Parser/tokenizer.c - platform/external/python/cpython3 - Gitiles

 /***********************************************************
 Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
 The Netherlands.

                         All Rights Reserved

 Permission to use, copy, modify, and distribute this software and its
 documentation for any purpose and without fee is hereby granted,
 provided that the above copyright notice appear in all copies and that
 both that copyright notice and this permission notice appear in
 supporting documentation, and that the names of Stichting Mathematisch
 Centrum or CWI or Corporation for National Research Initiatives or
 CNRI not be used in advertising or publicity pertaining to
 distribution of the software without specific, written prior
 permission.

 While CWI is the initial source for this software, a modified version
 is made available by the Corporation for National Research Initiatives
 (CNRI) at the Internet address ftp://ftp.python.org.

 STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH
 REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
 MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH
 CENTRUM OR CNRI BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
 DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 PERFORMANCE OF THIS SOFTWARE.

 ******************************************************************/

 /* Tokenizer implementation */

 #include "pgenheaders.h"

 #include <ctype.h>

 #include "tokenizer.h"
 #include "errcode.h"

 extern char *PyOS_Readline Py_PROTO((char *));
 /* Return malloc'ed string including trailing \n;
    empty malloc'ed string for EOF;
    NULL if interrupted */

 /* Don't ever change this -- it would break the portability of Python code */
 #define TABSIZE 8

 /* Convert a possibly signed character to a nonnegative int */
 /* XXX This assumes characters are 8 bits wide */
 #ifdef __CHAR_UNSIGNED__
 #define Py_CHARMASK(c)		(c)
 #else
 #define Py_CHARMASK(c)		((c) & 0xff)
 #endif

 /* Forward */
 static struct tok_state *tok_new Py_PROTO((void));
 static int tok_nextc Py_PROTO((struct tok_state *tok));
 static void tok_backup Py_PROTO((struct tok_state *tok, int c));

 /* Token names */

 char *_PyParser_TokenNames[] = {
 	"ENDMARKER",
 	"NAME",
 	"NUMBER",
 	"STRING",
 	"NEWLINE",
 	"INDENT",
 	"DEDENT",
 	"LPAR",
 	"RPAR",
 	"LSQB",
 	"RSQB",
 	"COLON",
 	"COMMA",
 	"SEMI",
 	"PLUS",
 	"MINUS",
 	"STAR",
 	"SLASH",
 	"VBAR",
 	"AMPER",
 	"LESS",
 	"GREATER",
 	"EQUAL",
 	"DOT",
 	"PERCENT",
 	"BACKQUOTE",
 	"LBRACE",
 	"RBRACE",
 	"EQEQUAL",
 	"NOTEQUAL",
 	"LESSEQUAL",
 	"GREATEREQUAL",
 	"TILDE",
 	"CIRCUMFLEX",
 	"LEFTSHIFT",
 	"RIGHTSHIFT",
 	"DOUBLESTAR",
 	/* This table must match the #defines in token.h! */
 	"OP",
 	"<ERRORTOKEN>",
 	"<N_TOKENS>"
 };


 /* Create and initialize a new tok_state structure */

 static struct tok_state *
 tok_new()
 {
 	struct tok_state *tok = PyMem_NEW(struct tok_state, 1);
 	if (tok == NULL)
 		return NULL;
 	tok->buf = tok->cur = tok->end = tok->inp = tok->start = NULL;
 	tok->done = E_OK;
 	tok->fp = NULL;
 	tok->tabsize = TABSIZE;
 	tok->indent = 0;
 	tok->indstack[0] = 0;
 	tok->atbol = 1;
 	tok->pendin = 0;
 	tok->prompt = tok->nextprompt = NULL;
 	tok->lineno = 0;
 	tok->level = 0;
 	tok->filename = NULL;
 	tok->altwarning = 0;
 	tok->alterror = 0;
 	tok->alttabsize = 1;
 	tok->altindstack[0] = 0;
 	return tok;
 }


 /* Set up tokenizer for string */

 struct tok_state *
 PyTokenizer_FromString(str)
 	char *str;
 {
 	struct tok_state *tok = tok_new();
 	if (tok == NULL)
 		return NULL;
 	tok->buf = tok->cur = tok->end = tok->inp = str;
 	return tok;
 }


 /* Set up tokenizer for file */

 struct tok_state *
 PyTokenizer_FromFile(fp, ps1, ps2)
 	FILE *fp;
 	char *ps1, *ps2;
 {
 	struct tok_state *tok = tok_new();
 	if (tok == NULL)
 		return NULL;
 	if ((tok->buf = PyMem_NEW(char, BUFSIZ)) == NULL) {
 		PyMem_DEL(tok);
 		return NULL;
 	}
 	tok->cur = tok->inp = tok->buf;
 	tok->end = tok->buf + BUFSIZ;
 	tok->fp = fp;
 	tok->prompt = ps1;
 	tok->nextprompt = ps2;
 	return tok;
 }


 /* Free a tok_state structure */

 void
 PyTokenizer_Free(tok)
 	struct tok_state *tok;
 {
 	if (tok->fp != NULL && tok->buf != NULL)
 		PyMem_DEL(tok->buf);
 	PyMem_DEL(tok);
 }


