add Table apis to SkFontHost

need to implement in _win backend



git-svn-id: http://skia.googlecode.com/svn/trunk@149 2bbb7eff-a529-9590-31e7-b0007b416f81

2 files changed, 261 insertions, 0 deletions

diff --git a/src/ports/SkFontHost_mac.cpp b/src/ports/SkFontHost_mac.cpp
index b088c1e8da..06f1f312d8 100755
--- a/src/ports/SkFontHost_mac.cpp
+++ b/src/ports/SkFontHost_mac.cpp
@@ -483,3 +483,91 @@ void SkFontHost::GetGammaTables(const uint8_t* tables[2]) {
     tables[1] = NULL;   // white gamma (e.g. exp= 1/1.4)
 }
 
+///////////////////////////////////////////////////////////////////////////////
+
+struct SkSFNTHeader {
+    uint32_t    fVersion;
+    uint16_t    fNumTables;
+    uint16_t    fSearchRange;
+    uint16_t    fEntrySelector;
+    uint16_t    fRangeShift;
+};
+
+struct SkSFNTDirEntry {
+    uint32_t    fTag;
+    uint32_t    fChecksum;
+    uint32_t    fOffset;
+    uint32_t    fLength;
+};
+
+struct SfntHeader {
+    SfntHeader(SkFontID fontID, bool needDir) : fCount(0), fData(NULL) {
+        ByteCount size;
+        if (ATSFontGetTableDirectory(fontID, 0, NULL, &size)) {
+            return;
+        }
+        
+        SkAutoMalloc storage(size);
+        SkSFNTHeader* header = reinterpret_cast<SkSFNTHeader*>(storage.get());
+        if (ATSFontGetTableDirectory(fontID, size, header, &size)) {
+            return;
+        }
+        
+        fCount = SkEndian_SwapBE16(header->fNumTables);
+        fData = header;
+        storage.detach();
+    }
+    
+    ~SfntHeader() {
+        sk_free(fData);
+    }
+    
+    int count() const { return fCount; }
+    const SkSFNTDirEntry* entries() const {
+        return reinterpret_cast<const SkSFNTDirEntry*>
+            (reinterpret_cast<char*>(fData) + sizeof(SkSFNTHeader));
+    }
+    
+private:
+    int     fCount;
+    void*   fData;
+};
+        
+int SkFontHost::CountTables(SkFontID fontID) {
+    SfntHeader header(fontID, false);
+    return header.count();
+}
+
+int SkFontHost::GetTableTags(SkFontID fontID, SkFontTableTag tags[]) {
+    SfntHeader header(fontID, true);
+    int count = header.count();
+    const SkSFNTDirEntry* entry = header.entries();
+    for (int i = 0; i < count; i++) {
+        tags[i] = SkEndian_SwapBE32(entry[i].fTag);
+    }
+    return count;
+}
+
+size_t SkFontHost::GetTableSize(SkFontID fontID, SkFontTableTag tag) {
+    ByteCount size;
+    if (ATSFontGetTable(fontID, tag, 0, 0, NULL, &size)) {
+        return 0;
+    }
+    return size;
+}
+
+size_t SkFontHost::GetTableData(SkFontID fontID, SkFontTableTag tag,
+                                size_t offset, size_t length, void* data) {
+    ByteCount size;
+    if (ATSFontGetTable(fontID, tag, offset, length, data, &size)) {
+        return 0;
+    }
+    if (offset >= size) {
+        return 0;
+    }
+    if (offset + length > size) {
+        length = size - offset;
+    }
+    return length;
+}
+
diff --git a/src/ports/SkFontHost_tables.cpp b/src/ports/SkFontHost_tables.cpp
new file mode 100644
index 0000000000..f14e085575
--- /dev/null
+++ b/src/ports/SkFontHost_tables.cpp
@@ -0,0 +1,173 @@
+#include "SkEndian.h"
+#include "SkFontHost.h"
+#include "SkStream.h"
+
+struct SkSFNTHeader {
+    uint32_t    fVersion;
+    uint16_t    fNumTables;
+    uint16_t    fSearchRange;
+    uint16_t    fEntrySelector;
+    uint16_t    fRangeShift;
+};
+
+struct SkTTCFHeader {
+    uint32_t    fTag;
+    uint32_t    fVersion;
+    uint32_t    fNumOffsets;
+    uint32_t    fOffset0;   // the first of N (fNumOffsets)
+};
+
+union SkSharedTTHeader {
+    SkSFNTHeader    fSingle;
+    SkTTCFHeader    fCollection;
+};
+
+struct SkSFNTDirEntry {
+    uint32_t    fTag;
+    uint32_t    fChecksum;
+    uint32_t    fOffset;
+    uint32_t    fLength;
+};
+
+static int count_tables(SkStream* stream, size_t* offsetToDir = NULL) {
+    SkSharedTTHeader shared;
+    if (stream->read(&shared, sizeof(shared)) != sizeof(shared)) {
