-#include <stdio.h>
-#include <stdlib.h>
-#include <stdarg.h>
-#include <assert.h>
+/*
+ * Render C declarations as English.
+ * Copyright © 2011, 2021, 2023-2024 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 <inttypes.h>
#include "cdecl.h"
-#include "typemap.h"
+#include "cdecl-internal.h"
-/* declare [ident] as [storage] [function specs] [other crap] [qualifiers] [type specs] */
+#define PRE_SPECS (CDECL_SPEC_FUNC|CDECL_SPEC_STOR)
+#define POST_SPECS (CDECL_SPEC_QUAL|CDECL_SPEC_TYPE)
-static size_t
-voutput(char *buf, size_t n, size_t off, const char *fmt, va_list ap)
+static void explain_specs(struct output_state *dst, struct cdecl_declspec *s, unsigned mask)
{
- if (off >= n)
- return vsnprintf(NULL, 0, fmt, ap);
- return vsnprintf(buf+off, n-off, fmt, ap);
+ cdecl__emit(dst, cdecl__emit_specs(dst, s, mask));
}
-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 void
+explain_name(struct output_state *dst, struct cdecl_declarator *d)
{
- va_list ap;
- size_t ret;
+ while (d->child)
+ d = d->child;
- va_start(ap, fmt);
- ret = voutput(buf, n, off, fmt, ap);
- va_end(ap);
-
- return ret;
-}
-
-static size_t advance(char **buf, size_t *n, size_t amount)
-{
- if (!amount)
- 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;
- }
+ if (d->type == CDECL_DECL_IDENT) {
+ cdecl__emit(dst, d->u.ident);
+ cdecl__emit(dst, " as ");
}
-
- return amount + 1;
}
-static size_t
-explain_qualifiers(char *buf, size_t n, struct cdecl_declspec *s)
+/*
+ * For a pointer declarator, emit "[QUAL ]pointer to ", where
+ * QUAL is the (possibly empty) list of qualifiers.
+ */
+static void
+explain_pointer(struct output_state *dst, struct cdecl_pointer *p)
{
- unsigned long qualmap = 0;
- size_t ret = 0, rc = 0;
-
- for (struct cdecl_declspec *c = s; c; c = c->next) {
- if (cdecl_spec_kind(c) != CDECL_SPEC_QUAL)
- continue;
- qualmap |= 1ul << (c->type & 0xff);
- }
-
- if (qualmap & (1ul << (CDECL_QUAL_RESTRICT & 0xff))) {
- ret += advance(&buf, &n, rc);
- rc = snprintf(buf, n, "restrict");
- }
- if (qualmap & (1ul << (CDECL_QUAL_VOLATILE & 0xff))) {
- ret += advance(&buf, &n, rc);
- rc = snprintf(buf, n, "volatile");
- }
- if (qualmap & (1ul << (CDECL_QUAL_CONST & 0xff))) {
- ret += advance(&buf, &n, rc);
- rc = snprintf(buf, n, "const");
- }
-
- return ret + rc;
+ explain_specs(dst, p->qualifiers, -1);
+ cdecl__emit(dst, "pointer to ");
}
-/* Renders the type qualifiers and type specifiers in canonical form. */
-static size_t
-explain_post_specs(char *buf, size_t n, struct cdecl_declspec *s)
+/*
+ * 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 void
+explain_array(struct output_state *dst, struct cdecl_array *a)
{
- const char *tag = NULL;
- unsigned long typemap;
- size_t ret = 0, rc;
-
- typemap = cdecl__build_typemap(s);
- if (typemap == -1)
- return 0;
+ size_t rc = 0;
- for (struct cdecl_declspec *c = s; c; c = c->next) {
- if (cdecl_spec_kind(c) != CDECL_SPEC_TYPE)
- continue;
-
- /* Valid C types have at most one identifier. */
- if (c->ident)
- tag = c->ident;
- }
-
- rc = explain_qualifiers(buf, n, s);
- ret += advance(&buf, &n, rc);
-
- rc = snprintf(buf, n, "%s", cdecl__explain_typemap(typemap));
- if (tag) {
- ret += advance(&buf, &n, rc);
- rc = snprintf(buf, n, "%s", tag);
- }
-
- return ret + rc;
-}
-
-static const char *explain_storage(unsigned spec)
-{
- 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:
- assert(0);
- }
-}
-
-/* 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)
-{
- 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;
- }
+ cdecl__emit(dst, "variable-length array " + (a->vla ? 0 : 16));
+ if (a->vla) {
+ rc = cdecl__emit(dst, a->vla);
+ } else {
+ rc = cdecl__emit_uint(dst, a->length);
