = 0;
119	tok->prompt = tok->nextprompt = NULL;
120	tok->lineno = 0;
121	tok->level = 0;
122	tok->filename = NULL;
123	tok->altwarning = 0;
124	tok->alterror = 0;
125	tok->alttabsize = 1;
126	tok->altindstack[0] = 0;
127	tok->decoding_state = 0;
128	tok->decoding_erred = 0;
129	tok->read_coding_spec = 0;
130	tok->issued_encoding_warning = 0;
131	tok->encoding = NULL;
132        tok->cont_line = 0;
133#ifndef PGEN
134	tok->decoding_readline = NULL;
135	tok->decoding_buffer = NULL;
136#endif
137	return tok;
138}
139
140#ifdef PGEN
141
142static char *
143decoding_fgets(char *s, int size, struct tok_state *tok)
144{
145	return fgets(s, size, tok->fp);
146}
147
148static int
149decoding_feof(struct tok_state *tok)
150{
151	return feof(tok->fp);
152}
153
154static const char *
155decode_str(const char *str, struct tok_state *tok)
156{
157	return str;
158}
159
160#else /* PGEN */
161
162static char *
163error_ret(struct tok_state *tok) /* XXX */
164{
165	tok->decoding_erred = 1;
166	if (tok->fp != NULL && tok->buf != NULL) /* see PyTokenizer_Free */
167		PyMem_DEL(tok->buf);
168	tok->buf = NULL;
169	return NULL;		/* as if it were EOF */
170}
171
172static char *
173new_string(const char *s, int len)
174{
175	char* result = PyMem_NEW(char, len + 1);
176	if (result != NULL) {
177		memcpy(result, s, len);
178		result[len] = '\0';
179	}
180	return result;
181}
182
183static char *
184get_normal_name(char *s)	/* for utf-8 and latin-1 */
185{
186	char buf[13];
187	int i;
188	for (i = 0; i < 12; i++) {
189		int c = s[i];
190		if (c == '\0') break;
191		else if (c == '_') buf[i] = '-';
192		else buf[i] = tolower(c);
193	}
194	buf[i] = '\0';
195	if (strcmp(buf, "utf-8") == 0 ||
196	    strncmp(buf, "utf-8-", 6) == 0) return "utf-8";
197	else if (strcmp(buf, "latin-1") == 0 ||
198		 strcmp(buf, "iso-8859-1") == 0 ||
199		 strcmp(buf, "iso-latin-1") == 0 ||
200		 strncmp(buf, "latin-1-", 8) == 0 ||
201		 strncmp(buf, "iso-8859-1-", 11) == 0 ||
202		 strncmp(buf, "iso-latin-1-", 12) == 0) return "iso-8859-1";
203	else return s;
204}
205
206/* Return the coding spec in S, or NULL if none is found.  */
207
208static char *
209get_coding_spec(const char *s, int size)
210{
211	int i;
212	/* Coding spec must be in a comment, and that comment must be
213         * the only statement on the source code line. */
214        for (i = 0; i < size - 6; i++) {
215		if (s[i] == '#')
216			break;
217		if (s[i] != ' ' && s[i] != '\t' && s[i] != '\014')
218			return NULL;
219	}
220	for (; i < size - 6; i++) { /* XXX inefficient search */
221		const char* t = s + i;
222		if (strncmp(t, "coding", 6) == 0) {
223			const char* begin = NULL;
224			t += 6;
225			if (t[0] != ':' && t[0] != '=')
226				continue;
227			do {
228				t++;
229			} while (t[0] == '\x20' || t[0] == '\t');
230
231			begin = t;
232			while (isalnum((int)t[0]) ||
233			       t[0] == '-' || t[0] == '_' || t[0] == '.')
234				t++;
235
236			if (begin < t) {
237				char* r = new_string(begin, t - begin);
238				char* q = get_normal_name(r);
239				if (r != q) {
240					PyMem_DEL(r);
241					r = new_string(q, strlen(q));
242				}
243				return r;
244			}
245		}
246	}
247	return NULL;
248}
249
250/* Check whether the line contains a coding spec. If it does,
251   invoke the set_readline function for the new encoding.
252   This function receives the tok_state and the new encoding.
253   Return 1 on success, 0 on failure.  */
254
255static int
256check_coding_spec(const char* line, int size, struct tok_state *tok,
257		  int set_readline(struct tok_state *, const char *))
258{
259	char * cs;
260	int r = 1;
261
262        if (tok->cont_line)
263		/* It's a continuation line, so it can't be a coding spec. */
264		return 1;
265	cs = get_coding_spec(line, size);
266	if (cs != NULL) {
267		tok->read_coding_spec = 1;
268		if (tok->encoding == NULL) {
269			assert(tok->decoding_state == 1); /* raw */
270			if (strcmp(cs, "utf-8") == 0 ||
271			    strcmp(cs, "iso-8859-1") == 0) {
272				tok->encoding = cs;
273			} else {
274#ifdef Py_USING_UNICODE
275				r = set_readline(tok, cs);
276				if (r) {
277					tok->encoding = cs;
278					tok->decoding_state = -1;
279				}
280				else
281					PyMem_DEL(cs);
282#else
283                                /* Without Unicode support, we cannot
284                                   process the coding spec. Since there
285                                   won't be any Unicode literals, that
286                                   won't matter. */
287				PyMem_DEL(cs);
288#endif
289			}
290		} else {	/* then, compare cs with BOM */
291			r = (strcmp(tok->encoding, cs) == 0);
292			PyMem_DEL(cs);
293		}
294	}
295	return r;
296}
297
298/* See whether the file starts with a BOM. If it does,
299   invoke the set_readline function with the new encoding.
