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Arquivotheca.AIX-4.1.3/bos/usr/bin/expr/expr.c
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static char sccsid[] = "@(#)69 1.18 src/bos/usr/bin/expr/expr.c, cmdsh, bos41J, bai15 4/11/95 09:49:29";
/*
* COMPONENT_NAME: (CMDSH) Bourne shell and related commands
*
* FUNCTIONS: expr
*
* ORIGINS: 3, 26, 27, 71
*
* This module contains IBM CONFIDENTIAL code. -- (IBM
* Confidential Restricted when combined with the aggregated
* modules for this product)
* SOURCE MATERIALS
* (C) COPYRIGHT International Business Machines Corp. 1989, 1995
* All Rights Reserved
*
* US Government Users Restricted Rights - Use, duplication or
* disclosure restricted by GSA ADP Schedule Contract with IBM Corp.
*
* Copyright (c) 1980 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*
* Copyright 1976, Bell Telephone Laboratories, Inc.
*
* (c) Copyright 1990, 1991, 1992 OPEN SOFTWARE FOUNDATION, INC.
* ALL RIGHTS RESERVED
*
* OSF/1 1.1
*/
/*
* NAME: expr
*
* FUNCTION: expr - evaluate arguments as an expression
*
* SYNOPSIS: expr expression ...
*
*/
/*
* operator constants, most self-explanatory
*/
#define A_STRING 258
#define NOARG 259
#define OR 260
#define AND 261
#define EQ 262
#define LT 263
#define GT 264
#define GEQ 265
#define LEQ 266
#define NEQ 267
#define ADD 268
#define SUBT 269
#define MULT 270
#define DIV 271
#define REM 272
#define MCH 273
#define MATCH 274
#define SUBSTR 275
#define LENGTH 276
#define INDEX 277
#define EQL(x,y) (strcmp(x, y) == 0) /* string collation compare */
/*
* POSIX required exit values
*/
#define ERR_RE 2 /* Regular Expression syntax error */
#define ERR_SYNTAX 2 /* expr syntax error */
#define ERR_MALLOC 4 /* malloc error */
#define ERR_NUMBER 2 /* invalid number in numeric field */
/*
* includes
*/
#include <sys/types.h>
#include <stdio.h> /* for NULL */
#include <string.h>
#include <stdlib.h>
#include <locale.h>
#include <regex.h>
#include <nl_types.h>
/*
* message file stuff
*/
# include "expr_msg.h"
# define MSGSTR(Num, Str) catgets(catd, MS_EXPR, Num, Str)
/*
* local functions
*/
char *ltoa(), *rel(), *strsave(), *arith(), *conj();
char *substr(), *length(), *expr_index(), *match();
int yylex(), number();
void yyerror();
/*
* globals
*/
static char **Av; /* global 'argv' */
static int Ac; /* global 'argc' */
static int Argi; /* index of current argv */
static int paren; /* found a paren? */
static nl_catd catd; /* msg catalog descriptor */
/*
* operators
*/
static char *operator[] = {
"|", "&", "+", "-", "*", "/", "%", ":",
"=", "==", "<", "<=", ">", ">=", "!=",
"match", "substr", "length", "index", "\0" };
/*
* operator values
*/
static int op[] = {
OR, AND, ADD, SUBT, MULT, DIV, REM, MCH,
EQ, EQ, LT, LEQ, GT, GEQ, NEQ,
MATCH, SUBSTR, LENGTH, INDEX };
/*
* operator precedence table
*/
static int pri[] = { 1,2,3,3,3,3,3,3,4,4,5,5,5,6,7,8,9,9,9 };
/*
* NAME: yylex
*
* FUNCTION: yylex - determine next command line token type
*
* NOTES: Yylex looks at the next command line token and returns
* a value indicating its type.
*
* RETURN VALUE DESCRIPTION: NOARG if no more command line args exist,
* an operator constant if the token is an operator, '(' or ')'
* if the token is a parenthesis, else A_STRING indicating
* an operand.
*/
int
yylex()
{
register char *p;
register int i;
/*
* any args left?
*/
if(Argi >= Ac)
return NOARG;
p = Av[Argi];
/*
* paren?