 /* Get next char, updating state; error code goes into tok->done */

 static int
 tok_nextc(tok)
 	register struct tok_state *tok;
 {
 	for (;;) {
 		if (tok->cur != tok->inp) {
 			return Py_CHARMASK(*tok->cur++); /* Fast path */
 		}
 		if (tok->done != E_OK)
 			return EOF;
 		if (tok->fp == NULL) {
 			char *end = strchr(tok->inp, '\n');
 			if (end != NULL)
 				end++;
 			else {
 				end = strchr(tok->inp, '\0');
 				if (end == tok->inp) {
 					tok->done = E_EOF;
 					return EOF;
 				}
 			}
 			if (tok->start == NULL)
 				tok->buf = tok->cur;
 			tok->lineno++;
 			tok->inp = end;
 			return Py_CHARMASK(*tok->cur++);
 		}
 		if (tok->prompt != NULL) {
 			char *new = PyOS_Readline(tok->prompt);
 			if (tok->nextprompt != NULL)
 				tok->prompt = tok->nextprompt;
 			if (new == NULL)
 				tok->done = E_INTR;
 			else if (*new == '\0') {
 				free(new);
 				tok->done = E_EOF;
 			}
 			else if (tok->start != NULL) {
 				int start = tok->start - tok->buf;
 				int oldlen = tok->cur - tok->buf;
 				int newlen = oldlen + strlen(new);
 				char *buf = realloc(tok->buf, newlen+1);
 				tok->lineno++;
 				if (buf == NULL) {
 					free(tok->buf);
 					tok->buf = NULL;
 					free(new);
 					tok->done = E_NOMEM;
 					return EOF;
 				}
 				tok->buf = buf;
 				tok->cur = tok->buf + oldlen;
 				strcpy(tok->buf + oldlen, new);
 				free(new);
 				tok->inp = tok->buf + newlen;
 				tok->end = tok->inp + 1;
 				tok->start = tok->buf + start;
 			}
 			else {
 				tok->lineno++;
 				if (tok->buf != NULL)
 					free(tok->buf);
 				tok->buf = new;
 				tok->cur = tok->buf;
 				tok->inp = strchr(tok->buf, '\0');
 				tok->end = tok->inp + 1;
 			}
 		}
 		else {
 			int done = 0;
 			int cur = 0;
 			char *pt;
 			if (tok->start == NULL) {
 				if (tok->buf == NULL) {
 					tok->buf = PyMem_NEW(char, BUFSIZ);
 					if (tok->buf == NULL) {
 						tok->done = E_NOMEM;
 						return EOF;
 					}
 					tok->end = tok->buf + BUFSIZ;
 				}
 				if (fgets(tok->buf, (int)(tok->end - tok->buf),
 					  tok->fp) == NULL) {
 					tok->done = E_EOF;
 					done = 1;
 				}
 				else {
 					tok->done = E_OK;
 					tok->inp = strchr(tok->buf, '\0');
 					done = tok->inp[-1] == '\n';
 				}
 			}
 			else {
 				cur = tok->cur - tok->buf;
 				if (feof(tok->fp)) {
 					tok->done = E_EOF;
 					done = 1;
 				}
 				else
 					tok->done = E_OK;
 			}
 			tok->lineno++;
 			/* Read until '\n' or EOF */
 			while (!done) {
 				int curstart = tok->start == NULL ? -1 :
 					       tok->start - tok->buf;
 				int curvalid = tok->inp - tok->buf;
 				int newsize = curvalid + BUFSIZ;
 				char *newbuf = tok->buf;
 				PyMem_RESIZE(newbuf, char, newsize);
 				if (newbuf == NULL) {
 					tok->done = E_NOMEM;
 					tok->cur = tok->inp;
 					return EOF;
 				}
 				tok->buf = newbuf;
 				tok->inp = tok->buf + curvalid;
 				tok->end = tok->buf + newsize;
 				tok->start = curstart < 0 ? NULL :
 					     tok->buf + curstart;
 				if (fgets(tok->inp,
 					       (int)(tok->end - tok->inp),
 					       tok->fp) == NULL) {
 					/* Last line does not end in \n,
 					   fake one */
 					strcpy(tok->inp, "\n");
 				}
 				tok->inp = strchr(tok->inp, '\0');
 				done = tok->inp[-1] == '\n';
 			}
 			tok->cur = tok->buf + cur;
 #ifndef macintosh
 			/* replace "\r\n" with "\n" */
 			/* For Mac we leave the \r, giving a syntax error */
 			pt = tok->inp - 2;
 			if (pt >= tok->buf && *pt == '\r') {
 				*pt++ = '\n';
 				*pt = '\0';
 				tok->inp = pt;
 			}
 #endif
 		}
 		if (tok->done != E_OK) {
 			if (tok->prompt != NULL)
 				PySys_WriteStderr("\n");
 			tok->cur = tok->inp;
 			return EOF;
 		}
 	}
 	/*NOTREACHED*/
 }


 /* Back-up one character */

 static void
 tok_backup(tok, c)
 	register struct tok_state *tok;
 	register int c;
 {
 	if (c != EOF) {
 		if (--tok->cur < tok->buf)
 			Py_FatalError("tok_backup: begin of buffer");
 		if (*tok->cur != c)
 			*tok->cur = c;
 	}
 }


 /* Return the token corresponding to a single character */

 int
 PyToken_OneChar(c)
 	int c;
 {
 	switch (c) {
 	case '(':	return LPAR;
 	case ')':	return RPAR;
 	case '[':	return LSQB;
 	case ']':	return RSQB;
 	case ':':	return COLON;
 	case ',':	return COMMA;
 	case ';':	return SEMI;
 	case '+':	return PLUS;
 	case '-':	return MINUS;
 	case '*':	return STAR;
 	case '/':	return SLASH;
 	case '|':	return VBAR;
 	case '&':	return AMPER;
 	case '<':	return LESS;
 	case '>':	return GREATER;
 	case '=':	return EQUAL;
 	case '.':	return DOT;
 	case '%':	return PERCENT;
 	case '`':	return BACKQUOTE;
 	case '{':	return LBRACE;
 	case '}':	return RBRACE;
 	case '^':	return CIRCUMFLEX;
 	case '~':	return TILDE;
 	default:	return OP;
 	}
 }