300   Return 1 on success, 0 on failure.  */
301
302static int
303check_bom(int get_char(struct tok_state *),
304	  void unget_char(int, struct tok_state *),
305	  int set_readline(struct tok_state *, const char *),
306	  struct tok_state *tok)
307{
308	int ch = get_char(tok);
309	tok->decoding_state = 1;
310	if (ch == EOF) {
311		return 1;
312	} else if (ch == 0xEF) {
313		ch = get_char(tok); if (ch != 0xBB) goto NON_BOM;
314		ch = get_char(tok); if (ch != 0xBF) goto NON_BOM;
315#if 0
316	/* Disable support for UTF-16 BOMs until a decision
317	   is made whether this needs to be supported.  */
318	} else if (ch == 0xFE) {
319		ch = get_char(tok); if (ch != 0xFF) goto NON_BOM;
320		if (!set_readline(tok, "utf-16-be")) return 0;
321		tok->decoding_state = -1;
322	} else if (ch == 0xFF) {
323		ch = get_char(tok); if (ch != 0xFE) goto NON_BOM;
324		if (!set_readline(tok, "utf-16-le")) return 0;
325		tok->decoding_state = -1;
326#endif
327	} else {
328		unget_char(ch, tok);
329		return 1;
330	}
331	if (tok->encoding != NULL)
332		PyMem_DEL(tok->encoding);
333	tok->encoding = new_string("utf-8", 5);	/* resulting is in utf-8 */
334	return 1;
335  NON_BOM:
336	/* any token beginning with '\xEF', '\xFE', '\xFF' is a bad token */
337	unget_char(0xFF, tok);	/* XXX this will cause a syntax error */
338	return 1;
339}
340
341/* Read a line of text from TOK into S, using the stream in TOK.
342   Return NULL on failure, else S.
343
344   On entry, tok->decoding_buffer will be one of:
345     1) NULL: need to call tok->decoding_readline to get a new line
346     2) PyUnicodeObject *: decoding_feof has called tok->decoding_readline and
347           stored the result in tok->decoding_buffer
348     3) PyStringObject *: previous call to fp_readl did not have enough room
349           (in the s buffer) to copy entire contents of the line read
350           by tok->decoding_readline.  tok->decoding_buffer has the overflow.
351           In this case, fp_readl is called in a loop (with an expanded buffer)
352           until the buffer ends with a '\n' (or until the end of the file is
353           reached): see tok_nextc and its calls to decoding_fgets.
354*/
355
356static char *
357fp_readl(char *s, int size, struct tok_state *tok)
358{
359#ifndef Py_USING_UNICODE
360	/* In a non-Unicode built, this should never be called. */
361	Py_FatalError("fp_readl should not be called in this build.");
362	return NULL; /* Keep compiler happy (not reachable) */
363#else
364	PyObject* utf8 = NULL;
365	PyObject* buf = tok->decoding_buffer;
366	char *str;
367	int utf8len;
368
369	/* Ask for one less byte so we can terminate it */
370	assert(size > 0);
371	size--;
372
373	if (buf == NULL) {
374		buf = PyObject_CallObject(tok->decoding_readline, NULL);
375		if (buf == NULL)
376			return error_ret(tok);
377	} else {
378		tok->decoding_buffer = NULL;
379		if (PyString_CheckExact(buf))
380			utf8 = buf;
381	}
382	if (utf8 == NULL) {
383		utf8 = PyUnicode_AsUTF8String(buf);
384		Py_DECREF(buf);
385		if (utf8 == NULL)
386			return error_ret(tok);
387	}
388	str = PyString_AsString(utf8);
389	utf8len = PyString_GET_SIZE(utf8);
390	if (utf8len > size) {
391		tok->decoding_buffer = PyString_FromStringAndSize(str+size, utf8len-size);
392		if (tok->decoding_buffer == NULL) {
393			Py_DECREF(utf8);
394			return error_ret(tok);
395		}
396		utf8len = size;
397	}
398	memcpy(s, str, utf8len);
399	s[utf8len] = '\0';
400	Py_DECREF(utf8);
401	if (utf8len == 0) return NULL; /* EOF */
402	return s;
403#endif
404}
405
406/* Set the readline function for TOK to a StreamReader's
407   readline function. The StreamReader is named ENC.
408
409   This function is called from check_bom and check_coding_spec.
410
411   ENC is usually identical to the future value of tok->encoding,
412   except for the (currently unsupported) case of UTF-16.
413
414   Return 1 on success, 0 on failure. */
415
416static int
417fp_setreadl(struct tok_state *tok, const char* enc)
418{
419	PyObject *reader, *stream, *readline;
420
421	/* XXX: constify filename argument. */
422	stream = PyFile_FromFile(tok->fp, (char*)tok->filename, "rb", NULL);
423	if (stream == NULL)
424		return 0;
425
426	reader = PyCodec_StreamReader(enc, stream, NULL);
427	Py_DECREF(stream);
428	if (reader == NULL)
429		return 0;
430
431	readline = PyObject_GetAttrString(reader, "readline");
432	Py_DECREF(reader);
433	if (readline == NULL)
434		return 0;
435
436	tok->decoding_readline = readline;
437	return 1;
438}
439
440/* Fetch the next byte from TOK. */
441
442static int fp_getc(struct tok_state *tok) {
443	return getc(tok->fp);
444}
445
446/* Unfetch the last byte back into TOK.  */
447
448static void fp_ungetc(int c, struct tok_state *tok) {
449	ungetc(c, tok->fp);
450}
451
452/* Read a line of input from TOK. Determine encoding
453   if necessary.  */
454
455static char *
456decoding_fgets(char *s, int size, struct tok_state *tok)
457{
458	char *line = NULL;
459	int warn = 0, badchar = 0;
460	for (;;) {
461		if (tok->decoding_state < 0) {
462			/* We already have a codec associated with
463			   this input. */
464			line = fp_readl(s, size, tok);
465			break;
466		} else if (tok->decoding_state > 0) {
467			/* We want a 'raw' read. */
468			line = Py_UniversalNewlineFgets(s, size,
469							tok->fp, NULL);
470			warn = 1;
471			break;
472		} else {
473			/* We have not yet determined the encoding.
