First commit

1 files changed, 180 insertions, 0 deletions

diff --git a/src/section/type.c b/src/section/type.c
new file mode 100644
index 0000000..0bf7a06
--- /dev/null
+++ b/src/section/type.c
@@ -0,0 +1,180 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2024  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nw/log.h>
+#include <nw/sections.h>
+#include <nanowasm/nw.h>
+#include <nw/types.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+static int check_value_type(FILE *const f, enum value_type *const vtype)
+{
+    varint7 value_type;
+
+    if (varint7_read(f, &value_type))
+    {
+        LOG("%s: varint7_read failed\n", __func__);
+        return -1;
+    }
+    else if (vtype && get_value_type(value_type, vtype))
+    {
+        LOG("%s: get_value_type failed\n", __func__);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int check_func_type(FILE *const f, struct retval *const r)
+{
+    varint7 form;
+    varuint32 param_count;
+
+    if (varint7_read(f, &form))
+    {
+        LOG("%s: varint7_read failed\n", __func__);
+        return -1;
+    }
+    else if (varuint32_read(f, &param_count))
+    {
+        LOG("%s: varuint32_read failed\n", __func__);
+        return -1;
+    }
+
+    for (varuint32 i = 0; i < param_count; i++)
+        if (check_value_type(f, NULL))
+        {
+            LOG("%s: check_value_type failed\n", __func__);
+            return -1;
+        }
+
+    varuint1 return_count;
+    enum value_type vtype;
+
+    if (varuint1_read(f, &return_count))
+    {
+        LOG("%s: varuint1_read failed\n", __func__);
+        return -1;
+    }
+    else if (return_count && check_value_type(f, &vtype))
+    {
+        LOG("%s: check_value_type 2 failed\n", __func__);
+        return -1;
+    }
+
+    *r = (const struct retval)
+    {
+        .returns = return_count,
+        .type = vtype
+    };
+
+    return 0;
+}
+
+static int run(FILE *const f, const unsigned long len, const varuint32 idx,
+    struct nw_frame *const fr)
+{
+    const long start = ftell(f);
+    varuint32 count;
+
+    if (start < 0)
+    {
+        LOG("%s: ftell(3): %s\n", __func__, strerror(errno));
+        return -1;
+    }
+    else if (varuint32_read(f, &count))
+    {
+        LOG("%s: varuint32_read failed\n", __func__);
+        return -1;
+    }
+
+    for (varuint32 i = 0; i < count; i++)
+    {
+        struct retval r;
+
+        if (check_func_type(f, &r))
+        {
+            LOG("%s: check_func_type failed\n", __func__);
+            return -1;
+        }
+        else if (fr && i == idx)
+        {
+            fr->retval = r;
+            return 0;
+        }
+    }
+
+    const long end = ftell(f);
+
+    if (end < 0)
+    {
+        LOG("%s: ftell(3): %s\n", __func__, strerror(errno));
+        return -1;
+    }
+
+    const unsigned long size = end - start;
+
+    if (size != len)
+    {
+        LOG("%s: size exceeded (%lu expected, got %lu)\n",
+                __func__, len, size);
+        return -1;
+    }
+
+    return 0;
+}
+
+int section_type_check(const struct section *const s, struct nw_mod *const m,
+    const unsigned long len)
+{
+    FILE *const f = s->f;
+
+    if (m->sections.type)
+    {
+        LOG("%s: ignoring duplicate section\n", __func__);
+        return fseek(f, len, SEEK_CUR);
+    }
+
+    const long offset = ftell(f);
+
+    if (offset < 0)
+    {
+        LOG("%s: ftell(3): %s\n", __func__, strerror(errno));
+        return -1;
+    }
+    else if (run(f, len, 0, NULL))
+    {
+        LOG("%s: check failed\n", __func__);
+        return -1;
+    }
+
+    m->sections.type = offset;
+    return 0;
+}
+
+int section_type_push(FILE *const f, const struct nw_mod *const m,
+    const varuint32 idx, struct nw_frame *const fr)
+{
+    const long offset = m->sections.type;
+
+    if (offset <= 0)
+    {
+        LOG("%s: function section not found", __func__);
+        return -1;
+    }
+    else if (fseek(f, offset, SEEK_SET))
+    {
+        LOG("%s: fseek(3): %s\n", __func__, strerror(errno));
+        return -1;
+    }
+
+    return run(f, 0, idx, fr);
+}