1 files changed, 339 insertions, 0 deletions
diff --git a/gfx/skia/skia/src/pdf/SkPDFType1Font.cpp b/gfx/skia/skia/src/pdf/SkPDFType1Font.cpp
new file mode 100644
index 0000000000..da17281ef4
--- /dev/null
+++ b/gfx/skia/skia/src/pdf/SkPDFType1Font.cpp
@@ -0,0 +1,339 @@
+// Copyright 2019 Google LLC.
+// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
+
+#include "src/pdf/SkPDFType1Font.h"
+
+#include "include/private/base/SkTemplates.h"
+#include "include/private/base/SkTo.h"
+#include "src/core/SkStrike.h"
+#include "src/core/SkStrikeSpec.h"
+
+#include <ctype.h>
+
+using namespace skia_private;
+
+/*
+  "A standard Type 1 font program, as described in the Adobe Type 1
+  Font Format specification, consists of three parts: a clear-text
+  portion (written using PostScript syntax), an encrypted portion, and
+  a fixed-content portion.  The fixed-content portion contains 512
+  ASCII zeros followed by a cleartomark operator, and perhaps followed
+  by additional data. Although the encrypted portion of a standard
+  Type 1 font may be in binary or ASCII hexadecimal format, PDF
+  supports only the binary format."
+*/
+static bool parsePFBSection(const uint8_t** src, size_t* len, int sectionType,
+                            size_t* size) {
+    // PFB sections have a two or six bytes header. 0x80 and a one byte
+    // section type followed by a four byte section length.  Type one is
+    // an ASCII section (includes a length), type two is a binary section
+    // (includes a length) and type three is an EOF marker with no length.
+    const uint8_t* buf = *src;
+    if (*len < 2 || buf[0] != 0x80 || buf[1] != sectionType) {
+        return false;
+    } else if (buf[1] == 3) {
+        return true;
+    } else if (*len < 6) {
+        return false;
+    }
+
+    *size = (size_t)buf[2] | ((size_t)buf[3] << 8) | ((size_t)buf[4] << 16) |
+            ((size_t)buf[5] << 24);
+    size_t consumed = *size + 6;
+    if (consumed > *len) {
+        return false;
+    }
+    *src = *src + consumed;
+    *len = *len - consumed;
+    return true;
+}
+
+static bool parsePFB(const uint8_t* src, size_t size, size_t* headerLen,
+                     size_t* dataLen, size_t* trailerLen) {
+    const uint8_t* srcPtr = src;
+    size_t remaining = size;
+
+    return parsePFBSection(&srcPtr, &remaining, 1, headerLen) &&
+           parsePFBSection(&srcPtr, &remaining, 2, dataLen) &&
+           parsePFBSection(&srcPtr, &remaining, 1, trailerLen) &&
+           parsePFBSection(&srcPtr, &remaining, 3, nullptr);
+}
+
+/* The sections of a PFA file are implicitly defined.  The body starts
+ * after the line containing "eexec," and the trailer starts with 512
+ * literal 0's followed by "cleartomark" (plus arbitrary white space).
+ *
+ * This function assumes that src is NUL terminated, but the NUL
+ * termination is not included in size.
+ *
+ */
+static bool parsePFA(const char* src, size_t size, size_t* headerLen,
+                     size_t* hexDataLen, size_t* dataLen, size_t* trailerLen) {
+    const char* end = src + size;
+
+    const char* dataPos = strstr(src, "eexec");
+    if (!dataPos) {
+        return false;
+    }
+    dataPos += strlen("eexec");
+    while ((*dataPos == '\n' || *dataPos == '\r' || *dataPos == ' ') &&
+            dataPos < end) {
+        dataPos++;
+    }
+    *headerLen = dataPos - src;
+
+    const char* trailerPos = strstr(dataPos, "cleartomark");
+    if (!trailerPos) {
+        return false;
+    }
+    int zeroCount = 0;
+    for (trailerPos--; trailerPos > dataPos && zeroCount < 512; trailerPos--) {
+        if (*trailerPos == '\n' || *trailerPos == '\r' || *trailerPos == ' ') {
+            continue;
+        } else if (*trailerPos == '0') {
+            zeroCount++;
+        } else {
+            return false;
+        }
+    }
+    if (zeroCount != 512) {
+        return false;
+    }
+
+    *hexDataLen = trailerPos - src - *headerLen;
+    *trailerLen = size - *headerLen - *hexDataLen;
+
+    // Verify that the data section is hex encoded and count the bytes.