 int
 PyToken_TwoChars(c1, c2)
 	int c1, c2;
 {
 	switch (c1) {
 	case '=':
 		switch (c2) {
 		case '=':	return EQEQUAL;
 		}
 		break;
 	case '!':
 		switch (c2) {
 		case '=':	return NOTEQUAL;
 		}
 		break;
 	case '<':
 		switch (c2) {
 		case '>':	return NOTEQUAL;
 		case '=':	return LESSEQUAL;
 		case '<':	return LEFTSHIFT;
 		}
 		break;
 	case '>':
 		switch (c2) {
 		case '=':	return GREATEREQUAL;
 		case '>':	return RIGHTSHIFT;
 		}
 		break;
 	case '*':
 		switch (c2) {
 		case '*':	return DOUBLESTAR;
 		}
 		break;
 	}
 	return OP;
 }


 static int
 indenterror(tok)
 	struct tok_state *tok;
 {
 	if (tok->alterror) {
 		tok->done = E_INDENT;
 		tok->cur = tok->inp;
 		return 1;
 	}
 	if (tok->altwarning) {
 		PySys_WriteStderr("%s: inconsistent tab/space usage\n",
 			tok->filename);
 		tok->altwarning = 0;
 	}
 	return 0;
 }


 /* Get next token, after space stripping etc. */

 int
 PyTokenizer_Get(tok, p_start, p_end)
 	register struct tok_state *tok; /* In/out: tokenizer state */
 	char **p_start, **p_end; /* Out: point to start/end of token */
 {
 	register int c;
 	int blankline;

 	*p_start = *p_end = NULL;
   nextline:
 	tok->start = NULL;
 	blankline = 0;

 	/* Get indentation level */
 	if (tok->atbol) {
 		register int col = 0;
 		register int altcol = 0;
 		tok->atbol = 0;
 		for (;;) {
 			c = tok_nextc(tok);
 			if (c == ' ')
 				col++, altcol++;
 			else if (c == '\t') {
 				col = (col/tok->tabsize + 1) * tok->tabsize;
 				altcol = (altcol/tok->alttabsize + 1)
 					* tok->alttabsize;
 			}
 			else if (c == '\014') /* Control-L (formfeed) */
 				col = altcol = 0; /* For Emacs users */
 			else
 				break;
 		}
 		tok_backup(tok, c);
 		if (c == '#' || c == '\n') {
 			/* Lines with only whitespace and/or comments
 			   shouldn't affect the indentation and are
 			   not passed to the parser as NEWLINE tokens,
 			   except *totally* empty lines in interactive
 			   mode, which signal the end of a command group. */
 			if (col == 0 && c == '\n' && tok->prompt != NULL)
 				blankline = 0; /* Let it through */
 			else
 				blankline = 1; /* Ignore completely */
 			/* We can't jump back right here since we still
 			   may need to skip to the end of a comment */
 		}
 		if (!blankline && tok->level == 0) {
 			if (col == tok->indstack[tok->indent]) {
 				/* No change */
 				if (altcol != tok->altindstack[tok->indent]) {
 					if (indenterror(tok))
 						return ERRORTOKEN;
 				}
 			}
 			else if (col > tok->indstack[tok->indent]) {
 				/* Indent -- always one */
 				if (tok->indent+1 >= MAXINDENT) {
 					PySys_WriteStderr(
 						"excessive indent\n");
 					tok->done = E_TOKEN;
 					tok->cur = tok->inp;
 					return ERRORTOKEN;
 				}
 				if (altcol <= tok->altindstack[tok->indent]) {
 					if (indenterror(tok))
 						return ERRORTOKEN;
 				}
 				tok->pendin++;
 				tok->indstack[++tok->indent] = col;
 				tok->altindstack[tok->indent] = altcol;
 			}
 			else /* col < tok->indstack[tok->indent] */ {
 				/* Dedent -- any number, must be consistent */
 				while (tok->indent > 0 &&
 					col < tok->indstack[tok->indent]) {
 					tok->pendin--;
 					tok->indent--;
 				}
 				if (col != tok->indstack[tok->indent]) {
 					PySys_WriteStderr(
 						"inconsistent dedent\n");
 					tok->done = E_TOKEN;
 					tok->cur = tok->inp;
 					return ERRORTOKEN;
 				}
 				if (altcol != tok->altindstack[tok->indent]) {
 					if (indenterror(tok))
 						return ERRORTOKEN;
 				}
 			}
 		}
 	}

 	tok->start = tok->cur;

 	/* Return pending indents/dedents */
 	if (tok->pendin != 0) {
 		if (tok->pendin < 0) {
 			tok->pendin++;
 			return DEDENT;
 		}
 		else {
 			tok->pendin--;
 			return INDENT;
 		}
 	}

  again:
 	tok->start = NULL;
 	/* Skip spaces */
 	do {
 		c = tok_nextc(tok);
 	} while (c == ' ' || c == '\t' || c == '\014');

 	/* Set start of current token */
 	tok->start = tok->cur - 1;

 	/* Skip comment */
 	if (c == '#') {
 		/* Hack to allow overriding the tabsize in the file.
 		   This is also recognized by vi, when it occurs near the
 		   beginning or end of the file.  (Will vi never die...?)
 		   For Python it must be at the beginning of the file! */
 		/* XXX The real vi syntax is actually different :-( */
 		/* XXX Should recognize Emacs syntax, too */
 		int x;
 		if (sscanf(tok->cur,
 				" vi:set tabsize=%d:", &x) == 1 &&
 						x >= 1 && x <= 40) {
 			/* PySys_WriteStderr("# vi:set tabsize=%d:\n", x); */
 			tok->tabsize = x;
 		}
 		do {
 			c = tok_nextc(tok);
 		} while (c != EOF && c != '\n');
 	}

