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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 01:47:29 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 01:47:29 +0000
commit0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d (patch)
treea31f07c9bcca9d56ce61e9a1ffd30ef350d513aa /intl/icu/source/common/utf_impl.cpp
parentInitial commit. (diff)
downloadfirefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.tar.xz
firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.zip
Adding upstream version 115.8.0esr.upstream/115.8.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'intl/icu/source/common/utf_impl.cpp')
-rw-r--r--intl/icu/source/common/utf_impl.cpp329
1 files changed, 329 insertions, 0 deletions
diff --git a/intl/icu/source/common/utf_impl.cpp b/intl/icu/source/common/utf_impl.cpp
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+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+******************************************************************************
+*
+* Copyright (C) 1999-2012, International Business Machines
+* Corporation and others. All Rights Reserved.
+*
+******************************************************************************
+* file name: utf_impl.cpp
+* encoding: UTF-8
+* tab size: 8 (not used)
+* indentation:4
+*
+* created on: 1999sep13
+* created by: Markus W. Scherer
+*
+* This file provides implementation functions for macros in the utfXX.h
+* that would otherwise be too long as macros.
+*/
+
+/* set import/export definitions */
+#ifndef U_UTF8_IMPL
+# define U_UTF8_IMPL
+#endif
+
+#include "unicode/utypes.h"
+#include "unicode/utf.h"
+#include "unicode/utf8.h"
+#include "uassert.h"
+
+/*
+ * Table of the number of utf8 trail bytes, indexed by the lead byte.
+ * Used by the deprecated macro UTF8_COUNT_TRAIL_BYTES, defined in utf_old.h
+ *
+ * The current macro, U8_COUNT_TRAIL_BYTES, does _not_ use this table.
+ *
+ * Note that this table cannot be removed, even if UTF8_COUNT_TRAIL_BYTES were
+ * changed to no longer use it. References to the table from expansions of UTF8_COUNT_TRAIL_BYTES
+ * may exist in old client code that must continue to run with newer icu library versions.
+ *
+ * This table could be replaced on many machines by
+ * a few lines of assembler code using an
+ * "index of first 0-bit from msb" instruction and
+ * one or two more integer instructions.
+ *
+ * For example, on an i386, do something like
+ * - MOV AL, leadByte
+ * - NOT AL (8-bit, leave b15..b8==0..0, reverse only b7..b0)
+ * - MOV AH, 0
+ * - BSR BX, AX (16-bit)
+ * - MOV AX, 6 (result)
+ * - JZ finish (ZF==1 if leadByte==0xff)
+ * - SUB AX, BX (result)
+ * -finish:
+ * (BSR: Bit Scan Reverse, scans for a 1-bit, starting from the MSB)
+ */
+U_CAPI const uint8_t
+utf8_countTrailBytes[256]={
+ 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,
+ 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,
+
+ 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,
+ 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,
+
+ 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,
+ 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,
+
+ // illegal C0 & C1
+ // 2-byte lead bytes C2..DF
+ 0, 0, 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,
+
+ // 3-byte lead bytes E0..EF
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ // 4-byte lead bytes F0..F4
+ // illegal F5..FF
+ 3, 3, 3, 3, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+};
+
+static const UChar32
+utf8_errorValue[6]={
+ // Same values as UTF8_ERROR_VALUE_1, UTF8_ERROR_VALUE_2, UTF_ERROR_VALUE,
+ // but without relying on the obsolete unicode/utf_old.h.
+ 0x15, 0x9f, 0xffff,
+ 0x10ffff
+};
+
+static UChar32
+errorValue(int32_t count, int8_t strict) {
+ if(strict>=0) {
+ return utf8_errorValue[count];
+ } else if(strict==-3) {
+ return 0xfffd;
+ } else {
+ return U_SENTINEL;
+ }
+}
+
+/*
+ * Handle the non-inline part of the U8_NEXT() and U8_NEXT_FFFD() macros
+ * and their obsolete sibling UTF8_NEXT_CHAR_SAFE().
+ *
+ * U8_NEXT() supports NUL-terminated strings indicated via length<0.
+ *
+ * The "strict" parameter controls the error behavior:
+ * <0 "Safe" behavior of U8_NEXT():
+ * -1: All illegal byte sequences yield U_SENTINEL=-1.
+ * -2: Same as -1, except for lenient treatment of surrogate code points as legal.
+ * Some implementations use this for roundtripping of
+ * Unicode 16-bit strings that are not well-formed UTF-16, that is, they
+ * contain unpaired surrogates.
+ * -3: All illegal byte sequences yield U+FFFD.
