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cpython/Parser/tokenizer.c

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/***********************************************************
Copyright (c) 2000, BeOpen.com.
Copyright (c) 1995-2000, Corporation for National Research Initiatives.
Copyright (c) 1990-1995, Stichting Mathematisch Centrum.
All rights reserved.
See the file "Misc/COPYRIGHT" for information on usage and
redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES.
******************************************************************/
/* 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') {
PyMem_FREE(new);
tok->done = E_EOF;
}
else if (tok->start != NULL) {
size_t start = tok->start - tok->buf;
size_t oldlen = tok->cur - tok->buf;
size_t newlen = oldlen + strlen(new);
char *buf = tok->buf;
PyMem_RESIZE(buf, char, newlen+1);
tok->lineno++;
if (buf == NULL) {
PyMem_DEL(tok->buf);
tok->buf = NULL;
PyMem_FREE(new);
tok->done = E_NOMEM;
return EOF;
}
tok->buf = buf;
tok->cur = tok->buf + oldlen;
strcpy(tok->buf + oldlen, new);
PyMem_FREE(new);
tok->inp = tok->buf + newlen;
tok->end = tok->inp + 1;
tok->start = tok->buf + start;
}
else {
tok->lineno++;
if (tok->buf != NULL)
PyMem_DEL(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, while looking for tab-setting magic */
if (c == '#') {
static char *tabforms[] = {
"tab-width:", /* Emacs */
":tabstop=", /* vim, full form */
":ts=", /* vim, abbreviated form */
"set tabsize=", /* will vi never die? */
/* more templates can be added here to support other editors */
};
char cbuf[80];
char *tp, **cp;
tp = cbuf;
do {
*tp++ = c = tok_nextc(tok);
} while (c != EOF && c != '\n' &&
tp - cbuf + 1 < sizeof(cbuf));
*tp = '\0';
for (cp = tabforms;
cp < tabforms + sizeof(tabforms)/sizeof(tabforms[0]);
cp++) {
if ((tp = strstr(cbuf, *cp))) {
int newsize = atoi(tp + strlen(*cp));
if (newsize >= 1 && newsize <= 40) {
tok->tabsize = newsize;
if (Py_VerboseFlag)
PySys_WriteStderr(
"Tab size set to %d\n",
newsize);
}
}
}
while (c != EOF && c != '\n')
c = tok_nextc(tok);
}
/* 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
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