 	/* Check for EOF and errors now */
 	if (c == EOF) {
 		return tok->done == E_EOF ? ENDMARKER : ERRORTOKEN;
 	}

 	/* Identifier (most frequent token!) */
 	if (isalpha(c) || c == '_') {
 		/* Process r"", u"" and ur"" */
 		switch (c) {
 		case 'r':
 		case 'R':
 			c = tok_nextc(tok);
 			if (c == '"' || c == '\'')
 				goto letter_quote;
 			break;
 		case 'u':
 		case 'U':
 			c = tok_nextc(tok);
 			if (c == 'r' || c == 'R')
 				c = tok_nextc(tok);
 			if (c == '"' || c == '\'')
 				goto letter_quote;
 			break;
 		}
 		while (isalnum(c) || c == '_') {
 			c = tok_nextc(tok);
 		}
 		tok_backup(tok, c);
 		*p_start = tok->start;
 		*p_end = tok->cur;
 		return NAME;
 	}

 	/* Newline */
 	if (c == '\n') {
 		tok->atbol = 1;
 		if (blankline || tok->level > 0)
 			goto nextline;
 		*p_start = tok->start;
 		*p_end = tok->cur - 1; /* Leave '\n' out of the string */
 		return NEWLINE;
 	}

 #ifdef macintosh
 	if (c == '\r') {
 		PySys_WriteStderr(
 		  "File contains \\r characters (incorrect line endings?)\n");
 		tok->done = E_TOKEN;
 		tok->cur = tok->inp;
 		return ERRORTOKEN;
 	}
 #endif
 	/* Period or number starting with period? */
 	if (c == '.') {
 		c = tok_nextc(tok);
 		if (isdigit(c)) {
 			goto fraction;
 		}
 		else {
 			tok_backup(tok, c);
 			*p_start = tok->start;
 			*p_end = tok->cur;
 			return DOT;
 		}
 	}

 	/* Number */
 	if (isdigit(c)) {
 		if (c == '0') {
 			/* Hex or octal */
 			c = tok_nextc(tok);
 			if (c == '.')
 				goto fraction;
 #ifndef WITHOUT_COMPLEX
 			if (c == 'j' || c == 'J')
 				goto imaginary;
 #endif
 			if (c == 'x' || c == 'X') {
 				/* Hex */
 				do {
 					c = tok_nextc(tok);
 				} while (isxdigit(c));
 			}
 			else {
 				/* XXX This is broken!  E.g.,
 				   09.9 should be accepted as float! */
 				/* Octal; c is first char of it */
 				/* There's no 'isoctdigit' macro, sigh */
 				while ('0' <= c && c < '8') {
 					c = tok_nextc(tok);
 				}
 			}
 			if (c == 'l' || c == 'L')
 				c = tok_nextc(tok);
 		}
 		else {
 			/* Decimal */
 			do {
 				c = tok_nextc(tok);
 			} while (isdigit(c));
 			if (c == 'l' || c == 'L')
 				c = tok_nextc(tok);
 			else {
 				/* Accept floating point numbers.
 				   XXX This accepts incomplete things like
 				   XXX 12e or 1e+; worry run-time */
 				if (c == '.') {
 		fraction:
 					/* Fraction */
 					do {
 						c = tok_nextc(tok);
 					} while (isdigit(c));
 				}
 				if (c == 'e' || c == 'E') {
 					/* Exponent part */
 					c = tok_nextc(tok);
 					if (c == '+' || c == '-')
 						c = tok_nextc(tok);
 					while (isdigit(c)) {
 						c = tok_nextc(tok);
 					}
 				}
 #ifndef WITHOUT_COMPLEX
 				if (c == 'j' || c == 'J')
 					/* Imaginary part */
 		imaginary:
 					c = tok_nextc(tok);
 #endif
 			}
 		}
 		tok_backup(tok, c);
 		*p_start = tok->start;
 		*p_end = tok->cur;
 		return NUMBER;
 	}

   letter_quote:
 	/* String */
 	if (c == '\'' || c == '"') {
 		int quote2 = tok->cur - tok->start + 1;
 		int quote = c;
 		int triple = 0;
 		int tripcount = 0;
 		for (;;) {
 			c = tok_nextc(tok);
 			if (c == '\n') {
 				if (!triple) {
 					tok->done = E_TOKEN;
 					tok_backup(tok, c);
 					return ERRORTOKEN;
 				}
 				tripcount = 0;
 			}
 			else if (c == EOF) {
 				tok->done = E_TOKEN;
 				tok->cur = tok->inp;
 				return ERRORTOKEN;
 			}
 			else if (c == quote) {
 				tripcount++;
 				if (tok->cur - tok->start == quote2) {
 					c = tok_nextc(tok);
 					if (c == quote) {
 						triple = 1;
 						tripcount = 0;
 						continue;
 					}
 					tok_backup(tok, c);
 				}
 				if (!triple || tripcount == 3)
 					break;
 			}
 			else if (c == '\\') {
 				tripcount = 0;
 				c = tok_nextc(tok);
 				if (c == EOF) {
 					tok->done = E_TOKEN;
 					tok->cur = tok->inp;
 					return ERRORTOKEN;
 				}
 			}
 			else
 				tripcount = 0;
 		}
 		*p_start = tok->start;
 		*p_end = tok->cur;
 		return STRING;
 	}

 	/* Line continuation */
 	if (c == '\\') {
 		c = tok_nextc(tok);
 		if (c != '\n') {
 			tok->done = E_TOKEN;
 			tok->cur = tok->inp;
 			return ERRORTOKEN;
 		}
 		goto again; /* Read next line */
 	}

 	/* Check for two-character token */
 	{
 		int c2 = tok_nextc(tok);
 		int token = PyToken_TwoChars(c, c2);
 		if (token != OP) {
 			*p_start = tok->start;
 			*p_end = tok->cur;
 			return token;
 		}
 		tok_backup(tok, c2);
 	}