+ * 0 Obsolete "safe" behavior of UTF8_NEXT_CHAR_SAFE(..., false):
+ * All illegal byte sequences yield a positive code point such that this
+ * result code point would be encoded with the same number of bytes as
+ * the illegal sequence.
+ * >0 Obsolete "strict" behavior of UTF8_NEXT_CHAR_SAFE(..., true):
+ * Same as the obsolete "safe" behavior, but non-characters are also treated
+ * like illegal sequences.
+ *
+ * Note that a UBool is the same as an int8_t.
+ */
+U_CAPI UChar32 U_EXPORT2
+utf8_nextCharSafeBody(const uint8_t *s, int32_t *pi, int32_t length, UChar32 c, UBool strict) {
+ // *pi is one after byte c.
+ int32_t i=*pi;
+ // length can be negative for NUL-terminated strings: Read and validate one byte at a time.
+ if(i==length || c>0xf4) {
+ // end of string, or not a lead byte
+ } else if(c>=0xf0) {
+ // Test for 4-byte sequences first because
+ // U8_NEXT() handles shorter valid sequences inline.
+ uint8_t t1=s[i], t2, t3;
+ c&=7;
+ if(U8_IS_VALID_LEAD4_AND_T1(c, t1) &&
+ ++i!=length && (t2=s[i]-0x80)<=0x3f &&
+ ++i!=length && (t3=s[i]-0x80)<=0x3f) {
+ ++i;
+ c=(c<<18)|((t1&0x3f)<<12)|(t2<<6)|t3;
+ // strict: forbid non-characters like U+fffe
+ if(strict<=0 || !U_IS_UNICODE_NONCHAR(c)) {
+ *pi=i;
+ return c;
+ }
+ }
+ } else if(c>=0xe0) {
+ c&=0xf;
+ if(strict!=-2) {
+ uint8_t t1=s[i], t2;
+ if(U8_IS_VALID_LEAD3_AND_T1(c, t1) &&
+ ++i!=length && (t2=s[i]-0x80)<=0x3f) {
+ ++i;
+ c=(c<<12)|((t1&0x3f)<<6)|t2;
+ // strict: forbid non-characters like U+fffe
+ if(strict<=0 || !U_IS_UNICODE_NONCHAR(c)) {
+ *pi=i;
+ return c;
+ }
+ }
+ } else {
+ // strict=-2 -> lenient: allow surrogates
+ uint8_t t1=s[i]-0x80, t2;
+ if(t1<=0x3f && (c>0 || t1>=0x20) &&
+ ++i!=length && (t2=s[i]-0x80)<=0x3f) {
+ *pi=i+1;
+ return (c<<12)|(t1<<6)|t2;
+ }
+ }
+ } else if(c>=0xc2) {
+ uint8_t t1=s[i]-0x80;
+ if(t1<=0x3f) {
+ *pi=i+1;
+ return ((c-0xc0)<<6)|t1;
+ }
+ } // else 0x80<=c<0xc2 is not a lead byte
+
+ /* error handling */
+ c=errorValue(i-*pi, strict);
+ *pi=i;
+ return c;
+}
+
+U_CAPI int32_t U_EXPORT2
+utf8_appendCharSafeBody(uint8_t *s, int32_t i, int32_t length, UChar32 c, UBool *pIsError) {
+ if((uint32_t)(c)<=0x7ff) {
+ if((i)+1<(length)) {
+ (s)[(i)++]=(uint8_t)(((c)>>6)|0xc0);
+ (s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80);
+ return i;
+ }
+ } else if((uint32_t)(c)<=0xffff) {
+ /* Starting with Unicode 3.2, surrogate code points must not be encoded in UTF-8. */
+ if((i)+2<(length) && !U_IS_SURROGATE(c)) {
+ (s)[(i)++]=(uint8_t)(((c)>>12)|0xe0);
+ (s)[(i)++]=(uint8_t)((((c)>>6)&0x3f)|0x80);
+ (s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80);
+ return i;
+ }
+ } else if((uint32_t)(c)<=0x10ffff) {
+ if((i)+3<(length)) {
+ (s)[(i)++]=(uint8_t)(((c)>>18)|0xf0);
+ (s)[(i)++]=(uint8_t)((((c)>>12)&0x3f)|0x80);
+ (s)[(i)++]=(uint8_t)((((c)>>6)&0x3f)|0x80);
+ (s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80);
+ return i;
+ }
+ }
+ /* c>0x10ffff or not enough space, write an error value */
+ if(pIsError!=nullptr) {
+ *pIsError=true;
+ } else {
+ length-=i;
+ if(length>0) {
+ int32_t offset;
+ if(length>3) {
+ length=3;
+ }
+ s+=i;
+ offset=0;
+ c=utf8_errorValue[length-1];
+ U8_APPEND_UNSAFE(s, offset, c);
+ i=i+offset;
+ }
+ }
+ return i;
+}
+
+U_CAPI UChar32 U_EXPORT2
+utf8_prevCharSafeBody(const uint8_t *s, int32_t start, int32_t *pi, UChar32 c, UBool strict) {
+ // *pi is the index of byte c.