474			   If an encoding is found, use the file-pointer
475			   reader functions from now on. */
476			if (!check_bom(fp_getc, fp_ungetc, fp_setreadl, tok))
477				return error_ret(tok);
478			assert(tok->decoding_state != 0);
479		}
480	}
481	if (line != NULL && tok->lineno < 2 && !tok->read_coding_spec) {
482		if (!check_coding_spec(line, strlen(line), tok, fp_setreadl)) {
483			return error_ret(tok);
484		}
485	}
486#ifndef PGEN
487	if (warn && line && !tok->issued_encoding_warning && !tok->encoding) {
488		unsigned char *c;
489		for (c = (unsigned char *)line; *c; c++)
490			if (*c > 127) {
491				badchar = *c;
492				break;
493			}
494	}
495	if (badchar) {
496		char buf[500];
497		/* Need to add 1 to the line number, since this line
498		   has not been counted, yet.  */
499		sprintf(buf,
500			"Non-ASCII character '\\x%.2x' "
501			"in file %.200s on line %i, "
502			"but no encoding declared; "
503			"see http://www.python.org/peps/pep-0263.html for details",
504			badchar, tok->filename, tok->lineno + 1);
505		/* We don't use PyErr_WarnExplicit() here because
506		   printing the line in question to e.g. a log file
507		   could result in sensitive information being
508		   exposed. */
509		PyErr_Warn(PyExc_DeprecationWarning, buf);
510		tok->issued_encoding_warning = 1;
511	}
512#endif
513	return line;
514}
515
516static int
517decoding_feof(struct tok_state *tok)
518{
519	if (tok->decoding_state >= 0) {
520		return feof(tok->fp);
521	} else {
522		PyObject* buf = tok->decoding_buffer;
523		if (buf == NULL) {
524			buf = PyObject_CallObject(tok->decoding_readline, NULL);
525			if (buf == NULL) {
526				error_ret(tok);
527				return 1;
528			} else {
529				tok->decoding_buffer = buf;
530			}
531		}
532		return PyObject_Length(buf) == 0;
533	}
534}
535
536/* Fetch a byte from TOK, using the string buffer. */
537
538static int buf_getc(struct tok_state *tok) {
539	return Py_CHARMASK(*tok->str++);
540}
541
542/* Unfetch a byte from TOK, using the string buffer. */
543
544static void buf_ungetc(int c, struct tok_state *tok) {
545	tok->str--;
546	assert(Py_CHARMASK(*tok->str) == c);	/* tok->cur may point to read-only segment */
547}
548
549/* Set the readline function for TOK to ENC. For the string-based
550   tokenizer, this means to just record the encoding. */
551
552static int buf_setreadl(struct tok_state *tok, const char* enc) {
553	tok->enc = enc;
554	return 1;
555}
556
557/* Return a UTF-8 encoding Python string object from the
558   C byte string STR, which is encoded with ENC. */
559
560#ifdef Py_USING_UNICODE
561static PyObject *
562translate_into_utf8(const char* str, const char* enc) {
563	PyObject *utf8;
564	PyObject* buf = PyUnicode_Decode(str, strlen(str), enc, NULL);
565	if (buf == NULL)
566		return NULL;
567	utf8 = PyUnicode_AsUTF8String(buf);
568	Py_DECREF(buf);
569	return utf8;
570}
571#endif
572
573/* Decode a byte string STR for use as the buffer of TOK.
