First commit

1 files changed, 229 insertions, 0 deletions

diff --git a/src/interp/routines/find_export.c b/src/interp/routines/find_export.c
new file mode 100644
index 0000000..effa8d1
--- /dev/null
+++ b/src/interp/routines/find_export.c
@@ -0,0 +1,229 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  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 <nanowasm/types.h>
+#include <nw/interp.h>
+#include <nw/io.h>
+#include <nw/log.h>
+#include <nw/routines.h>
+#include <string.h>
+
+static enum nw_state entry_loop(struct nw_interp *i);
+
+static enum nw_state get_index(struct nw_interp *const i)
+{
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    struct nw_i_sm_exp *const e = &i->sm.export;
+    struct nw_sm_leb128 *const l = &e->leb128;
+    const enum nw_state n = nwp_varuint32(cfg, l, &e->index, cfg->user);
+
+    if (n)
+        return n;
+
+    i->next = e->next;
+    return NW_AGAIN;
+}
+
+static enum nw_state get_kind(struct nw_interp *const i)
+{
+    unsigned char kind;
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    struct nw_i_sm_exp *const e = &i->sm.export;
+    struct nw_sm_io io = {0};
+    enum nw_state n;
+
+    io.buf = &kind;
+    io.n = sizeof kind;
+
+    if ((n = nwp_io_read(cfg, &io, cfg->user)))
+        return n;
+    else if (kind >= NW_KINDS)
+    {
+        static const char *const exc = "invalid export kind";
+
+        i->exception = exc;
+#ifdef NW_LOG
+        nwp_log("%s: %#x\n", exc, (unsigned)kind);
+#endif
+        return NW_FATAL;
+    }
+
+    e->kind = kind;
+    i->next = get_index;
+    return NW_AGAIN;
+}
+
+static enum nw_state skip_index(struct nw_interp *const i)
+{
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    struct nw_i_sm_exp *const e = &i->sm.export;
+    struct nw_sm_leb128 *const l = &e->leb128;
+    nw_varuint32 index;
+    const enum nw_state n = nwp_varuint32(cfg, l, &index, cfg->user);
+
+    if (n)
+        return n;
+
+    e->entry_i++;
+    i->next = entry_loop;
+    return NW_AGAIN;
+}
+
+static enum nw_state skip_kind(struct nw_interp *const i)
+{
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    unsigned char b;
+    struct nw_sm_io io = {0};
+    enum nw_state n;
+
+    io.buf = &b;
+    io.n = sizeof b;
+
+    if ((n = nwp_io_read(cfg, &io, cfg->user)))
+        return n;
+
+    i->next = skip_index;
+    return NW_AGAIN;
+}
+
+static enum nw_state skip_field_str(struct nw_interp *const i)
+{
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    const struct nw_i_sm_exp *const e = &i->sm.export;
+    const long offset = e->offset + (e->len - e->len_i);
+    const enum nw_state n = cfg->seek(offset, cfg->user);
+
+    if (n)
+        return n;
+
+    i->next = skip_kind;
+    return NW_AGAIN;
+}
+
+static enum nw_state tell(struct nw_interp *const i)
+{
+    struct nw_i_sm_exp *const e = &i->sm.export;
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    const enum nw_state n = cfg->tell(&e->offset, cfg->user);
+
+    if (n)
+        return n;
+
+    i->next = skip_field_str;
+    return NW_AGAIN;
+}
+
+static enum nw_state compare(struct nw_interp *const i)
+{
+    unsigned char b;
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    struct nw_i_sm_exp *const e = &i->sm.export;
+    struct nw_sm_io io = {0};
+    enum nw_state n;
+
+    io.buf = &b;
+    io.n = sizeof b;
+
+    if ((n = nwp_io_read(cfg, &io, cfg->user)))
+        return n;
+    else if (b != e->sym[e->len_i++])
+        i->next = tell;
+    else if (e->len_i >= e->len)
+        i->next = get_kind;
+
+    return NW_AGAIN;
+}
+
+static enum nw_state get_len(struct nw_interp *const i)
+{
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    struct nw_i_sm_exp *const e = &i->sm.export;
+    struct nw_sm_leb128 *const l = &e->leb128;
+    const enum nw_state n = nwp_varuint32(cfg, l, &e->len, cfg->user);
+
+    if (n)
+        return n;
+    else if (e->len != strlen(e->sym))
+        i->next = skip_field_str;
+    else
+        i->next = compare;
+
+    return NW_AGAIN;
+}
+
+static enum nw_state entry_loop(struct nw_interp *const i)
+{
+    struct nw_i_sm_exp *const e = &i->sm.export;
+
+    if (e->entry_i >= e->count)
+    {
+        static const char *const exc = "failed to find symbol";
+
+        i->exception = exc;
+#ifdef NW_LOG
+        nwp_log("%s: %s\n", exc, e->sym);
+#endif
+        return NW_FATAL;
+    }
+
+    e->len_i = 0;
+    i->next = get_len;
+    return NW_AGAIN;
+}
+
+static enum nw_state get_count(struct nw_interp *const i)
+{
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    struct nw_i_sm_exp *const e = &i->sm.export;
+    struct nw_sm_leb128 *const l = &e->leb128;
+    const enum nw_state n = nwp_varuint32(cfg, l, &e->count, cfg->user);
+
+    if (n)
+        return n;
+
+    i->next = entry_loop;
+    return NW_AGAIN;
+}
+
+static enum nw_state seek(struct nw_interp *const i)
+{
+    const struct nw_mod *const m = i->cfg.m;
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    const long offset = m->sections[NW_SECTION_EXPORT];
+    enum nw_state n;
+
+    if (!offset)
+    {
+        static const char *const exc = "section not found";
+
+        i->exception = exc;
+#ifdef NW_LOG
+        nwp_log("%s: %s\n", exc, "export");
+#endif
+        return NW_FATAL;
+    }
+    else if ((n = cfg->seek(offset, cfg->user)))
+        return n;
+
+    i->next = get_count;
+    return NW_AGAIN;
+}
+
+void nwp_find_export(struct nw_interp *const i, const char *const sym,
+    enum nw_state (*const next)(struct nw_interp *))
+{
+    const struct nw_i_sm_exp e = {0};
+    struct nw_i_sm_exp *const pe = &i->sm.export;
+
+    *pe = e;
+    pe->sym = sym;
+    pe->next = next;
+    i->next = seek;
+}