SkFontStream Class Reference

#include <SkFontStream.h>

Static Public Member Functions
static int	CountTTCEntries (SkStream *)
static int	GetTableTags (SkStream *, int ttcIndex, SkFontTableTag tags[])
static size_t	GetTableData (SkStream *, int ttcIndex, SkFontTableTag tag, size_t offset, size_t length, void *data)
static size_t	GetTableSize (SkStream *stream, int ttcIndex, SkFontTableTag tag)

Detailed Description

Definition at line 17 of file SkFontStream.h.

Member Function Documentation

CountTTCEntries()

int SkFontStream::CountTTCEntries ( SkStream *  stream )

static

Return the number of shared directories inside a TTC sfnt, or return 1 if the stream is a normal sfnt (ttf). If there is an error or no directory is found, return 0.

Note: the stream is rewound initially, but is returned at an arbitrary read offset.

Definition at line 143 of file SkFontStream.cpp.

                                                  {
    stream->rewind();
 
    SkSharedTTHeader shared;
    if (!read(stream, &shared, sizeof(shared))) {
        return 0;
    }
 
    // if we're really a collection, the first 4-bytes will be 'ttcf'
    uint32_t tag = SkEndian_SwapBE32(shared.fCollection.fTag);
    if (SkSetFourByteTag('t', 't', 'c', 'f') == tag) {
        return SkEndian_SwapBE32(shared.fCollection.fNumOffsets);
    } else {
        return 1;   // normal 'sfnt' has 1 dir entry
    }
}

GetTableData()

size_t SkFontStream::GetTableData ( SkStream *  stream, int  ttcIndex, SkFontTableTag  tag, size_t  offset, size_t  length, void *  data  )

static

Parameters

ttcIndex

0 for normal sfnts, or the index within a TTC sfnt.

Note: the stream is rewound initially, but is returned at an arbitrary read offset.

Definition at line 175 of file SkFontStream.cpp.

                                                                            {
    SfntHeader  header;
    if (!header.init(stream, ttcIndex)) {
        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);
            if (offset >= realLength) {
                // invalid
                return 0;
            }
            // if the caller is trusting the length from the file, then a
            // hostile file might choose a value which would overflow offset +
            // length.
            if (offset + length < offset) {
                return 0;
            }
            if (length > realLength - offset) {
                length = realLength - offset;
            }
            if (data) {
                // skip the stream to the part of the table we want to copy from
                stream->rewind();
                size_t bytesToSkip = realOffset + offset;
                if (!skip(stream, bytesToSkip)) {
                    return 0;
                }
                if (!read(stream, data, length)) {
                    return 0;
                }
            }
            return length;
        }
    }
    return 0;
}

GetTableSize()

static size_t SkFontStream::GetTableSize ( SkStream *  stream, int  ttcIndex, SkFontTableTag  tag  )

inlinestatic

Definition at line 46 of file SkFontStream.h.

                                                                                   {
        return GetTableData(stream, ttcIndex, tag, 0, ~0U, nullptr);
    }

GetTableTags()

int SkFontStream::GetTableTags ( SkStream *  stream, int  ttcIndex, SkFontTableTag  tags[]  )

static

Parameters

ttcIndex

0 for normal sfnts, or the index within a TTC sfnt.

Note: the stream is rewound initially, but is returned at an arbitrary read offset.

Definition at line 160 of file SkFontStream.cpp.

                                                      {
    SfntHeader  header;
    if (!header.init(stream, ttcIndex)) {
        return 0;
    }
 
    if (tags) {
        for (int i = 0; i < header.fCount; i++) {
            tags[i] = SkEndian_SwapBE32(header.fDir[i].fTag);
        }
    }
    return header.fCount;
}

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The documentation for this class was generated from the following files:

• third_party/skia/src/core/SkFontStream.h
• third_party/skia/src/core/SkFontStream.cpp