+        return 0;
+    }
+
+    uint32_t tag = SkEndian_SwapBE32(shared.fCollection.fTag);
+    if (SkSetFourByteTag('t', 't', 'c', 'f') == tag) {
+        if (shared.fCollection.fNumOffsets == 0) {
+            return 0;
+        }
+        size_t offset = SkEndian_SwapBE32(shared.fCollection.fOffset0);
+        stream->rewind();
+        if (stream->skip(offset) != offset) {
+            return 0;
+        }
+        if (stream->read(&shared, sizeof(shared)) != sizeof(shared)) {
+            return 0;
+        }
+        if (offsetToDir) {
+            *offsetToDir = offset;
+        }
+    }
+    return SkEndian_SwapBE16(shared.fSingle.fNumTables);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+struct SfntHeader {
+    SfntHeader() : fCount(0), fDir(NULL) {}
+    ~SfntHeader() { sk_free(fDir); }
+    
+    bool init(SkStream* stream) {
+        size_t offsetToDir;
+        fCount = count_tables(stream, &offsetToDir);
+        if (0 == fCount) {
+            return false;
+        }
+
+        stream->rewind();
+        if (stream->skip(offsetToDir) != offsetToDir) {
+            return false;
+        }
+
+        size_t size = fCount * sizeof(SkSFNTDirEntry);
+        fDir = reinterpret_cast<SkSFNTDirEntry*>(sk_malloc_throw(size));
+        return stream->read(fDir, size) == size;
+    }
+    
+    int             fCount;
+    SkSFNTDirEntry* fDir;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+int SkFontHost::CountTables(SkFontID fontID) {
+    SkStream* stream = SkFontHost::OpenStream(fontID);
+    if (NULL == stream) {
+        return 0;
+    }
+
+    SkAutoUnref au(stream);
+    return count_tables(stream);
+}
+
+int SkFontHost::GetTableTags(SkFontID fontID, SkFontTableTag tags[]) {
+    SkStream* stream = SkFontHost::OpenStream(fontID);
+    if (NULL == stream) {
+        return 0;
+    }
+    
+    SkAutoUnref au(stream);
+    SfntHeader  header;
+    if (!header.init(stream)) {
+        return 0;
+    }
+    
+    for (int i = 0; i < header.fCount; i++) {
+        tags[i] = SkEndian_SwapBE32(header.fDir[i].fTag);
+    }
+    return header.fCount;
+}
+
+size_t SkFontHost::GetTableSize(SkFontID fontID, SkFontTableTag tag) {
+    SkStream* stream = SkFontHost::OpenStream(fontID);
+    if (NULL == stream) {
+        return 0;
+    }
+    
+    SkAutoUnref au(stream);
+    SfntHeader  header;
+    if (!header.init(stream)) {
+        return 0;
+    }
+
+    for (int i = 0; i < header.fCount; i++) {
+        if (SkEndian_SwapBE32(header.fDir[i].fTag) == tag) {
+            return SkEndian_SwapBE32(header.fDir[i].fLength);
+        }
+    }
+    return 0;
+}
+
+size_t SkFontHost::GetTableData(SkFontID fontID, SkFontTableTag tag,
+                                size_t offset, size_t length, void* data) {
+    SkStream* stream = SkFontHost::OpenStream(fontID);
+    if (NULL == stream) {
+        return 0;
+    }
+    
+    SkAutoUnref au(stream);
+    SfntHeader  header;
+    if (!header.init(stream)) {
+        return 0;
+    }
+
+    for (int i = 0; i < header.fCount; i++) {
+        if (SkEndian_SwapBE32(header.fDir[i].fTag) == tag) {
+            size_t realOffset = SkEndian_SwapBE32(header.fDir[i].fOffset);
+            size_t realLength = SkEndian_SwapBE32(header.fDir[i].fLength);
+            // now sanity check the caller's offset/length
+            if (offset >= realLength) {
+                return 0;
+            }
+            if (offset + length > realLength) {
+                length = realLength - offset;
+            }
+            // skip the stream to the part of the table we want to copy from
+            stream->rewind();
+            size_t bytesToSkip = realOffset + offset;
+            if (stream->skip(bytesToSkip) != bytesToSkip) {
+                return 0;
+            }
+            if (stream->read(data, length) != length) {
+                return 0;
+            }
+            return length;
+        }
+    }
+    return 0;
+}
+