umka/optparse.h

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2022-05-29 17:17:00 +02:00
/* Optparse --- portable, reentrant, embeddable, getopt-like option parser
*
* This is free and unencumbered software released into the public domain.
*
* To get the implementation, define OPTPARSE_IMPLEMENTATION.
* Optionally define OPTPARSE_API to control the API's visibility
* and/or linkage (static, __attribute__, __declspec).
*
* The POSIX getopt() option parser has three fatal flaws. These flaws
* are solved by Optparse.
*
* 1) Parser state is stored entirely in global variables, some of
* which are static and inaccessible. This means only one thread can
* use getopt(). It also means it's not possible to recursively parse
* nested sub-arguments while in the middle of argument parsing.
* Optparse fixes this by storing all state on a local struct.
*
* 2) The POSIX standard provides no way to properly reset the parser.
* This means for portable code that getopt() is only good for one
* run, over one argv with one option string. It also means subcommand
* options cannot be processed with getopt(). Most implementations
* provide a method to reset the parser, but it's not portable.
* Optparse provides an optparse_arg() function for stepping over
* subcommands and continuing parsing of options with another option
* string. The Optparse struct itself can be passed around to
* subcommand handlers for additional subcommand option parsing. A
* full reset can be achieved by with an additional optparse_init().
*
* 3) Error messages are printed to stderr. This can be disabled with
* opterr, but the messages themselves are still inaccessible.
* Optparse solves this by writing an error message in its errmsg
* field. The downside to Optparse is that this error message will
* always be in English rather than the current locale.
*
* Optparse should be familiar with anyone accustomed to getopt(), and
* it could be a nearly drop-in replacement. The option string is the
* same and the fields have the same names as the getopt() global
* variables (optarg, optind, optopt).
*
* Optparse also supports GNU-style long options with optparse_long().
* The interface is slightly different and simpler than getopt_long().
*
* By default, argv is permuted as it is parsed, moving non-option
* arguments to the end. This can be disabled by setting the `permute`
* field to 0 after initialization.
*/
#ifndef OPTPARSE_H
#define OPTPARSE_H
#ifndef OPTPARSE_API
# define OPTPARSE_API
#endif
struct optparse {
char **argv;
int permute;
int optind;
int optopt;
char *optarg;
char errmsg[64];
int subopt;
};
enum optparse_argtype {
OPTPARSE_NONE,
OPTPARSE_REQUIRED,
OPTPARSE_OPTIONAL
};
struct optparse_long {
const char *longname;
int shortname;
enum optparse_argtype argtype;
};
/**
* Initializes the parser state.
*/
OPTPARSE_API
void optparse_init(struct optparse *options, char **argv);
/**
* Read the next option in the argv array.
* @param optstring a getopt()-formatted option string.
* @return the next option character, -1 for done, or '?' for error
*
* Just like getopt(), a character followed by no colons means no
* argument. One colon means the option has a required argument. Two
* colons means the option takes an optional argument.
*/
OPTPARSE_API
int optparse(struct optparse *options, const char *optstring);
/**
* Handles GNU-style long options in addition to getopt() options.
* This works a lot like GNU's getopt_long(). The last option in
* longopts must be all zeros, marking the end of the array. The
* longindex argument may be NULL.
*/
OPTPARSE_API
int optparse_long(struct optparse *options,
const struct optparse_long *longopts,
int *longindex);
/**
* Used for stepping over non-option arguments.
* @return the next non-option argument, or NULL for no more arguments
*
* Argument parsing can continue with optparse() after using this
* function. That would be used to parse the options for the
* subcommand returned by optparse_arg(). This function allows you to
* ignore the value of optind.
*/
OPTPARSE_API
char *optparse_arg(struct optparse *options);
/* Implementation */
#ifdef OPTPARSE_IMPLEMENTATION
#define OPTPARSE_MSG_INVALID "invalid option"
#define OPTPARSE_MSG_MISSING "option requires an argument"
#define OPTPARSE_MSG_TOOMANY "option takes no arguments"
static int
optparse_error(struct optparse *options, const char *msg, const char *data)
{
unsigned p = 0;
const char *sep = " -- '";
while (*msg)
options->errmsg[p++] = *msg++;
while (*sep)
options->errmsg[p++] = *sep++;
while (p < sizeof(options->errmsg) - 2 && *data)
options->errmsg[p++] = *data++;
options->errmsg[p++] = '\'';
options->errmsg[p++] = '\0';
return '?';
}
OPTPARSE_API
void
optparse_init(struct optparse *options, char **argv)
{
options->argv = argv;
options->permute = 1;
options->optind = 1;
options->subopt = 0;
options->optarg = 0;
options->errmsg[0] = '\0';
}
static int
optparse_is_dashdash(const char *arg)
{
return arg != 0 && arg[0] == '-' && arg[1] == '-' && arg[2] == '\0';
}
static int
optparse_is_shortopt(const char *arg)
{
return arg != 0 && arg[0] == '-' && arg[1] != '-' && arg[1] != '\0';
}
static int
optparse_is_longopt(const char *arg)
{
return arg != 0 && arg[0] == '-' && arg[1] == '-' && arg[2] != '\0';
