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

third_party/ots/src/hdmx.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 "hdmx.h"
+#include "head.h"
+#include "maxp.h"
+
+// hdmx - Horizontal Device Metrics
+// http://www.microsoft.com/typography/otspec/hdmx.htm
+
+#define TABLE_NAME "hdmx"
+
+#define DROP_THIS_TABLE(...) \
+  do { \
+    OTS_FAILURE_MSG_(file, TABLE_NAME ": " __VA_ARGS__); \
+    OTS_FAILURE_MSG("Table discarded"); \
+    delete file->hdmx; \
+    file->hdmx = 0; \
+  } while (0)
+
+namespace ots {
+
+bool ots_hdmx_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {
+  Buffer table(data, length);
+  file->hdmx = new OpenTypeHDMX;
+  OpenTypeHDMX * const hdmx = file->hdmx;
+
+  if (!file->head || !file->maxp) {
+    return OTS_FAILURE_MSG("Missing maxp or head tables in font, needed by hdmx");
+  }
+
+  if ((file->head->flags & 0x14) == 0) {
+    // http://www.microsoft.com/typography/otspec/recom.htm
+    DROP_THIS_TABLE("the table should not be present when bit 2 and 4 of the "
+                    "head->flags are not set");
+    return true;
+  }
+
+  int16_t num_recs;
+  if (!table.ReadU16(&hdmx->version) ||
+      !table.ReadS16(&num_recs) ||
+      !table.ReadS32(&hdmx->size_device_record)) {
+    return OTS_FAILURE_MSG("Failed to read hdmx header");
+  }
+  if (hdmx->version != 0) {
+    DROP_THIS_TABLE("bad version: %u", hdmx->version);
+    return true;
+  }
+  if (num_recs <= 0) {
+    DROP_THIS_TABLE("bad num_recs: %d", num_recs);
+    return true;
+  }
+  const int32_t actual_size_device_record = file->maxp->num_glyphs + 2;
+  if (hdmx->size_device_record < actual_size_device_record) {
+    DROP_THIS_TABLE("bad hdmx->size_device_record: %d", hdmx->size_device_record);
+    return true;
+  }
+
+  hdmx->pad_len = hdmx->size_device_record - actual_size_device_record;
+  if (hdmx->pad_len > 3) {
+    return OTS_FAILURE_MSG("Bad padding %d", hdmx->pad_len);
+  }
+
+  uint8_t last_pixel_size = 0;
+  hdmx->records.reserve(num_recs);
+  for (int i = 0; i < num_recs; ++i) {
+    OpenTypeHDMXDeviceRecord rec;
+
+    if (!table.ReadU8(&rec.pixel_size) ||
+        !table.ReadU8(&rec.max_width)) {
+      return OTS_FAILURE_MSG("Failed to read hdmx record %d", i);
+    }
+    if ((i != 0) &&
+        (rec.pixel_size <= last_pixel_size)) {
+      DROP_THIS_TABLE("records are not sorted");
+      return true;
+    }
+    last_pixel_size = rec.pixel_size;
+
+    rec.widths.reserve(file->maxp->num_glyphs);
+    for (unsigned j = 0; j < file->maxp->num_glyphs; ++j) {
+      uint8_t width;
+      if (!table.ReadU8(&width)) {
+        return OTS_FAILURE_MSG("Failed to read glyph width %d in record %d", j, i);
+      }
+      rec.widths.push_back(width);
+    }
+
+    if ((hdmx->pad_len > 0) &&
+        !table.Skip(hdmx->pad_len)) {
+      return OTS_FAILURE_MSG("Failed to skip padding %d", hdmx->pad_len);
+    }
+
+    hdmx->records.push_back(rec);
+  }
+
+  return true;
+}
+
+bool ots_hdmx_should_serialise(OpenTypeFile *file) {
+  if (!file->hdmx) return false;
+  if (!file->glyf) return false;  // this table is not for CFF fonts.
+  return true;
+}
+
+bool ots_hdmx_serialise(OTSStream *out, OpenTypeFile *file) {
+  OpenTypeHDMX * const hdmx = file->hdmx;
+
+  const int16_t num_recs = static_cast<int16_t>(hdmx->records.size());
+  if (hdmx->records.size() >
+          static_cast<size_t>(std::numeric_limits<int16_t>::max()) ||
+      !out->WriteU16(hdmx->version) ||
+      !out->WriteS16(num_recs) ||
+      !out->WriteS32(hdmx->size_device_record)) {
+    return OTS_FAILURE_MSG("Failed to write hdmx header");
+  }
+
+  for (int16_t i = 0; i < num_recs; ++i) {
+    const OpenTypeHDMXDeviceRecord& rec = hdmx->records[i];
+    if (!out->Write(&rec.pixel_size, 1) ||
+        !out->Write(&rec.max_width, 1) ||
+        !out->Write(&rec.widths[0], rec.widths.size())) {
+      return OTS_FAILURE_MSG("Failed to write hdmx record %d", i);
+    }
+    if ((hdmx->pad_len > 0) &&
+        !out->Write((const uint8_t *)"\x00\x00\x00", hdmx->pad_len)) {
+      return OTS_FAILURE_MSG("Failed to write hdmx padding of length %d", hdmx->pad_len);
+    }
+  }
+
+  return true;
+}
+
+void ots_hdmx_free(OpenTypeFile *file) {
+  delete file->hdmx;
+}
+
+}  // namespace ots
+
+#undef TABLE_NAME
+#undef DROP_THIS_TABLE