 	/* Keep track of parentheses nesting level */
 	switch (c) {
 	case '(':
 	case '[':
 	case '{':
 		tok->level++;
 		break;
 	case ')':
 	case ']':
 	case '}':
 		tok->level--;
 		break;
 	}

 	/* Punctuation character */
 	*p_start = tok->start;
 	*p_end = tok->cur;
 	return PyToken_OneChar(c);
 }


 #ifdef Py_DEBUG

 void
 tok_dump(type, start, end)
 	int type;
 	char *start, *end;
 {
 	printf("%s", _PyParser_TokenNames[type]);
 	if (type == NAME || type == NUMBER || type == STRING || type == OP)
 		printf("(%.*s)", (int)(end - start), start);
 }

 #endif
	/***********************************************************
	Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
	The Netherlands.

	All Rights Reserved

	Permission to use, copy, modify, and distribute this software and its
	documentation for any purpose and without fee is hereby granted,
	provided that the above copyright notice appear in all copies and that
	both that copyright notice and this permission notice appear in
	supporting documentation, and that the names of Stichting Mathematisch
	Centrum or CWI or Corporation for National Research Initiatives or
	CNRI not be used in advertising or publicity pertaining to
	distribution of the software without specific, written prior
	permission.

	While CWI is the initial source for this software, a modified version
	is made available by the Corporation for National Research Initiatives
	(CNRI) at the Internet address ftp://ftp.python.org.

	STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH
	REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
	MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH
	CENTRUM OR CNRI BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
	DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
	PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
	TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
	PERFORMANCE OF THIS SOFTWARE.

	******************************************************************/

	/* Tokenizer implementation */

	#include "pgenheaders.h"

	#include <ctype.h>

	#include "tokenizer.h"
	#include "errcode.h"

	extern char PyOS_Readline Py_PROTO((char ));
	/* Return malloc'ed string including trailing \n;
	empty malloc'ed string for EOF;
	NULL if interrupted */

	/* Don't ever change this -- it would break the portability of Python code */
	#define TABSIZE 8

	/* Convert a possibly signed character to a nonnegative int */
	/* XXX This assumes characters are 8 bits wide */
	#ifdef __CHAR_UNSIGNED__
	#define Py_CHARMASK(c) (c)
	#else
	#define Py_CHARMASK(c) ((c) & 0xff)
	#endif

	/* Forward */
	static struct tok_state *tok_new Py_PROTO((void));
	static int tok_nextc Py_PROTO((struct tok_state *tok));
	static void tok_backup Py_PROTO((struct tok_state *tok, int c));

	/* Token names */

	char *_PyParser_TokenNames[] = {
	"ENDMARKER",
	"NAME",
	"NUMBER",
	"STRING",
	"NEWLINE",
	"INDENT",
	"DEDENT",
	"LPAR",
	"RPAR",
	"LSQB",
	"RSQB",
	"COLON",
	"COMMA",
	"SEMI",
	"PLUS",
	"MINUS",
	"STAR",
	"SLASH",
	"VBAR",
	"AMPER",
	"LESS",
	"GREATER",
	"EQUAL",
	"DOT",
	"PERCENT",
	"BACKQUOTE",
	"LBRACE",
	"RBRACE",
	"EQEQUAL",
	"NOTEQUAL",
	"LESSEQUAL",
	"GREATEREQUAL",
	"TILDE",
	"CIRCUMFLEX",
	"LEFTSHIFT",
	"RIGHTSHIFT",
	"DOUBLESTAR",
	/* This table must match the #defines in token.h! */
	"OP",
	"<ERRORTOKEN>",
	"<N_TOKENS>"
	};


	/* Create and initialize a new tok_state structure */

	static struct tok_state *
	tok_new()
	{
	struct tok_state *tok = PyMem_NEW(struct tok_state, 1);
	if (tok == NULL)
	return NULL;
	tok->buf = tok->cur = tok->end = tok->inp = tok->start = NULL;
	tok->done = E_OK;
	tok->fp = NULL;
	tok->tabsize = TABSIZE;
	tok->indent = 0;
	tok->indstack[0] = 0;
	tok->atbol = 1;
	tok->pendin = 0;
	tok->prompt = tok->nextprompt = NULL;
	tok->lineno = 0;
	tok->level = 0;
	tok->filename = NULL;
	tok->altwarning = 0;
	tok->alterror = 0;
	tok->alttabsize = 1;
	tok->altindstack[0] = 0;
	return tok;
	}


	/* Set up tokenizer for string */

	struct tok_state *
	PyTokenizer_FromString(str)
	char *str;
	{
	struct tok_state *tok = tok_new();
	if (tok == NULL)
	return NULL;
	tok->buf = tok->cur = tok->end = tok->inp = str;
	return tok;
	}


	/* Set up tokenizer for file */

	struct tok_state *
	PyTokenizer_FromFile(fp, ps1, ps2)
	FILE *fp;
	char ps1, ps2;
	{
	struct tok_state *tok = tok_new();
	if (tok == NULL)
	return NULL;
	if ((tok->buf = PyMem_NEW(char, BUFSIZ)) == NULL) {
	PyMem_DEL(tok);
	return NULL;
	}
	tok->cur = tok->inp = tok->buf;
	tok->end = tok->buf + BUFSIZ;
	tok->fp = fp;
	tok->prompt = ps1;
	tok->nextprompt = ps2;
	return tok;
	}


	/* Free a tok_state structure */

	void
	PyTokenizer_Free(tok)
	struct tok_state *tok;
	{
	if (tok->fp != NULL && tok->buf != NULL)
	PyMem_DEL(tok->buf);
	PyMem_DEL(tok);
	}


