package/gluon-web/src/template_lmo.c

+/*
+ * lmo - Lua Machine Objects - Base functions
+ *
+ *   Copyright (C) 2009-2010 Jo-Philipp Wich <jow@openwrt.org>
+ *   Copyright (C) 2018 Matthias Schiffer <mschiffer@universe-factory.net>
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+#include "template_lmo.h"
+
+#include <sys/stat.h>
+#include <sys/mman.h>
+
+#include <arpa/inet.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+
+static inline uint16_t get_le16(const void *data) {
+	const uint8_t *d = data;
+	return (((uint16_t)d[1]) << 8) | d[0];
+}
+
+static inline uint32_t get_be32(const void *data) {
+	const uint8_t *d = data;
+	return (((uint32_t)d[0]) << 24)
+		| (((uint32_t)d[1]) << 16)
+		| (((uint32_t)d[2]) << 8)
+		| d[3];
+}
+
+/*
+ * Hash function from http://www.azillionmonkeys.com/qed/hash.html
+ * Copyright (C) 2004-2008 by Paul Hsieh
+ */
+uint32_t sfh_hash(const void *input, size_t len)
+{
+	const uint8_t *data = input;
+	uint32_t hash = len, tmp;
+
+	/* Main loop */
+	for (; len > 3; len -= 4) {
+		hash  += get_le16(data);
+		tmp    = (get_le16(data+2) << 11) ^ hash;
+		hash   = (hash << 16) ^ tmp;
+		data  += 4;
+		hash  += hash >> 11;
+	}
+
+	/* Handle end cases */
+	switch (len) {
+	case 3: hash += get_le16(data);
+		hash ^= hash << 16;
+		hash ^= data[2] << 18;
+		hash += hash >> 11;
+		break;
+	case 2: hash += get_le16(data);
+		hash ^= hash << 11;
+		hash += hash >> 17;
+		break;
+	case 1: hash += *data;
+		hash ^= hash << 10;
+		hash += hash >> 1;
+	}
+
+	/* Force "avalanching" of final 127 bits */
+	hash ^= hash << 3;
+	hash += hash >> 5;
+	hash ^= hash << 4;
+	hash += hash >> 17;
+	hash ^= hash << 25;
+	hash += hash >> 6;
+
+	return hash;
+}
+
+bool lmo_load(lmo_catalog_t *cat, const char *file)
+{
+	int fd = -1;
+	struct stat s;
+
+	cat->data = MAP_FAILED;
+
+	fd = open(file, O_RDONLY|O_CLOEXEC);
+	if (fd < 0)
+		goto err;
+
+	if (fstat(fd, &s))
+		goto err;
+
+	cat->data = mmap(NULL, s.st_size, PROT_READ, MAP_SHARED, fd, 0);
+
+	close(fd);
+	fd = -1;
+
+	if (cat->data == MAP_FAILED)
+		goto err;
+
+	cat->end = cat->data + s.st_size;
+
+	uint32_t idx_offset = get_be32(cat->end - sizeof(uint32_t));
+	cat->index = (const lmo_entry_t *)(cat->data + idx_offset);
+
+	if ((const char *)cat->index > (cat->end - sizeof(uint32_t)))
+		goto err;
+
+	cat->length = (cat->end - sizeof(uint32_t) - (const char *)cat->index) / sizeof(lmo_entry_t);
+
+	return true;
+
+err:
+	if (fd >= 0)
+		close(fd);
+
+	if (cat->data != MAP_FAILED)
+		munmap(cat->data, cat->end - cat->data);
+
+	return false;
+}
+
+void lmo_unload(lmo_catalog_t *cat)
+{
+	if (cat->data != MAP_FAILED)
+		munmap(cat->data, cat->end - cat->data);
+}
+
+
+static int lmo_compare_entry(const void *a, const void *b)
+{
+	const lmo_entry_t *ea = a, *eb = b;
+	uint32_t ka = ntohl(ea->key_id), kb = ntohl(eb->key_id);
+
+	if (ka < kb)
+		return -1;
+	else if (ka > kb)
+		return 1;
+	else
+		return 0;
+}
+
+static const lmo_entry_t * lmo_find_entry(const lmo_catalog_t *cat, uint32_t hash)
+{
+	lmo_entry_t key;
+	key.key_id = htonl(hash);
+
+	return bsearch(&key, cat->index, cat->length, sizeof(lmo_entry_t), lmo_compare_entry);
+}
+
+bool lmo_translate(const lmo_catalog_t *cat, const char *key, size_t keylen, const char **out, size_t *outlen)
+{
+	uint32_t hash = sfh_hash(key, keylen);
+	const lmo_entry_t *e = lmo_find_entry(cat, hash);
+	if (!e)
+		return false;
+
+	*out = cat->data + ntohl(e->offset);
+	*outlen = ntohl(e->length);
+
+	if (*out + *outlen > cat->end)
+		return false;
+
+	return true;
+}

package/gluon-web/src/template_lmo.h

+/*
+ * lmo - Lua Machine Objects - General header
+ *
+ *   Copyright (C) 2009-2012 Jo-Philipp Wich <jow@openwrt.org>
+ *   Copyright (C) 2018 Matthias Schiffer <mschiffer@universe-factory.net>
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+#ifndef _TEMPLATE_LMO_H_
+#define _TEMPLATE_LMO_H_
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+
+struct lmo_entry {
+	uint32_t key_id;
+	uint32_t val_id;
+	uint32_t offset;
+	uint32_t length;
+} __attribute__((packed));
+typedef struct lmo_entry lmo_entry_t;
+
+
+struct lmo_catalog {
+	size_t length;
+	const lmo_entry_t *index;
+	char *data;
+	const char *end;
+};
+
+typedef struct lmo_catalog lmo_catalog_t;
+
+
+uint32_t sfh_hash(const void *input, size_t len);
+
+bool lmo_load(lmo_catalog_t *cat, const char *file);
+void lmo_unload(lmo_catalog_t *cat);
+bool lmo_translate(const lmo_catalog_t *cat, const char *key, size_t keylen, const char **out, size_t *outlen);
+
+#endif