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lexer.c
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lexer.c
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/* $Id$ $Revision$ */
/* vim:set shiftwidth=4 ts=8: */
/*************************************************************************
* Copyright (c) 2011 AT&T Intellectual Property
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors: See CVS logs. Details at http://www.graphviz.org/
*************************************************************************/
#include <stdarg.h>
#include <stdlib.h>
#include "libgraph.h"
#include "parser.h"
#include "triefa.cP"
#include "agxbuf.h"
#ifdef DMALLOC
#include "dmalloc.h"
#endif
#define InfileName (InputFile?InputFile:"<unknown>")
static FILE *Lexer_fp;
static char *LexPtr, *TokenBuf;
static int LineBufSize;
static unsigned char In_comment;
static unsigned char Comment_start;
static unsigned char Start_html_string;
int Line_number;
static char *InputFile;
static int agmaxerr;
static void
storeFileName (char* fname, int len)
{
static int cnt;
static char* buf;
if (len > cnt) {
if (cnt) buf = (char*)realloc (buf, len+1);
else buf = (char*)malloc (len+1);
cnt = len;
}
strcpy (buf, fname);
InputFile = buf;
}
/* Reset line number.
* Argument n is indexed from 1, so we decrement it.
*/
void agreadline(int n)
{
Line_number = n - 1;
}
int aglinenumber ()
{
return Line_number;
}
/* (Re)set file:
*/
void agsetfile(char *f)
{
InputFile = f;
Line_number = 0;
}
void aglexinit(FILE * fp, gets_f mygets)
{
if (Lexer_fp != fp)
LexPtr = NULL;
Lexer_fp = fp;
if (mygets)
AG.fgets = mygets;
if (AG.fgets == NULL)
AG.fgets = fgets;
if (AG.linebuf == NULL) {
LineBufSize = BUFSIZ;
AG.linebuf = N_NEW(LineBufSize, char);
TokenBuf = N_NEW(LineBufSize, char);
}
AG.fgets (AG.linebuf, 0, fp); /* reset mygets */
AG.syntax_errors = 0;
}
#define ISSPACE(c) ((c != 0) && ((isspace(c) || iscntrl(c))))
/* skip leading white space and comments in a string p
* whitespace includes control characters
*/
static char *skip_wscomments(char *pp)
{
unsigned char *p = (unsigned char *) pp;
do {
while (ISSPACE(*p))
p++;
while (In_comment && p[0]) {
while (p[0] && (p[0] != '*'))
p++;
if (p[0]) {
if (p[1] == '/') {
In_comment = FALSE;
p += 2;
break;
} else
p++;
}
}
if (p[0] == '/') {
if (p[1] == '/')
while (*p)
p++; /* skip to end of line */
else {
if (p[1] == '*') {
In_comment = TRUE;
Comment_start = Line_number;
p += 2;
continue;
} else
break; /* return a slash */
}
} else {
if (!ISSPACE(*p))
break;
}
} while (p[0]);
return (char *) p;
}
/* scan an unquoted token and return the position after its terminator */
static char *scan_token(unsigned char *p, unsigned char *token)
{
unsigned char *q;
q = token;
if (p == '\0')
return NULL;
while (ISALNUM(*p)) {
*q++ = *p++;
}
*q = '\0';
return p;
}
static char *scan_num(char *p, char *token)
{
unsigned char *q, *z;
int saw_rp = FALSE;
int saw_digit = FALSE;
z = (unsigned char *) p;
q = (unsigned char *) token;
if (*z == '-')
*q++ = *z++;
if (*z == '.') {
saw_rp = TRUE;
*q++ = *z++;
}
while (isdigit(*z)) {
saw_digit = TRUE;
*q++ = *z++;
}
if ((*z == '.') && (saw_rp == FALSE)) {
saw_rp = TRUE;
*q++ = *z++;
while (isdigit(*z)) {
saw_digit = TRUE;
*q++ = *z++;
}
}
*q = '\0';
