*.c: General spring-clean of the coding style.

[anag] / anag.c

/* -*-c-*-
 *
 * Main driver for anag
 *
 * (c) 2001 Mark Wooding
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * This file is part of Anag: a simple wordgame helper.
 *
 * Anag is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Anag is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Anag; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*----- Header files ------------------------------------------------------*/

#include "anag.h"

/*----- Static variables --------------------------------------------------*/

static const char *file = DICTIONARY;

/*----- Help text functions -----------------------------------------------*/

static void usage(FILE *fp)
  { pquis(fp, "Usage: $ [-f file] expression\n"); }

static void version(FILE *fp)
  { pquis(fp, "$, version " VERSION "\n"); }

static void help(FILE *fp)
{
  version(fp);
  fputc('\n', fp);
  usage(fp);
  fputs("\n\
Searches a wordlist, printing all of the words which match an expression.\n\
\n\
Options supported are:\n\
\n\
-h, --help		display this help text\n\
-v, --version		display the program's version number\n\
-u, --usage		display a very brief usage message\n\
-f, --file FILE		read wordlist from FILE, not `" DICTIONARY "'\n\
\n\
The basic tests in the expression are:\n\
\n\
-anagram WORD		matches a full-length anagram\n\
-subgram WORD		matches words which only use letters in WORD\n\
-wildcard PATTERN	matches with wildcards `*' and `?'\n\
-trackword WORD		matches words which can be found in a trackword\n\
-mono PATTERN		matches words isomorphic to the given PATTERN\n\
"
#ifdef HAVE_REGCOMP
"\
-regexp REGEXP		matches with an (extended) regular expression\n\
"
#endif
#if defined(HAVE_PCRE) || defined(HAVE_PCRE2)
"\
-pcre REGEXP		matches with a Perl-like regular expression\n\
"
#endif
"\
-length [+|-]N		matches if length is [at least|at most] N\n\
-longest		output longest matches found here\n\
-shortest		output shortest matches found here\n\
\n\
These simple tests can be combined using the operators `-a', `-o' and `-n'\n\
(for `and', `or' and `not'; they may also be written `&', `|' and `!' if\n\
you like), and grouped using parentheses `(' and `)'.\n\
", fp); /*"*/
}

/*----- The options parser ------------------------------------------------*/

/* --- Options table structure --- */

struct opt {
  const char *name;
  unsigned nargs;
  unsigned f;
  unsigned tag;
};

enum {
  O_HELP, O_VERSION, O_USAGE,
  O_FILE,
  O_AND, O_OR, O_NOT, O_LPAREN, O_RPAREN,
  O_ANAG, O_SUBG, O_WILD, O_TRACK, O_REGEXP, O_PCRE, O_MONO, O_LENGTH,
  O_LONGEST, O_SHORTEST,
  O_EOF
};

#define OF_SHORT 1u

static const struct opt opttab[] = {

  /* --- Options -- don't form part of the language --- */

  { "help",		0,	OF_SHORT,	O_HELP },
  { "version",		0,	OF_SHORT,	O_VERSION },
  { "usage",		0,	OF_SHORT,	O_USAGE },
  { "file",		1,	OF_SHORT,	O_FILE },

  /* --- Operators -- provide the basic structure of the language --- *
   *
   * These are also given magical names by the parser.
   */

  { "and",		0,	OF_SHORT,	O_AND },
  { "or",		0,	OF_SHORT,	O_OR },
  { "not",		0,	OF_SHORT,	O_NOT },

  /* --- Actual matching operations -- do something useful --- */

  { "anagram",		1,	0,		O_ANAG },
  { "subgram",		1,	0,		O_SUBG },
  { "wildcard",		1,	0,		O_WILD },
  { "trackword",	1,	0,		O_TRACK },
  { "mono",		1,	0,		O_MONO },
#ifdef HAVE_REGCOMP
  { "regexp",		1,	0,		O_REGEXP },
#endif
#if defined(HAVE_PCRE) || defined(HAVE_PCRE2)
  { "pcre",		1,	0,		O_PCRE },
#endif
  { "length",		1,	0,		O_LENGTH },
  { "longest",		0,	0,		O_LONGEST },
  { "shortest",		0,	0,		O_SHORTEST },

