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authorMichael Lutz <michi@icosahedron.de>2018-05-26 16:13:12 +0200
committerMichael Lutz <michi@icosahedron.de>2018-06-06 21:37:09 +0200
commit768a31bfe3bc8da1482e0c7115bc46bf90b1e7ec (patch)
treebf5534df4faf1a9d48edbf355b8e7c1fa2ef2cb9 /src/os/windows
parenta4278c302b7721d22e4501315b5a1713f5471163 (diff)
downloadopenttd-768a31bfe3bc8da1482e0c7115bc46bf90b1e7ec.tar.xz
Add: [Win32] Text layout using the native Windows Uniscribe library.
Uniscribe is sometimes producing different results compared to ICU, especially when RTL and LTR content is mixed. Comparing the results to other programs (like editors or web browsers) leads me to believe that the result are at least not worse than ICU and possibly better.
Diffstat (limited to 'src/os/windows')
-rw-r--r--src/os/windows/string_uniscribe.cpp508
-rw-r--r--src/os/windows/string_uniscribe.h70
2 files changed, 578 insertions, 0 deletions
diff --git a/src/os/windows/string_uniscribe.cpp b/src/os/windows/string_uniscribe.cpp
new file mode 100644
index 000000000..fbf908e09
--- /dev/null
+++ b/src/os/windows/string_uniscribe.cpp
@@ -0,0 +1,508 @@
+/* $Id$ */
+
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
+ * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file string_uniscribe.cpp Functions related to laying out text on Win32. */
+
+#if defined(WITH_UNISCRIBE)
+
+#include "../../stdafx.h"
+#include "../../debug.h"
+#include "string_uniscribe.h"
+#include "../../language.h"
+#include "../../strings_func.h"
+#include "../../table/control_codes.h"
+#include "win32.h"
+#include <vector>
+
+#include <windows.h>
+#include <usp10.h>
+
+#include "../../safeguards.h"
+
+#ifdef _MSC_VER
+# pragma comment(lib, "usp10")
+#endif
+
+
+/** Uniscribe cache for internal font information, cleared when OTTD changes fonts. */
+static SCRIPT_CACHE _script_cache[FS_END];
+
+/**
+ * Contains all information about a run of characters. A run are consecutive
+ * characters that share a single font and language.
+ */
+struct UniscribeRun {
+ int pos;
+ int len;
+ Font *font;
+
+ std::vector<GlyphID> ft_glyphs;
+
+ SCRIPT_ANALYSIS sa;
+ std::vector<WORD> char_to_glyph;
+
+ std::vector<SCRIPT_VISATTR> vis_attribs;
+ std::vector<WORD> glyphs;
+ std::vector<int> advances;
+ std::vector<GOFFSET> offsets;
+ int total_advance;
+
+ UniscribeRun(int pos, int len, Font *font, SCRIPT_ANALYSIS &sa) : pos(pos), len(len), font(font), sa(sa) {}
+};
+
+/** Break a string into language formatting ranges. */
+static std::vector<SCRIPT_ITEM> UniscribeItemizeString(UniscribeParagraphLayoutFactory::CharType *buff, int32 length);
+/** Generate and place glyphs for a run of characters. */
+static bool UniscribeShapeRun(const UniscribeParagraphLayoutFactory::CharType *buff, UniscribeRun &range);
+
+/**
+ * Wrapper for doing layouts with Uniscribe.
+ */
+class UniscribeParagraphLayout : public ParagraphLayouter {
+private:
+ const UniscribeParagraphLayoutFactory::CharType *text_buffer;
+
+ std::vector<UniscribeRun> ranges; ///< All runs of the text.
+ std::vector<UniscribeRun>::iterator cur_range; ///< The next run to be output.
+ int cur_range_offset = 0; ///< Offset from the start of the current run from where to output.
