diff options
Diffstat (limited to 'src/vdmx.cc')
| -rw-r--r-- | src/vdmx.cc | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/src/vdmx.cc b/src/vdmx.cc new file mode 100644 index 0000000..73236c1 --- /dev/null +++ b/src/vdmx.cc @@ -0,0 +1,176 @@ +// Copyright (c) 2009 The Chromium Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +#include "vdmx.h" + +// VDMX - Vertical Device Metrics +// http://www.microsoft.com/opentype/otspec/vdmx.htm + +#define DROP_THIS_TABLE \ + do { delete file->vdmx; file->vdmx = 0; } while (0) + +namespace ots { + +bool ots_vdmx_parse(OpenTypeFile *file, const uint8_t *data, size_t length) { + Buffer table(data, length); + file->vdmx = new OpenTypeVDMX; + OpenTypeVDMX * const vdmx = file->vdmx; + + if (!table.ReadU16(&vdmx->version) || + !table.ReadU16(&vdmx->num_recs) || + !table.ReadU16(&vdmx->num_ratios)) { + return OTS_FAILURE(); + } + + if (vdmx->version > 1) { + OTS_WARNING("bad version: %u", vdmx->version); + DROP_THIS_TABLE; + return true; // continue transcoding + } + + vdmx->rat_ranges.reserve(vdmx->num_ratios); + for (unsigned i = 0; i < vdmx->num_ratios; ++i) { + OpenTypeVDMXRatioRecord rec; + + if (!table.ReadU8(&rec.charset) || + !table.ReadU8(&rec.x_ratio) || + !table.ReadU8(&rec.y_start_ratio) || + !table.ReadU8(&rec.y_end_ratio)) { + return OTS_FAILURE(); + } + + if (rec.charset > 1) { + OTS_WARNING("bad charset: %u", rec.charset); + DROP_THIS_TABLE; + return true; + } + if (rec.y_start_ratio < rec.y_end_ratio) { + OTS_WARNING("bad y ratio"); + DROP_THIS_TABLE; + return true; + } + + // All values set to zero signal the default grouping to use; + // if present, this must be the last Ratio group in the table. + if ((i < vdmx->num_ratios - 1u) && + (rec.x_ratio == 0) && + (rec.y_start_ratio == 0) && + (rec.y_end_ratio == 0)) { + // workaround for fonts which have 2 or more {0, 0, 0} terminators. + OTS_WARNING("superfluous terminator found"); + DROP_THIS_TABLE; + return true; // continue transcoding + } + + vdmx->rat_ranges.push_back(rec); + } + + vdmx->offsets.reserve(vdmx->num_ratios); + const size_t current_offset = table.offset(); + // current_offset is less than (2 bytes * 3) + (4 bytes * USHRT_MAX) = 256k. + for (unsigned i = 0; i < vdmx->num_ratios; ++i) { + uint16_t offset; + if (!table.ReadU16(&offset)) { + return OTS_FAILURE(); + } + if (current_offset + offset >= length) { // thus doesn't overflow. + return OTS_FAILURE(); + } + + vdmx->offsets.push_back(offset); + } + + vdmx->groups.reserve(vdmx->num_recs); + for (unsigned i = 0; i < vdmx->num_recs; ++i) { + OpenTypeVDMXGroup group; + if (!table.ReadU16(&group.recs) || + !table.ReadU8(&group.startsz) || + !table.ReadU8(&group.endsz)) { + return OTS_FAILURE(); + } + group.entries.reserve(group.recs); + for (unsigned j = 0; j < group.recs; ++j) { + OpenTypeVDMXVTable vt; + if (!table.ReadU16(&vt.y_pel_height) || + !table.ReadS16(&vt.y_max) || + !table.ReadS16(&vt.y_min)) { + return OTS_FAILURE(); + } + if (vt.y_max < vt.y_min) { + OTS_WARNING("bad y min/max"); + DROP_THIS_TABLE; + return true; + } + + // This table must appear in sorted order (sorted by yPelHeight), + // but need not be continuous. + if ((j != 0) && (group.entries[j - 1].y_pel_height >= vt.y_pel_height)) { + OTS_WARNING("the table is not sorted"); + DROP_THIS_TABLE; + return true; + } + + group.entries.push_back(vt); + } + vdmx->groups.push_back(group); + } + + return true; +} + +bool ots_vdmx_should_serialise(OpenTypeFile *file) { + if (!file->glyf) return false; // this table is not for CFF fonts. + return file->vdmx; +} + +bool ots_vdmx_serialise(OTSStream *out, OpenTypeFile *file) { + OpenTypeVDMX * const vdmx = file->vdmx; + + if (!out->WriteU16(vdmx->version) || + !out->WriteU16(vdmx->num_recs) || + !out->WriteU16(vdmx->num_ratios)) { + return OTS_FAILURE(); + } + + for (unsigned i = 0; i < vdmx->rat_ranges.size(); ++i) { + const OpenTypeVDMXRatioRecord& rec = vdmx->rat_ranges[i]; + if (!out->Write(&rec.charset, 1) || + !out->Write(&rec.x_ratio, 1) || + !out->Write(&rec.y_start_ratio, 1) || + !out->Write(&rec.y_end_ratio, 1)) { + return OTS_FAILURE(); + } + } + + for (unsigned i = 0; i < vdmx->offsets.size(); ++i) { + if (!out->WriteU16(vdmx->offsets[i])) { + return OTS_FAILURE(); + } + } + + for (unsigned i = 0; i < vdmx->groups.size(); ++i) { + const OpenTypeVDMXGroup& group = vdmx->groups[i]; + if (!out->WriteU16(group.recs) || + !out->Write(&group.startsz, 1) || + !out->Write(&group.endsz, 1)) { + return OTS_FAILURE(); + } + for (unsigned j = 0; j < group.entries.size(); ++j) { + const OpenTypeVDMXVTable& vt = group.entries[j]; + if (!out->WriteU16(vt.y_pel_height) || + !out->WriteS16(vt.y_max) || + !out->WriteS16(vt.y_min)) { + return OTS_FAILURE(); + } + } + } + + return true; +} + +void ots_vdmx_free(OpenTypeFile *file) { + delete file->vdmx; +} + +} // namespace ots |