178 lines
8.3 KiB
C
178 lines
8.3 KiB
C
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/*****************************************************************************
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*
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* MODULE NAME : GETOPT.C
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*
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* COPYRIGHTS:
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* This module contains code made available by IBM
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* Corporation on an AS IS basis. Any one receiving the
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* module is considered to be licensed under IBM copyrights
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* to use the IBM-provided source code in any way he or she
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* deems fit, including copying it, compiling it, modifying
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* it, and redistributing it, with or without
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* modifications. No license under any IBM patents or
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* patent applications is to be implied from this copyright
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* license.
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*
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* A user of the module should understand that IBM cannot
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* provide technical support for the module and will not be
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* responsible for any consequences of use of the program.
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*
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* Any notices, including this one, are not to be removed
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* from the module without the prior written consent of
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* IBM.
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*
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* AUTHOR: Original author:
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* G. R. Blair (BOBBLAIR at AUSVM1)
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* Internet: bobblair@bobblair.austin.ibm.com
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*
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* Extensively revised by:
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* John Q. Walker II, Ph.D. (JOHHQ at RALVM6)
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* Internet: johnq@ralvm6.vnet.ibm.com
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*
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*****************************************************************************/
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/******************************************************************************
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* getopt()
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*
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* The getopt() function is a command line parser. It returns the next
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* option character in argv that matches an option character in opstring.
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*
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* The argv argument points to an array of argc+1 elements containing argc
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* pointers to character strings followed by a null pointer.
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*
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* The opstring argument points to a string of option characters; if an
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* option character is followed by a colon, the option is expected to have
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* an argument that may or may not be separated from it by white space.
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* The external variable optarg is set to point to the start of the option
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* argument on return from getopt().
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*
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* The getopt() function places in optind the argv index of the next argument
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* to be processed. The system initializes the external variable optind to
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* 1 before the first call to getopt().
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*
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* When all options have been processed (that is, up to the first nonoption
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* argument), getopt() returns EOF. The special option "--" may be used to
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* delimit the end of the options; EOF will be returned, and "--" will be
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* skipped.
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*
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* The getopt() function returns a question mark (?) when it encounters an
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* option character not included in opstring. This error message can be
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* disabled by setting opterr to zero. Otherwise, it returns the option
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* character that was detected.
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*
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* If the special option "--" is detected, or all options have been
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* processed, EOF is returned.
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*
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* Options are marked by either a minus sign (-) or a slash (/).
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*
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* No errors are defined.
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*****************************************************************************/
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#include <stdio.h> /* for EOF */
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#include <string.h> /* for strchr() */
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/* static (global) variables that are specified as exported by getopt() */
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extern char *optarg; /* pointer to the start of the option argument */
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extern int optind; /* number of the next argv[] to be evaluated */
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extern int opterr; /* non-zero if a question mark should be returned
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when a non-valid option character is detected */
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/* handle possible future character set concerns by putting this in a macro */
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#define _next_char(string) (char)(*(string+1))
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int getopt(int argc, char *argv[], char *opstring)
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{
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static char *pIndexPosition = NULL; /* place inside current argv string */
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char *pArgString = NULL; /* where to start from next */
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char *pOptString; /* the string in our program */
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if (pIndexPosition != NULL) {
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/* we last left off inside an argv string */
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if (*(++pIndexPosition)) {
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/* there is more to come in the most recent argv */
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pArgString = pIndexPosition;
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}
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}
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if (pArgString == NULL) {
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/* we didn't leave off in the middle of an argv string */
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if (optind >= argc) {
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/* more command-line arguments than the argument count */
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pIndexPosition = NULL; /* not in the middle of anything */
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return EOF; /* used up all command-line arguments */
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}
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/*---------------------------------------------------------------------
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* If the next argv[] is not an option, there can be no more options.
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*-------------------------------------------------------------------*/
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pArgString = argv[optind++]; /* set this to the next argument ptr */
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if (('/' != *pArgString) && /* doesn't start with a slash or a dash? */
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('-' != *pArgString)) {
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--optind; /* point to current arg once we're done */
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optarg = NULL; /* no argument follows the option */
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pIndexPosition = NULL; /* not in the middle of anything */
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return EOF; /* used up all the command-line flags */
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}
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/* check for special end-of-flags markers */
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if ((strcmp(pArgString, "-") == 0) ||
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(strcmp(pArgString, "--") == 0)) {
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optarg = NULL; /* no argument follows the option */
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pIndexPosition = NULL; /* not in the middle of anything */
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return EOF; /* encountered the special flag */
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}
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pArgString++; /* look past the / or - */
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}
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if (':' == *pArgString) { /* is it a colon? */
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/*---------------------------------------------------------------------
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* Rare case: if opterr is non-zero, return a question mark;
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* otherwise, just return the colon we're on.
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*-------------------------------------------------------------------*/
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return (opterr ? (int)'?' : (int)':');
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}
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else if ((pOptString = strchr(opstring, *pArgString)) == 0) {
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/*---------------------------------------------------------------------
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* The letter on the command-line wasn't any good.
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*-------------------------------------------------------------------*/
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optarg = NULL; /* no argument follows the option */
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pIndexPosition = NULL; /* not in the middle of anything */
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return (opterr ? (int)'?' : (int)*pArgString);
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}
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else {
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/*---------------------------------------------------------------------
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* The letter on the command-line matches one we expect to see
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*-------------------------------------------------------------------*/
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if (':' == _next_char(pOptString)) { /* is the next letter a colon? */
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/* It is a colon. Look for an argument string. */
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if ('\0' != _next_char(pArgString)) { /* argument in this argv? */
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optarg = &pArgString[1]; /* Yes, it is */
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}
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else {
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/*-------------------------------------------------------------
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* The argument string must be in the next argv.
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* But, what if there is none (bad input from the user)?
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* In that case, return the letter, and optarg as NULL.
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*-----------------------------------------------------------*/
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if (optind < argc)
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optarg = argv[optind++];
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else {
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optarg = NULL;
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return (opterr ? (int)'?' : (int)*pArgString);
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}
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}
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pIndexPosition = NULL; /* not in the middle of anything */
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}
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else {
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/* it's not a colon, so just return the letter */
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optarg = NULL; /* no argument follows the option */
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pIndexPosition = pArgString; /* point to the letter we're on */
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}
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return (int)*pArgString; /* return the letter that matched */
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}
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}
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