119 lines
4.4 KiB
C
119 lines
4.4 KiB
C
/*
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* Copyright 2009-2010 10gen, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "encoding_helpers.h"
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/*
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* Portions Copyright 2001 Unicode, Inc.
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*
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* Disclaimer
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*
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* This source code is provided as is by Unicode, Inc. No claims are
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* made as to fitness for any particular purpose. No warranties of any
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* kind are expressed or implied. The recipient agrees to determine
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* applicability of information provided. If this file has been
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* purchased on magnetic or optical media from Unicode, Inc., the
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* sole remedy for any claim will be exchange of defective media
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* within 90 days of receipt.
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*
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* Limitations on Rights to Redistribute This Code
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*
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* Unicode, Inc. hereby grants the right to freely use the information
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* supplied in this file in the creation of products supporting the
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* Unicode Standard, and to make copies of this file in any form
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* for internal or external distribution as long as this notice
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* remains attached.
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*/
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/*
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* Index into the table below with the first byte of a UTF-8 sequence to
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* get the number of trailing bytes that are supposed to follow it.
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*/
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static const char trailingBytesForUTF8[256] = {
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, 3,3,3,3,3,3,3,3,4,4,4,4,5,5,5,5
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};
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/* --------------------------------------------------------------------- */
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/*
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* Utility routine to tell whether a sequence of bytes is legal UTF-8.
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* This must be called with the length pre-determined by the first byte.
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* The length can be set by:
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* length = trailingBytesForUTF8[*source]+1;
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* and the sequence is illegal right away if there aren't that many bytes
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* available.
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* If presented with a length > 4, this returns 0. The Unicode
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* definition of UTF-8 goes up to 4-byte sequences.
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*/
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static unsigned char isLegalUTF8(const unsigned char* source, int length) {
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unsigned char a;
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const unsigned char* srcptr = source + length;
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switch (length) {
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default: return 0;
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/* Everything else falls through when "true"... */
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case 4: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return 0;
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case 3: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return 0;
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case 2: if ((a = (*--srcptr)) > 0xBF) return 0;
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switch (*source) {
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/* no fall-through in this inner switch */
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case 0xE0: if (a < 0xA0) return 0; break;
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case 0xF0: if (a < 0x90) return 0; break;
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case 0xF4: if (a > 0x8F) return 0; break;
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default: if (a < 0x80) return 0;
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}
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case 1: if (*source >= 0x80 && *source < 0xC2) return 0;
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if (*source > 0xF4) return 0;
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}
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return 1;
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}
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result_t check_string(const unsigned char* string, const int length,
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const char check_utf8, const char check_null) {
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int position = 0;
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/* By default we go character by character. Will be different for checking
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* UTF-8 */
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int sequence_length = 1;
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if (!check_utf8 && !check_null) {
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return VALID;
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}
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while (position < length) {
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if (check_null && *(string + position) == 0) {
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return HAS_NULL;
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}
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if (check_utf8) {
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sequence_length = trailingBytesForUTF8[*(string + position)] + 1;
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if ((position + sequence_length) > length) {
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return NOT_UTF_8;
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}
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if (!isLegalUTF8(string + position, sequence_length)) {
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return NOT_UTF_8;
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}
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}
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position += sequence_length;
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}
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return VALID;
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}
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