1 files changed, 308 insertions, 0 deletions
diff --git a/src/routines/section/import.c b/src/routines/section/import.c
new file mode 100644
index 0000000..1ea54eb
--- /dev/null
+++ b/src/routines/section/import.c
@@ -0,0 +1,308 @@
+/*
+ * 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 <nanowasm/nw.h>
+#include <nw/io.h>
+#include <nw/log.h>
+#include <nw/routines.h>
+#include <string.h>
+
+static enum nw_state entry_loop(struct nw_mod *);
+static enum nw_state find_import(struct nw_mod *);
+
+static enum nw_state get_function_type(struct nw_mod *const m)
+{
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    struct nw_sm_imp *const imp = &m->sm.import;
+    struct nw_sm_leb128 *const l = &imp->leb128;
+    nw_varuint32 type;
+    const enum nw_state n = nwp_varuint32(cfg, l, &type);
+
+    if (n)
+        return n;
+
+    m->next = nwp_section_exit;
+    return NW_AGAIN;
+}
+
+static enum nw_state get_kind(struct nw_mod *const m)
+{
+    uint8_t kind;
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    struct nw_sm_io io = {.buf = &kind, .n = sizeof kind};
+    const enum nw_state n = nwp_io_read(cfg, &io);
+
+    if (n)
+        return n;
+
+    struct nw_sm_imp *const imp = &m->sm.import;
+    const struct nw_import *const i = &m->cfg.imports[imp->imp_i];
+
+    if (kind != i->kind)
+    {
+        m->next = find_import;
+        imp->imp_i++;
+    }
+    /* TODO: process every import type. */
+    else if (kind != NW_KIND_FUNCTION)
+        m->next = nwp_section_exit;
+    else
+        m->next = get_function_type;
+
+    return NW_AGAIN;
+}
+
+static enum nw_state compare_field(struct nw_mod *const m)
+{
+    uint8_t byte;
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    struct nw_sm_io io = {.buf = &byte, .n = sizeof byte};
+    const enum nw_state n = nwp_io_read(cfg, &io);
+
+    if (n)
+        return n;
+
+    struct nw_sm_imp *const imp = &m->sm.import;
+    const struct nw_import *const i = &m->cfg.imports[imp->imp_i];
+
+    if (byte != i->field[imp->len_i])
+    {
+        m->next = find_import;
+        imp->imp_i++;
+        imp->len_i = 0;
+    }
+    else if (++imp->len_i >= imp->field_len)
+    {
+        m->next = get_kind;
+        imp->len_i = 0;
+    }
+
+    return NW_AGAIN;
+}
+
+static enum nw_state get_field_offset(struct nw_mod *const m)
+{
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    struct nw_sm_imp *const imp = &m->sm.import;
+    const enum nw_state n = cfg->tell(&imp->field_off, cfg->user);
+    const struct nw_import *const i = &m->cfg.imports[imp->imp_i];
+
+    if (n)
+        return n;
+    else if (imp->field_len != strlen(i->field))
+    {
+        m->next = find_import;
+        imp->imp_i++;
+    }
+    else
+        m->next = compare_field;
+
+    return NW_AGAIN;
+}
+
+static enum nw_state get_field_len(struct nw_mod *const m)
+{
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    struct nw_sm_imp *const imp = &m->sm.import;
+    struct nw_sm_leb128 *const l = &imp->leb128;
+    const enum nw_state n = nwp_varuint32(cfg, l, &imp->field_len);
+
+    if (n)
+        return n;
+    else
+        m->next = get_field_offset;
+
+    return NW_AGAIN;
+}
+
+static enum nw_state compare_name(struct nw_mod *const m)
+{
+    uint8_t byte;
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    struct nw_sm_io io = {.buf = &byte, .n = sizeof byte};
+    const enum nw_state n = nwp_io_read(cfg, &io);
+
+    if (n)
+        return n;
+
+    struct nw_sm_imp *const imp = &m->sm.import;
+    const struct nw_import *const i = &m->cfg.imports[imp->imp_i];
+
+    if (byte != i->module[imp->len_i])
+    {
+        m->next = find_import;
+        imp->imp_i++;
+        imp->len_i = 0;
+    }
+    else if (++imp->len_i >= imp->mod_len)
+    {
+        m->next = get_field_len;
+        imp->len_i = 0;
