neetdraw/utils.c

350 lines
8.6 KiB
C

/*
* utils.c: utilities
*
* Copyright (c) 2014, Přemysl Janouch <p.janouch@gmail.com>
* All rights reserved.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/
#include <getopt.h>
#if defined __GNUC__
#define ATTRIBUTE_PRINTF(x, y) __attribute__ ((format (printf, x, y)))
#else // ! __GNUC__
#define ATTRIBUTE_PRINTF(x, y)
#endif // ! __GNUC__
#if defined __GNUC__ && __GNUC__ >= 4
#define ATTRIBUTE_SENTINEL __attribute__ ((sentinel))
#else // ! __GNUC__ || __GNUC__ < 4
#define ATTRIBUTE_SENTINEL
#endif // ! __GNUC__ || __GNUC__ < 4
#define N_ELEMENTS(a) (sizeof (a) / sizeof ((a)[0]))
// --- Safe memory management --------------------------------------------------
// When a memory allocation fails and we need the memory, we're usually pretty
// much fucked. Use the non-prefixed versions when there's a legitimate
// worry that an unrealistic amount of memory may be requested for allocation.
static void *
xmalloc (size_t n)
{
void *p = malloc (n);
if (!p)
{
perror ("malloc");
exit (EXIT_FAILURE);
}
return p;
}
static void *
xcalloc (size_t n, size_t m)
{
void *p = calloc (n, m);
if (!p && n && m)
{
perror ("calloc");
exit (EXIT_FAILURE);
}
return p;
}
static void *
xrealloc (void *o, size_t n)
{
void *p = realloc (o, n);
if (!p && n)
{
perror ("realloc");
exit (EXIT_FAILURE);
}
return p;
}
// --- Dynamically allocated strings -------------------------------------------
// Basically a string builder to abstract away manual memory management.
struct str
{
char *str; ///< String data, null terminated
size_t alloc; ///< How many bytes are allocated
size_t len; ///< How long the string actually is
};
/// We don't care about allocations that are way too large for the content, as
/// long as the allocation is below the given threshold. (Trivial heuristics.)
#define STR_SHRINK_THRESHOLD (1 << 20)
static void
str_init (struct str *self)
{
self->alloc = 16;
self->len = 0;
self->str = strcpy (xmalloc (self->alloc), "");
}
static void
str_free (struct str *self)
{
free (self->str);
self->str = NULL;
self->alloc = 0;
self->len = 0;
}
static char *
str_steal (struct str *self)
{
char *str = self->str;
self->str = NULL;
str_free (self);
return str;
}
static void
str_ensure_space (struct str *self, size_t n)
{
// We allocate at least one more byte for the terminating null character
size_t new_alloc = self->alloc;
while (new_alloc <= self->len + n)
new_alloc <<= 1;
if (new_alloc != self->alloc)
self->str = xrealloc (self->str, (self->alloc = new_alloc));
}
static void
str_append_data (struct str *self, const void *data, size_t n)
{
str_ensure_space (self, n);
memcpy (self->str + self->len, data, n);
self->len += n;
self->str[self->len] = '\0';
}
static void
str_append_c (struct str *self, char c)
{
str_append_data (self, &c, 1);
}
static void
str_append (struct str *self, const char *s)
{
str_append_data (self, s, strlen (s));
}
static int
str_append_vprintf (struct str *self, const char *fmt, va_list va)
{
va_list ap;
int size;
va_copy (ap, va);
size = vsnprintf (NULL, 0, fmt, ap);
va_end (ap);
if (size < 0)
return -1;
va_copy (ap, va);
str_ensure_space (self, size);
size = vsnprintf (self->str + self->len, self->alloc - self->len, fmt, ap);
va_end (ap);
if (size > 0)
self->len += size;
return size;
}
static int
str_append_printf (struct str *self, const char *fmt, ...)
ATTRIBUTE_PRINTF (2, 3);
static int
str_append_printf (struct str *self, const char *fmt, ...)
{
va_list ap;
va_start (ap, fmt);
int size = str_append_vprintf (self, fmt, ap);
va_end (ap);
return size;
}
// --- Utilities ---------------------------------------------------------------
static bool
xstrtoul (unsigned long *out, const char *s, int base)
{
char *end;
errno = 0;
*out = strtoul (s, &end, base);
return errno == 0 && !*end && end != s;
}
// --- Option handler ----------------------------------------------------------
// Simple wrapper for the getopt_long API to make it easier to use and maintain.