	/* Get next char, updating state; error code goes into tok->done */

	static int
	tok_nextc(tok)
	register struct tok_state *tok;
	{
	for (;;) {
	if (tok->cur != tok->inp) {
	return Py_CHARMASK(tok->cur++); / Fast path */
	}
	if (tok->done != E_OK)
	return EOF;
	if (tok->fp == NULL) {
	char *end = strchr(tok->inp, '\n');
	if (end != NULL)
	end++;
	else {
	end = strchr(tok->inp, '\0');
	if (end == tok->inp) {
	tok->done = E_EOF;
	return EOF;
	}
	}
	if (tok->start == NULL)
	tok->buf = tok->cur;
	tok->lineno++;
	tok->inp = end;
	return Py_CHARMASK(*tok->cur++);
	}
	if (tok->prompt != NULL) {
	char *new = PyOS_Readline(tok->prompt);
	if (tok->nextprompt != NULL)
	tok->prompt = tok->nextprompt;
	if (new == NULL)
	tok->done = E_INTR;
	else if (*new == '\0') {
	free(new);
	tok->done = E_EOF;
	}
	else if (tok->start != NULL) {
	int start = tok->start - tok->buf;
	int oldlen = tok->cur - tok->buf;
	int newlen = oldlen + strlen(new);
	char *buf = realloc(tok->buf, newlen+1);
	tok->lineno++;
	if (buf == NULL) {
	free(tok->buf);
	tok->buf = NULL;
	free(new);
	tok->done = E_NOMEM;
	return EOF;
	}
	tok->buf = buf;
	tok->cur = tok->buf + oldlen;
	strcpy(tok->buf + oldlen, new);
	free(new);
	tok->inp = tok->buf + newlen;
	tok->end = tok->inp + 1;
	tok->start = tok->buf + start;
	}
	else {
	tok->lineno++;
	if (tok->buf != NULL)
	free(tok->buf);
	tok->buf = new;
	tok->cur = tok->buf;
	tok->inp = strchr(tok->buf, '\0');
	tok->end = tok->inp + 1;
	}
	}
	else {
	int done = 0;
	int cur = 0;
	char *pt;
	if (tok->start == NULL) {
	if (tok->buf == NULL) {
	tok->buf = PyMem_NEW(char, BUFSIZ);
	if (tok->buf == NULL) {
	tok->done = E_NOMEM;
	return EOF;
	}
	tok->end = tok->buf + BUFSIZ;
	}
	if (fgets(tok->buf, (int)(tok->end - tok->buf),
	tok->fp) == NULL) {
	tok->done = E_EOF;
	done = 1;
	}
	else {
	tok->done = E_OK;
	tok->inp = strchr(tok->buf, '\0');
	done = tok->inp[-1] == '\n';
	}
	}
	else {
	cur = tok->cur - tok->buf;
	if (feof(tok->fp)) {
	tok->done = E_EOF;
	done = 1;
	}
	else
	tok->done = E_OK;
	}
	tok->lineno++;
	/* Read until '\n' or EOF */
	while (!done) {
	int curstart = tok->start == NULL ? -1 :
	tok->start - tok->buf;
	int curvalid = tok->inp - tok->buf;
	int newsize = curvalid + BUFSIZ;
	char *newbuf = tok->buf;
	PyMem_RESIZE(newbuf, char, newsize);
	if (newbuf == NULL) {
	tok->done = E_NOMEM;
	tok->cur = tok->inp;
	return EOF;
	}
	tok->buf = newbuf;
	tok->inp = tok->buf + curvalid;
	tok->end = tok->buf + newsize;
	tok->start = curstart < 0 ? NULL :
	tok->buf + curstart;
	if (fgets(tok->inp,
	(int)(tok->end - tok->inp),
	tok->fp) == NULL) {
	/* Last line does not end in \n,
	fake one */
	strcpy(tok->inp, "\n");
	}
	tok->inp = strchr(tok->inp, '\0');
	done = tok->inp[-1] == '\n';
	}
	tok->cur = tok->buf + cur;
	#ifndef macintosh
	/* replace "\r\n" with "\n" */
	/* For Mac we leave the \r, giving a syntax error */
	pt = tok->inp - 2;
	if (pt >= tok->buf && *pt == '\r') {
	*pt++ = '\n';
	*pt = '\0';
	tok->inp = pt;
	}
	#endif
	}
	if (tok->done != E_OK) {
	if (tok->prompt != NULL)
	PySys_WriteStderr("\n");
	tok->cur = tok->inp;
	return EOF;
	}
	}
	/NOTREACHED/
	}


	/* Back-up one character */

	static void
	tok_backup(tok, c)
	register struct tok_state *tok;
	register int c;
	{
	if (c != EOF) {
	if (--tok->cur < tok->buf)
	Py_FatalError("tok_backup: begin of buffer");
	if (*tok->cur != c)
	*tok->cur = c;
	}
	}


	/* Return the token corresponding to a single character */

	int
	PyToken_OneChar(c)
	int c;
	{
	switch (c) {
	case '(': return LPAR;
	case ')': return RPAR;
	case '[': return LSQB;
	case ']': return RSQB;
	case ':': return COLON;
	case ',': return COMMA;
	case ';': return SEMI;
	case '+': return PLUS;
	case '-': return MINUS;
	case '*': return STAR;
	case '/': return SLASH;
	case '\|': return VBAR;
	case '&': return AMPER;
	case '<': return LESS;
	case '>': return GREATER;
	case '=': return EQUAL;
	case '.': return DOT;
	case '%': return PERCENT;
	case '`': return BACKQUOTE;
	case '{': return LBRACE;
	case '}': return RBRACE;
	case '^': return CIRCUMFLEX;
	case '~': return TILDE;
	default: return OP;
	}
	}