if (saw_digit && *z && ((isalpha(*z)) || (*z == '_'))) {
unsigned char *endp = z + 1;
unsigned char c;
while ((c = *endp) && ((isalpha(c)) || (c == '_')))
endp++;
*endp = '\0';
agerr(AGWARN,
"%s:%d: ambiguous \"%s\" splits into two names: \"%s\" and \"%s\"\n",
InfileName, Line_number, p, token, z);
*endp = c;
}
if (saw_digit == FALSE)
z = NULL;
return (char *) z;
}
/* scan a quoted string and return the position after its terminator */
static char *quoted_string(char *p, char *token)
{
char quote, *q;
quote = *p++;
q = token;
while ((*p) && (*p != quote)) {
if (*p == '\\') {
if (*(p + 1) == quote)
p++;
else {
if (*(p + 1) == '\\')
*q++ = *p++;
}
}
*q++ = *p++;
}
if (*p == '\0')
agerr(AGWARN, "%s:%d: string ran past end of line\n",
InfileName, Line_number);
else
p++;
*q = 0;
return p;
}
int myaglex(void)
{ /* for debugging */
int rv = aglex();
fprintf(stderr, "returning %d\n", rv);
if (rv == T_symbol)
fprintf(stderr, "string val is %s\n", aglval.str);
return rv;
}
/*
* Return a logical line in AG.linebuf.
* In particular, the buffer will contain a '\n' as the last non-null char.
* Ignore lines beginning with '#'; update cpp line number if applicable.
* Fold long lines, i.e., ignore escaped newlines.
* Assume the AG.fgets function reads upto newline or buffer length
* like fgets.
* Need to be careful that AG.fgets might not return full physical line
* because buffer is too small to hold it.
*/
static char *lex_gets(void)
{
char *clp;
int len, curlen;
len = curlen = 0;
do {
/* make sure there is room for at least another SMALLBUF worth */
if (curlen + SMALLBUF >= LineBufSize) {
LineBufSize += BUFSIZ;
AG.linebuf = (char*)realloc(AG.linebuf, LineBufSize);
TokenBuf = (char*)realloc(TokenBuf, LineBufSize);
}
/* off by one so we can back up in LineBuf */
clp = AG.fgets (AG.linebuf + curlen + 1,
LineBufSize - curlen - 1, Lexer_fp);
if (clp == NULL)
break;
len = strlen(clp); /* since clp != NULL, len > 0 */
if (clp[len - 1] == '\n') { /* have physical line */
if ((clp[0] == '#') && (curlen == 0)) {
/* comment line or cpp line sync */
int r, cnt;
char buf[2];
char* s = clp + 1;
if (strncmp(s, "line", 4) == 0) s += 4;
r = sscanf(s, "%d %1[\"]%n", &Line_number, buf, &cnt);
if (r <= 0) Line_number++;
else { /* got line number */
Line_number--;
if (r > 1) { /* saw quote */
char* p = s + cnt;
char* e = p;
while (*e && (*e != '"')) e++;
if (e != p) {
*e = '\0';
storeFileName (p, e-p);
}
}
}
clp[0] = 0;
len = 1; /* this will make the while test below succeed */
continue;
}
Line_number++;
/* Note it is possible len == 1 and last character in
* previous read was '\\'
* It is also possible to have curlen=0, and read in
* "\\\n".
*/
if (clp[len - 2] == '\\') { /* escaped newline */
len = len - 2;
clp[len] = '\0';
}
}
curlen += len;
/* the following test relies on having AG.linebuf[0] == '\0' */
} while (clp[len - 1] != '\n');
if (curlen > 0)
return AG.linebuf + 1;
else
return NULL;
}
/* html_pair:
* Iteratively scan nested "<...>"
* p points to first character after initial '<'
* Store characters up to but not including matching '>'
* Return pointer to matching '>'
* We do not check for any escape sequences; pure HTML is
* expected, so special characters need to be HTML escapes.
* We read them in and allow the HTML parser to convert them.