+
+public:
+ /** Visual run contains data about the bit of text with the same font. */
+ class UniscribeVisualRun : public ParagraphLayouter::VisualRun {
+ private:
+ std::vector<GlyphID> glyphs;
+ std::vector<float> positions;
+ std::vector<WORD> char_to_glyph;
+
+ int start_pos;
+ int total_advance;
+ int num_glyphs;
+ Font *font;
+
+ mutable int *glyph_to_char = NULL;
+
+ public:
+ UniscribeVisualRun(const UniscribeRun &range, int x);
+ virtual ~UniscribeVisualRun()
+ {
+ free(this->glyph_to_char);
+ }
+
+ virtual const GlyphID *GetGlyphs() const { return &this->glyphs[0]; }
+ virtual const float *GetPositions() const { return &this->positions[0]; }
+ virtual const int *GetGlyphToCharMap() const;
+
+ virtual const Font *GetFont() const { return this->font; }
+ virtual int GetLeading() const { return this->font->fc->GetHeight(); }
+ virtual int GetGlyphCount() const { return this->num_glyphs; }
+ int GetAdvance() const { return this->total_advance; }
+ };
+
+ /** A single line worth of VisualRuns. */
+ class UniscribeLine : public AutoDeleteSmallVector<UniscribeVisualRun *, 4>, public ParagraphLayouter::Line {
+ public:
+ virtual int GetLeading() const;
+ virtual int GetWidth() const;
+ virtual int CountRuns() const { return this->Length(); }
+ virtual const VisualRun *GetVisualRun(int run) const { return *this->Get(run); }
+
+ int GetInternalCharLength(WChar c) const
+ {
+ /* Uniscribe uses UTF-16 internally which means we need to account for surrogate pairs. */
+ return c >= 0x010000U ? 2 : 1;
+ }
+ };
+
+ UniscribeParagraphLayout(std::vector<UniscribeRun> &ranges, const UniscribeParagraphLayoutFactory::CharType *buffer) : text_buffer(buffer), ranges(ranges)
+ {
+ this->Reflow();
+ }
+
+ virtual ~UniscribeParagraphLayout() {}
+
+ virtual void Reflow()
+ {
+ this->cur_range = this->ranges.begin();
+ this->cur_range_offset = 0;
+ }
+
+ virtual const Line *NextLine(int max_width);
+};
+
+void UniscribeResetScriptCache(FontSize size)
+{
+ if (_script_cache[size] != NULL) {
+ ScriptFreeCache(&_script_cache[size]);
+ _script_cache[size] = NULL;
+ }
+}
+
+/** Load the matching native Windows font. */
+static HFONT HFontFromFont(Font *font)
+{
+ LOGFONT logfont;
+ ZeroMemory(&logfont, sizeof(LOGFONT));
+ logfont.lfHeight = font->fc->GetHeight();
+ logfont.lfWeight = FW_NORMAL;
+ logfont.lfCharSet = DEFAULT_CHARSET;
+ convert_to_fs(font->fc->GetFontName(), logfont.lfFaceName, lengthof(logfont.lfFaceName));
+
+ return CreateFontIndirect(&logfont);
+}
+
+/** Determine the glyph positions for a run. */
+static bool UniscribeShapeRun(const UniscribeParagraphLayoutFactory::CharType *buff, UniscribeRun &range)
+{
+ /* Initial size guess for the number of glyphs recommended by Uniscribe. */
+ range.glyphs.resize(range.len * 3 / 2 + 16);
+ range.vis_attribs.resize(range.glyphs.size());
+
+ /* The char-to-glyph array is the same size as the input. */
+ range.char_to_glyph.resize(range.len);
+
+ HDC temp_dc = NULL;
+ HFONT old_font = NULL;
+ HFONT cur_font = NULL;
+
+ while (true) {
+ /* Shape the text run by determining the glyphs needed for display. */
+ int glyphs_used = 0;
+ HRESULT hr = ScriptShape(temp_dc, &_script_cache[range.font->fc->GetSize()], buff + range.pos, range.len, (int)range.glyphs.size(), &range.sa, &range.glyphs[0], &range.char_to_glyph[0], &range.vis_attribs[0], &glyphs_used);
+