574   Look for encoding declarations inside STR, and record them
575   inside TOK.  */
576
577static const char *
578decode_str(const char *str, struct tok_state *tok)
579{
580	PyObject* utf8 = NULL;
581	const char *s;
582	int lineno = 0;
583	tok->enc = NULL;
584	tok->str = str;
585	if (!check_bom(buf_getc, buf_ungetc, buf_setreadl, tok))
586		return error_ret(tok);
587	str = tok->str;		/* string after BOM if any */
588	assert(str);
589#ifdef Py_USING_UNICODE
590	if (tok->enc != NULL) {
591		utf8 = translate_into_utf8(str, tok->enc);
592		if (utf8 == NULL)
593			return error_ret(tok);
594		str = PyString_AsString(utf8);
595	}
596#endif
597	for (s = str;; s++) {
598		if (*s == '\0') break;
599		else if (*s == '\n') {
600			lineno++;
601			if (lineno == 2) break;
602		}
603	}
604	tok->enc = NULL;
605	if (!check_coding_spec(str, s - str, tok, buf_setreadl))
606		return error_ret(tok);
607#ifdef Py_USING_UNICODE
608	if (tok->enc != NULL) {
609		assert(utf8 == NULL);
610		utf8 = translate_into_utf8(str, tok->enc);
611		if (utf8 == NULL) {
612			PyErr_Format(PyExc_SyntaxError,
613				"unknown encoding: %s", tok->enc);
614			return error_ret(tok);
615		}
616		str = PyString_AsString(utf8);
617	}
618#endif
619	assert(tok->decoding_buffer == NULL);
620	tok->decoding_buffer = utf8; /* CAUTION */
621	return str;
622}
623
624#endif /* PGEN */
625
626/* Set up tokenizer for string */
627
628struct tok_state *
629PyTokenizer_FromString(const char *str)
630{
631	struct tok_state *tok = tok_new();
632	if (tok == NULL)
633		return NULL;
634	str = (char *)decode_str(str, tok);
635	if (str == NULL) {
636		PyTokenizer_Free(tok);
637		return NULL;
638	}
639
640	/* XXX: constify members. */
641	tok->buf = tok->cur = tok->end = tok->inp = (char*)str;
642	return tok;
643}
644
645
646/* Set up tokenizer for file */
647
648struct tok_state *
649PyTokenizer_FromFile(FILE *fp, char *ps1, char *ps2)
650{
651	struct tok_state *tok = tok_new();
652	if (tok == NULL)
653		return NULL;
654	if ((tok->buf = PyMem_NEW(char, BUFSIZ)) == NULL) {
655		PyTokenizer_Free(tok);
656		return NULL;
657	}
658	tok->cur = tok->inp = tok->buf;
659	tok->end = tok->buf + BUFSIZ;
660	tok->fp = fp;
661	tok->prompt = ps1;
662	tok->nextprompt = ps2;
663	return tok;
664}
665
666
667/* Free a tok_state structure */
668
669void
670PyTokenizer_Free(struct tok_state *tok)
671{
672	if (tok->encoding != NULL)
673		PyMem_DEL(tok->encoding);
674#ifndef PGEN
675	Py_XDECREF(tok->decoding_readline);
676	Py_XDECREF(tok->decoding_buffer);
677#endif
678	if (tok->fp != NULL && tok->buf != NULL)
679		PyMem_DEL(tok->buf);
680	PyMem_DEL(tok);
681}
682
683#if !defined(PGEN) && defined(Py_USING_UNICODE)
684static int
685tok_stdin_decode(struct tok_state *tok, char **inp)
686{
687	PyObject *enc, *sysstdin, *decoded, *utf8;
688	const char *encoding;
689	char *converted;
690
691	if (PySys_GetFile((char *)"stdin", NULL) != stdin)
692		return 0;
693	sysstdin = PySys_GetObject("stdin");
694	if (sysstdin == NULL || !PyFile_Check(sysstdin))
695		return 0;
696
697	enc = ((PyFileObject *)sysstdin)->f_encoding;
698	if (enc == NULL || !PyString_Check(enc))
699		return 0;
700	Py_INCREF(enc);
701
702	encoding = PyString_AsString(enc);
703	decoded = PyUnicode_Decode(*inp, strlen(*inp), encoding, NULL);
704	if (decoded == NULL)
705		goto error_clear;
706
707	utf8 = PyUnicode_AsEncodedString(decoded, "utf-8", NULL);
708	Py_DECREF(decoded);
709	if (utf8 == NULL)
710		goto error_clear;
711
712	converted = new_string(PyString_AsString(utf8), PyString_Size(utf8));
713	Py_DECREF(utf8);
714	if (converted == NULL)
715		goto error_nomem;
716
717	PyMem_FREE(*inp);
718	*inp = converted;
719	if (tok->encoding != NULL)
720		PyMem_DEL(tok->encoding);
721	tok->encoding = new_string(encoding, strlen(encoding));
722	if (tok->encoding == NULL)
723		goto error_nomem;
724
725	Py_DECREF(enc);
726	return 0;
727
728error_nomem:
729	Py_DECREF(enc);
730	tok->done = E_NOMEM;
731	return -1;
732
733error_clear:
734	/* Fallback to iso-8859-1: for backward compatibility */
735	Py_DECREF(enc);
736	PyErr_Clear();
737	return 0;
738}
739#endif
740
741/* Get next char, updating state; error code goes into tok->done */
742
743static int
744tok_nextc(register struct tok_state *tok)
745{
746	for (;;) {
747		if (tok->cur != tok->inp) {
748			return Py_CHARMASK(*tok->cur++); /* Fast path */
749		}
750		if (tok->done != E_OK)
751			return EOF;
752		if (tok->fp == NULL) {
753			char *end = strchr(tok->inp, '\n');
754			if (end != NULL)
755				end++;
756			else {
757				end = strchr(tok->inp, '\0');
758				if (end == tok->inp) {
