Dactyloidae/js/src/vm/CharacterEncoding.cpp

531 lines
17 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* 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 http://mozilla.org/MPL/2.0/. */
#include "js/CharacterEncoding.h"
#include "mozilla/Range.h"
#include "mozilla/Sprintf.h"
#include <algorithm>
#include <type_traits>
#include "jscntxt.h"
#include "jsprf.h"
using namespace js;
Latin1CharsZ
JS::LossyTwoByteCharsToNewLatin1CharsZ(js::ExclusiveContext* cx,
const mozilla::Range<const char16_t> tbchars)
{
MOZ_ASSERT(cx);
size_t len = tbchars.length();
unsigned char* latin1 = cx->pod_malloc<unsigned char>(len + 1);
if (!latin1)
return Latin1CharsZ();
for (size_t i = 0; i < len; ++i)
latin1[i] = static_cast<unsigned char>(tbchars[i]);
latin1[len] = '\0';
return Latin1CharsZ(latin1, len);
}
template <typename CharT>
static size_t
GetDeflatedUTF8StringLength(const CharT* chars, size_t nchars)
{
size_t nbytes = nchars;
for (const CharT* end = chars + nchars; chars < end; chars++) {
char16_t c = *chars;
if (c < 0x80)
continue;
uint32_t v;
if (0xD800 <= c && c <= 0xDFFF) {
/* nbytes sets 1 length since this is surrogate pair. */
if (c >= 0xDC00 || (chars + 1) == end) {
nbytes += 2; /* Bad Surrogate */
continue;
}
char16_t c2 = chars[1];
if (c2 < 0xDC00 || c2 > 0xDFFF) {
nbytes += 2; /* Bad Surrogate */
continue;
}
v = ((c - 0xD800) << 10) + (c2 - 0xDC00) + 0x10000;
nbytes--;
chars++;
} else {
v = c;
}
v >>= 11;
nbytes++;
while (v) {
v >>= 5;
nbytes++;
}
}
return nbytes;
}
JS_PUBLIC_API(size_t)
JS::GetDeflatedUTF8StringLength(JSFlatString* s)
{
JS::AutoCheckCannotGC nogc;
return s->hasLatin1Chars()
? ::GetDeflatedUTF8StringLength(s->latin1Chars(nogc), s->length())
: ::GetDeflatedUTF8StringLength(s->twoByteChars(nogc), s->length());
}
static const char16_t UTF8_REPLACEMENT_CHAR = 0xFFFD;
template <typename CharT>
static void
DeflateStringToUTF8Buffer(const CharT* src, size_t srclen, mozilla::RangedPtr<char> dst,
size_t* dstlenp = nullptr, size_t* numcharsp = nullptr)
{
size_t capacity = 0;
if (dstlenp) {
capacity = *dstlenp;
*dstlenp = 0;
}
if (numcharsp)
*numcharsp = 0;
while (srclen) {
uint32_t v;
char16_t c = *src++;
srclen--;
if (c >= 0xDC00 && c <= 0xDFFF) {
v = UTF8_REPLACEMENT_CHAR;
} else if (c < 0xD800 || c > 0xDBFF) {
v = c;
} else {
if (srclen < 1) {
v = UTF8_REPLACEMENT_CHAR;
} else {
char16_t c2 = *src;
if (c2 < 0xDC00 || c2 > 0xDFFF) {
v = UTF8_REPLACEMENT_CHAR;
} else {
src++;
srclen--;
v = ((c - 0xD800) << 10) + (c2 - 0xDC00) + 0x10000;
}
}
}
size_t utf8Len;
if (v < 0x0080) {
/* no encoding necessary - performance hack */
if (dstlenp && *dstlenp + 1 > capacity)
return;
*dst++ = char(v);
utf8Len = 1;
} else {
uint8_t utf8buf[4];
utf8Len = OneUcs4ToUtf8Char(utf8buf, v);
if (dstlenp && *dstlenp + utf8Len > capacity)
return;
for (size_t i = 0; i < utf8Len; i++)
*dst++ = char(utf8buf[i]);
}
if (dstlenp)
*dstlenp += utf8Len;
if (numcharsp)
(*numcharsp)++;
}
}
JS_PUBLIC_API(void)
JS::DeflateStringToUTF8Buffer(JSFlatString* src, mozilla::RangedPtr<char> dst,
size_t* dstlenp, size_t* numcharsp)
{
JS::AutoCheckCannotGC nogc;
return src->hasLatin1Chars()
? ::DeflateStringToUTF8Buffer(src->latin1Chars(nogc), src->length(), dst,
dstlenp, numcharsp)
: ::DeflateStringToUTF8Buffer(src->twoByteChars(nogc), src->length(), dst,
dstlenp, numcharsp);
}
template <typename CharT>
UTF8CharsZ
JS::CharsToNewUTF8CharsZ(js::ExclusiveContext* maybeCx, const mozilla::Range<CharT> chars)
{
/* Get required buffer size. */
const CharT* str = chars.begin().get();
size_t len = ::GetDeflatedUTF8StringLength(str, chars.length());
