59b3c10563
This prevents an overflow reported by @hexcoder- in https://github.com/davidgiven/ack/issues/56 lang/cem/cpp.ansi/LLlex.c used a plain 1 << ... and caused an overflow on machines where sizeof(int) < sizeof(long). Using 1L << ... would work for now but might fail later if arith became long long. C doesn't specify whether negative integers use 2's complement or some other format. Therefore, (arith) 1 << ... has an undefined value. It should still work because the value is some integer where the sign bit is set and all other bits are clear. (unsigned arith) 1 << ... would also get the sign bit, but casting it from unsigned back to signed would make the same undefined value. (arith) -1 << ... would assume 2's complement.
577 lines
12 KiB
C
577 lines
12 KiB
C
/*
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* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
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* See the copyright notice in the ACK home directory, in the file "Copyright".
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*/
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/* $Id$ */
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/* L E X I C A L A N A L Y Z E R */
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#include "parameters.h"
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#include <alloc.h>
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#include "input.h"
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#include "arith.h"
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#include "macro.h"
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#include "idf.h"
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#include "LLlex.h"
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#include "Lpars.h"
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#include "class.h"
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#include "bits.h"
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#define BUFSIZ 1024
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struct token dot;
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int ReplaceMacros = 1; /* replacing macros */
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int AccDefined = 0; /* accept "defined(...)" */
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int UnknownIdIsZero = 0; /* interpret unknown id as integer 0 */
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int Unstacked = 0; /* an unstack is done */
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int AccFileSpecifier = 0; /* return filespecifier <...> */
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int LexSave = 0; /* last character read by GetChar */
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extern int InputLevel; /* # of current macro expansions */
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extern char *string_token();
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extern arith char_constant();
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#define FLG_ESEEN 0x01 /* possibly a floating point number */
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#define FLG_DOTSEEN 0x02 /* certainly a floating point number */
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void skipcomment();
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int
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LLlex()
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{
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return (DOT != EOF) ? GetToken(&dot) : EOF;
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}
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int
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GetToken(ptok)
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register struct token *ptok;
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{
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/* GetToken() is the actual token recognizer. It calls the
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control line interpreter if it encounters a "\n{w}*#"
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combination. Macro replacement is also performed if it is
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needed.
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*/
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char buf[BUFSIZ];
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register int ch, nch;
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again: /* rescan the input after an error or replacement */
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ch = GetChar();
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/* rescan, the following character has been read */
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if ((ch & 0200) && ch != EOI) /* stop on non-ascii character */
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fatal("non-ascii '\\%03o' read", ch & 0377);
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/* keep track of the place of the token in the file */
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switch (class(ch)) { /* detect character class */
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case STNL: /* newline, vertical space or formfeed */
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LineNumber++;
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return ptok->tk_symb = EOF;
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case STSKIP: /* just skip the skip characters */
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goto again;
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case STGARB: /* garbage character */
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garbage:
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if (040 < ch && ch < 0177)
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error("garbage char %c", ch);
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else
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error("garbage char \\%03o", ch);
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goto again;
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case STSIMP: /* a simple character, no part of compound token*/
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return ptok->tk_symb = ch;
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case STCOMP: /* maybe the start of a compound token */
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nch = GetChar(); /* character lookahead */
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switch (ch) {
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case '!':
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if (nch == '=')
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return ptok->tk_symb = NOTEQUAL;
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UnGetChar();
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return ptok->tk_symb = ch;
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case '&':
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if (nch == '&')
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return ptok->tk_symb = AND;
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else if (nch == '=')
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return ptok->tk_symb = ANDAB;
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UnGetChar();
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return ptok->tk_symb = ch;
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case '+':
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if (nch == '+')
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return ptok->tk_symb = PLUSPLUS;
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else if (nch == '=')
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return ptok->tk_symb = PLUSAB;
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UnGetChar();
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return ptok->tk_symb = ch;
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case '-':
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if (nch == '-')
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return ptok->tk_symb = MINMIN;
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else if (nch == '>')
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return ptok->tk_symb = ARROW;
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else if (nch == '=')
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return ptok->tk_symb = MINAB;
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UnGetChar();
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return ptok->tk_symb = ch;
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case '<':
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if (AccFileSpecifier) {
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UnGetChar(); /* pushback nch */
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ptok->tk_str =
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string_token("file specifier", '>');
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return ptok->tk_symb = FILESPECIFIER;
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} else if (nch == '<') {
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if ((nch = GetChar()) == '=')
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return ptok->tk_symb = LEFTAB;
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UnGetChar();
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return ptok->tk_symb = LEFT;
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} else if (nch == '=')
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return ptok->tk_symb = LESSEQ;
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UnGetChar();
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return ptok->tk_symb = ch;
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case '=':
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if (nch == '=')
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return ptok->tk_symb = EQUAL;