	int
	PyToken_TwoChars(c1, c2)
	int c1, c2;
	{
	switch (c1) {
	case '=':
	switch (c2) {
	case '=': return EQEQUAL;
	}
	break;
	case '!':
	switch (c2) {
	case '=': return NOTEQUAL;
	}
	break;
	case '<':
	switch (c2) {
	case '>': return NOTEQUAL;
	case '=': return LESSEQUAL;
	case '<': return LEFTSHIFT;
	}
	break;
	case '>':
	switch (c2) {
	case '=': return GREATEREQUAL;
	case '>': return RIGHTSHIFT;
	}
	break;
	case '*':
	switch (c2) {
	case '*': return DOUBLESTAR;
	}
	break;
	}
	return OP;
	}


	static int
	indenterror(tok)
	struct tok_state *tok;
	{
	if (tok->alterror) {
	tok->done = E_INDENT;
	tok->cur = tok->inp;
	return 1;
	}
	if (tok->altwarning) {
	PySys_WriteStderr("%s: inconsistent tab/space usage\n",
	tok->filename);
	tok->altwarning = 0;
	}
	return 0;
	}


	/* Get next token, after space stripping etc. */

	int
	PyTokenizer_Get(tok, p_start, p_end)
	register struct tok_state tok; / In/out: tokenizer state */
	char p_start, p_end; /* Out: point to start/end of token */
	{
	register int c;
	int blankline;

	p_start = p_end = NULL;
	nextline:
	tok->start = NULL;
	blankline = 0;

	/* Get indentation level */
	if (tok->atbol) {
	register int col = 0;
	register int altcol = 0;
	tok->atbol = 0;
	for (;;) {
	c = tok_nextc(tok);
	if (c == ' ')
	col++, altcol++;
	else if (c == '\t') {
	col = (col/tok->tabsize + 1) * tok->tabsize;
	altcol = (altcol/tok->alttabsize + 1)
	* tok->alttabsize;
	}
	else if (c == '\014') /* Control-L (formfeed) */
	col = altcol = 0; /* For Emacs users */
	else
	break;
	}
	tok_backup(tok, c);
	if (c == '#' \|\| c == '\n') {
	/* Lines with only whitespace and/or comments
	shouldn't affect the indentation and are
	not passed to the parser as NEWLINE tokens,
	except totally empty lines in interactive
	mode, which signal the end of a command group. */
	if (col == 0 && c == '\n' && tok->prompt != NULL)
	blankline = 0; /* Let it through */
	else
	blankline = 1; /* Ignore completely */
	/* We can't jump back right here since we still
	may need to skip to the end of a comment */
	}
	if (!blankline && tok->level == 0) {
	if (col == tok->indstack[tok->indent]) {
	/* No change */
	if (altcol != tok->altindstack[tok->indent]) {
	if (indenterror(tok))
	return ERRORTOKEN;
	}
	}
	else if (col > tok->indstack[tok->indent]) {
	/* Indent -- always one */
	if (tok->indent+1 >= MAXINDENT) {
	PySys_WriteStderr(
	"excessive indent\n");
	tok->done = E_TOKEN;
	tok->cur = tok->inp;
	return ERRORTOKEN;
	}
	if (altcol <= tok->altindstack[tok->indent]) {
	if (indenterror(tok))
	return ERRORTOKEN;
	}
	tok->pendin++;
	tok->indstack[++tok->indent] = col;
	tok->altindstack[tok->indent] = altcol;
	}
	else /* col < tok->indstack[tok->indent] */ {
	/* Dedent -- any number, must be consistent */
	while (tok->indent > 0 &&
	col < tok->indstack[tok->indent]) {
	tok->pendin--;
	tok->indent--;
	}
	if (col != tok->indstack[tok->indent]) {
	PySys_WriteStderr(
	"inconsistent dedent\n");
	tok->done = E_TOKEN;
	tok->cur = tok->inp;
	return ERRORTOKEN;
	}
	if (altcol != tok->altindstack[tok->indent]) {
	if (indenterror(tok))
	return ERRORTOKEN;
	}
	}
	}
	}

	tok->start = tok->cur;

	/* Return pending indents/dedents */
	if (tok->pendin != 0) {
	if (tok->pendin < 0) {
	tok->pendin++;
	return DEDENT;
	}
	else {
	tok->pendin--;
	return INDENT;
	}
	}

	again:
	tok->start = NULL;
	/* Skip spaces */
	do {
	c = tok_nextc(tok);
	} while (c == ' ' \|\| c == '\t' \|\| c == '\014');

	/* Set start of current token */
	tok->start = tok->cur - 1;

	/* Skip comment */
	if (c == '#') {
	/* Hack to allow overriding the tabsize in the file.
	This is also recognized by vi, when it occurs near the
	beginning or end of the file. (Will vi never die...?)
	For Python it must be at the beginning of the file! */
	/* XXX The real vi syntax is actually different :-( */
	/* XXX Should recognize Emacs syntax, too */
	int x;
	if (sscanf(tok->cur,
	" vi:set tabsize=%d:", &x) == 1 &&
	x >= 1 && x <= 40) {
	/* PySys_WriteStderr("# vi:set tabsize=%d:\n", x); */
	tok->tabsize = x;
	}
	do {
	c = tok_nextc(tok);
	} while (c != EOF && c != '\n');
	}

	/* Check for EOF and errors now */
	if (c == EOF) {
	return tok->done == E_EOF ? ENDMARKER : ERRORTOKEN;
	}