+ if (SUCCEEDED(hr)) {
+ range.glyphs.resize(glyphs_used);
+ range.vis_attribs.resize(glyphs_used);
+
+ /* Calculate the glyph positions. */
+ ABC abc;
+ range.advances.resize(range.glyphs.size());
+ range.offsets.resize(range.glyphs.size());
+ hr = ScriptPlace(temp_dc, &_script_cache[range.font->fc->GetSize()], &range.glyphs[0], (int)range.glyphs.size(), &range.vis_attribs[0], &range.sa, &range.advances[0], &range.offsets[0], &abc);
+ if (SUCCEEDED(hr)) {
+ /* We map our special sprite chars to values that don't fit into a WORD. Copy the glyphs
+ * into a new vector and query the real glyph to use for these special chars. */
+ range.ft_glyphs.resize(range.glyphs.size());
+ for (size_t g_id = 0; g_id < range.glyphs.size(); g_id++) {
+ range.ft_glyphs[g_id] = range.glyphs[g_id];
+ }
+ for (int i = 0; i < range.len; i++) {
+ if (buff[range.pos + i] >= SCC_SPRITE_START && buff[range.pos + i] <= SCC_SPRITE_END) {
+ range.ft_glyphs[range.char_to_glyph[i]] = range.font->fc->MapCharToGlyph(buff[range.pos + i]);
+ }
+ }
+
+ /* FreeType and GDI/Uniscribe seems to occasionally disagree over the width of a glyph. */
+ range.total_advance = 0;
+ for (size_t i = 0; i < range.advances.size(); i++) {
+ if (range.advances[i] > 0 && range.ft_glyphs[i] != 0xFFFF) range.advances[i] = range.font->fc->GetGlyphWidth(range.ft_glyphs[i]);
+ range.total_advance += range.advances[i];
+ }
+ break;
+ }
+ }
+
+ if (hr == E_OUTOFMEMORY) {
+ /* The glyph buffer needs to be larger. Just double it every time. */
+ range.glyphs.resize(range.glyphs.size() * 2);
+ range.vis_attribs.resize(range.vis_attribs.size() * 2);
+ } else if (hr == E_PENDING) {
+ /* Glyph data is not in cache, load native font. */
+ cur_font = HFontFromFont(range.font);
+ if (cur_font == NULL) return false; // Sorry, no dice.
+
+ temp_dc = CreateCompatibleDC(NULL);
+ SetMapMode(temp_dc, MM_TEXT);
+ old_font = (HFONT)SelectObject(temp_dc, cur_font);
+ } else if (hr == USP_E_SCRIPT_NOT_IN_FONT && range.sa.eScript != SCRIPT_UNDEFINED) {
+ /* Try again with the generic shaping engine. */
+ range.sa.eScript = SCRIPT_UNDEFINED;
+ } else {
+ /* Some unknown other error. */
+ if (temp_dc != NULL) {
+ SelectObject(temp_dc, old_font);
+ DeleteObject(cur_font);
+ ReleaseDC(NULL, temp_dc);
+ }
+ return false;
+ }
+ }
+
+ if (temp_dc != NULL) {
+ SelectObject(temp_dc, old_font);
+ DeleteObject(cur_font);
+ ReleaseDC(NULL, temp_dc);
+ }
+
+ return true;
+}
+
+static std::vector<SCRIPT_ITEM> UniscribeItemizeString(UniscribeParagraphLayoutFactory::CharType *buff, int32 length)
+{
+ /* Itemize text. */
+ SCRIPT_CONTROL control;
+ ZeroMemory(&control, sizeof(SCRIPT_CONTROL));
+ control.uDefaultLanguage = _current_language->winlangid;
+
+ SCRIPT_STATE state;
+ ZeroMemory(&state, sizeof(SCRIPT_STATE));
+ state.uBidiLevel = _current_text_dir == TD_RTL ? 1 : 0;
+
+ std::vector<SCRIPT_ITEM> items(16);
+ while (true) {
+ /* We subtract one from max_items to work around a buffer overflow on some older versions of Windows. */
+ int generated = 0;
+ HRESULT hr = ScriptItemize(buff, length, (int)items.size() - 1, &control, &state, &items[0], &generated);
+
+ if (SUCCEEDED(hr)) {
+ /* Resize the item buffer. Note that Uniscribe will always add an additional end sentinel item. */
+ items.resize(generated + 1);
+ break;
+ }
+ /* Some kind of error except item buffer too small. */