}
-
- 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;
+ cdecl__emit(dst, " of " + !rc);
}
-static struct cdecl_declarator *next_declarator(struct cdecl_declarator *d)
-{
- switch (d->type) {
- case CDECL_DECL_IDENT:
- return NULL;
- case CDECL_DECL_POINTER:
- return d->u.pointer.declarator;
- case CDECL_DECL_ARRAY:
- return d->u.array.declarator;
- default:
- assert(0);
- }
-}
+static void
+explain_declarators(struct output_state *dst, struct cdecl_declarator *decl);
-/* Renders the name of the thing being declared. */
-static size_t
-explain_prologue(char *buf, size_t n, struct cdecl_declarator *d)
+static void explain_decl(struct output_state *dst, struct cdecl *decl)
{
- while (d) {
- if (d->type == CDECL_DECL_IDENT) {
- if (!d->u.ident)
- return snprintf(buf, n, "type");
- return snprintf(buf, n, "declare %s as", d->u.ident);
- }
- d = next_declarator(d);
- }
+ explain_name(dst, decl->declarators);
+ explain_specs(dst, decl->specifiers, PRE_SPECS);
+ explain_declarators(dst, decl->declarators);
+ cdecl__emit_specs(dst, decl->specifiers, POST_SPECS);
}
-static size_t
-explain_pointer(char *buf, size_t n, struct cdecl_pointer *p)
+/*
+ * 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 void
+explain_function(struct output_state *dst, struct cdecl_function *f)
{
- size_t ret = 0, rc;
-
- rc = explain_qualifiers(buf, n, p->qualifiers);
- ret += advance(&buf, &n, rc);
+ int tail_offset = 7;
- return ret + snprintf(buf, n, "pointer to");
-}
+ cdecl__emit(dst, "function ");
+ if (f->parameters) {
+ struct cdecl *p;
-static size_t
-explain_array(char *buf, size_t n, struct cdecl_array *a)
-{
- size_t ret = 0, rc = 0;
+ cdecl__emit(dst, "(");
- if (a->vla)
- rc = snprintf(buf, n, "variable-length array");
- else
- rc = snprintf(buf, n, "array");
- ret += advance(&buf, &n, rc);
+ for (p = f->parameters; p; p = p->next) {
+ explain_decl(dst, p);
+ if (p->next)
+ cdecl__emit(dst, ", ");
+ }
- if (a->vla) {
- rc = snprintf(buf, n, "%s", a->vla);
- ret += advance(&buf, &n, rc);
- } else if (a->length) {
- rc = snprintf(buf, n, "%ju", a->length);
- ret += advance(&buf, &n, rc);
+ tail_offset = f->variadic ? 0 : 5;
}
-
- return ret + snprintf(buf, n, "of");
+ cdecl__emit(dst, ", ...) returning " + tail_offset);
}
-static size_t
-explain_declarators(char *buf, size_t n, struct cdecl_declarator *d)
+static void
+explain_declarators(struct output_state *dst, struct cdecl_declarator *d)
{
- size_t ret = 0, rc;
-
- if (d->type == CDECL_DECL_IDENT)
- return 0;
-
- rc = explain_declarators(buf, n, next_declarator(d));
- ret += advance(&buf, &n, rc);
+ if (d->child)
+ explain_declarators(dst, d->child);
switch (d->type) {
case CDECL_DECL_POINTER:
- return ret + explain_pointer(buf, n, &d->u.pointer);
+ explain_pointer(dst, &d->u.pointer);
+ return;
case CDECL_DECL_ARRAY:
- return ret + explain_array(buf, n, &d->u.array);
- default:
- assert(0);
+ explain_array(dst, &d->u.array);
+ return;
+ case CDECL_DECL_FUNCTION:
+ explain_function(dst, &d->u.function);
+ return;
}
}
size_t cdecl_explain(char *buf, size_t n, struct cdecl *decl)
{
- size_t ret = 0, rc;
+ struct output_state dst = { buf, n };
- rc = explain_prologue(buf, n, decl->declarators);
- ret += advance(&buf, &n, rc);
-
- rc = explain_pre_specs(buf, n, decl->specifiers);
- ret += advance(&buf, &n, rc);
-
- rc = explain_declarators(buf, n, decl->declarators);
- ret += advance(&buf, &n, rc);
+ if (cdecl_is_abstract(decl->declarators))
+ cdecl__emit(&dst, "type ");
+ else
+ cdecl__emit(&dst, "declare ");
- return ret + explain_post_specs(buf, n, decl->specifiers);
+ explain_decl(&dst, decl);
+ return dst.accum;
}
projects / cdecl99.git / blobdiff