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UnGetChar();
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return ptok->tk_symb = ch;
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case '>':
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if (nch == '=')
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return ptok->tk_symb = GREATEREQ;
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else if (nch == '>') {
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if ((nch = GetChar()) == '=')
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return ptok->tk_symb = RIGHTAB;
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UnGetChar();
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return ptok->tk_symb = RIGHT;
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}
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UnGetChar();
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return ptok->tk_symb = ch;
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case '|':
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if (nch == '|')
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return ptok->tk_symb = OR;
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else if (nch == '=')
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return ptok->tk_symb = ORAB;
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UnGetChar();
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return ptok->tk_symb = ch;
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case '%':
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if (nch == '=')
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return ptok->tk_symb = MODAB;
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UnGetChar();
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return ptok->tk_symb = ch;
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case '*':
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if (nch == '=')
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return ptok->tk_symb = TIMESAB;
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UnGetChar();
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return ptok->tk_symb = ch;
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case '^':
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if (nch == '=')
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return ptok->tk_symb = XORAB;
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UnGetChar();
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return ptok->tk_symb = ch;
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case '/':
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if (nch == '*' && !InputLevel) {
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skipcomment();
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goto again;
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}
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else if (nch == '=')
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return ptok->tk_symb = DIVAB;
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UnGetChar();
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return ptok->tk_symb = ch;
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default:
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crash("bad class for char 0%o", ch);
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/* NOTREACHED */
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}
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case STCHAR: /* character constant */
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ptok->tk_val = char_constant("character");
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return ptok->tk_symb = INTEGER;
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case STSTR: /* string */
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ptok->tk_str = string_token("string", '"');
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return ptok->tk_symb = STRING;
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case STELL: /* wide character constant/string prefix */
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nch = GetChar();
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if (nch == '"') {
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ptok->tk_str =
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string_token("wide character string", '"');
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return ptok->tk_symb = STRING;
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} else if (nch == '\'') {
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ptok->tk_val = char_constant("wide character");
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return ptok->tk_symb = INTEGER;
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}
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UnGetChar();
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/* fallthrough */
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case STIDF:
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{
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extern int idfsize; /* ??? */
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register char *tg = &buf[0];
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register char *maxpos = &buf[idfsize];
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int NoExpandNext = 0;
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#define tstmac(bx) if (!(bits[ch] & bx)) goto nomac
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#define cpy *tg++ = ch
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#define load (ch = GetChar()); if (!in_idf(ch)) goto endidf
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if (Unstacked) EnableMacros(); /* unstack macro's when allowed. */
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if (ch == NOEXPM) {
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NoExpandNext = 1;
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ch = GetChar();
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}
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#ifdef DOBITS
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cpy; tstmac(bit0); load;
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cpy; tstmac(bit1); load;
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cpy; tstmac(bit2); load;
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cpy; tstmac(bit3); load;
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cpy; tstmac(bit4); load;
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cpy; tstmac(bit5); load;
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cpy; tstmac(bit6); load;
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cpy; tstmac(bit7); load;
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#endif
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for(;;) {
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if (tg < maxpos) {
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cpy;
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}
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load;
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}
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endidf:
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/*if (ch != EOI) UnGetChar();*/
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UnGetChar();
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*tg++ = '\0'; /* mark the end of the identifier */
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if (ReplaceMacros) {
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register struct idf *idef = findidf(buf);
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if (idef && idef->id_macro && !NoExpandNext) {
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if (replace(idef))
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goto again;
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}
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}
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nomac: /* buf can already be null-terminated. soit */
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ch = GetChar();
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while (in_idf(ch)) {
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if (tg < maxpos) *tg++ = ch;
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ch = GetChar();
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}
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UnGetChar();
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*tg++ = '\0'; /* mark the end of the identifier */
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NoExpandNext = 0;
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if (UnknownIdIsZero) {
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ptok->tk_val = (arith)0;
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return ptok->tk_symb = INTEGER;
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}
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ptok->tk_str = Malloc((unsigned)(tg - buf));
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strcpy(ptok->tk_str, buf);
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return IDENTIFIER;
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}
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case STNUM: /* a numeric constant */
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{ /* it may only be an integer constant */
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register int base = 10, vch;
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register arith val = 0;
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int ovfl = 0;
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arith ubound = max_arith/(base/2);
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/* Since the preprocessor only knows integers and has
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* nothing to do with ellipsis we just return when the
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* pp-number starts with a '.'