+    int nibbles = 0;
+    for (; dataPos < trailerPos; dataPos++) {
+        if (isspace(*dataPos)) {
+            continue;
+        }
+        // isxdigit() is locale-sensitive https://bugs.skia.org/8285
+        if (nullptr == strchr("0123456789abcdefABCDEF", *dataPos)) {
+            return false;
+        }
+        nibbles++;
+    }
+    *dataLen = (nibbles + 1) / 2;
+
+    return true;
+}
+
+static int8_t hexToBin(uint8_t c) {
+    if (!isxdigit(c)) {
+        return -1;
+    } else if (c <= '9') {
+        return c - '0';
+    } else if (c <= 'F') {
+        return c - 'A' + 10;
+    } else if (c <= 'f') {
+        return c - 'a' + 10;
+    }
+    return -1;
+}
+
+static sk_sp<SkData> convert_type1_font_stream(std::unique_ptr<SkStreamAsset> srcStream,
+                                               size_t* headerLen,
+                                               size_t* dataLen,
+                                               size_t* trailerLen) {
+    size_t srcLen = srcStream ? srcStream->getLength() : 0;
+    SkASSERT(srcLen);
+    if (!srcLen) {
+        return nullptr;
+    }
+    // Flatten and Nul-terminate the source stream so that we can use
+    // strstr() to search it.
+    AutoTMalloc<uint8_t> sourceBuffer(SkToInt(srcLen + 1));
+    (void)srcStream->read(sourceBuffer.get(), srcLen);
+    sourceBuffer[SkToInt(srcLen)] = 0;
+    const uint8_t* src = sourceBuffer.get();
+
+    if (parsePFB(src, srcLen, headerLen, dataLen, trailerLen)) {
+        static const int kPFBSectionHeaderLength = 6;
+        const size_t length = *headerLen + *dataLen + *trailerLen;
+        SkASSERT(length > 0);
+        SkASSERT(length + (2 * kPFBSectionHeaderLength) <= srcLen);
+
+        sk_sp<SkData> data(SkData::MakeUninitialized(length));
+
+        const uint8_t* const srcHeader = src + kPFBSectionHeaderLength;
+        // There is a six-byte section header before header and data
+        // (but not trailer) that we're not going to copy.
+        const uint8_t* const srcData = srcHeader + *headerLen + kPFBSectionHeaderLength;
+        const uint8_t* const srcTrailer = srcData + *headerLen;
+
+        uint8_t* const resultHeader = (uint8_t*)data->writable_data();
+        uint8_t* const resultData = resultHeader + *headerLen;
+        uint8_t* const resultTrailer = resultData + *dataLen;
+
+        SkASSERT(resultTrailer + *trailerLen == resultHeader + length);
+
+        memcpy(resultHeader,  srcHeader,  *headerLen);
+        memcpy(resultData,    srcData,    *dataLen);
+        memcpy(resultTrailer, srcTrailer, *trailerLen);
+
+        return data;
+    }
+
+    // A PFA has to be converted for PDF.
+    size_t hexDataLen;
+    if (!parsePFA((const char*)src, srcLen, headerLen, &hexDataLen, dataLen,
+                 trailerLen)) {
+        return nullptr;
+    }
+    const size_t length = *headerLen + *dataLen + *trailerLen;
+    SkASSERT(length > 0);
+    auto data = SkData::MakeUninitialized(length);
+    uint8_t* buffer = (uint8_t*)data->writable_data();
+
+    memcpy(buffer, src, *headerLen);
+    uint8_t* const resultData = &(buffer[*headerLen]);
+
+    const uint8_t* hexData = src + *headerLen;
+    const uint8_t* trailer = hexData + hexDataLen;
+    size_t outputOffset = 0;
+    uint8_t dataByte = 0;  // To hush compiler.
+    bool highNibble = true;
+    for (; hexData < trailer; hexData++) {
+        int8_t curNibble = hexToBin(*hexData);
+        if (curNibble < 0) {
+            continue;
+        }
+        if (highNibble) {
+            dataByte = curNibble << 4;
+            highNibble = false;
+        } else {
+            dataByte |= curNibble;
+            highNibble = true;
+            resultData[outputOffset++] = dataByte;
+        }
+    }
+    if (!highNibble) {
+        resultData[outputOffset++] = dataByte;
+    }
+    SkASSERT(outputOffset == *dataLen);
+
+    uint8_t* const resultTrailer = &(buffer[SkToInt(*headerLen + outputOffset)]);
+    memcpy(resultTrailer, src + *headerLen + hexDataLen, *trailerLen);
+    return data;
+}
+
+inline static bool can_embed(const SkAdvancedTypefaceMetrics& metrics) {
+    return !SkToBool(metrics.fFlags & SkAdvancedTypefaceMetrics::kNotEmbeddable_FontFlag);
+}
+
+inline static SkScalar from_font_units(SkScalar scaled, uint16_t emSize) {
+    return emSize == 1000 ? scaled : scaled * 1000 / emSize;
+}
+
+static SkPDFIndirectReference make_type1_font_descriptor(SkPDFDocument* doc,
+                                                         const SkTypeface* typeface,
+                                                         const SkAdvancedTypefaceMetrics* info) {
+    SkPDFDict descriptor("FontDescriptor");
+    uint16_t emSize = SkToU16(typeface->getUnitsPerEm());