*/
if((*p == '(' || *p == ')') && p[1] == '\0' )
return (int)*p;
/*
* operator?
*/
for(i = 0; *operator[i]; ++i)
if(EQL(operator[i], p))
return op[i];
/*
* must be an operand
*/
return A_STRING;
}
/*
* NAME: number
*
* FUNCTION: number - determine whether string is a number
*
* NOTES: Number scans a string for non-digit characters. If any
* are found, other than a leading minus, then the string is
* not a number.
*
* RETURN VALUE DESCRIPTION: "TRUE" if the string is a number, "FALSE" if not
*/
static int
number(s)
register char *s;
{
if ( *s == '\0' )
return(0);
if (*s == '-')
*s++;
while (*s>='0' && *s<='9')
*s++;
return (*s == '\0');
}
/*
* NAME: rel
*
* FUNCTION: rel - evaluate relational operators (=, !=, >, <, <=, >=)
*
* NOTES: Rel evaluates a relational operator and 2 operands.
* If the operands are numerical, they are compared
* mathematically, else they are compared as strings
* using collation sequence.
*
* RETURN VALUE DESCRIPTION: "1" if the expression evaluates to true, else "0"
*/
static char *
rel(oper, r1, r2)
int oper; /* operator */
register char *r1; /* operand 1 */
register char *r2; /* operand 2 */
{
register double i;
double atof();
/*
* compare numerically or as strings?
*/
if(number(r1) && number(r2))
{
i = atof(r1) - atof(r2);
}
else
i = (double) strcoll(r1, r2);
/*
* evaluate
*/
switch(oper) {
case EQ: /* equal */
i = i==0;
break;
case GT: /* greater than */
i = i>0;
break;
case GEQ: /* greater than or equal */
i = i>=0;
break;
case LT: /* less than */
i = i<0;
break;
case LEQ: /* less than or equal */
i = i<=0;
break;
case NEQ: /* not equal */
i = i!=0;
break;
}
return i ? "1": "0";
}
/*
* NAME: arith
*
* FUNCTION: arith - evaluate an arithmetic operator
*
* NOTES: Arith evaluates an arithmetic operator (+, -, *, /, %).
* Both operands must be numeric.
*
* RETURN VALUE DESCRIPTION: string containing the answer
*/
static char *
arith(oper, r1, r2)
int oper; /* operator */
char *r1; /* operand 1 */
char *r2; /* operand 2 */
{
register long i1, i2;
/*
* make sure both operands are numeric
*/
if(!(number(r1) && number(r2)))
yyerror(ERR_NUMBER, MSGSTR(NANARG,"non-numeric argument"));
/*
* convert
*/
i1 = atol(r1);
i2 = atol(r2);
/*
* evaluate
*/
switch(oper) {
case ADD: /* add */
i1 = i1 + i2;
break;
case SUBT: /* subtract */
i1 = i1 - i2;
break;
case MULT: /* multiply */
i1 = i1 * i2;
break;
case DIV: /* divide */
if (i2 == 0)
yyerror(ERR_NUMBER, MSGSTR(INVALID, "cannot divide by zero"));
else
i1 = i1 / i2;
break;
case REM: /* remainder */
if (i2 == 0)
yyerror(ERR_NUMBER, MSGSTR(INVALID, "cannot divide by zero"));
else
i1 = i1 % i2;
break;
}
/*
* convert back to ascii and return
*/
return (strsave(ltoa(i1)));
}
/*
* NAME: conj
*
* FUNCTION: conj - handle and/or operators
*
* NOTES: Conj evaluates and/or operators (&,|).