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*/
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if (ch == '.') {
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return ptok->tk_symb = ch;
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}
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if (ch == '0') {
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ch = GetChar();
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if (ch == 'x' || ch == 'X') {
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base = 16;
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ch = GetChar();
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} else {
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base = 8;
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}
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}
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while ((vch = val_in_base(ch, base)) >= 0) {
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if (val < 0 || val > ubound) ovfl++;
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val *= base;
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if (val < 0 && val + vch >= 0) ovfl++;
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val += vch;
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ch = GetChar();
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}
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ptok->tk_unsigned = 0;
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if (ch == 'u' || ch == 'U') {
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ptok->tk_unsigned = 1;
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ch = GetChar();
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if (ch == 'l' || ch == 'L') {
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ch = GetChar();
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}
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}
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else if (ch == 'l' || ch == 'L') {
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ch = GetChar();
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if (ch == 'u' || ch == 'U') {
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ptok->tk_unsigned = 1;
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ch = GetChar();
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}
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}
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if (ovfl) {
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warning("overflow in constant");
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ptok->tk_unsigned = 1;
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}
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else if (val < 0) {
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/* give warning??? */
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ptok->tk_unsigned = 1;
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}
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UnGetChar();
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ptok->tk_val = val;
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return ptok->tk_symb = INTEGER;
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}
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case STEOI: /* end of text on source file */
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return ptok->tk_symb = EOF;
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case STMSPEC:
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if (!InputLevel) goto garbage;
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if (ch == TOKSEP) goto again;
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/* fallthrough shouldn't happen */
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default: /* this cannot happen */
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crash("bad class for char 0%o", ch);
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}
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/*NOTREACHED*/
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}
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void
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skipcomment()
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{
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/* The last character read has been the '*' of '/_*'. The
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characters, except NL and EOI, between '/_*' and the first
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occurring '*_/' are not interpreted.
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NL only affects the LineNumber. EOI is not legal.
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Important note: it is not possible to stop skipping comment
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beyond the end-of-file of an included file.
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EOI is returned by LoadChar only on encountering EOF of the
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top-level file...
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*/
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register int c;
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NoUnstack++;
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c = GetChar();
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do {
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while (c != '*') {
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if (class(c) == STNL) {
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++LineNumber;
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} else if (c == EOI) {
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NoUnstack--;
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return;
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}
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c = GetChar();
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} /* last Character seen was '*' */
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c = GetChar();
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} while (c != '/');
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NoUnstack--;
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}
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arith
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char_constant(nm)
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char *nm;
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{
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register arith val = 0;
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register int ch;
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int size = 0;
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ch = GetChar();
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if (ch == '\'')
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error("%s constant too short", nm);
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else
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while (ch != '\'') {
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if (ch == '\n') {
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error("newline in %s constant", nm);
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LineNumber++;
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break;
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}
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if (ch == '\\')
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ch = quoted(GetChar());
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if (ch >= 128) ch -= 256;
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if (size < sizeof(arith))
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val |= ch << (8 * size);
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size++;
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ch = GetChar();
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}
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if (size > sizeof(arith))
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error("%s constant too long", nm);
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else if (size > 1)
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strict("%s constant includes more than one character", nm);
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return val;
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}
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char *
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string_token(nm, stop_char)
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char *nm;
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{
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register int ch;
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register int str_size;
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register char *str = Malloc((unsigned) (str_size = ISTRSIZE));
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register int pos = 0;
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ch = GetChar();
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while (ch != stop_char) {
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if (ch == '\n') {
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error("newline in %s", nm);
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LineNumber++;
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break;
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}
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if (ch == EOI) {
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error("end-of-file inside %s", nm);
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break;
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}
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if (ch == '\\' && !AccFileSpecifier)
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ch = quoted(GetChar());
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str[pos++] = ch;
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if (pos == str_size)
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str = Realloc(str, (unsigned)(str_size <<= 1));
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ch = GetChar();
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}
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str[pos++] = '\0'; /* for filenames etc. */
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str = Realloc(str, (unsigned)pos);
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return str;
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}
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int
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quoted(ch)
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register int ch;
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{
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/* quoted() replaces an escaped character sequence by the
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character meant.