}
static void
optparse_permute(struct optparse *options, int index)
{
char *nonoption = options->argv[index];
int i;
for (i = index; i < options->optind - 1; i++)
options->argv[i] = options->argv[i + 1];
options->argv[options->optind - 1] = nonoption;
}
static int
optparse_argtype(const char *optstring, char c)
{
int count = OPTPARSE_NONE;
if (c == ':')
return -1;
for (; *optstring && c != *optstring; optstring++);
if (!*optstring)
return -1;
if (optstring[1] == ':')
count += optstring[2] == ':' ? 2 : 1;
return count;
}
OPTPARSE_API
int
optparse(struct optparse *options, const char *optstring)
{
int type;
char *next;
char *option = options->argv[options->optind];
options->errmsg[0] = '\0';
options->optopt = 0;
options->optarg = 0;
if (option == 0) {
return -1;
} else if (optparse_is_dashdash(option)) {
options->optind++; /* consume "--" */
return -1;
} else if (!optparse_is_shortopt(option)) {
if (options->permute) {
int index = options->optind++;
int r = optparse(options, optstring);
optparse_permute(options, index);
options->optind--;
return r;
} else {
return -1;
}
}
option += options->subopt + 1;
options->optopt = option[0];
type = optparse_argtype(optstring, option[0]);
next = options->argv[options->optind + 1];
switch (type) {
case -1: {
char str[2] = {0, 0};
str[0] = option[0];
options->optind++;
return optparse_error(options, OPTPARSE_MSG_INVALID, str);
}
case OPTPARSE_NONE:
if (option[1]) {
options->subopt++;
} else {
options->subopt = 0;
options->optind++;
}
return option[0];
case OPTPARSE_REQUIRED:
options->subopt = 0;
options->optind++;
if (option[1]) {
options->optarg = option + 1;
} else if (next != 0) {
options->optarg = next;
options->optind++;
} else {
char str[2] = {0, 0};
str[0] = option[0];
options->optarg = 0;
return optparse_error(options, OPTPARSE_MSG_MISSING, str);
}
return option[0];
case OPTPARSE_OPTIONAL:
options->subopt = 0;
options->optind++;
if (option[1])
options->optarg = option + 1;
else
options->optarg = 0;
return option[0];
}
return 0;
}
OPTPARSE_API
char *
optparse_arg(struct optparse *options)
{
char *option = options->argv[options->optind];
options->subopt = 0;
if (option != 0)
options->optind++;
return option;
}
static int
optparse_longopts_end(const struct optparse_long *longopts, int i)
{
return !longopts[i].longname && !longopts[i].shortname;
}
static void
optparse_from_long(const struct optparse_long *longopts, char *optstring)
{
char *p = optstring;
int i;
for (i = 0; !optparse_longopts_end(longopts, i); i++) {
if (longopts[i].shortname && longopts[i].shortname < 127) {
int a;
*p++ = longopts[i].shortname;
for (a = 0; a < (int)longopts[i].argtype; a++)
*p++ = ':';
}
}
*p = '\0';
}
/* Unlike strcmp(), handles options containing "=". */
static int
optparse_longopts_match(const char *longname, const char *option)
{
const char *a = option, *n = longname;
if (longname == 0)
return 0;
for (; *a && *n && *a != '='; a++, n++)
if (*a != *n)
return 0;
return *n == '\0' && (*a == '\0' || *a == '=');
}
/* Return the part after "=", or NULL. */
static char *
optparse_longopts_arg(char *option)
{
for (; *option && *option != '='; option++);
if (*option == '=')
return option + 1;
else
return 0;
}
static int
optparse_long_fallback(struct optparse *options,
const struct optparse_long *longopts,
int *longindex)
{
int result;
char optstring[96 * 3 + 1]; /* 96 ASCII printable characters */
optparse_from_long(longopts, optstring);
result = optparse(options, optstring);
if (longindex != 0) {
*longindex = -1;
if (result != -1) {
int i;
for (i = 0; !optparse_longopts_end(longopts, i); i++)
if (longopts[i].shortname == options->optopt)
*longindex = i;
}
}
return result;
}
OPTPARSE_API
int
optparse_long(struct optparse *options,
const struct optparse_long *longopts,
int *longindex)
{
int i;
char *option = options->argv[options->optind];
if (option == 0) {
return -1;
} else if (optparse_is_dashdash(option)) {
options->optind++; /* consume "--" */
return -1;
} else if (optparse_is_shortopt(option)) {
return optparse_long_fallback(options, longopts, longindex);
} else if (!optparse_is_longopt(option)) {
if (options->permute) {
int index = options->optind++;
int r = optparse_long(options, longopts, longindex);
optparse_permute(options, index);
options->optind--;
return r;
} else {
return -1;
}
}
/* Parse as long option. */
options->errmsg[0] = '\0';
options->optopt = 0;
options->optarg = 0;
option += 2; /* skip "--" */
options->optind++;
for (i = 0; !optparse_longopts_end(longopts, i); i++) {
const char *name = longopts[i].longname;
if (optparse_longopts_match(name, option)) {
char *arg;
if (longindex)
*longindex = i;
options->optopt = longopts[i].shortname;
arg = optparse_longopts_arg(option);
if (longopts[i].argtype == OPTPARSE_NONE && arg != 0) {
return optparse_error(options, OPTPARSE_MSG_TOOMANY, name);
} if (arg != 0) {
options->optarg = arg;
} else if (longopts[i].argtype == OPTPARSE_REQUIRED) {
options->optarg = options->argv[options->optind];
if (options->optarg == 0)
return optparse_error(options, OPTPARSE_MSG_MISSING, name);
else
options->optind++;
}
return options->optopt;
}
}
return optparse_error(options, OPTPARSE_MSG_INVALID, option);
}
#endif /* OPTPARSE_IMPLEMENTATION */
#endif /* OPTPARSE_H */