*/
static char *html_pair(char *p, agxbuf * tokp)
{
unsigned char c;
int rc, depth = 1;
while (1) {
while ((c = *p)) {
if (c == '>') {
depth--;
if (depth == 0)
return p; /* p points to closing > */
} else if (c == '<')
depth++;
rc = agxbputc(tokp, c);
p++;
}
if ((p = lex_gets()) == NULL) {
agerr(AGWARN,
"non-terminated HTML string starting line %d, file %s\n",
Start_html_string, InfileName);
return 0;
}
}
}
/* html_string:
* scan an html string and return the position after its terminator
* The string is stored in token.
* p points to the opening <.
*/
static char *html_string(char *p, agxbuf * token)
{
Start_html_string = Line_number;
p = html_pair(p + 1, token);
if (p)
p++; /* skip closing '>' */
return p;
}
int agtoken(char *p)
{
char ch;
TFA_Init();
while ((ch = *p)) {
/* any non-ascii characters converted to ascii DEL (127) */
TFA_Advance(ch & ~127 ? 127 : ch);
p++;
}
return TFA_Definition();
}
int aglex(void)
{
int token;
char *tbuf, *p;
static unsigned char BOM[] = { 0xEF, 0xBB, 0xBF }; /* UTF-8 byte order marker */
/* if the parser has accepted a graph, reset and return EOF */
if (AG.accepting_state) {
AG.accepting_state = FALSE;
return EOF;
}
/* get a nonempty lex buffer */
do {
if ((LexPtr == NULL) || (LexPtr[0] == '\0'))
if ((LexPtr = lex_gets()) == NULL) {
if (In_comment)
agerr(AGWARN, "nonterminated comment in line %d\n",
Comment_start);
return EOF;
}
/* skip UTF-8 Byte Order Marker if at beginning of file */
if ((Line_number == 1) && !strncmp(LexPtr, (char *) BOM, 3))
LexPtr += 3;
LexPtr = (char *) skip_wscomments(LexPtr);
} while (LexPtr[0] == '\0');
tbuf = TokenBuf;
/* scan quoted strings */
if (LexPtr[0] == '\"') {
LexPtr = quoted_string(LexPtr, tbuf);
aglval.str = agstrdup(tbuf);
return T_qsymbol;
}
/* scan HTML strings */
if (LexPtr[0] == '<') {
agxbuf xb;
unsigned char htmlbuf[BUFSIZ];
agxbinit(&xb, BUFSIZ, htmlbuf);
LexPtr = html_string(LexPtr, &xb);
aglval.str = agstrdup_html(agxbuse(&xb));
agxbfree(&xb);
return T_symbol;
}
/* scan edge operator */
if (AG.edge_op
&& (strncmp(LexPtr, AG.edge_op, strlen(AG.edge_op)) == 0)) {
LexPtr += strlen(AG.edge_op);
return T_edgeop;
}
/* scan numbers */
if ((p = scan_num(LexPtr, tbuf))) {
LexPtr = p;
aglval.str = agstrdup(tbuf);
return T_symbol;
} else {
unsigned char uc = *(unsigned char *) LexPtr;
if (ispunct(uc) && (uc != '_'))
return *LexPtr++;
else
LexPtr = scan_token(LexPtr, tbuf);
}
/* scan other tokens */
token = agtoken(tbuf);
if (token == -1) {
aglval.str = agstrdup(tbuf);
token = T_symbol;
}
return token;
}
static void error_context(void)
{
char *p;
char c;
char *buf = AG.linebuf + 1; /* characters are always put at AG.linebuf[1] */
/* or later; AG.linebuf[0] = '\0' */
if (LexPtr == NULL)
return;
agerr(AGPREV, "context: ");
for (p = LexPtr - 1; (p > buf) && (!isspace(*(unsigned char *) p));
p--);
if (buf < p) {
c = *p;
*p = '\0';
agerr(AGPREV, buf);
*p = c;
}
agerr(AGPREV, " >>> ");
c = *LexPtr;
*LexPtr = '\0';
agerr(AGPREV, p);
*LexPtr = c;
agerr(AGPREV, " <<< ");
agerr(AGPREV, LexPtr);
}
void agerror(char *msg)
{
if (AG.syntax_errors++)
return;
agerr(AGERR, "%s:%d: %s near line %d\n",