+    if (info) {
+        SkPDFFont::PopulateCommonFontDescriptor(&descriptor, *info, emSize, 0);
+        if (can_embed(*info)) {
+            int ttcIndex;
+            size_t header SK_INIT_TO_AVOID_WARNING;
+            size_t data SK_INIT_TO_AVOID_WARNING;
+            size_t trailer SK_INIT_TO_AVOID_WARNING;
+            std::unique_ptr<SkStreamAsset> rawFontData = typeface->openStream(&ttcIndex);
+            sk_sp<SkData> fontData = convert_type1_font_stream(std::move(rawFontData),
+                                                               &header, &data, &trailer);
+            if (fontData) {
+                std::unique_ptr<SkPDFDict> dict = SkPDFMakeDict();
+                dict->insertInt("Length1", header);
+                dict->insertInt("Length2", data);
+                dict->insertInt("Length3", trailer);
+                auto fontStream = SkMemoryStream::Make(std::move(fontData));
+                descriptor.insertRef("FontFile",
+                                     SkPDFStreamOut(std::move(dict), std::move(fontStream),
+                                                    doc, SkPDFSteamCompressionEnabled::Yes));
+            }
+        }
+    }
+    return doc->emit(descriptor);
+}
+
+
+static const std::vector<SkString>& type_1_glyphnames(SkPDFDocument* canon,
+                                                      const SkTypeface* typeface) {
+    SkTypefaceID typefaceID = typeface->uniqueID();
+    const std::vector<SkString>* glyphNames = canon->fType1GlyphNames.find(typefaceID);
+    if (!glyphNames) {
+        std::vector<SkString> names(typeface->countGlyphs());
+        SkPDFFont::GetType1GlyphNames(*typeface, names.data());
+        glyphNames = canon->fType1GlyphNames.set(typefaceID, std::move(names));
+    }
+    SkASSERT(glyphNames);
+    return *glyphNames;
+}
+
+static SkPDFIndirectReference type1_font_descriptor(SkPDFDocument* doc,
+                                                    const SkTypeface* typeface) {
+    SkTypefaceID typefaceID = typeface->uniqueID();
+    if (SkPDFIndirectReference* ptr = doc->fFontDescriptors.find(typefaceID)) {
+        return *ptr;
+    }
+    const SkAdvancedTypefaceMetrics* info = SkPDFFont::GetMetrics(typeface, doc);
+    auto fontDescriptor = make_type1_font_descriptor(doc, typeface, info);
+    doc->fFontDescriptors.set(typefaceID, fontDescriptor);
+    return fontDescriptor;
+}
+
+
+void SkPDFEmitType1Font(const SkPDFFont& pdfFont, SkPDFDocument* doc) {
+    SkTypeface* typeface = pdfFont.typeface();
+    const std::vector<SkString>& glyphNames = type_1_glyphnames(doc, typeface);
+    SkGlyphID firstGlyphID = pdfFont.firstGlyphID();
+    SkGlyphID lastGlyphID = pdfFont.lastGlyphID();
+
+    SkPDFDict font("Font");
+    font.insertRef("FontDescriptor", type1_font_descriptor(doc, typeface));
+    font.insertName("Subtype", "Type1");
+    if (const SkAdvancedTypefaceMetrics* info = SkPDFFont::GetMetrics(typeface, doc)) {
+        font.insertName("BaseFont", info->fPostScriptName);
+    }
+
+    // glyphCount not including glyph 0
+    unsigned glyphCount = 1 + lastGlyphID - firstGlyphID;
+    SkASSERT(glyphCount > 0 && glyphCount <= 255);
+    font.insertInt("FirstChar", (size_t)0);
+    font.insertInt("LastChar", (size_t)glyphCount);
+    {
+        int emSize;
+        auto widths = SkPDFMakeArray();
+
+        int glyphRangeSize = lastGlyphID - firstGlyphID + 2;
+        AutoTArray<SkGlyphID> glyphIDs{glyphRangeSize};
+        glyphIDs[0] = 0;
+        for (unsigned gId = firstGlyphID; gId <= lastGlyphID; gId++) {
+            glyphIDs[gId - firstGlyphID + 1] = gId;
+        }
+        SkStrikeSpec strikeSpec = SkStrikeSpec::MakePDFVector(*typeface, &emSize);
+        SkBulkGlyphMetrics metrics{strikeSpec};
+        auto glyphs = metrics.glyphs(SkSpan(glyphIDs.get(), glyphRangeSize));
+        for (int i = 0; i < glyphRangeSize; ++i) {
+            widths->appendScalar(from_font_units(glyphs[i]->advanceX(), SkToU16(emSize)));
+        }
+        font.insertObject("Widths", std::move(widths));
+    }
+    auto encDiffs = SkPDFMakeArray();
+    encDiffs->reserve(lastGlyphID - firstGlyphID + 3);
+    encDiffs->appendInt(0);
+
+    SkASSERT(glyphNames.size() > lastGlyphID);
+    const SkString unknown("UNKNOWN");
+    encDiffs->appendName(glyphNames[0].isEmpty() ? unknown : glyphNames[0]);
+    for (int gID = firstGlyphID; gID <= lastGlyphID; gID++) {
+        encDiffs->appendName(glyphNames[gID].isEmpty() ? unknown : glyphNames[gID]);
+    }
+
+    auto encoding = SkPDFMakeDict("Encoding");
+    encoding->insertObject("Differences", std::move(encDiffs));
+    font.insertObject("Encoding", std::move(encoding));
+
+    doc->emit(font, pdfFont.indirectReference());
+}