  /* --- End marker --- */

  { 0,			0,	0,		0 }
};

static int ac;
static const char *const *av;
static int ai;

/* --- @nextopt@ --- *
 *
 * Arguments:	@const char ***arg@ = where to store the arg pointer
 *
 * Returns:	The tag of the next option.
 *
 * Use:		Scans the next option off the command line.  If the option
 *		doesn't form part of the language, it's processed internally,
 *		and you'll never see it from here.  On exit, the @arg@
 *		pointer is set to contain the address of the option scanned,
 *		followed by its arguments if any.  You're expected to know
 *		how many arguments there are for your option.
 */

static unsigned nextopt(const char *const **arg)
{
  for (;;) {
    const struct opt *o, *oo;
    size_t sz;
    const char *p;

    /* Pick the next option off the front. */
    *arg = av + ai;
    if (ai >= ac) return (O_EOF);
    p = av[ai++];

    /* Cope with various forms of magic. */
    if (p[0] != '-') {
      if (!p[1]) switch (*p) {
	case '&': return (O_AND);
	case '|': return (O_OR);
	case '!': return (O_NOT);
	case '(': return (O_LPAREN);
	case ')': return (O_RPAREN);
      }
      goto bad;
    }

    /* Now cope with other sorts of weirdies.  By the end of this, a leading
     * `-' or `--' will have been stripped.
     */
    p++;
    if (!*p) goto bad;
    if (*p == '-') p++;
    if (!*p) {
      if (ai < ac) die("syntax error near `--': rubbish at end of line");
      return (O_EOF);
    }

    /*Now look the word up in my table. */
    sz = strlen(p);
    oo = 0;
    for (o = opttab; o->name; o++) {
      if (strncmp(p, o->name, sz) == 0) {
	if (strlen(o->name) == sz || ((o->f & OF_SHORT) && sz == 1))
	  { oo = o; break; }
	if (oo)
	  die("ambiguous option name `-%s' (could match `-%s' or `-%s')",
	      p, oo->name, o->name);
	oo = o;
      }
    }
    if (!oo) die("unrecognized option name `-%s'", p);

    /* Sort out the arguments. */
    if (ai + oo->nargs > ac)
      die("too few arguments for `-%s' (need %u)", oo->name, oo->nargs);
    ai += oo->nargs;

    /* Now process the option. */
    switch (oo->tag) {
      case O_HELP: help(stdout); exit(0);
      case O_VERSION: version(stdout); exit(0);
      case O_USAGE: usage(stdout); exit(0);
      case O_FILE: file = (*arg)[1]; break;
      default: return (oo->tag);
    }
    continue;
  bad:
    die("syntax error near `%s': unknown token type", av[ai - 1]);
  }
}

/*----- Node types for operators ------------------------------------------*/

/* --- Node structures --- */

typedef struct node_bin {
  node n;
  node *left;
  node *right;
} node_bin;

typedef struct node_un {
  node n;
  node *arg;
} node_un;

/* --- Node functions --- */

static int n_or(node *nn, const char *p, size_t sz)
{
  node_bin *n = (node_bin *)nn;
  return (n->left->func(n->left, p, sz) || n->right->func(n->right, p, sz));
}

static int n_and(node *nn, const char *p, size_t sz)
{
  node_bin *n = (node_bin *)nn;
  return (n->left->func(n->left, p, sz) && n->right->func(n->right, p, sz));
}

static int n_not(node *nn, const char *p, size_t sz)
{
  node_un *n = (node_un *)nn;
  return (!n->arg->func(n->arg, p, sz));
}