/* Allocate buffer. */
char* utf8;
if (maybeCx)
utf8 = maybeCx->pod_malloc<char>(len + 1);
else
utf8 = js_pod_malloc<char>(len + 1);
if (!utf8)
return UTF8CharsZ();
/* Encode to UTF8. */
::DeflateStringToUTF8Buffer(str, chars.length(), mozilla::RangedPtr<char>(utf8, len));
utf8[len] = '\0';
return UTF8CharsZ(utf8, len);
}
template UTF8CharsZ
JS::CharsToNewUTF8CharsZ(js::ExclusiveContext* maybeCx,
const mozilla::Range<Latin1Char> chars);
template UTF8CharsZ
JS::CharsToNewUTF8CharsZ(js::ExclusiveContext* maybeCx,
const mozilla::Range<char16_t> chars);
template UTF8CharsZ
JS::CharsToNewUTF8CharsZ(js::ExclusiveContext* maybeCx,
const mozilla::Range<const Latin1Char> chars);
template UTF8CharsZ
JS::CharsToNewUTF8CharsZ(js::ExclusiveContext* maybeCx,
const mozilla::Range<const char16_t> chars);
static const uint32_t INVALID_UTF8 = UINT32_MAX;
/*
* Convert a utf8 character sequence into a UCS-4 character and return that
* character. It is assumed that the caller already checked that the sequence
* is valid.
*/
uint32_t
JS::Utf8ToOneUcs4Char(const uint8_t* utf8Buffer, int utf8Length)
{
MOZ_ASSERT(1 <= utf8Length && utf8Length <= 4);
if (utf8Length == 1) {
MOZ_ASSERT(!(*utf8Buffer & 0x80));
return *utf8Buffer;
}
/* from Unicode 3.1, non-shortest form is illegal */
static const uint32_t minucs4Table[] = { 0x80, 0x800, 0x10000 };
MOZ_ASSERT((*utf8Buffer & (0x100 - (1 << (7 - utf8Length)))) ==
(0x100 - (1 << (8 - utf8Length))));
uint32_t ucs4Char = *utf8Buffer++ & ((1 << (7 - utf8Length)) - 1);
uint32_t minucs4Char = minucs4Table[utf8Length - 2];
while (--utf8Length) {
MOZ_ASSERT((*utf8Buffer & 0xC0) == 0x80);
ucs4Char = (ucs4Char << 6) | (*utf8Buffer++ & 0x3F);
}
if (MOZ_UNLIKELY(ucs4Char < minucs4Char || (ucs4Char >= 0xD800 && ucs4Char <= 0xDFFF)))
return INVALID_UTF8;
return ucs4Char;
}
static void
ReportInvalidCharacter(JSContext* cx, uint32_t offset)
{
char buffer[10];
SprintfLiteral(buffer, "%u", offset);
JS_ReportErrorFlagsAndNumberASCII(cx, JSREPORT_ERROR, GetErrorMessage, nullptr,
JSMSG_MALFORMED_UTF8_CHAR, buffer);
}
static void
ReportInvalidCharacter(js::ExclusiveContext* cx, uint32_t offset)
{
}
static void
ReportBufferTooSmall(JSContext* cx, uint32_t dummy)
{
JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, JSMSG_BUFFER_TOO_SMALL);
}
static void
ReportBufferTooSmall(js::ExclusiveContext* cx, uint32_t dummy)
{
}
static void
ReportTooBigCharacter(JSContext* cx, uint32_t v)
{
char buffer[10];
SprintfLiteral(buffer, "0x%x", v + 0x10000);
JS_ReportErrorFlagsAndNumberASCII(cx, JSREPORT_ERROR, GetErrorMessage, nullptr,
JSMSG_UTF8_CHAR_TOO_LARGE, buffer);
}
static void
ReportTooBigCharacter(js::ExclusiveContext* cx, uint32_t v)
{
}
enum InflateUTF8Action {
CountAndReportInvalids,
CountAndIgnoreInvalids,
AssertNoInvalids,
Copy,
FindEncoding
};
static const char16_t REPLACE_UTF8 = 0xFFFD;
static const Latin1Char REPLACE_UTF8_LATIN1 = '?';
// If making changes to this algorithm, make sure to also update
// LossyConvertUTF8toUTF16() in dom/wifi/WifiUtils.cpp
template <InflateUTF8Action Action, typename CharT, class ContextT>
static bool
InflateUTF8StringToBuffer(ContextT* cx, const UTF8Chars src, CharT* dst, size_t* dstlenp,
JS::SmallestEncoding *smallestEncoding)
{
if (Action != AssertNoInvalids)
*smallestEncoding = JS::SmallestEncoding::ASCII;
auto RequireLatin1 = [&smallestEncoding]{
*smallestEncoding = std::max(JS::SmallestEncoding::Latin1, *smallestEncoding);
};
auto RequireUTF16 = [&smallestEncoding]{
*smallestEncoding = JS::SmallestEncoding::UTF16;
};
// Count how many code units need to be in the inflated string.