*
* RETURN VALUE DESCRIPTION: result of evaluation
*/
static char *
conj(oper, r1, r2)
int oper;
char *r1;
char *r2;
{
register char *rv;
switch(oper) {
case OR: /* or (|) */
/*
* return r1 if it's not 0 or NULL, else
* return r2 if it's not 0 or NULL, else
* return "0"
*/
if(EQL(r1, "0") || EQL(r1, ""))
if(EQL(r2, "0"))
rv = "0";
else if(EQL(r2, ""))
rv = "";
else
rv = r2;
else
rv = r1;
break;
case AND: /* and (&) */
/*
* return "0" if either r1 or r2 is 0 or null, else
* return r1
*/
if(EQL(r1, "0") || EQL(r1, "") ||
EQL(r2, "0") || EQL(r2, ""))
rv = "0";
else
rv = r1;
break;
}
return rv;
}
/*
* NAME: substr
*
* FUNCTION: substr - implement substring operation
*
* NOTES: Substr implements the substring operation. It
* requires 3 operators: a string, a starting character index,
* and number of characters.
* Example: expr substr "Hi Mom" 1 3 prints "Hi ".
*
* RETURN VALUE DESCRIPTION: the substring
*/
static char *
substr(v, s, w)
char *v; /* string */
char *s; /* start character index*/
char *w; /* # of characters */
{
register long si, wi;
register char *res, *rv;
int len;
/*
* make sure index and width are numeric
*/
if(!(number(s) && number(w)))
yyerror(ERR_NUMBER, MSGSTR(NANARG,"non-numeric argument"));
/*
* convert index and width to numbers
* make sure index is positive and width not negative
*/
si = atol(s);
wi = atol(w);
if (si <= 0 || wi < 0)
yyerror(ERR_SYNTAX, MSGSTR(SYNTAX,"syntax error"));
/*
* find starting character location using start index
* MB_CUR_MAX == 1 is the path for single-byte code sets
*/
if (MB_CUR_MAX == 1)
{
while(--si)
if(*v)
++v;
/*
* and save it
*/
res = v;
/*
* find ending location using width
*/
while(wi--)
if(*v)
++v;
}
/*
* MB_CUR_MAX != 1 is the path for multi-byte code set
*/
else
{
while (--si > 0 && (len = mblen(v, MB_CUR_MAX)) > 0)
v += len;
res = v;
while (wi-- > 0 && (len = mblen(v, MB_CUR_MAX)) > 0)
v += len;
}
/*
* allocate space and return value
*/
if ((rv = malloc((size_t) (v - res + 1))) == NULL)
yyerror(ERR_MALLOC, MSGSTR(MALLOC, "malloc error"));
(void) strncpy(rv, res, (size_t)(v - res));
rv[v - res] = '\0';
return rv;
}
/*
* NAME: length
*
* FUNCTION: length - compute character length of a string
*
* NOTES: Length computes the number of characters of a string and returns
* it. Illegal multibyte characters are treated as a NUL.
*
* RETURN VALUE DESCRIPTION: string containing character length of input string
*/
static char *
length(s)
char *s; /* input string */
{
register long count; /* # characters in string */
register int len; /* # bytes in character */
if (MB_CUR_MAX == 1)
return (strsave(ltoa((long) strlen(s))));
/*
* count characters one at a time
* note: could use mbstowcs but that needs a process code array of
* unknown length
*/
count = 0;
while ((len = mblen(s, MB_CUR_MAX)) > 0)
{
count++;
s += len;
}
/*
* convert character count to string, malloc and return
*/
return (strsave(ltoa((long) count)));
}
/*
* NAME: expr_index
*
* FUNCTION: expr_index - find part of one string in another
*
* NOTES: Index looks in one string for any character
* that matches the other.
*
* RETURN VALUE DESCRIPTION: if found, a string containing the index of the
* char found in the first string, else "0"
*/
static char *
expr_index(s, t)
char *s; /* string to look at */
char *t; /* string to look for */
{
/*
* compare next s character to all t characters
* return first index in s where any t character is found
*/
if (MB_CUR_MAX == 1)
{
register int i, j;
for(i = 0; s[i] ; ++i)
for(j = 0; t[j] ; ++j)
if(s[i]==t[j])
return (strsave(ltoa((long) ++i)));
}
else
{
long count;
int slen;
int tlen;
wchar_t wcs;
wchar_t wct;
char *tt;
count = 0;
while ((slen = mbtowc(&wcs, s, MB_CUR_MAX)) > 0)
{
count++;
s += slen;
tt = t;
while ((tlen = mbtowc(&wct, tt, MB_CUR_MAX)) > 0)
{
tt += tlen;
if (wcs == wct)
return strsave(ltoa(count));
}
}
}
return "0";
}
/*
* NAME: match
*
* FUNCTION: match - implement match ("match" or ":") function
*
* NOTES: Match implements the 'match' function. This function
* is called by using either of the match operators. E.g.
