First commit

1 files changed, 150 insertions, 0 deletions

diff --git a/src/section/common.c b/src/section/common.c
new file mode 100644
index 0000000..b768470
--- /dev/null
+++ b/src/section/common.c
@@ -0,0 +1,150 @@
+/*
+ * 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 <nw/types.h>
+#include <errno.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+
+int check_resizable_limits(FILE *const f, struct resizable_limits *const r)
+{
+    varuint1 flags;
+    varuint32 initial;
+
+    *r = (const struct resizable_limits){0};
+
+    if (varuint1_read(f, &flags))
+    {
+        LOG("%s: varuint1_read failed\n", __func__);
+        return -1;
+    }
+    else if (varuint32_read(f, &initial))
+    {
+        LOG("%s: varuint32_read failed\n", __func__);
+        return -1;
+    }
+
+    if (flags)
+    {
+        varuint32 maximum;
+
+        if (varuint32_read(f, &maximum))
+        {
+            LOG("%s: varuint32_read failed\n", __func__);
+            return -1;
+        }
+
+        r->max = maximum;
+        r->max_available = true;
+    }
+
+    static const unsigned long page_size = 64lu * 1024lu;
+
+    if (initial > UINT32_MAX / page_size)
+    {
+        LOG("%s: initial size (%lu) overflow \n", __func__,
+            (unsigned long)initial);
+        return 1;
+    }
+
+    r->sz = initial * page_size;
+    return 0;
+}
+
+size_t get_type_size(const enum value_type type)
+{
+    static const size_t list[] =
+    {
+        [VALUE_TYPE_I32] = sizeof (int32_t),
+        [VALUE_TYPE_I64] = sizeof (int64_t),
+        [VALUE_TYPE_F32] = sizeof (float),
+        [VALUE_TYPE_F64] = sizeof (double)
+    };
+
+    return list[type];
+}
+
+enum
+{
+    I32 = 0x7f,
+    I64 = 0x7e,
+    F32 = 0x7d,
+    F64 = 0x7c,
+    ANYFUNC = 0x70,
+    FUNC = 0x60,
+    BLOCK_TYPE = 0x40
+};
+
+int get_value_type(const varint7 type, enum value_type *const vtype)
+{
+    static const struct size
+    {
+        varint7 type;
+        enum value_type vtype;
+    } sizes[] =
+    {
+        {.type = I32, .vtype = VALUE_TYPE_I32},
+        {.type = I64, .vtype = VALUE_TYPE_I64},
+        {.type = F32, .vtype = VALUE_TYPE_F32},
+        {.type = F64, .vtype = VALUE_TYPE_F64},
+        /* TODO: check this. */
+        {.type = ANYFUNC, .vtype = VALUE_TYPE_I32},
+        /* TODO: check this. */
+        {.type = FUNC, .vtype = VALUE_TYPE_I32},
+        /* TODO: check this. */
+        {.type = BLOCK_TYPE, .vtype = VALUE_TYPE_I32}
+    };
+
+    for (size_t i = 0; i < sizeof sizes / sizeof *sizes; i++)
+    {
+        const struct size *const s = &sizes[i];
+
+        if (type == s->type)
+        {
+            *vtype = s->vtype;
+            return 0;
+        }
+    }
+
+    LOG("%s: unknown type %#hhx\n", __func__, (char)type);
+    return -1;
+}
+
+static int32_t swap_i32(const int32_t in)
+{
+    const int8_t *const p = (const int8_t *)&in;
+
+    return p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
+}
+
+int32_t htoni32(const int32_t in)
+{
+    return swap_i32(in);
+}
+
+int32_t ntohi32(const int32_t in)
+{
+    return swap_i32(in);
+}
+
+const char *value_type_tostr(const enum value_type v)
+{
+    static const char *const s[] =
+    {
+#define X(x) [x] = #x,
+        VALUE_TYPES
+#undef X
+    };
+
+    return s[v];
+}