// |i| is the index into |src|, and |j| is the the index into |dst|.
size_t srclen = src.length();
uint32_t j = 0;
for (uint32_t i = 0; i < srclen; i++, j++) {
uint32_t v = uint32_t(src[i]);
if (!(v & 0x80)) {
// ASCII code unit. Simple copy.
if (Action == Copy)
dst[j] = CharT(v);
} else {
// Non-ASCII code unit. Determine its length in bytes (n).
uint32_t n = 1;
while (v & (0x80 >> n))
n++;
#define INVALID(report, arg, n2) \
do { \
if (Action == CountAndReportInvalids) { \
report(cx, arg); \
return false; \
} else if (Action == AssertNoInvalids) { \
MOZ_CRASH("invalid UTF-8 string: " # report); \
} else { \
if (Action == Copy) { \
if (std::is_same<decltype(dst[0]), Latin1Char>::value) \
dst[j] = CharT(REPLACE_UTF8_LATIN1); \
else \
dst[j] = CharT(REPLACE_UTF8); \
} else { \
MOZ_ASSERT(Action == CountAndIgnoreInvalids || \
Action == FindEncoding); \
} \
n = n2; \
goto invalidMultiByteCodeUnit; \
} \
} while (0)
// Check the leading byte.
if (n < 2 || n > 4)
INVALID(ReportInvalidCharacter, i, 1);
// Check that |src| is large enough to hold an n-byte code unit.
if (i + n > srclen)
INVALID(ReportBufferTooSmall, /* dummy = */ 0, 1);
// Check the second byte. From Unicode Standard v6.2, Table 3-7
// Well-Formed UTF-8 Byte Sequences.
if ((v == 0xE0 && ((uint8_t)src[i + 1] & 0xE0) != 0xA0) || // E0 A0~BF
(v == 0xED && ((uint8_t)src[i + 1] & 0xE0) != 0x80) || // ED 80~9F
(v == 0xF0 && ((uint8_t)src[i + 1] & 0xF0) == 0x80) || // F0 90~BF
(v == 0xF4 && ((uint8_t)src[i + 1] & 0xF0) != 0x80)) // F4 80~8F
{
INVALID(ReportInvalidCharacter, i, 1);
}
// Check the continuation bytes.
for (uint32_t m = 1; m < n; m++) {
if ((src[i + m] & 0xC0) != 0x80)
INVALID(ReportInvalidCharacter, i, m);
}
// Determine the code unit's length in CharT and act accordingly.
v = JS::Utf8ToOneUcs4Char((uint8_t*)&src[i], n);
if (Action != AssertNoInvalids) {
if (v > 0xff) {
RequireUTF16();
if (Action == FindEncoding) {
MOZ_ASSERT(dst == nullptr);
return true;
}
} else {
RequireLatin1();
}
}
if (v < 0x10000) {
// The n-byte UTF8 code unit will fit in a single CharT.
if (Action == Copy)
dst[j] = CharT(v);
} else {
v -= 0x10000;
if (v <= 0xFFFFF) {
// The n-byte UTF8 code unit will fit in two CharT units.
if (Action == Copy)
dst[j] = CharT((v >> 10) + 0xD800);
j++;
if (Action == Copy)
dst[j] = CharT((v & 0x3FF) + 0xDC00);
} else {
// The n-byte UTF8 code unit won't fit in two CharT units.
INVALID(ReportTooBigCharacter, v, 1);
}
}
invalidMultiByteCodeUnit:
// Move i to the last byte of the multi-byte code unit; the loop
// header will do the final i++ to move to the start of the next
// code unit.
