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- /*
- * gluon-web Template - Utility functions
- *
- * Copyright (C) 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_utils.h"
- #include "template_lmo.h"
- #include <stdlib.h>
- #include <stdio.h>
- #include <string.h>
- /* initialize a buffer object */
- struct template_buffer * buf_init(size_t size)
- {
- struct template_buffer *buf = malloc(sizeof(*buf));
- if (buf != NULL) {
- buf->size = size;
- buf->data = malloc(buf->size);
- buf->dptr = buf->data;
- if (buf->data != NULL || size == 0)
- return buf;
- free(buf);
- }
- return NULL;
- }
- /* grow buffer */
- static bool buf_grow(struct template_buffer *buf, size_t len)
- {
- size_t off = buf->dptr - buf->data, left = buf->size - off;
- if (len <= left)
- return true;
- size_t diff = len - left;
- if (diff < 1024)
- diff = 1024;
- char *data = realloc(buf->data, buf->size + diff);
- if (data == NULL)
- return false;
- buf->data = data;
- buf->dptr = data + off;
- buf->size += diff;
- return true;
- }
- /* put one char into buffer object */
- bool buf_putchar(struct template_buffer *buf, char c)
- {
- if (!buf_grow(buf, 1))
- return false;
- *(buf->dptr++) = c;
- return true;
- }
- /* append data to buffer */
- bool buf_append(struct template_buffer *buf, const char *s, size_t len)
- {
- if (!buf_grow(buf, len))
- return false;
- memcpy(buf->dptr, s, len);
- buf->dptr += len;
- return true;
- }
- /* destroy buffer object and return pointer to data */
- char * buf_destroy(struct template_buffer *buf)
- {
- char *data = buf->data;
- free(buf);
- return data;
- }
- /* calculate the number of expected continuation chars */
- static inline size_t mb_num_chars(unsigned char c)
- {
- if ((c & 0xE0) == 0xC0)
- return 2;
- else if ((c & 0xF0) == 0xE0)
- return 3;
- else if ((c & 0xF8) == 0xF0)
- return 4;
- else if ((c & 0xFC) == 0xF8)
- return 5;
- else if ((c & 0xFE) == 0xFC)
- return 6;
- return 1;
- }
- /* test whether the given byte is a valid continuation char */
- static inline bool mb_is_cont(unsigned char c)
- {
- return ((c >= 0x80) && (c <= 0xBF));
- }
- /* test whether the byte sequence at the given pointer with the given
- * length is the shortest possible representation of the code point */
- static inline bool mb_is_shortest(const unsigned char *s, size_t n)
- {
- switch (n)
- {
- case 2:
- /* 1100000x (10xxxxxx) */
- return !(((*s >> 1) == 0x60) &&
- ((*(s+1) >> 6) == 0x02));
- case 3:
- /* 11100000 100xxxxx (10xxxxxx) */
- return !((*s == 0xE0) &&
- ((*(s+1) >> 5) == 0x04) &&
- ((*(s+2) >> 6) == 0x02));
- case 4:
- /* 11110000 1000xxxx (10xxxxxx 10xxxxxx) */
- return !((*s == 0xF0) &&
- ((*(s+1) >> 4) == 0x08) &&
- ((*(s+2) >> 6) == 0x02) &&
- ((*(s+3) >> 6) == 0x02));
- case 5:
- /* 11111000 10000xxx (10xxxxxx 10xxxxxx 10xxxxxx) */
- return !((*s == 0xF8) &&
- ((*(s+1) >> 3) == 0x10) &&
- ((*(s+2) >> 6) == 0x02) &&
- ((*(s+3) >> 6) == 0x02) &&
- ((*(s+4) >> 6) == 0x02));
- case 6:
- /* 11111100 100000xx (10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx) */
- return !((*s == 0xF8) &&
- ((*(s+1) >> 2) == 0x20) &&
- ((*(s+2) >> 6) == 0x02) &&
- ((*(s+3) >> 6) == 0x02) &&
- ((*(s+4) >> 6) == 0x02) &&