759					tok->done = E_EOF;
760					return EOF;
761				}
762			}
763			if (tok->start == NULL)
764				tok->buf = tok->cur;
765			tok->lineno++;
766			tok->inp = end;
767			return Py_CHARMASK(*tok->cur++);
768		}
769		if (tok->prompt != NULL) {
770			char *new = PyOS_Readline(stdin, stdout, tok->prompt);
771			if (tok->nextprompt != NULL)
772				tok->prompt = tok->nextprompt;
773			if (new == NULL)
774				tok->done = E_INTR;
775			else if (*new == '\0') {
776				PyMem_FREE(new);
777				tok->done = E_EOF;
778			}
779#if !defined(PGEN) && defined(Py_USING_UNICODE)
780			else if (tok_stdin_decode(tok, &new) != 0)
781				PyMem_FREE(new);
782#endif
783			else if (tok->start != NULL) {
784				size_t start = tok->start - tok->buf;
785				size_t oldlen = tok->cur - tok->buf;
786				size_t newlen = oldlen + strlen(new);
787				char *buf = tok->buf;
788				PyMem_RESIZE(buf, char, newlen+1);
789				tok->lineno++;
790				if (buf == NULL) {
791					PyMem_DEL(tok->buf);
792					tok->buf = NULL;
793					PyMem_FREE(new);
794					tok->done = E_NOMEM;
795					return EOF;
796				}
797				tok->buf = buf;
798				tok->cur = tok->buf + oldlen;
799				strcpy(tok->buf + oldlen, new);
800				PyMem_FREE(new);
801				tok->inp = tok->buf + newlen;
802				tok->end = tok->inp + 1;
803				tok->start = tok->buf + start;
804			}
805			else {
806				tok->lineno++;
807				if (tok->buf != NULL)
808					PyMem_DEL(tok->buf);
809				tok->buf = new;
810				tok->cur = tok->buf;
811				tok->inp = strchr(tok->buf, '\0');
812				tok->end = tok->inp + 1;
813			}
814		}
815		else {
816			int done = 0;
817			int cur = 0;
818			char *pt;
819			if (tok->start == NULL) {
820				if (tok->buf == NULL) {
821					tok->buf = PyMem_NEW(char, BUFSIZ);
822					if (tok->buf == NULL) {
823						tok->done = E_NOMEM;
824						return EOF;
825					}
826					tok->end = tok->buf + BUFSIZ;
827				}
828				if (decoding_fgets(tok->buf, (int)(tok->end - tok->buf),
829					  tok) == NULL) {
830					tok->done = E_EOF;
831					done = 1;
832				}
833				else {
834					tok->done = E_OK;
835					tok->inp = strchr(tok->buf, '\0');
836					done = tok->inp[-1] == '\n';
837				}
838			}
839			else {
840				cur = tok->cur - tok->buf;
841				if (decoding_feof(tok)) {
842					tok->done = E_EOF;
843					done = 1;
844				}
845				else
846					tok->done = E_OK;
847			}
848			tok->lineno++;
849			/* Read until '\n' or EOF */
850			while (!done) {
851				int curstart = tok->start == NULL ? -1 :
852					       tok->start - tok->buf;
853				int curvalid = tok->inp - tok->buf;
854				int newsize = curvalid + BUFSIZ;
855				char *newbuf = tok->buf;
856				PyMem_RESIZE(newbuf, char, newsize);
857				if (newbuf == NULL) {
858					tok->done = E_NOMEM;
859					tok->cur = tok->inp;
860					return EOF;
861				}
862				tok->buf = newbuf;
863				tok->inp = tok->buf + curvalid;
864				tok->end = tok->buf + newsize;
865				tok->start = curstart < 0 ? NULL :
866					     tok->buf + curstart;
867				if (decoding_fgets(tok->inp,
868					       (int)(tok->end - tok->inp),
869					       tok) == NULL) {
870					/* Last line does not end in \n,
871					   fake one */
872					strcpy(tok->inp, "\n");
873				}
874				tok->inp = strchr(tok->inp, '\0');
875				done = tok->inp[-1] == '\n';
876			}
877			tok->cur = tok->buf + cur;
878			/* replace "\r\n" with "\n" */
879			/* For Mac we leave the \r, giving a syntax error */
880			pt = tok->inp - 2;
881			if (pt >= tok->buf && *pt == '\r') {
882				*pt++ = '\n';
883				*pt = '\0';
884				tok->inp = pt;
885			}
886		}
887		if (tok->done != E_OK) {
888			if (tok->prompt != NULL)
889				PySys_WriteStderr("\n");
890			tok->cur = tok->inp;
891			return EOF;
892		}
893	}
894	/*NOTREACHED*/
895}
896
897
898/* Back-up one character */
899
900static void
901tok_backup(register struct tok_state *tok, register int c)
902{
903	if (c != EOF) {
904		if (--tok->cur < tok->buf)
905			Py_FatalError("tok_backup: begin of buffer");
906		if (*tok->cur != c)
907			*tok->cur = c;
908	}
909}
910
911
912/* Return the token corresponding to a single character */
913
914int
915PyToken_OneChar(int c)
916{
917	switch (c) {
918	case '(':	return LPAR;
919	case ')':	return RPAR;
920	case '[':	return LSQB;
921	case ']':	return RSQB;
922	case ':':	return COLON;
923	case ',':	return COMMA;
924	case ';':	return SEMI;
925	case '+':	return PLUS;
926	case '-':	return MINUS;
927	case '*':	return STAR;
928	case '/':	return SLASH;
929	case '|':	return VBAR;
930	case '&':	return AMPER;
931	case '<':	return LESS;
932	case '>':	return GREATER;
933	case '=':	return EQUAL;
934	case '.':	return DOT;