* "expr match string expr" or "expr string : expr".
*
* RETURN VALUE DESCRIPTION: either the number of chars matched, or
* a portion of 'string' (if "\(" and "\)" are used in expr)
*/
static char *
match(s, p)
char *s;
char *p;
{
long count; /* multibyte character count */
char *ra; /* subexpression return address */
int rtn; /* regcomp() errror code */
long num; /* # of matched charcters */
regmatch_t off[2]; /* subexpression offsets */
regex_t reg; /* RE structure */
char errbuf[128]; /* RE error buffer */
/*
* compile the basic RE, stop on syntax error
*/
rtn = regcomp(&reg, p, 0);
if (rtn != 0)
{
regerror(rtn, &reg, errbuf, sizeof(errbuf));
yyerror(ERR_RE, errbuf);
}
/*
* determine if string is matched by RE pattern
*/
if ((regexec(&reg, s, 2, off, 0) == 0) && (off[0].rm_so == 0))
{
/*
* if \(subexpression\) exists, return ptr to matched substring
*/
if (reg.re_nsub != 0)
{
num = off[1].rm_eo - off[1].rm_so;
if ((ra = (char *)malloc((size_t) num+1)) == NULL)
yyerror(ERR_MALLOC, MSGSTR(MALLOC, "malloc error"));
(void)strncpy(ra, s+off[1].rm_so, (size_t)num);
ra[num] = '\0';
return ra;
}
/*
* else return ptr to string which is number of matched characters
*/
else
{
num = off[0].rm_eo - off[0].rm_so;
if (MB_CUR_MAX == 1)
return strsave(ltoa(num));
else
{
ra = s+off[0].rm_so;
count = 0;
while (num > 0 && (rtn = mblen(ra, MB_CUR_MAX)) > 0)
{
count++;
ra += rtn;
num -= rtn;
}
return strsave(ltoa(count));
}
}
}
else
{
/* Determine if the failed matched string by RE pattern contained
a sub-expression */
if(reg.re_nsub >= 1)
return "";
else
return "0";
}
}
/*
* NAME: yyerror
*
* FUNCTION: yyerror - print an error and exit
*
* NOTES: Yyerror prints an error and exits with value of 2.
*
* RETURN VALUE DESCRIPTION: none
*/
void
yyerror(i, s)
int i; /* exit status */
char *s; /* error text */
{
(void) write(2, "expr: ", 6);
(void) write(2, s, (unsigned) strlen(s));
(void) write(2, "\n", 1);
exit(i);
/* NOTREACHED */
}
/*
* NAME: ltoa
*
* FUNCTION: ltoa - long to ascii
*
* NOTES: Ltoa formats a long integer into a string and returns
* it. The return value is static.
*
* RETURN VALUE DESCRIPTION: the formatted string
*/
static char *
ltoa(l)
long l;
{
static char str[20]; /* must be big enuf to hold a long... */
(void) sprintf(str, "%ld", l);
return str;
}
/*
* NAME: expres
*
* FUNCTION: expres
*
* NOTES:
*
* RETURN VALUE DESCRIPTION:
*/
static char *
expres(prior, par)
int prior;
int par;
{
static int noarg = 0;
int ylex, temp, op1;
char *r1, *ra, *rb, *rc;
long i1;
/*
* retrieve next token and check validity
*/
if ((ylex = yylex()) >= NOARG && ylex < MATCH)
yyerror(ERR_SYNTAX, MSGSTR(SYNTAX, "syntax error"));
/*
* string?
*/
if (ylex == A_STRING) {
r1 = Av[Argi++];
temp = Argi;
}
/*
* left paren?