i += n - 1;
if (Action != AssertNoInvalids)
RequireUTF16();
}
}
if (Action != AssertNoInvalids && Action != FindEncoding)
*dstlenp = j;
return true;
}
template <InflateUTF8Action Action, typename CharsT, class ContextT>
static CharsT
InflateUTF8StringHelper(ContextT* cx, const UTF8Chars src, size_t* outlen)
{
using CharT = typename CharsT::CharT;
*outlen = 0;
JS::SmallestEncoding encoding;
if (!InflateUTF8StringToBuffer<Action, CharT>(cx, src, /* dst = */ nullptr, outlen, &encoding))
return CharsT();
CharT* dst = cx->template pod_malloc<CharT>(*outlen + 1); // +1 for NUL
if (!dst) {
ReportOutOfMemory(cx);
return CharsT();
}
if (encoding == JS::SmallestEncoding::ASCII) {
size_t srclen = src.length();
MOZ_ASSERT(*outlen == srclen);
for (uint32_t i = 0; i < srclen; i++)
dst[i] = CharT(src[i]);
} else {
MOZ_ALWAYS_TRUE((InflateUTF8StringToBuffer<Copy, CharT>(cx, src, dst, outlen, &encoding)));
}
dst[*outlen] = 0; // NUL char
return CharsT(dst, *outlen);
}
TwoByteCharsZ
JS::UTF8CharsToNewTwoByteCharsZ(JSContext* cx, const UTF8Chars utf8, size_t* outlen)
{
return InflateUTF8StringHelper<CountAndReportInvalids, TwoByteCharsZ>(cx, utf8, outlen);
}
TwoByteCharsZ
JS::UTF8CharsToNewTwoByteCharsZ(JSContext* cx, const ConstUTF8CharsZ& utf8, size_t* outlen)
{
UTF8Chars chars(utf8.c_str(), strlen(utf8.c_str()));
return InflateUTF8StringHelper<CountAndReportInvalids, TwoByteCharsZ>(cx, chars, outlen);
}
TwoByteCharsZ
js::LossyUTF8CharsToNewTwoByteCharsZ(js::ExclusiveContext* cx, const JS::UTF8Chars utf8, size_t* outlen)
{
return InflateUTF8StringHelper<CountAndIgnoreInvalids, TwoByteCharsZ>(cx, utf8, outlen);
}
TwoByteCharsZ
JS::LossyUTF8CharsToNewTwoByteCharsZ(JSContext* cx, const UTF8Chars utf8, size_t* outlen)
{
return js::LossyUTF8CharsToNewTwoByteCharsZ(cx, utf8, outlen);
}
TwoByteCharsZ
js::LossyUTF8CharsToNewTwoByteCharsZ(js::ExclusiveContext* cx, const JS::ConstUTF8CharsZ& utf8, size_t* outlen)
{
UTF8Chars chars(utf8.c_str(), strlen(utf8.c_str()));
return InflateUTF8StringHelper<CountAndIgnoreInvalids, TwoByteCharsZ>(cx, chars, outlen);
}
TwoByteCharsZ
JS::LossyUTF8CharsToNewTwoByteCharsZ(JSContext* cx, const ConstUTF8CharsZ& utf8, size_t* outlen)
{
return js::LossyUTF8CharsToNewTwoByteCharsZ(cx, utf8, outlen);
}
JS::SmallestEncoding
JS::FindSmallestEncoding(UTF8Chars utf8)
{
JS::SmallestEncoding encoding;
MOZ_ALWAYS_TRUE((InflateUTF8StringToBuffer<FindEncoding, char16_t, JSContext>(
/* cx = */ nullptr,
utf8,
/* dst = */ nullptr,
/* dstlen = */ nullptr,
&encoding)));
return encoding;
}
Latin1CharsZ
JS::UTF8CharsToNewLatin1CharsZ(JSContext* cx, const UTF8Chars utf8, size_t* outlen)
{
return InflateUTF8StringHelper<CountAndReportInvalids, Latin1CharsZ>(cx, utf8, outlen);
}
Latin1CharsZ
js::LossyUTF8CharsToNewLatin1CharsZ(js::ExclusiveContext* cx, const JS::UTF8Chars utf8, size_t* outlen)
{
return InflateUTF8StringHelper<CountAndIgnoreInvalids, Latin1CharsZ>(cx, utf8, outlen);
}
Latin1CharsZ
JS::LossyUTF8CharsToNewLatin1CharsZ(JSContext* cx, const UTF8Chars utf8, size_t* outlen)
{
return js::LossyUTF8CharsToNewLatin1CharsZ(cx, utf8, outlen);
}
#ifdef DEBUG
void
JS::ConstUTF8CharsZ::validate(size_t aLength)
{
MOZ_ASSERT(data_);
UTF8Chars chars(data_, aLength);
InflateUTF8StringToBuffer<AssertNoInvalids, char16_t, JSContext>(
/* cx = */ nullptr,
chars,
/* dst = */ nullptr,
/* dstlen = */ nullptr,
/* smallestEncoding = */ nullptr);
}
#endif
bool
JS::StringIsASCII(const char* s)
{
while (*s) {
if (*s & 0x80)
return false;
s++;
}
return true;
}