+/*
+ * Render C declarations as English.
+ * Copyright © 2011, 2021, 2023 Nick Bowler
+ *
+ * This program 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
#include <stdio.h>
-#include <stdlib.h>
-#include <stdarg.h>
+#include <inttypes.h>
+#include <assert.h>
+
#include "cdecl.h"
-#include "typemap.h"
+#include "cdecl-internal.h"
+
+#define PRE_SPECS (CDECL_SPEC_FUNC|CDECL_SPEC_STOR)
+#define POST_SPECS (CDECL_SPEC_QUAL|CDECL_SPEC_TYPE)
+
+static size_t explain_specs(char **dst, size_t *dstlen, struct cdecl_declspec *s, unsigned mask)
+{
+ size_t rc;
-/* declare [ident] as [storage] [function specs] [other crap] [qualifiers] [type specs] */
+ rc = cdecl__explain_specs(*dst, *dstlen, s, mask);
+ return cdecl__advance(dst, dstlen, rc);
+}
static size_t
-voutput(char *buf, size_t n, size_t off, const char *fmt, va_list ap)
+explain_specs_post(char **dst, size_t *dstlen, struct cdecl_declspec *s)
{
- if (off >= n)
- return vsnprintf(NULL, 0, fmt, ap);
- return vsnprintf(buf+off, n-off, fmt, ap);
+ size_t rc;
+
+ rc = cdecl__explain_specs(*dst, *dstlen, s, POST_SPECS);
+ return cdecl__advance_(dst, dstlen, rc);
}
-static size_t output(char *buf, size_t n, size_t off, const char *fmt, ...)
+/*
+ * If declarator declares an identifier foo, then emit "foo as "; otherwise
+ * emit nothing.
+ */
+static size_t
+explain_name(char **dst, size_t *dstlen, struct cdecl_declarator *d)
{
- va_list ap;
size_t ret;
- va_start(ap, fmt);
- ret = voutput(buf, n, off, fmt, ap);
- va_end(ap);
+ while (d->child)
+ d = d->child;
- return ret;
+ if (d->type != CDECL_DECL_IDENT)
+ return 0;
+
+ ret = cdecl__emit(dst, dstlen, d->u.ident);
+ return ret + cdecl__emit(dst, dstlen, " as ");
}
-/* Renders the type qualifiers and type specifiers in canonical form. */
+/*
+ * For a pointer declarator, emit "[QUAL ]pointer to ", where
+ * QUAL is the (possibly empty) list of qualifiers.
+ */
static size_t
-explain_post_specs(char *buf, size_t n, struct cdecl_declspec *s)
+explain_pointer(char **dst, size_t *dstlen, struct cdecl_pointer *p)
{
- unsigned long qualmap = 0, typemap;
- const char *tag = NULL;
- size_t ret = 0;
+ size_t ret;
- typemap = cdecl__build_typemap(s);
- if (typemap == -1)
- return 0;
+ ret = explain_specs(dst, dstlen, p->qualifiers, -1);
+ return ret + cdecl__emit(dst, dstlen, "pointer to ");
+}
- for (struct cdecl_declspec *c = s; c; c = c->next) {
- switch (cdecl_spec_kind(c)) {
- case CDECL_SPEC_QUAL:
- qualmap |= 1ul << (c->type & 0xff);
- break;
- case CDECL_SPEC_TYPE:
- /* Valid C types have at most one identifier. */
- if (c->ident)
- tag = c->ident;
- break;
- }
- }
+/*
+ * For an array declarator, emit "[variable-length ]array [X ]of ", where
+ * for a variable-length array X is the (possibly omitted) identifier name,
+ * and for normal arrays X is the (possibly omitted) length.
