First commit

1 files changed, 145 insertions, 0 deletions

diff --git a/src/routines/section/custom.c b/src/routines/section/custom.c
new file mode 100644
index 0000000..926f46b
--- /dev/null
+++ b/src/routines/section/custom.c
@@ -0,0 +1,145 @@
+/*
+ * 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 <nw/io.h>
+#include <nw/log.h>
+#include <nw/routines.h>
+#include <string.h>
+
+static enum nw_state get_byte(struct nw_mod *);
+
+static enum nw_state skip(struct nw_mod *const m)
+{
+    const struct nw_sm_custom *const c = &m->sm.custom;
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    const enum nw_state n = cfg->seek(c->start, cfg->user);
+
+    if (n)
+        return n;
+
+    nwp_section_skip(m);
+    return NW_AGAIN;
+}
+
+static enum nw_state compare(struct nw_mod *const m)
+{
+    struct nw_sm_custom *const c = &m->sm.custom;
+    const struct entry *out = NULL;
+    size_t i;
+    static const struct entry
+    {
+        const char *section;
+        void (*f)(struct nw_mod *);
+    } s[] =
+    {
+        {"nw_to", nwp_section_to},
+        {"nw_fti", nwp_section_fti},
+        {"nw_fbo", nwp_section_fbo},
+        {"nw_lo", nwp_section_lo},
+        {"nw_iti", nwp_section_iti}
+    };
+
+    for (i = 0; i < sizeof s / sizeof *s; i++)
+    {
+        int *const candidate = &c->candidate[i];
+        const struct entry *const e = &s[i];
+
+        if (!*candidate)
+            continue;
+        else if (strlen(e->section) != c->name_len
+            || e->section[c->len_i] != c->byte)
+        {
+            *candidate = 0;
+            continue;
+        }
+
+        out = e;
+        break;
+    }
+
+    if (++c->len_i >= c->name_len)
+    {
+        if (out)
+        {
+            if (m->c_sections[out - s])
+            {
+#ifdef NW_LOG
+                nwp_log("duplicate section: %s\n", out->section);
+#endif
+                return NW_FATAL;
+            }
+
+            out->f(m);
+        }
+        else
+            m->next = skip;
+    }
+    else
+        m->next = get_byte;
+
+    return NW_AGAIN;
+}
+
+static enum nw_state get_byte(struct nw_mod *const m)
+{
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    struct nw_sm_custom *const c = &m->sm.custom;
+    struct nw_sm_io io = {0};
+    enum nw_state n;
+
+    io.buf = &c->byte;
+    io.n = sizeof c->byte;
+
+    if ((n = nwp_io_read(cfg, &io, cfg->user)))
+        return n;
+
+    m->next = compare;
+    return NW_AGAIN;
+}
+
+static enum nw_state get_name_len(struct nw_mod *const m)
+{
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    struct nw_sm_custom *const c = &m->sm.custom;
+    struct nw_sm_leb128 *const l = &c->leb128;
+    const enum nw_state n = nwp_varuint32(cfg, l, &c->name_len, cfg->user);
+
+    if (n)
+        return n;
+
+    m->next = get_byte;
+    return NW_AGAIN;
+}
+
+static enum nw_state get_start(struct nw_mod *const m)
+{
+    struct nw_sm_custom *const c = &m->sm.custom;
+    const struct nw_io_cfg *const cfg = &m->cfg.io;
+    const enum nw_state n = cfg->tell(&c->start, cfg->user);
+
+    if (n)
+        return n;
+
+    m->next = get_name_len;
+    return NW_AGAIN;
+}
+
+void nwp_section_custom(struct nw_mod *const m)
+{
+    const struct nw_sm_custom c = {0};
+    struct nw_sm_custom *const pc = &m->sm.custom;
+    size_t i;
+
+    m->next = get_start;
+    *pc = c;
+
+    for (i = 0; i < sizeof pc->candidate / sizeof *pc->candidate; i++)
+        pc->candidate[i] = 1;
+}