+ if (hr != E_OUTOFMEMORY) return std::vector<SCRIPT_ITEM>();
+
+ items.resize(items.size() * 2);
+ }
+
+ return items;
+}
+
+/* static */ ParagraphLayouter *UniscribeParagraphLayoutFactory::GetParagraphLayout(CharType *buff, CharType *buff_end, FontMap &fontMapping)
+{
+ int32 length = buff_end - buff;
+ /* Can't layout an empty string. */
+ if (length == 0) return NULL;
+
+ /* Can't layout our in-built sprite fonts. */
+ for (FontMap::const_iterator i = fontMapping.Begin(); i != fontMapping.End(); i++) {
+ if (i->second->fc->IsBuiltInFont()) return NULL;
+ }
+
+ /* Itemize text. */
+ std::vector<SCRIPT_ITEM> items = UniscribeItemizeString(buff, length);
+ if (items.size() == 0) return NULL;
+
+ /* Build ranges from the items and the font map. A range is a run of text
+ * that is part of a single item and formatted using a single font style. */
+ std::vector<UniscribeRun> ranges;
+
+ int cur_pos = 0;
+ std::vector<SCRIPT_ITEM>::iterator cur_item = items.begin();
+ for (FontMap::const_iterator i = fontMapping.Begin(); i != fontMapping.End(); i++) {
+ while (cur_pos < i->first && cur_item != items.end() - 1) {
+ /* Add a range that spans the intersection of the remaining item and font run. */
+ int stop_pos = min(i->first, (cur_item + 1)->iCharPos);
+ assert(stop_pos - cur_pos > 0);
+ ranges.push_back(UniscribeRun(cur_pos, stop_pos - cur_pos, i->second, cur_item->a));
+
+ /* Shape the range. */
+ if (!UniscribeShapeRun(buff, ranges.back())) {
+ return NULL;
+ }
+
+ /* If we are at the end of the current item, advance to the next item. */
+ if (stop_pos == (cur_item + 1)->iCharPos) cur_item++;
+ cur_pos = stop_pos;
+ }
+ }
+
+ return new UniscribeParagraphLayout(ranges, buff);
+}
+
+/* virtual */ const ParagraphLayouter::Line *UniscribeParagraphLayout::NextLine(int max_width)
+{
+ std::vector<UniscribeRun>::iterator start_run = this->cur_range;
+ std::vector<UniscribeRun>::iterator last_run = this->cur_range;
+
+ if (start_run == this->ranges.end()) return NULL;
+
+ /* Add remaining width of the first run if it is a broken run. */
+ int cur_width = 0;
+ if (this->cur_range_offset != 0) {
+ std::vector<int> dx(start_run->len);
+ ScriptGetLogicalWidths(&start_run->sa, start_run->len, (int)start_run->glyphs.size(), &start_run->advances[0], &start_run->char_to_glyph[0], &start_run->vis_attribs[0], &dx[0]);
+
+ for (std::vector<int>::const_iterator c = dx.begin() + this->cur_range_offset; c != dx.end(); c++) {
+ cur_width += *c;
+ }
+ ++last_run;
+ }
+
+ /* Gather runs until the line is full. */
+ while (last_run != this->ranges.end() && cur_width < max_width) {
+ cur_width += last_run->total_advance;
+ ++last_run;
+ }
+
+ /* If the text does not fit into the available width, find a suitable breaking point. */
+ int remaing_offset = (last_run - 1)->len;
+ if (cur_width > max_width) {
+ std::vector<SCRIPT_LOGATTR> log_attribs;
+
+ /* Get word break information. */
+ int width_avail = max_width;
+ int num_chars = this->cur_range_offset;
+ int start_offs = this->cur_range_offset;
+ int last_cluster = this->cur_range_offset + 1;
+ for (std::vector<UniscribeRun>::iterator r = start_run; r != last_run; r++) {
+ log_attribs.resize(r->pos - start_run->pos + r->len);
+ if (FAILED(ScriptBreak(this->text_buffer + r->pos + start_offs, r->len - start_offs, &r->sa, &log_attribs[r->pos - start_run->pos + start_offs]))) return NULL;