+ */
+static size_t
+explain_array(char **dst, size_t *dstlen, struct cdecl_array *a)
+{
+ size_t ret = 0, rc = 0;
- if (qualmap & (1ul << (CDECL_QUAL_RESTRICT & 0xff)))
- ret += output(buf, n, ret, "restrict ");
- if (qualmap & (1ul << (CDECL_QUAL_VOLATILE & 0xff)))
- ret += output(buf, n, ret, "volatile ");
- if (qualmap & (1ul << (CDECL_QUAL_CONST & 0xff)))
- ret += output(buf, n, ret, "const ");
+ if (a->vla)
+ ret += cdecl__emit(dst, dstlen, "variable-length ");
+ ret += cdecl__emit(dst, dstlen, "array ");
- ret += output(buf, n, ret, "%s", cdecl__explain_typemap(typemap));
- if (tag)
- ret += output(buf, n, ret, " %s", tag);
- return ret;
+ if (a->vla) {
+ rc = cdecl__emit(dst, dstlen, a->vla);
+ ret += rc;
+ } else {
+ rc = snprintf(*dst, *dstlen, "%.0" PRIuMAX, a->length);
+ ret += cdecl__advance_(dst, dstlen, rc);
+ }
+
+ return ret + cdecl__emit(dst, dstlen, " of " + !rc);
}
-static const char *explain_storage(unsigned spec)
+static size_t
+explain_declarators(char **dst, size_t *dstlen, struct cdecl_declarator *decl);
+
+static size_t explain_decl(char **dst, size_t *dstlen, struct cdecl *decl)
{
- switch (spec) {
- case CDECL_STOR_TYPEDEF:
- return "typedef";
- case CDECL_STOR_EXTERN:
- return "extern";
- case CDECL_STOR_STATIC:
- return "static";
- case CDECL_STOR_AUTO:
- return "auto";
- case CDECL_STOR_REGISTER:
- return "register";
- default:
- abort();
- }
+ size_t ret;
+
+ ret = explain_name(dst, dstlen, decl->declarators);
+ ret += explain_specs(dst, dstlen, decl->specifiers, PRE_SPECS);
+ ret += explain_declarators(dst, dstlen, decl->declarators);
+ ret += explain_specs_post(dst, dstlen, decl->specifiers);
+
+ return ret;
}
-/* Renders the storage-class and function specifiers in canonical form. */
-static size_t explain_pre_specs(char *buf, size_t n, struct cdecl_declspec *s)
+/*
+ * For a function declarator, emit "function [PARAM ]returning ", where
+ * PARAM is the (omitted in the case of an empty non-prototype identifier
+ * list) parameter or identifier lists enclosed in parentheses.
+ */
+static size_t
+explain_function(char **dst, size_t *dstlen, struct cdecl_function *f)
{
- unsigned long funcmap = 0;
- const char *storage = NULL;
size_t ret = 0;
- for (struct cdecl_declspec *c = s; c; c = c->next) {
- switch (cdecl_spec_kind(c)) {
- case CDECL_SPEC_FUNC:
- funcmap |= 1ul << (c->type & 0xff);
- break;
- case CDECL_SPEC_STOR:
- /* Valid C declarations have at most one
- * storage-class specifier. */
- storage = explain_storage(c->type);
- break;
+ ret += cdecl__emit(dst, dstlen, "function ");
+
+ if (f->parameters) {
+ struct cdecl *p;
+
+ ret += cdecl__emit(dst, dstlen, "(");
+
+ for (p = f->parameters; p; p = p->next) {
+ ret += explain_decl(dst, dstlen, p);
+ if (p->next)
+ ret += cdecl__emit(dst, dstlen, ", ");
}
+
+ if (f->variadic)
+ ret += cdecl__emit(dst, dstlen, ", ...) ");
+ else
+ ret += cdecl__emit(dst, dstlen, ") ");
}
- if (storage)
- ret += output(buf, n, ret, "%s", storage);
- if (funcmap & (1ul << (CDECL_FUNC_INLINE & 0xff)))
- ret += output(buf, n, ret, "%.*s%s", !!ret, "", "inline");
- return ret;
+ return ret + cdecl__emit(dst, dstlen, "returning ");
}
-static size_t advance(char **buf, size_t *n, size_t amount)
+static size_t
+explain_declarators(char **dst, size_t *dstlen, struct cdecl_declarator *d)
{
- if (!amount)
+ size_t ret;
+
+ if (d->type == CDECL_DECL_IDENT || d->type == CDECL_DECL_NULL)
return 0;
- if (amount >= *n) {
- *n = 0;
- *buf = 0;
- } else {
- (*buf)[amount] = ' ';
- if (amount + 1 >= *n) {
- *buf = 0;
- *n = 0;
- } else {
- *buf += amount + 1;
- *n -= amount + 1;
- }
- }
+ ret = explain_declarators(dst, dstlen, d->child);
- return amount + 1;
+ switch (d->type) {
+ case CDECL_DECL_POINTER:
+ return ret + explain_pointer(dst, dstlen, &d->u.pointer);
+ case CDECL_DECL_ARRAY:
+ return ret + explain_array(dst, dstlen, &d->u.array);
+ case CDECL_DECL_FUNCTION:
+ return ret + explain_function(dst, dstlen, &d->u.function);
+ default:
+ assert(0);
+ }
}
size_t cdecl_explain(char *buf, size_t n, struct cdecl *decl)
{
- size_t ret = 0, rc;
-
- /*
- * XXX: This won't work when we add support for more complicated
- * declarators.
- */
- rc = output(buf, n, 0, "declare %s as", decl->declarators->ident);
- ret += advance(&buf, &n, rc);
+ size_t ret;
- rc = explain_pre_specs(buf, n, decl->specifiers);
- ret += advance(&buf, &n, rc);
+ if (cdecl_is_abstract(decl->declarators))
+ ret = cdecl__emit(&buf, &n, "type ");
+ else
+ ret = cdecl__emit(&buf, &n, "declare ");
- return ret + explain_post_specs(buf, n, decl->specifiers);
+ return ret + explain_decl(&buf, &n, decl);
}