935	case '%':	return PERCENT;
936	case '`':	return BACKQUOTE;
937	case '{':	return LBRACE;
938	case '}':	return RBRACE;
939	case '^':	return CIRCUMFLEX;
940	case '~':	return TILDE;
941	case '@':       return AT;
942	default:	return OP;
943	}
944}
945
946
947int
948PyToken_TwoChars(int c1, int c2)
949{
950	switch (c1) {
951	case '=':
952		switch (c2) {
953		case '=':	return EQEQUAL;
954		}
955		break;
956	case '!':
957		switch (c2) {
958		case '=':	return NOTEQUAL;
959		}
960		break;
961	case '<':
962		switch (c2) {
963		case '>':	return NOTEQUAL;
964		case '=':	return LESSEQUAL;
965		case '<':	return LEFTSHIFT;
966		}
967		break;
968	case '>':
969		switch (c2) {
970		case '=':	return GREATEREQUAL;
971		case '>':	return RIGHTSHIFT;
972		}
973		break;
974	case '+':
975		switch (c2) {
976		case '=':	return PLUSEQUAL;
977		}
978		break;
979	case '-':
980		switch (c2) {
981		case '=':	return MINEQUAL;
982		}
983		break;
984	case '*':
985		switch (c2) {
986		case '*':	return DOUBLESTAR;
987		case '=':	return STAREQUAL;
988		}
989		break;
990	case '/':
991		switch (c2) {
992		case '/':	return DOUBLESLASH;
993		case '=':	return SLASHEQUAL;
994		}
995		break;
996	case '|':
997		switch (c2) {
998		case '=':	return VBAREQUAL;
999		}
1000		break;
1001	case '%':
1002		switch (c2) {
1003		case '=':	return PERCENTEQUAL;
1004		}
1005		break;
1006	case '&':
1007		switch (c2) {
1008		case '=':	return AMPEREQUAL;
1009		}
1010		break;
1011	case '^':
1012		switch (c2) {
1013		case '=':	return CIRCUMFLEXEQUAL;
1014		}
1015		break;
1016	}
1017	return OP;
1018}
1019
1020int
1021PyToken_ThreeChars(int c1, int c2, int c3)
1022{
1023	switch (c1) {
1024	case '<':
1025		switch (c2) {
1026		case '<':
1027			switch (c3) {
1028			case '=':
1029				return LEFTSHIFTEQUAL;
1030			}
1031			break;
1032		}
1033		break;
1034	case '>':
1035		switch (c2) {
1036		case '>':
1037			switch (c3) {
1038			case '=':
1039				return RIGHTSHIFTEQUAL;
1040			}
1041			break;
1042		}
1043		break;
1044	case '*':
1045		switch (c2) {
1046		case '*':
1047			switch (c3) {
1048			case '=':
1049				return DOUBLESTAREQUAL;
1050			}
1051			break;
1052		}
1053		break;
1054	case '/':
1055		switch (c2) {
1056		case '/':
1057			switch (c3) {
1058			case '=':
1059				return DOUBLESLASHEQUAL;
1060			}
1061			break;
1062		}
1063		break;
1064	}
1065	return OP;
1066}
1067
1068static int
1069indenterror(struct tok_state *tok)
1070{
1071	if (tok->alterror) {
1072		tok->done = E_TABSPACE;
1073		tok->cur = tok->inp;
1074		return 1;
1075	}
1076	if (tok->altwarning) {
1077		PySys_WriteStderr("%s: inconsistent use of tabs and spaces "
1078                                  "in indentation\n", tok->filename);
1079		tok->altwarning = 0;
1080	}
1081	return 0;
1082}
1083
1084
1085/* Get next token, after space stripping etc. */
1086
1087static int
1088tok_get(register struct tok_state *tok, char **p_start, char **p_end)
1089{
1090	register int c;
1091	int blankline;
1092
1093	*p_start = *p_end = NULL;
1094  nextline:
1095	tok->start = NULL;
1096	blankline = 0;
1097
1098	/* Get indentation level */
1099	if (tok->atbol) {
1100		register int col = 0;
1101		register int altcol = 0;
1102		tok->atbol = 0;
1103		for (;;) {
1104			c = tok_nextc(tok);
1105			if (c == ' ')
1106				col++, altcol++;
1107			else if (c == '\t') {
1108				col = (col/tok->tabsize + 1) * tok->tabsize;
1109				altcol = (altcol/tok->alttabsize + 1)
1110					* tok->alttabsize;
1111			}
1112			else if (c == '\014') /* Control-L (formfeed) */
1113				col = altcol = 0; /* For Emacs users */
1114			else
1115				break;
1116		}
1117		tok_backup(tok, c);
1118		if (c == '#' || c == '\n') {
1119			/* Lines with only whitespace and/or comments
1120			   shouldn't affect the indentation and are
1121			   not passed to the parser as NEWLINE tokens,
1122			   except *totally* empty lines in interactive
1123			   mode, which signal the end of a command group. */
1124			if (col == 0 && c == '\n' && tok->prompt != NULL)
1125				blankline = 0; /* Let it through */
1126			else
1127				blankline = 1; /* Ignore completely */
1128			/* We can't jump back right here since we still
1129			   may need to skip to the end of a comment */
1130		}
1131		if (!blankline && tok->level == 0) {
1132			if (col == tok->indstack[tok->indent]) {
1133				/* No change */
1134				if (altcol != tok->altindstack[tok->indent]) {
1135					if (indenterror(tok))
1136						return ERRORTOKEN;
1137				}
1138			}
1139			else if (col > tok->indstack[tok->indent]) {
1140				/* Indent -- always one */
1141				if (tok->indent+1 >= MAXINDENT) {
1142					tok->done = E_TOODEEP;