	/* Identifier (most frequent token!) */
	if (isalpha(c) \|\| c == '_') {
	/* Process r"", u"" and ur"" */
	switch (c) {
	case 'r':
	case 'R':
	c = tok_nextc(tok);
	if (c == '"' \|\| c == '\'')
	goto letter_quote;
	break;
	case 'u':
	case 'U':
	c = tok_nextc(tok);
	if (c == 'r' \|\| c == 'R')
	c = tok_nextc(tok);
	if (c == '"' \|\| c == '\'')
	goto letter_quote;
	break;
	}
	while (isalnum(c) \|\| c == '_') {
	c = tok_nextc(tok);
	}
	tok_backup(tok, c);
	*p_start = tok->start;
	*p_end = tok->cur;
	return NAME;
	}

	/* Newline */
	if (c == '\n') {
	tok->atbol = 1;
	if (blankline \|\| tok->level > 0)
	goto nextline;
	*p_start = tok->start;
	p_end = tok->cur - 1; / Leave '\n' out of the string */
	return NEWLINE;
	}

	#ifdef macintosh
	if (c == '\r') {
	PySys_WriteStderr(
	"File contains \\r characters (incorrect line endings?)\n");
	tok->done = E_TOKEN;
	tok->cur = tok->inp;
	return ERRORTOKEN;
	}
	#endif
	/* Period or number starting with period? */
	if (c == '.') {
	c = tok_nextc(tok);
	if (isdigit(c)) {
	goto fraction;
	}
	else {
	tok_backup(tok, c);
	*p_start = tok->start;
	*p_end = tok->cur;
	return DOT;
	}
	}

	/* Number */
	if (isdigit(c)) {
	if (c == '0') {
	/* Hex or octal */
	c = tok_nextc(tok);
	if (c == '.')
	goto fraction;
	#ifndef WITHOUT_COMPLEX
	if (c == 'j' \|\| c == 'J')
	goto imaginary;
	#endif
	if (c == 'x' \|\| c == 'X') {
	/* Hex */
	do {
	c = tok_nextc(tok);
	} while (isxdigit(c));
	}
	else {
	/* XXX This is broken! E.g.,
	09.9 should be accepted as float! */
	/* Octal; c is first char of it */
	/* There's no 'isoctdigit' macro, sigh */
	while ('0' <= c && c < '8') {
	c = tok_nextc(tok);
	}
	}
	if (c == 'l' \|\| c == 'L')
	c = tok_nextc(tok);
	}
	else {
	/* Decimal */
	do {
	c = tok_nextc(tok);
	} while (isdigit(c));
	if (c == 'l' \|\| c == 'L')
	c = tok_nextc(tok);
	else {
	/* Accept floating point numbers.
	XXX This accepts incomplete things like
	XXX 12e or 1e+; worry run-time */
	if (c == '.') {
	fraction:
	/* Fraction */
	do {
	c = tok_nextc(tok);
	} while (isdigit(c));
	}
	if (c == 'e' \|\| c == 'E') {
	/* Exponent part */
	c = tok_nextc(tok);
	if (c == '+' \|\| c == '-')
	c = tok_nextc(tok);
	while (isdigit(c)) {
	c = tok_nextc(tok);
	}
	}
	#ifndef WITHOUT_COMPLEX
	if (c == 'j' \|\| c == 'J')
	/* Imaginary part */
	imaginary:
	c = tok_nextc(tok);
	#endif
	}
	}
	tok_backup(tok, c);
	*p_start = tok->start;
	*p_end = tok->cur;
	return NUMBER;
	}

	letter_quote:
	/* String */
	if (c == '\'' \|\| c == '"') {
	int quote2 = tok->cur - tok->start + 1;
	int quote = c;
	int triple = 0;
	int tripcount = 0;
	for (;;) {
	c = tok_nextc(tok);
	if (c == '\n') {
	if (!triple) {
	tok->done = E_TOKEN;
	tok_backup(tok, c);
	return ERRORTOKEN;
	}
	tripcount = 0;
	}
	else if (c == EOF) {
	tok->done = E_TOKEN;
	tok->cur = tok->inp;
	return ERRORTOKEN;
	}
	else if (c == quote) {
	tripcount++;
	if (tok->cur - tok->start == quote2) {
	c = tok_nextc(tok);
	if (c == quote) {
	triple = 1;
	tripcount = 0;
	continue;
	}
	tok_backup(tok, c);
	}
	if (!triple \|\| tripcount == 3)
	break;
	}
	else if (c == '\\') {
	tripcount = 0;
	c = tok_nextc(tok);
	if (c == EOF) {
	tok->done = E_TOKEN;
	tok->cur = tok->inp;
	return ERRORTOKEN;
	}
	}
	else
	tripcount = 0;
	}
	*p_start = tok->start;
	*p_end = tok->cur;
	return STRING;
	}

	/* Line continuation */
	if (c == '\\') {
	c = tok_nextc(tok);
	if (c != '\n') {
	tok->done = E_TOKEN;
	tok->cur = tok->inp;
	return ERRORTOKEN;
	}
	goto again; /* Read next line */
	}

	/* Check for two-character token */
	{
	int c2 = tok_nextc(tok);
	int token = PyToken_TwoChars(c, c2);
	if (token != OP) {
	*p_start = tok->start;
	*p_end = tok->cur;
	return token;
	}
	tok_backup(tok, c2);
	}

	/* Keep track of parentheses nesting level */
	switch (c) {
	case '(':
	case '[':
	case '{':
	tok->level++;
	break;
	case ')':
	case ']':
	case '}':
	tok->level--;
	break;
	}

	/* Punctuation character */
	*p_start = tok->start;
	*p_end = tok->cur;
	return PyToken_OneChar(c);
	}


	#ifdef Py_DEBUG

	void
	tok_dump(type, start, end)
	int type;
	char start, end;
	{
	printf("%s", _PyParser_TokenNames[type]);
	if (type == NAME \|\| type == NUMBER \|\| type == STRING \|\| type == OP)
	printf("(%.*s)", (int)(end - start), start);
	}

	#endif