/*----- Other simple node types -------------------------------------------*/

enum { LESS = -1, EQUAL = 0, GREATER = 1 };

typedef struct node_numeric {
  node n;
  int dir;
  int i;
} node_numeric;

static void parse_numeric(const char *p, int *dir, int *i)
{
  long l;
  const char *pp = p;
  char *q;

  switch (*pp) {
    case '-': *dir = LESS; pp++; break;
    case '+': *dir = GREATER; pp++; break;
    default: *dir = EQUAL; break;
  }
  errno = 0;
  l = strtol(pp, &q, 0);
  if (*q || errno || l < INT_MIN || l > INT_MAX)
    die("bad numeric parameter `%s'", p);
  *i = l;
}

static node *make_numeric(const char *const *av,
			  int (*func)(struct node *, const char *, size_t))
{
  node_numeric *n = xmalloc(sizeof(*n));
  parse_numeric(av[0], &n->dir, &n->i);
  n->n.func = func;
  return (&n->n);
}

static int cmp_numeric(int x, int dir, int n)
{
  switch (dir) {
    case LESS: return (x <= n);
    case EQUAL: return (x == n);
    case GREATER: return (x >= n);
  }
  abort();
}

static int n_length(node *nn, const char *p, size_t sz)
{
  node_numeric *n = (node_numeric *)nn;
  return (cmp_numeric(sz, n->dir, n->i));
}

/*----- Parser for the expression syntax ----------------------------------*/

/* --- A parser context --- */

typedef struct p_ctx {
  unsigned t;
  const char *const *a;
} p_ctx;

/* --- Parser structure --- *
 *
 * This is a simple recursive descent parser.  The context retains
 * information about the current token.  Each function is passed the address
 * of a node pointer to fill in.  This simplifies the binary operator code
 * somewhat, relative to returning pointers to node trees.
 */

static void p_expr(p_ctx *p, node **/*nn*/);

static void p_next(p_ctx *p)
{
  static const char *const eof[] = { "<end>", 0 };
  p->t = nextopt(&p->a);
  if (p->t == O_EOF) p->a = eof;
}

static void p_factor(p_ctx *p, node **nn)
{
  node_un *n;
  if (p->t == O_LPAREN) {
    p_next(p);
    p_expr(p, nn);
    if (p->t != O_RPAREN) die("syntax error near `%s': missing `)'", *p->a);
    p_next(p);
  } else if (p->t == O_NOT) {
    n = xmalloc(sizeof(node_un));
    n->n.func = n_not;
    *nn = &n->n;
    p_next(p);
    p_factor(p, &n->arg);
  } else {
    switch (p->t) {
      case O_ANAG: *nn = anagram(p->a + 1); break;
      case O_SUBG: *nn = subgram(p->a + 1); break;
      case O_WILD: *nn = wildcard(p->a + 1); break;
      case O_TRACK: *nn = trackword(p->a + 1); break;
#ifdef HAVE_REGCOMP
      case O_REGEXP: *nn = regexp(p->a + 1); break;
#endif
#if defined(HAVE_PCRE) || defined(HAVE_PCRE2)
      case O_PCRE: *nn = pcrenode(p->a + 1); break;
#endif
      case O_MONO: *nn = mono(p->a + 1); break;
      case O_LENGTH: *nn = make_numeric(p->a + 1, n_length); break;
      case O_LONGEST: *nn = longest(p->a + 1); break;
      case O_SHORTEST: *nn = shortest(p->a + 1); break;
      default: die("syntax error near `%s': unexpected token", *p->a);
    }
    p_next(p);
  }
}

static void p_term(p_ctx *p, node **nn)
{
  node_bin *n;
  for (;;) {
    p_factor(p, nn);
    switch (p->t) {
      case O_AND: p_next(p); break;
      default: break;
      case O_RPAREN: case O_OR: case O_EOF: return;
    }
    n = xmalloc(sizeof(node_bin));
    n->left = *nn;
    n->n.func = n_and;
    *nn = &n->n;
    nn = &n->right;
  }
}

static void p_expr(p_ctx *p, node **nn)
{
  node_bin *n;
  for (;;) {
    p_term(p, nn);
    if (p->t != O_OR) break;
    p_next(p);
    n = xmalloc(sizeof(node_bin));
    n->left = *nn;
    n->n.func = n_or;
    *nn = &n->n;
    nn = &n->right;
  }
}