*/
else if (ylex == '(') {
paren++;
Argi++;
/*
* get embedded expression
*/
r1 = expres(0, Argi);
Argi--;
}
lop:
if ((ylex = yylex()) > NOARG && ylex < MATCH) {
op1 = ylex;
Argi++;
if (pri[op1-OR] <= prior )
return r1;
else {
switch(op1) {
case OR:
case AND:
r1 = conj(op1,r1,expres(pri[op1-OR],0));
break;
case EQ:
case LT:
case GT:
case LEQ:
case GEQ:
case NEQ:
r1=rel(op1,r1,expres(pri[op1-OR],0));
break;
case ADD:
case SUBT:
case MULT:
case DIV:
case REM:
r1=arith(op1,r1,expres(pri[op1-OR],0));
break;
case MCH:
r1=match(r1,expres(pri[op1-OR],0));
break;
}
if(noarg == 1) {
return r1;
}
Argi--;
goto lop;
}
}
/*
* right paren?
*/
if((ylex = yylex()) == ')') {
if(par == Argi)
yyerror(ERR_SYNTAX, MSGSTR(SYNTAX,"syntax error"));
if(par != 0) {
paren--;
Argi++;
}
Argi++;
return r1;
}
if((ylex = yylex()) > MCH && ylex <= INDEX) {
if (Argi == temp)
return r1;
op1 = ylex;
Argi++;
switch(op1) {
case SUBSTR:
rc = expres(pri[op1-OR],0);
case MATCH:
case INDEX:
rb = expres(pri[op1-OR],0);
case LENGTH:
ra = expres(pri[op1-OR],0);
}
switch(op1) {
case MATCH:
r1 = match(rb,ra);
break;
case INDEX:
r1 = expr_index(rb,ra);
break;
case SUBSTR:
r1 = substr(rc,rb,ra);
break;
case LENGTH:
r1 = length(ra);
break;
}
if(noarg == 1)
return r1;
Argi--;
goto lop;
}
if ((ylex = yylex()) == NOARG)
noarg = 1;
if (number(r1)) {
/*
* convert string to number and back to remove leading
* zeros. This is required by POSIX so that strings
* such as "000" are converted to "0", causing expr to
* correctly print "0" and exit with a value of 1.
*/
i1 = atol(r1);
return (strsave(ltoa(i1)));
} else
return r1;
}
/*
* NAME: strsave
*
* FUNCTION: strsave - save a string somewhere
*
* NOTES: Strsave allocates memory for a string. The new memory
* is returned. Inspired by K&R, pg 103.
*
* RETURN VALUE DESCRIPTION: NULL if no memory could be allocated,
* else a pointer to the memory containing the new string.
*/
static char *
strsave(string)
char *string;
{
register char *new;
if ((new = (char *) malloc((size_t) (strlen(string) + 1))) == NULL)
yyerror(ERR_MALLOC, MSGSTR(MALLOC, "malloc error"));
return ((char *) strcpy(new, string));
}
/*
* NAME: main
*
* FUNCTION: main - main routine
*
* NOTES: Main inits globals, calls expres() to evaluate the
* command line, prints out the value, and exits with
* either a true (0) or false (1) value.
*
* RETURN VALUE DESCRIPTION: 0 if the expression is true, else 1
*/
int
main(argc, argv)
int argc;
char **argv;
{
char *buf;
(void) setlocale (LC_ALL, "");
/*
* initialization
*/
catd = catopen(MF_EXPR, NL_CAT_LOCALE);
if (strcmp(argv[1], "-?") == 0){
fprintf(stderr, MSGSTR(USAGE, "Usage: expr expression\n"));
exit(3);
}
if (strcmp(argv[1], "--") == 0)
Argi = 2;
else
Argi = 1;
Ac = argc;
paren = 0;
Av = argv;
/*
* evaluate expression on the command line
*/
buf = expres(0, 1);
/*
* check syntax error
*/
if(Ac != Argi || paren != 0) {
yyerror(ERR_SYNTAX, MSGSTR(SYNTAX,"syntax error"));
}
/*
* write result
*/
if(*buf != '\0')
{
(void) write(1, buf, (unsigned) strlen(buf));
(void) write(1, "\n", 1);
}
/*
* exit true or false depending on result
*/
exit(EQL(buf, "0") || buf[0] == '\0' ? 1 : 0);
/* NOTREACHED */
}
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