1 files changed, 94 insertions, 0 deletions
diff --git a/src/routines/section.c b/src/routines/section.c
new file mode 100644
index 0000000..7ed8899
--- /dev/null
+++ b/src/routines/section.c
@@ -0,0 +1,94 @@
+/*
+ * 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>
+
+static void (*const fn[])(struct nw_mod *) =
+{
+    nwp_section_custom,
+    nwp_section_type,
+    nwp_section_import,
+    nwp_section_function,
+    nwp_section_table,
+    nwp_section_memory,
+    nwp_section_global,
+    nwp_section_export,
+    nwp_section_start,
+    nwp_section_element,
+    nwp_section_code,
+    nwp_section_data,
+};
+
+static enum nw_state get_offset(struct nw_mod *const m)
+{
+    struct nw_mod_section *const s = &m->section;
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    const enum nw_state n = cfg->tell(&s->offset, cfg->user);
+    long *const offset = &m->sections[s->section];
+
+    if (n)
+        return n;
+    /* Custom section can appear more than once. */
+    else if (s->section != NW_SECTION_CUSTOM && *offset)
+    {
+        LOG("%s: ignoring duplicate section %hhu\n", __func__,
+            (unsigned char)s->section);
+        return nwp_section_skip(m);
+    }
+
+    *offset = s->offset;
+    fn[s->section](m);
+    return NW_AGAIN;
+}
+
+static enum nw_state get_length(struct nw_mod *const m)
+{
+    struct nw_mod_section *const s = &m->section;
+    struct nw_sm_leb128 *const l = &s->leb128;
+    const enum nw_state n = nwp_varuint32(&m->cfg.io, l, &s->len);
+
+    if (n)
+        return n;
+
+    m->next = get_offset;
+    return NW_AGAIN;
+}
+
+static enum nw_state get_section(struct nw_mod *const m)
+{
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    struct nw_mod_section *const s = &m->section;
+    struct nw_sm_leb128 *const l = &s->leb128;
+    const enum nw_state n = nwp_varuint7(cfg, l, &s->section);
+
+    if (n)
+    {
+        if (cfg->eof(cfg->user))
+            return NW_OK;
+
+        return n;
+    }
+    else if (s->section >= sizeof fn / sizeof *fn)
+    {
+        LOG("%s: invalid section %u\n", __func__, (unsigned)s->section);
+        return NW_FATAL;
+    }
+
+    m->next = get_length;
+    return NW_AGAIN;
+}
+
+void nwp_section(struct nw_mod *const m)
+{
+    m->section = (const struct nw_mod_section){0};
+    m->next = get_section;
+}