- ((*(s+5) >> 6) == 0x02));
- }
- return true;
- }
- /* test whether the byte sequence at the given pointer with the given
- * length is an UTF-16 surrogate */
- static inline bool mb_is_surrogate(const unsigned char *s, size_t n)
- {
- return ((n == 3) && (*s == 0xED) && (*(s+1) >= 0xA0) && (*(s+1) <= 0xBF));
- }
- /* test whether the byte sequence at the given pointer with the given
- * length is an illegal UTF-8 code point */
- static inline bool mb_is_illegal(const unsigned char *s, size_t n)
- {
- return ((n == 3) && (*s == 0xEF) && (*(s+1) == 0xBF) &&
- (*(s+2) >= 0xBE) && (*(s+2) <= 0xBF));
- }
- /* scan given source string, validate UTF-8 sequence and store result
- * in given buffer object */
- static size_t validate_utf8(const unsigned char **s, size_t l, struct template_buffer *buf)
- {
- const unsigned char *ptr = *s;
- size_t o = 0, v, n;
- /* ascii byte without null */
- if ((*(ptr+0) >= 0x01) && (*(ptr+0) <= 0x7F)) {
- if (!buf_putchar(buf, *ptr++))
- return 0;
- o = 1;
- }
- /* multi byte sequence */
- else if ((n = mb_num_chars(*ptr)) > 1) {
- /* count valid chars */
- for (v = 1; (v <= n) && ((o+v) < l) && mb_is_cont(*(ptr+v)); v++);
- switch (n)
- {
- case 6:
- case 5:
- /* five and six byte sequences are always invalid */
- if (!buf_putchar(buf, '?'))
- return 0;
- break;
- default:
- /* if the number of valid continuation bytes matches the
- * expected number and if the sequence is legal, copy
- * the bytes to the destination buffer */
- if ((v == n) && mb_is_shortest(ptr, n) &&
- !mb_is_surrogate(ptr, n) && !mb_is_illegal(ptr, n))
- {
- /* copy sequence */
- if (!buf_append(buf, (const char *)ptr, n))
- return 0;
- }
- /* the found sequence is illegal, skip it */
- else
- {
- /* invalid sequence */
- if (!buf_putchar(buf, '?'))
- return 0;
- }
- break;
- }
- /* advance beyound the last found valid continuation char */
- o = v;
- ptr += v;
- }
- /* invalid byte (0x00) */
- else {
- if (!buf_putchar(buf, '?')) /* or 0xEF, 0xBF, 0xBD */
- return 0;
- o = 1;
- ptr++;
- }
- *s = ptr;
- return o;
- }
- /* Sanitize given string and strip all invalid XML bytes
- * Validate UTF-8 sequences
- * Escape XML control chars */
- bool pcdata(const char *s, size_t l, char **out, size_t *outl)
- {
- struct template_buffer *buf = buf_init(l);
- const unsigned char *ptr = (const unsigned char *)s;
- size_t o, v;
- char esq[8];
- int esl;
- if (!buf)
- return false;
- for (o = 0; o < l; o++) {
- /* Invalid XML bytes */
- if ((*ptr <= 0x08) ||
- ((*ptr >= 0x0B) && (*ptr <= 0x0C)) ||
- ((*ptr >= 0x0E) && (*ptr <= 0x1F)) ||
- (*ptr == 0x7F)) {
- ptr++;
- }
- /* Escapes */
- else if ((*ptr == '\'') ||
- (*ptr == '"') ||
- (*ptr == '&') ||
- (*ptr == '<') ||
- (*ptr == '>')) {
- esl = snprintf(esq, sizeof(esq), "&#%i;", *ptr);
- if (!buf_append(buf, esq, esl))
- break;
- ptr++;
- }
- /* ascii char */
- else if (*ptr <= 0x7F) {
- buf_putchar(buf, (char)*ptr++);
- }
- /* multi byte sequence */
- else {
- if (!(v = validate_utf8(&ptr, l - o, buf)))
- break;
- o += (v - 1);
- }
- }
- *outl = buf_length(buf);
- *out = buf_destroy(buf);
- return true;
- }
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