/* --- @p_argv@ --- *
 *
 * Arguments:	@int argc@ = number of command-line arguments
 *		@const char *const argv[]@ = vectoor of arguments
 *
 * Returns:	A compiled node, parsed from the arguments.
 *
 * Use:		Does the donkey-work of parsing a command-line.
 */

static node *p_argv(int argc, const char *const argv[])
{
  p_ctx p;
  node *n;

  av = argv;
  ac = argc;
  ai = 1;
  p_next(&p);
  if (p.t == O_EOF) {
    usage(stderr);
    pquis(stderr, "(Run `$ --help' for more detail.)\n");
    exit(EXIT_FAILURE);
  }
  p_expr(&p, &n);
  if (p.t != O_EOF)
    die("syntax error near `%s': rubbish at end of line (too many `)'s?)",
	*p.a);
  return (n);
}

/*----- At-end stuff ------------------------------------------------------*/

/* --- @atend_register@ --- *
 *
 * Arguments:	@int (*func)(void *)@ = function to call
 *		@void *p@ = handle to pass to it
 *
 * Returns:	---
 *
 * Use:		Adds a function to the list of things to do at the end of the
 *		program.  The function should return nonzero if it produced
 *		any output.
 */

typedef struct atend {
  struct atend *next;
  int (*func)(void */*p*/);
  void *p;
} atend;

static atend *aa_head = 0, **aa_tail = &aa_head;

void atend_register(int (*func)(void */*p*/), void *p)
{
  atend *a = xmalloc(sizeof(*a));
  a->next = 0;
  a->func = func;
  a->p = p;
  *aa_tail = a;
  aa_tail = &a->next;
}

/*----- Main code ---------------------------------------------------------*/

/* --- @main@ --- *
 *
 * Arguments:	@int argc@ = number of command-line arguments
 *		@char *argv[]@ = vector of argument words
 *
 * Returns:	Zero on success, nonzero on failure.
 *
 * Use:		Picks entries from a word list which match particular
 *		expressions.  This might be of assistance to word-game types.
 */

int main(int argc, char *argv[])
{
  node *n;
  FILE *fp;
  dstr d = DSTR_INIT;
  int ok = 0;
  char *p, *q, *l;
  atend *a;

  ego(argv[0]);
  n = p_argv(argc, (const char *const *)argv);

  if ((fp = fopen(file, "r")) == 0)
    die("error opening `%s': %s", file, strerror(errno));
  for (;;) {
    dstr_reset(&d);
    if (dstr_putline(&d, fp) < 0) break;
    l = d.buf + d.len;
    for (p = q = d.buf; p < l; p++) {
      if (!isalnum((unsigned char)*p)) continue;
      *q++ = tolower((unsigned char)*p);
    }
    *q = 0;
    d.len = q - d.buf;
    if (n->func(n, d.buf, d.len)) {
      fwrite(d.buf, 1, d.len, stdout);
      fputc('\n', stdout);
      ok = 1;
    }
  }
  if (ferror(fp) || fclose(fp))
    die("error reading `%s': %s", file, strerror(errno));
  for (a = aa_head; a; a = a->next)
    if (a->func(a->p)) ok = 1;
  if (fflush(stdout) || ferror(stdout) || fclose(stdout))
    die("error writing output: %s", strerror(errno));
  if (!ok) pquis(stderr, "$: no matches found\n");
  return (ok ? EX_OK : EX_NONE);
}

/*----- That's all, folks -------------------------------------------------*/