nsPangoBreaker.cpp (2288B)
1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ 2 /* This Source Code Form is subject to the terms of the Mozilla Public 3 * License, v. 2.0. If a copy of the MPL was not distributed with this 4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ 5 6 #include "nsComplexBreaker.h" 7 8 #include <pango/pango-break.h> 9 #include "nsUTF8Utils.h" 10 #include "nsString.h" 11 #include "nsTArray.h" 12 13 void NS_GetComplexLineBreaks(const char16_t* aText, uint32_t aLength, 14 uint8_t* aBreakBefore) { 15 NS_ASSERTION(aText, "aText shouldn't be null"); 16 17 memset(aBreakBefore, uint8_t(false), aLength * sizeof(uint8_t)); 18 19 AutoTArray<PangoLogAttr, 2000> attrBuffer; 20 // XXX(Bug 1631371) Check if this should use a fallible operation as it 21 // pretended earlier. 22 attrBuffer.AppendElements(aLength + 1); 23 // `PangoLogAttr` doesn't have a default constructor (it is a C struct), so 24 // we need to manually initialize the new elements. See bug 1808182. 25 memset(attrBuffer.Elements(), 0, attrBuffer.Length() * sizeof(PangoLogAttr)); 26 27 NS_ConvertUTF16toUTF8 aUTF8(aText, aLength); 28 29 const gchar* p = aUTF8.Data(); 30 const gchar* end = p + aUTF8.Length(); 31 uint32_t u16Offset = 0; 32 33 static PangoLanguage* language = pango_language_from_string("en"); 34 35 while (p < end) { 36 PangoLogAttr* attr = attrBuffer.Elements(); 37 pango_get_log_attrs(p, end - p, -1, language, attr, attrBuffer.Length()); 38 39 while (p < end) { 40 aBreakBefore[u16Offset] = attr->is_line_break; 41 if (NS_IS_LOW_SURROGATE(aText[u16Offset])) 42 aBreakBefore[++u16Offset] = false; // Skip high surrogate 43 ++u16Offset; 44 45 // We're iterating over text obtained from NS_ConvertUTF16toUTF8, 46 // so we know we have valid UTF-8 and don't need to check for 47 // errors. 48 uint32_t ch = UTF8CharEnumerator::NextChar(&p, end); 49 ++attr; 50 51 if (!ch) { 52 // pango_break (pango 1.16.2) only analyses text before the 53 // first NUL (but sets one extra attr). Workaround loop to call 54 // pango_break again to analyse after the NUL is done somewhere else 55 // (gfx/thebes/gfxFontconfigFonts.cpp: SetupClusterBoundaries()). 56 // So, we do the same here for pango_get_log_attrs. 57 break; 58 } 59 } 60 } 61 }