X-Git-Url: https://git.draconx.ca/gitweb/cdecl99.git/blobdiff_plain/c92cdbdde6876aa06ad07828c8c315c7967128d5..6f166c6c36bda84191ed916a52b311ab417a4890:/src/explain.c

diff --git a/src/explain.c b/src/explain.c
index d7edc74..fe3ed7d 100644
--- a/src/explain.c
+++ b/src/explain.c
@@ -1,149 +1,166 @@
+/*
+ *  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 <stdbool.h>
+#include <assert.h>
+
 #include "cdecl.h"
-#include "typemap.h"
+#include "cdecl-internal.h"
 
-/* declare [ident] as [storage] [function specs] [other crap] [qualifiers] [type specs] */
+static size_t explain_pre_specs(char *buf, size_t n, struct cdecl_declspec *s)
+{
+	return cdecl__explain_specs(buf, n, s, CDECL_SPEC_FUNC|CDECL_SPEC_STOR);
+}
 
-static size_t
-voutput(char *buf, size_t n, size_t off, const char *fmt, va_list ap)
+static size_t explain_post_specs(char *buf, size_t n, struct cdecl_declspec *s)
 {
-	if (off >= n)
-		return vsnprintf(NULL, 0, fmt, ap);
-	return vsnprintf(buf+off, n-off, fmt, ap);
+	return cdecl__explain_specs(buf, n, s, CDECL_SPEC_QUAL|CDECL_SPEC_TYPE);
 }
 
-static size_t output(char *buf, size_t n, size_t off, const char *fmt, ...)
+static size_t
+explain_name(char *buf, size_t n, 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);
+	if (d->type != CDECL_DECL_IDENT)
+		return 0;
 
-	return ret;
+	return snprintf(buf, n, "%s as", d->u.ident);
 }
 
-/* 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)
+explain_pointer(char *buf, size_t n, struct cdecl_pointer *p)
 {
-	unsigned long qualmap = 0, typemap;
-	const char *tag = NULL;
-	size_t ret = 0;
+	size_t ret = 0, rc;
 
-	typemap = cdecl__build_typemap(s);
-	if (typemap == -1)
-		return 0;
+	rc = cdecl__explain_specs(buf, n, p->qualifiers, CDECL_SPEC_QUAL);
+	ret += cdecl__advance(&buf, &n, rc);
 
-	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;
-		}
+	return ret + snprintf(buf, n, "pointer to");
+}
+
+static size_t
+explain_array(char *buf, size_t n, struct cdecl_array *a)
+{
+	size_t ret = 0, rc = 0;
+
+	if (a->vla)
+		rc = snprintf(buf, n, "variable-length array");
+	else
+		rc = snprintf(buf, n, "array");
+	ret += cdecl__advance(&buf, &n, rc);
+
+	if (a->vla) {
+		rc = snprintf(buf, n, "%s", a->vla);
+		ret += cdecl__advance(&buf, &n, rc);
+	} else if (a->length) {
+		rc = snprintf(buf, n, "%" PRIuMAX, a->length);
+		ret += cdecl__advance(&buf, &n, rc);
 	}
 
-	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 ");
-
-	ret += output(buf, n, ret, "%s", cdecl__explain_typemap(typemap));
-	if (tag)
-		ret += output(buf, n, ret, " %s", tag);
-	return ret;
+	return ret + snprintf(buf, n, "of");
 }
 
-static const char *explain_storage(unsigned spec)
+static size_t
+explain_declarators(char *buf, size_t n, struct cdecl_declarator *decl);
+
+static size_t explain_decl(char *buf, size_t n, 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 = 0, rc;
+
+	rc = explain_name(buf, n, decl->declarators);
+	ret += cdecl__advance(&buf, &n, rc);
+
+	rc = explain_pre_specs(buf, n, decl->specifiers);
+	ret += cdecl__advance(&buf, &n, rc);
+
+	rc = explain_declarators(buf, n, decl->declarators);
+	ret += cdecl__advance(&buf, &n, rc);
+
+	return ret + explain_post_specs(buf, n, decl->specifiers);
 }
 
-/* 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)
+static size_t explain_function(char *buf, size_t n, 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;
+	size_t ret = 0, rc = 0;
+
+	rc = snprintf(buf, n, "function");
+	ret += cdecl__advance(&buf, &n, rc);
+
+	if (f->parameters) {
+		rc = snprintf(buf, n, "(");
+		ret += cdecl__advance_(&buf, &n, rc);
+
+		for (struct cdecl *p = f->parameters; p; p = p->next) {
+			rc = explain_decl(buf, n, p);
+			ret += cdecl__advance_(&buf, &n, rc);
+
+			if (p->next)
+				rc = snprintf(buf, n, ",");
+			else if (f->variadic)
+				rc = snprintf(buf, n, ", ...)");
+			else
+				rc = snprintf(buf, n, ")");
+			ret += cdecl__advance(&buf, &n, rc);
 		}
 	}
 
-	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 + snprintf(buf, n, "returning");
 }
 
-static size_t advance(char **buf, size_t *n, size_t amount)
+static size_t
+explain_declarators(char *buf, size_t n, struct cdecl_declarator *d)
 {
-	if (!amount)
+	size_t ret = 0, rc;
+
+	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;
-		}
-	}
+	rc = explain_declarators(buf, n, d->child);
+	ret += cdecl__advance(&buf, &n, rc);
 
-	return amount + 1;
+	switch (d->type) {
+	case CDECL_DECL_POINTER:
+		return ret + explain_pointer(buf, n, &d->u.pointer);
+	case CDECL_DECL_ARRAY:
+		return ret + explain_array(buf, n, &d->u.array);
+	case CDECL_DECL_FUNCTION:
+		return ret + explain_function(buf, n, &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;
 
-	rc = explain_pre_specs(buf, n, decl->specifiers);
-	ret += advance(&buf, &n, rc);
+	if (cdecl_is_abstract(decl->declarators))
+		rc = snprintf(buf, n, "type");
+	else
+		rc = snprintf(buf, n, "declare");
+	ret = cdecl__advance(&buf, &n, rc);
 
-	return ret + explain_post_specs(buf, n, decl->specifiers);
+	return ret + explain_decl(buf, n, decl);
 }