+
+ std::vector<int> dx(r->len);
+ ScriptGetLogicalWidths(&r->sa, r->len, (int)r->glyphs.size(), &r->advances[0], &r->char_to_glyph[0], &r->vis_attribs[0], &dx[0]);
+
+ /* Count absolute max character count on the line. */
+ for (int c = start_offs; c < r->len && width_avail > 0; c++, num_chars++) {
+ if (c > start_offs && log_attribs[num_chars].fCharStop) last_cluster = num_chars;
+ width_avail -= dx[c];
+ }
+
+ start_offs = 0;
+ }
+
+ /* Walk backwards to find the last suitable breaking point. */
+ while (--num_chars > this->cur_range_offset && !log_attribs[num_chars].fSoftBreak && !log_attribs[num_chars].fWhiteSpace) {}
+
+ if (num_chars == this->cur_range_offset) {
+ /* Didn't find any suitable word break point, just break on the last cluster boundary. */
+ num_chars = last_cluster;
+ }
+
+ /* Include whitespace characters after the breaking point. */
+ while (num_chars < (int)log_attribs.size() && log_attribs[num_chars].fWhiteSpace) {
+ num_chars++;
+ }
+
+ /* Get last run that corresponds to the number of characters to show. */
+ for (std::vector<UniscribeRun>::iterator run = start_run; run != last_run; run++) {
+ num_chars -= run->len;
+
+ if (num_chars <= 0) {
+ remaing_offset = num_chars + run->len + 1;
+ last_run = run + 1;
+ assert(remaing_offset - 1 > 0);
+ break;
+ }
+ }
+ }
+
+ /* Build display order from the runs. */
+ std::vector<BYTE> bidi_level;
+ for (std::vector<UniscribeRun>::iterator r = start_run; r != last_run; r++) {
+ bidi_level.push_back(r->sa.s.uBidiLevel);
+ }
+ std::vector<INT> vis_to_log(bidi_level.size());
+ if (FAILED(ScriptLayout((int)bidi_level.size(), &bidi_level[0], &vis_to_log[0], NULL))) return NULL;
+
+ /* Create line. */
+ UniscribeLine *line = new UniscribeLine();
+
+ int cur_pos = 0;
+ for (std::vector<INT>::iterator l = vis_to_log.begin(); l != vis_to_log.end(); l++) {
+ std::vector<UniscribeRun>::iterator i_run = start_run + *l;
+ UniscribeRun run = *i_run;
+
+ /* Partial run after line break (either start or end)? Reshape run to get the first/last glyphs right. */
+ if (i_run == last_run - 1 && remaing_offset < (last_run - 1)->len) {
+ run.len = remaing_offset - 1;
+
+ if (!UniscribeShapeRun(this->text_buffer, run)) return NULL;
+ }
+ if (i_run == start_run && this->cur_range_offset > 0) {
+ assert(run.len - this->cur_range_offset > 0);
+ run.pos += this->cur_range_offset;
+ run.len -= this->cur_range_offset;
+
+ if (!UniscribeShapeRun(this->text_buffer, run)) return NULL;
+ }
+
+ *line->Append() = new UniscribeVisualRun(run, cur_pos);
+ cur_pos += run.total_advance;
+ }
+
+ if (remaing_offset < (last_run - 1)->len) {
+ /* We didn't use up all of the last run, store remainder for the next line. */
+ this->cur_range_offset = remaing_offset - 1;
+ this->cur_range = last_run - 1;
+ assert(this->cur_range->len > this->cur_range_offset);
+ } else {
+ this->cur_range_offset = 0;
+ this->cur_range = last_run;
+ }
+
+ return line;
+}
+
+/**
+ * Get the height of the line.
+ * @return The maximum height of the line.
+ */
+int UniscribeParagraphLayout::UniscribeLine::GetLeading() const
+{
+ int leading = 0;
+ for (const UniscribeVisualRun * const *run = this->Begin(); run != this->End(); run++) {
+ leading = max(leading, (*run)->GetLeading());
+ }
+
+ return leading;
+}
+
+/**
+ * Get the width of this line.
+ * @return The width of the line.