1143					tok->cur = tok->inp;
1144					return ERRORTOKEN;
1145				}
1146				if (altcol <= tok->altindstack[tok->indent]) {
1147					if (indenterror(tok))
1148						return ERRORTOKEN;
1149				}
1150				tok->pendin++;
1151				tok->indstack[++tok->indent] = col;
1152				tok->altindstack[tok->indent] = altcol;
1153			}
1154			else /* col < tok->indstack[tok->indent] */ {
1155				/* Dedent -- any number, must be consistent */
1156				while (tok->indent > 0 &&
1157					col < tok->indstack[tok->indent]) {
1158					tok->pendin--;
1159					tok->indent--;
1160				}
1161				if (col != tok->indstack[tok->indent]) {
1162					tok->done = E_DEDENT;
1163					tok->cur = tok->inp;
1164					return ERRORTOKEN;
1165				}
1166				if (altcol != tok->altindstack[tok->indent]) {
1167					if (indenterror(tok))
1168						return ERRORTOKEN;
1169				}
1170			}
1171		}
1172	}
1173
1174	tok->start = tok->cur;
1175
1176	/* Return pending indents/dedents */
1177	if (tok->pendin != 0) {
1178		if (tok->pendin < 0) {
1179			tok->pendin++;
1180			return DEDENT;
1181		}
1182		else {
1183			tok->pendin--;
1184			return INDENT;
1185		}
1186	}
1187
1188 again:
1189	tok->start = NULL;
1190	/* Skip spaces */
1191	do {
1192		c = tok_nextc(tok);
1193	} while (c == ' ' || c == '\t' || c == '\014');
1194
1195	/* Set start of current token */
1196	tok->start = tok->cur - 1;
1197
1198	/* Skip comment, while looking for tab-setting magic */
1199	if (c == '#') {
1200		static char *tabforms[] = {
1201			"tab-width:",		/* Emacs */
1202			":tabstop=",		/* vim, full form */
1203			":ts=",			/* vim, abbreviated form */
1204			"set tabsize=",		/* will vi never die? */
1205		/* more templates can be added here to support other editors */
1206		};
1207		char cbuf[80];
1208		char *tp, **cp;
1209		tp = cbuf;
1210		do {
1211			*tp++ = c = tok_nextc(tok);
1212		} while (c != EOF && c != '\n' &&
1213			 tp - cbuf + 1 < sizeof(cbuf));
1214		*tp = '\0';
1215		for (cp = tabforms;
1216		     cp < tabforms + sizeof(tabforms)/sizeof(tabforms[0]);
1217		     cp++) {
1218			if ((tp = strstr(cbuf, *cp))) {
1219				int newsize = atoi(tp + strlen(*cp));
1220
1221				if (newsize >= 1 && newsize <= 40) {
1222					tok->tabsize = newsize;
1223					if (Py_VerboseFlag)
1224					    PySys_WriteStderr(
1225						"Tab size set to %d\n",
1226						newsize);
1227				}
1228			}
1229		}
1230		while (c != EOF && c != '\n')
1231			c = tok_nextc(tok);
1232	}
1233
1234	/* Check for EOF and errors now */
1235	if (c == EOF) {
1236		return tok->done == E_EOF ? ENDMARKER : ERRORTOKEN;
1237	}
1238
1239	/* Identifier (most frequent token!) */
1240	if (isalpha(c) || c == '_') {
1241		/* Process r"", u"" and ur"" */
1242		switch (c) {
1243		case 'r':
1244		case 'R':
1245			c = tok_nextc(tok);
1246			if (c == '"' || c == '\'')
1247				goto letter_quote;
1248			break;
1249		case 'u':
1250		case 'U':
1251			c = tok_nextc(tok);
1252			if (c == 'r' || c == 'R')
1253				c = tok_nextc(tok);
1254			if (c == '"' || c == '\'')
1255				goto letter_quote;
1256			break;
1257		}
1258		while (isalnum(c) || c == '_') {
1259			c = tok_nextc(tok);
1260		}
1261		tok_backup(tok, c);
1262		*p_start = tok->start;
1263		*p_end = tok->cur;
1264		return NAME;
1265	}
1266
1267	/* Newline */
1268	if (c == '\n') {
1269		tok->atbol = 1;
1270		if (blankline || tok->level > 0)
1271			goto nextline;
1272		*p_start = tok->start;
1273		*p_end = tok->cur - 1; /* Leave '\n' out of the string */
1274                tok->cont_line = 0;
1275		return NEWLINE;
1276	}
1277
1278	/* Period or number starting with period? */
1279	if (c == '.') {
1280		c = tok_nextc(tok);
1281		if (isdigit(c)) {
1282			goto fraction;
1283		}
1284		else {
1285			tok_backup(tok, c);
1286			*p_start = tok->start;
1287			*p_end = tok->cur;
1288			return DOT;
1289		}
1290	}
1291
1292	/* Number */
1293	if (isdigit(c)) {
1294		if (c == '0') {
1295			/* Hex or octal -- maybe. */
1296			c = tok_nextc(tok);
1297			if (c == '.')
1298				goto fraction;
1299#ifndef WITHOUT_COMPLEX
1300			if (c == 'j' || c == 'J')
1301				goto imaginary;
1302#endif
1303			if (c == 'x' || c == 'X') {
1304				/* Hex */
1305				do {
1306					c = tok_nextc(tok);
1307				} while (isxdigit(c));
1308			}
1309			else {
1310				int found_decimal = 0;
1311				/* Octal; c is first char of it */
1312				/* There's no 'isoctdigit' macro, sigh */
1313				while ('0' <= c && c < '8') {
1314					c = tok_nextc(tok);
1315				}
1316				if (isdigit(c)) {
1317					found_decimal = 1;
1318					do {
1319						c = tok_nextc(tok);
1320					} while (isdigit(c));
1321				}
1322				if (c == '.')