+    }
+
+    return NW_AGAIN;
+}
+
+static enum nw_state dump_import_field_name(struct nw_mod *const m)
+{
+    uint8_t byte;
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    struct nw_sm_io io = {.buf = &byte, .n = sizeof byte};
+    const enum nw_state n = nwp_io_read(cfg, &io);
+
+    if (n)
+        return n;
+
+    LOG("%c", (char)byte);
+
+    struct nw_sm_imp *const imp = &m->sm.import;
+
+    if (++imp->len_i >= imp->field_len)
+    {
+        LOG("\n");
+        return NW_FATAL;
+    }
+
+    return NW_AGAIN;
+}
+
+static enum nw_state rewind_to_field_name(struct nw_mod *const m)
+{
+    struct nw_sm_imp *const imp = &m->sm.import;
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    const enum nw_state n = cfg->seek(imp->field_off, NW_SEEK_SET, cfg->user);
+
+    if (n)
+        return n;
+
+    m->next = dump_import_field_name;
+    return NW_AGAIN;
+}
+
+static enum nw_state dump_import_mod_name(struct nw_mod *const m)
+{
+    uint8_t byte;
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    struct nw_sm_io io = {.buf = &byte, .n = sizeof byte};
+    const enum nw_state n = nwp_io_read(cfg, &io);
+
+    if (n)
+        return n;
+
+    LOG("%c", (char)byte);
+
+    struct nw_sm_imp *const imp = &m->sm.import;
+
+    if (++imp->len_i >= imp->mod_len)
+    {
+        imp->len_i = 0;
+
+        if (imp->field_off)
+        {
+            LOG("::");
+            m->next = rewind_to_field_name;
+        }
+        else
+        {
+            LOG("\n");
+            return NW_FATAL;
+        }
+    }
+
+    return NW_AGAIN;
+}
+
+static enum nw_state rewind_to_mod_name(struct nw_mod *const m)
+{
+    struct nw_sm_imp *const imp = &m->sm.import;
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    const enum nw_state n = cfg->seek(imp->mod_off, NW_SEEK_SET, cfg->user);
+
+    if (n)
+        return n;
+
+    m->next = dump_import_mod_name;
+    return NW_AGAIN;
+}
+
+static enum nw_state find_import(struct nw_mod *const m)
+{
+    struct nw_sm_imp *const imp = &m->sm.import;
+
+    if (imp->imp_i >= m->cfg.n_imports)
+    {
+        LOG("%s: required import: ", __func__);
+        m->next = rewind_to_mod_name;
+        return NW_AGAIN;
+    }
+
+    const struct nw_import *const i = &m->cfg.imports[imp->imp_i];
+
+    if (imp->mod_len == strlen(i->module))
+        m->next = compare_name;
+    else
+        imp->imp_i++;
+
+    return NW_AGAIN;
+}
+
+static enum nw_state get_module_offset(struct nw_mod *const m)
+{
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    struct nw_sm_imp *const imp = &m->sm.import;
+    const enum nw_state n = cfg->tell(&imp->mod_off, cfg->user);
+
+    if (n)
+        return n;
+
+    m->next = find_import;
+    return NW_AGAIN;
+}
+
+static enum nw_state get_module_len(struct nw_mod *const m)
+{
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    struct nw_sm_imp *const imp = &m->sm.import;
+    struct nw_sm_leb128 *const l = &imp->leb128;
+    const enum nw_state n = nwp_varuint32(cfg, l, &imp->mod_len);
+
+    if (n)
+        return n;
+
+    m->next = get_module_offset;
+    return NW_AGAIN;
+}
+
+static enum nw_state entry_loop(struct nw_mod *const m)
+{
+    const struct nw_sm_imp *const imp = &m->sm.import;
+
+    m->next = imp->entry_i < imp->count ? get_module_len : nwp_section_exit;
+    return NW_AGAIN;
+}
+
+static enum nw_state get_count(struct nw_mod *const m)
+{
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    struct nw_sm_imp *const imp = &m->sm.import;
+    struct nw_sm_leb128 *const l = &imp->leb128;
+    const enum nw_state n = nwp_varuint32(cfg, l, &imp->count);
+
+    if (n)
+        return n;
+
+    m->next = entry_loop;
+    return NW_AGAIN;
+}
+
+void nwp_section_import(struct nw_mod *const m)
+{
+    m->next = get_count;
+    m->sm.import = (const struct nw_sm_imp){0};
+}