+ */
+int UniscribeParagraphLayout::UniscribeLine::GetWidth() const
+{
+ int length = 0;
+ for (const UniscribeVisualRun * const *run = this->Begin(); run != this->End(); run++) {
+ length += (*run)->GetAdvance();
+ }
+
+ return length;
+}
+
+UniscribeParagraphLayout::UniscribeVisualRun::UniscribeVisualRun(const UniscribeRun &range, int x) : glyphs(range.ft_glyphs), char_to_glyph(range.char_to_glyph), start_pos(range.pos), total_advance(range.total_advance), font(range.font)
+{
+ this->num_glyphs = (int)glyphs.size();
+ this->positions.resize(this->num_glyphs * 2 + 2);
+
+ int advance = 0;
+ for (int i = 0; i < this->num_glyphs; i++) {
+ this->positions[i * 2 + 0] = range.offsets[i].du + advance + x;
+ this->positions[i * 2 + 1] = range.offsets[i].dv;
+
+ advance += range.advances[i];
+ }
+ this->positions[this->num_glyphs * 2] = advance + x;
+}
+
+const int *UniscribeParagraphLayout::UniscribeVisualRun::GetGlyphToCharMap() const
+{
+ if (this->glyph_to_char == NULL) {
+ this->glyph_to_char = CallocT<int>(this->GetGlyphCount());
+
+ /* The char to glyph array contains the first glyph index of the cluster that is associated
+ * with each character. It is possible for a cluster to be formed of several chars. */
+ for (int c = 0; c < (int)this->char_to_glyph.size(); c++) {
+ /* If multiple chars map to one glyph, only refer back to the first character. */
+ if (this->glyph_to_char[this->char_to_glyph[c]] == 0) this->glyph_to_char[this->char_to_glyph[c]] = c + this->start_pos;
+ }
+
+ /* We only marked the first glyph of each cluster in the loop above. Fill the gaps. */
+ int last_char = this->glyph_to_char[0];
+ for (int g = 0; g < this->GetGlyphCount(); g++) {
+ if (this->glyph_to_char[g] != 0) last_char = this->glyph_to_char[g];
+ this->glyph_to_char[g] = last_char;
+ }
+ }
+
+ return this->glyph_to_char;
+}
+
+#endif /* defined(WITH_UNISCRIBE) */
diff --git a/src/os/windows/string_uniscribe.h b/src/os/windows/string_uniscribe.h
new file mode 100644
index 000000000..a43a2a96e
--- /dev/null
+++ b/src/os/windows/string_uniscribe.h
@@ -0,0 +1,70 @@
+/* $Id$ */
+
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
+ * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file string_uniscribe.h Functions related to laying out text on Win32. */
+
+#ifndef STRING_UNISCRIBE_H
+#define STRING_UNISCRIBE_H
+
+#if defined(WITH_UNISCRIBE)
+
+#include "../../gfx_layout.h"
+
+
+void UniscribeResetScriptCache(FontSize size);
+
+
+/**
+ * Helper class to construct a new #UniscribeParagraphLayout.
+ */
+class UniscribeParagraphLayoutFactory {
+public:
+ /** Helper for GetLayouter, to get the right type. */
+ typedef wchar_t CharType;
+ /** Helper for GetLayouter, to get whether the layouter supports RTL. */
+ static const bool SUPPORTS_RTL = true;
+
+ /**
+ * Get the actual ParagraphLayout for the given buffer.
+ * @param buff The begin of the buffer.
+ * @param buff_end The location after the last element in the buffer.
+ * @param fontMapping THe mapping of the fonts.
+ * @return The ParagraphLayout instance.
+ */
+ static ParagraphLayouter *GetParagraphLayout(CharType *buff, CharType *buff_end, FontMap &fontMapping);
+
+ /**
+ * Append a wide character to the internal buffer.
+ * @param buff The buffer to append to.
+ * @param buffer_last The end of the buffer.
+ * @param c The character to add.
+ * @return The number of buffer spaces that were used.
+ */
+ static size_t AppendToBuffer(CharType *buff, const CharType *buffer_last, WChar c)
+ {
+ if (c >= 0x010000U) {
+ /* Character is encoded using surrogates in UTF-16. */
+ if (buff + 1 <= buffer_last) {
+ buff[0] = (CharType)(((c - 0x010000U) >> 10) + 0xD800);
+ buff[1] = (CharType)(((c - 0x010000U) & 0x3FF) + 0xDC00);
+ } else {
+ /* Not enough space in buffer. */
+ *buff = 0;
+ }
+ return 2;
+ } else {
+ *buff = (CharType)(c & 0xFFFF);
+ return 1;
+ }
+ }
+};
+
+#endif /* defined(WITH_UNISCRIBE) */
+
+#endif /* STRING_UNISCRIBE_H */