+ int32_t i=*pi;
+ if(U8_IS_TRAIL(c) && i>start) {
+ uint8_t b1=s[--i];
+ if(U8_IS_LEAD(b1)) {
+ if(b1<0xe0) {
+ *pi=i;
+ return ((b1-0xc0)<<6)|(c&0x3f);
+ } else if(b1<0xf0 ? U8_IS_VALID_LEAD3_AND_T1(b1, c) : U8_IS_VALID_LEAD4_AND_T1(b1, c)) {
+ // Truncated 3- or 4-byte sequence.
+ *pi=i;
+ return errorValue(1, strict);
+ }
+ } else if(U8_IS_TRAIL(b1) && i>start) {
+ // Extract the value bits from the last trail byte.
+ c&=0x3f;
+ uint8_t b2=s[--i];
+ if(0xe0<=b2 && b2<=0xf4) {
+ if(b2<0xf0) {
+ b2&=0xf;
+ if(strict!=-2) {
+ if(U8_IS_VALID_LEAD3_AND_T1(b2, b1)) {
+ *pi=i;
+ c=(b2<<12)|((b1&0x3f)<<6)|c;
+ if(strict<=0 || !U_IS_UNICODE_NONCHAR(c)) {
+ return c;
+ } else {
+ // strict: forbid non-characters like U+fffe
+ return errorValue(2, strict);
+ }
+ }
+ } else {
+ // strict=-2 -> lenient: allow surrogates
+ b1-=0x80;
+ if((b2>0 || b1>=0x20)) {
+ *pi=i;
+ return (b2<<12)|(b1<<6)|c;
+ }
+ }
+ } else if(U8_IS_VALID_LEAD4_AND_T1(b2, b1)) {
+ // Truncated 4-byte sequence.
+ *pi=i;
+ return errorValue(2, strict);
+ }
+ } else if(U8_IS_TRAIL(b2) && i>start) {
+ uint8_t b3=s[--i];
+ if(0xf0<=b3 && b3<=0xf4) {
+ b3&=7;
+ if(U8_IS_VALID_LEAD4_AND_T1(b3, b2)) {
+ *pi=i;
+ c=(b3<<18)|((b2&0x3f)<<12)|((b1&0x3f)<<6)|c;
+ if(strict<=0 || !U_IS_UNICODE_NONCHAR(c)) {
+ return c;
+ } else {
+ // strict: forbid non-characters like U+fffe
+ return errorValue(3, strict);
+ }
+ }
+ }
+ }
+ }
+ }
+ return errorValue(0, strict);
+}
+
+U_CAPI int32_t U_EXPORT2
+utf8_back1SafeBody(const uint8_t *s, int32_t start, int32_t i) {
+ // Same as utf8_prevCharSafeBody(..., strict=-1) minus assembling code points.
+ int32_t orig_i=i;
+ uint8_t c=s[i];
+ if(U8_IS_TRAIL(c) && i>start) {
+ uint8_t b1=s[--i];
+ if(U8_IS_LEAD(b1)) {
+ if(b1<0xe0 ||
+ (b1<0xf0 ? U8_IS_VALID_LEAD3_AND_T1(b1, c) : U8_IS_VALID_LEAD4_AND_T1(b1, c))) {
+ return i;
+ }
+ } else if(U8_IS_TRAIL(b1) && i>start) {
+ uint8_t b2=s[--i];
+ if(0xe0<=b2 && b2<=0xf4) {
+ if(b2<0xf0 ? U8_IS_VALID_LEAD3_AND_T1(b2, b1) : U8_IS_VALID_LEAD4_AND_T1(b2, b1)) {
+ return i;
+ }
+ } else if(U8_IS_TRAIL(b2) && i>start) {
+ uint8_t b3=s[--i];
+ if(0xf0<=b3 && b3<=0xf4 && U8_IS_VALID_LEAD4_AND_T1(b3, b2)) {
+ return i;
+ }
+ }
+ }
+ }
+ return orig_i;
+}