InfileName, Line_number, msg, Line_number);
error_context();
}
agerrlevel_t agerrno; /* Last error */
static agerrlevel_t agerrlevel = AGWARN; /* Report errors >= agerrlevel */
static long aglast; /* Last message */
static FILE *agerrout; /* Message file */
static agusererrf usererrf; /* User-set error function */
agusererrf
agseterrf (agusererrf newf)
{
agusererrf oldf = usererrf;
usererrf = newf;
return oldf;
}
void agseterr(agerrlevel_t lvl)
{
agerrlevel = lvl;
}
int agerrors(void)
{
return MAX(agmaxerr, AG.syntax_errors);
}
int agreseterrors(void)
{
int rc = MAX(agmaxerr, AG.syntax_errors);
agmaxerr = 0;
return rc;
}
char *aglasterr()
{
long endpos;
long len;
char *buf;
if (!agerrout)
return 0;
fflush(agerrout);
endpos = ftell(agerrout);
len = endpos - aglast;
buf = (char*)malloc(len + 1);
fseek(agerrout, aglast, SEEK_SET);
fread(buf, sizeof(char), len, agerrout);
buf[len] = '\0';
fseek(agerrout, endpos, SEEK_SET);
return buf;
}
static void
userout (agerrlevel_t level, const char *fmt, va_list args)
{
static char* buf;
static int bufsz = 1024;
char* np;
int n;
if (!buf) {
buf = (char*)malloc(bufsz);
if (!buf) {
fputs("userout: could not allocate memory\n", stderr );
return;
}
}
if (level != AGPREV) {
usererrf ((level == AGERR) ? "Error" : "Warning");
usererrf (": ");
}
while (1) {
n = vsnprintf(buf, bufsz, fmt, args);
if ((n > -1) && (n < bufsz)) {
usererrf (buf);
break;
}
bufsz = MAX(bufsz*2,n+1);
if ((np = (char*)realloc(buf, bufsz)) == NULL) {
fputs("userout: could not allocate memory\n", stderr );
return;
}
}
va_end(args);
}
/* agerr_va:
* Main error reporting function
*/
static int agerr_va(agerrlevel_t level, const char *fmt, va_list args)
{
agerrlevel_t lvl;
/* Use previous error level if continuation message;
* Convert AGMAX to AGERROR;
* else use input level
*/
lvl = (level == AGPREV ? agerrno : (level == AGMAX) ? AGERR : level);
/* store this error level and maximum error level used */
agerrno = lvl;
agmaxerr = MAX(agmaxerr, agerrno);
/* We report all messages whose level is bigger than the user set agerrlevel
* Setting agerrlevel to AGMAX turns off immediate error reporting.
*/
if (lvl >= agerrlevel) {
if (usererrf)
userout (level, fmt, args);
else {
if (level != AGPREV)
fprintf(stderr, "%s: ", (level == AGERR) ? "Error" : "Warning");
vfprintf(stderr, fmt, args);
va_end(args);
}
return 0;
}
/* If error is not immediately reported, store in log file */
if (!agerrout) {
agerrout = tmpfile();
if (!agerrout)
return 1;
}
if (level != AGPREV)
aglast = ftell(agerrout);
vfprintf(agerrout, fmt, args);
va_end(args);
return 0;
}
/* agerr:
* Varargs function for reporting errors with level argument
*/
int agerr(agerrlevel_t level, char *fmt, ...)
{
va_list args;
va_start(args, fmt);
return agerr_va(level, fmt, args);
}
/* agerrorf:
* Varargs function for reporting errors
*/
void agerrorf(const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
agerr_va(AGERR, fmt, args);
}
/* agwarningf:
* Varargs function for reporting warnings
*/
void agwarningf(char *fmt, ...)
{
va_list args;
va_start(args, fmt);
agerr_va(AGWARN, fmt, args);
}