1323					goto fraction;
1324				else if (c == 'e' || c == 'E')
1325					goto exponent;
1326#ifndef WITHOUT_COMPLEX
1327				else if (c == 'j' || c == 'J')
1328					goto imaginary;
1329#endif
1330				else if (found_decimal) {
1331					tok->done = E_TOKEN;
1332					tok_backup(tok, c);
1333					return ERRORTOKEN;
1334				}
1335			}
1336			if (c == 'l' || c == 'L')
1337				c = tok_nextc(tok);
1338		}
1339		else {
1340			/* Decimal */
1341			do {
1342				c = tok_nextc(tok);
1343			} while (isdigit(c));
1344			if (c == 'l' || c == 'L')
1345				c = tok_nextc(tok);
1346			else {
1347				/* Accept floating point numbers. */
1348				if (c == '.') {
1349		fraction:
1350					/* Fraction */
1351					do {
1352						c = tok_nextc(tok);
1353					} while (isdigit(c));
1354				}
1355				if (c == 'e' || c == 'E') {
1356		exponent:
1357					/* Exponent part */
1358					c = tok_nextc(tok);
1359					if (c == '+' || c == '-')
1360						c = tok_nextc(tok);
1361					if (!isdigit(c)) {
1362						tok->done = E_TOKEN;
1363						tok_backup(tok, c);
1364						return ERRORTOKEN;
1365					}
1366					do {
1367						c = tok_nextc(tok);
1368					} while (isdigit(c));
1369				}
1370#ifndef WITHOUT_COMPLEX
1371				if (c == 'j' || c == 'J')
1372					/* Imaginary part */
1373		imaginary:
1374					c = tok_nextc(tok);
1375#endif
1376			}
1377		}
1378		tok_backup(tok, c);
1379		*p_start = tok->start;
1380		*p_end = tok->cur;
1381		return NUMBER;
1382	}
1383
1384  letter_quote:
1385	/* String */
1386	if (c == '\'' || c == '"') {
1387		int quote2 = tok->cur - tok->start + 1;
1388		int quote = c;
1389		int triple = 0;
1390		int tripcount = 0;
1391		for (;;) {
1392			c = tok_nextc(tok);
1393			if (c == '\n') {
1394				if (!triple) {
1395					tok->done = E_EOLS;
1396					tok_backup(tok, c);
1397					return ERRORTOKEN;
1398				}
1399				tripcount = 0;
1400                                tok->cont_line = 1; /* multiline string. */
1401			}
1402			else if (c == EOF) {
1403				if (triple)
1404					tok->done = E_EOFS;
1405				else
1406					tok->done = E_EOLS;
1407				tok->cur = tok->inp;
1408				return ERRORTOKEN;
1409			}
1410			else if (c == quote) {
1411				tripcount++;
1412				if (tok->cur - tok->start == quote2) {
1413					c = tok_nextc(tok);
1414					if (c == quote) {
1415						triple = 1;
1416						tripcount = 0;
1417						continue;
1418					}
1419					tok_backup(tok, c);
1420				}
1421				if (!triple || tripcount == 3)
1422					break;
1423			}
1424			else if (c == '\\') {
1425				tripcount = 0;
1426				c = tok_nextc(tok);
1427				if (c == EOF) {
1428					tok->done = E_EOLS;
1429					tok->cur = tok->inp;
1430					return ERRORTOKEN;
1431				}
1432			}
1433			else
1434				tripcount = 0;
1435		}
1436		*p_start = tok->start;
1437		*p_end = tok->cur;
1438		return STRING;
1439	}
1440
1441	/* Line continuation */
1442	if (c == '\\') {
1443		c = tok_nextc(tok);
1444		if (c != '\n') {
1445			tok->done = E_LINECONT;
1446			tok->cur = tok->inp;
1447			return ERRORTOKEN;
1448		}
1449                tok->cont_line = 1;
1450		goto again; /* Read next line */
1451	}
1452
1453	/* Check for two-character token */
1454	{
1455		int c2 = tok_nextc(tok);
1456		int token = PyToken_TwoChars(c, c2);
1457		if (token != OP) {
1458			int c3 = tok_nextc(tok);
1459			int token3 = PyToken_ThreeChars(c, c2, c3);
1460			if (token3 != OP) {
1461				token = token3;
1462			} else {
1463				tok_backup(tok, c3);
1464			}
1465			*p_start = tok->start;
1466			*p_end = tok->cur;
1467			return token;
1468		}
1469		tok_backup(tok, c2);
1470	}
1471
1472	/* Keep track of parentheses nesting level */
1473	switch (c) {
1474	case '(':
1475	case '[':
1476	case '{':
1477		tok->level++;
1478		break;
1479	case ')':
1480	case ']':
1481	case '}':
1482		tok->level--;
1483		break;
1484	}
1485
1486	/* Punctuation character */
1487	*p_start = tok->start;
1488	*p_end = tok->cur;
1489	return PyToken_OneChar(c);
1490}
1491
1492int
1493PyTokenizer_Get(struct tok_state *tok, char **p_start, char **p_end)
1494{
1495	int result = tok_get(tok, p_start, p_end);
1496	if (tok->decoding_erred) {
1497		result = ERRORTOKEN;
1498		tok->done = E_DECODE;
1499	}
1500	return result;
1501}
1502
1503#ifdef Py_DEBUG
1504
1505void
1506tok_dump(int type, char *start, char *end)
1507{
1508	printf("%s", _PyParser_TokenNames[type]);
1509	if (type == NAME || type == NUMBER || type == STRING || type == OP)
1510		printf("(%.*s)", (int)(end - start), start);
1511}
1512
1513#endif
1514