#define OPT_USAGE_ALIGNMENT_COLUMN 30 ///< Alignment for option descriptions
enum
{
OPT_OPTIONAL_ARG = (1 << 0), ///< The argument is optional
OPT_LONG_ONLY = (1 << 1) ///< Ignore the short name in opt_string
};
// All options need to have both a short name, and a long name. The short name
// is what is returned from opt_handler_get(). It is possible to define a value
// completely out of the character range combined with the OPT_LONG_ONLY flag.
//
// When `arg_hint' is defined, the option is assumed to have an argument.
struct opt
{
int short_name; ///< The single-letter name
const char *long_name; ///< The long name
const char *arg_hint; ///< Option argument hint
int flags; ///< Option flags
const char *description; ///< Option description
};
struct opt_handler
{
int argc; ///< The number of program arguments
char **argv; ///< Program arguments
const char *arg_hint; ///< Program arguments hint
const char *description; ///< Description of the program
const struct opt *opts; ///< The list of options
size_t opts_len; ///< The length of the option array
struct option *options; ///< The list of options for getopt
char *opt_string; ///< The `optstring' for getopt
};
static void
opt_handler_free (struct opt_handler *self)
{
free (self->options);
free (self->opt_string);
}
static void
opt_handler_init (struct opt_handler *self, int argc, char **argv,
const struct opt *opts, const char *arg_hint, const char *description)
{
memset (self, 0, sizeof *self);
self->argc = argc;
self->argv = argv;
self->arg_hint = arg_hint;
self->description = description;
size_t len = 0;
for (const struct opt *iter = opts; iter->long_name; iter++)
len++;
self->opts = opts;
self->opts_len = len;
self->options = xcalloc (len + 1, sizeof *self->options);
struct str opt_string;
str_init (&opt_string);
for (size_t i = 0; i < len; i++)
{
const struct opt *opt = opts + i;
struct option *mapped = self->options + i;
mapped->name = opt->long_name;
if (!opt->arg_hint)
mapped->has_arg = no_argument;
else if (opt->flags & OPT_OPTIONAL_ARG)
mapped->has_arg = optional_argument;
else
mapped->has_arg = required_argument;
mapped->val = opt->short_name;
if (opt->flags & OPT_LONG_ONLY)
continue;
str_append_c (&opt_string, opt->short_name);
if (opt->arg_hint)
{
str_append_c (&opt_string, ':');
if (opt->flags & OPT_OPTIONAL_ARG)
str_append_c (&opt_string, ':');
}
}
self->opt_string = str_steal (&opt_string);
}
static void
opt_handler_usage (struct opt_handler *self, FILE *stream)
{
struct str usage;
str_init (&usage);
str_append_printf (&usage, "Usage: %s [OPTION]... %s\n",
self->argv[0], self->arg_hint ? self->arg_hint : "");
str_append_printf (&usage, "%s\n\n", self->description);
for (size_t i = 0; i < self->opts_len; i++)
{
struct str row;
str_init (&row);
const struct opt *opt = self->opts + i;
if (!(opt->flags & OPT_LONG_ONLY))
str_append_printf (&row, " -%c, ", opt->short_name);
else
str_append (&row, " ");
str_append_printf (&row, "--%s", opt->long_name);
if (opt->arg_hint)
str_append_printf (&row, (opt->flags & OPT_OPTIONAL_ARG)
? " [%s]" : " %s", opt->arg_hint);
// TODO: keep the indent if there are multiple lines
if (row.len + 2 <= OPT_USAGE_ALIGNMENT_COLUMN)
{
str_append (&row, " ");
str_append_printf (&usage, "%-*s%s\n",
OPT_USAGE_ALIGNMENT_COLUMN, row.str, opt->description);
}
else
str_append_printf (&usage, "%s\n%-*s%s\n", row.str,
OPT_USAGE_ALIGNMENT_COLUMN, "", opt->description);
str_free (&row);
}
fputs (usage.str, stream);
str_free (&usage);
}
static int
opt_handler_get (struct opt_handler *self)
{
return getopt_long (self->argc, self->argv,
self->opt_string, self->options, NULL);
}