Updating OTS repo from https://github.com/khaledhosny/ots.git

third_party/ots/src/vdmx.cc

+// 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/typography/otspec/vdmx.htm
+
+#define TABLE_NAME "VDMX"
+
+#define DROP_THIS_TABLE(...) \
+  do { \
+    OTS_FAILURE_MSG_(file, TABLE_NAME ": " __VA_ARGS__); \
+    OTS_FAILURE_MSG("Table discarded"); \
+    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_MSG("Failed to read table header");
+  }
+
+  if (vdmx->version > 1) {
+    DROP_THIS_TABLE("bad version: %u", vdmx->version);
+    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_MSG("Failed to read ratio header %d", i);
+    }
+
+    if (rec.charset > 1) {
+      DROP_THIS_TABLE("bad charset: %u", rec.charset);
+      return true;
+    }
+
+    if (rec.y_start_ratio > rec.y_end_ratio) {
+      DROP_THIS_TABLE("bad y ratio");
+      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.
+      DROP_THIS_TABLE("superfluous terminator found");
+      return true;
+    }
+
+    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_MSG("Failed to read ratio offset %d", i);
+    }
+    if (current_offset + offset >= length) {  // thus doesn't overflow.
+      return OTS_FAILURE_MSG("Bad ratio offset %d for ration %d", offset, i);
+    }
+
+    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_MSG("Failed to read record header %d", i);
+    }
+    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_MSG("Failed to read reacord %d group %d", i, j);
+      }
+      if (vt.y_max < vt.y_min) {
+        DROP_THIS_TABLE("bad y min/max");
+        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)) {
+        DROP_THIS_TABLE("the table is not sorted");
+        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 != NULL;
+}
+
+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_MSG("Failed to write table header");
+  }
+
+  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_MSG("Failed to write ratio %d", i);
+    }
+  }
+
+  for (unsigned i = 0; i < vdmx->offsets.size(); ++i) {
+    if (!out->WriteU16(vdmx->offsets[i])) {
+      return OTS_FAILURE_MSG("Failed to write ratio offset %d", i);
+    }
+  }
+
+  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_MSG("Failed to write group %d", i);
+    }
+    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_MSG("Failed to write group %d entry %d", i, j);
+      }
+    }
+  }
+
+  return true;
+}
+
+void ots_vdmx_free(OpenTypeFile *file) {
+  delete file->vdmx;
+}
+
+}  // namespace ots
+
+#undef TABLE_NAME
+#undef DROP_THIS_TABLE