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*/
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/* first char after backslash already in ch */
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if (!is_oct(ch)) { /* a quoted char */
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switch (ch) {
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case 'n':
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ch = '\n';
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break;
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case 't':
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ch = '\t';
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break;
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case 'b':
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ch = '\b';
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break;
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case 'r':
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ch = '\r';
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break;
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case 'f':
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ch = '\f';
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break;
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case 'a': /* alert */
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ch = '\007';
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break;
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case 'v': /* vertical tab */
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ch = '\013';
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break;
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case 'x': /* quoted hex */
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{
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register int hex = 0;
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register int vch;
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for (;;) {
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ch = GetChar();
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if (vch = val_in_base(ch, 16), vch == -1)
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break;
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hex = hex * 16 + vch;
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}
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UnGetChar();
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ch = hex;
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}
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}
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} else { /* a quoted octal */
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register int oct = 0, cnt = 0;
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do {
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oct = oct*8 + (ch-'0');
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ch = GetChar();
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} while (is_oct(ch) && ++cnt < 3);
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UnGetChar();
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ch = oct;
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}
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return ch&0377;
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}
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int
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val_in_base(ch, base)
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register int ch;
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{
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switch (base) {
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case 8:
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return (is_dig(ch) && ch < '9') ? ch - '0' : -1;
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case 10:
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return is_dig(ch) ? ch - '0' : -1;
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case 16:
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return is_dig(ch) ? ch - '0'
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: is_hex(ch) ? (ch - 'a' + 10) & 017
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: -1;
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default:
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fatal("(val_in_base) illegal base value %d", base);
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/* NOTREACHED */
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}
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}
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int
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GetChar()
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{
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/* The routines GetChar and trigraph parses the trigraph
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sequences and removes occurences of \\\n.
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*/
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register int ch;
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again:
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LoadChar(ch);
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/* possible trigraph sequence */
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if (ch == '?')
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ch = trigraph();
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/* \\\n are removed from the input stream */
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if (ch == '\\') {
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LoadChar(ch);
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if (ch == '\n') {
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++LineNumber;
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goto again;
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}
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PushBack();
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ch = '\\';
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}
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return(LexSave = ch);
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}
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int
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trigraph()
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{
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register int ch;
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LoadChar(ch);
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if (ch == '?') {
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LoadChar(ch);
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switch (ch) { /* its a trigraph */
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case '=':
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ch = '#';
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return(ch);
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case '(':
|
|
ch = '[';
|
|
return(ch);
|
|
case '/':
|
|
ch = '\\';
|
|
return(ch);
|
|
case ')':
|
|
ch = ']';
|
|
return(ch);
|
|
case '\'':
|
|
ch = '^';
|
|
return(ch);
|
|
case '<':
|
|
ch = '{';
|
|
return(ch);
|
|
case '!':
|
|
ch = '|';
|
|
return(ch);
|
|
case '>':
|
|
ch = '}';
|
|
return(ch);
|
|
case '-':
|
|
ch = '~';
|
|
return(ch);
|
|
}
|
|
PushBack();
|
|
}
|
|
PushBack();
|
|
return('?');
|
|
}
|