1 files changed, 374 insertions, 0 deletions
diff --git a/modules/woff2/src/glyph.cc b/modules/woff2/src/glyph.cc
new file mode 100644
index 0000000000..057174de21
--- /dev/null
+++ b/modules/woff2/src/glyph.cc
@@ -0,0 +1,374 @@
+/* Copyright 2013 Google Inc. All Rights Reserved.
+
+   Distributed under MIT license.
+   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
+*/
+
+/* Glyph manipulation */
+
+#include "./glyph.h"
+
+#include <stdlib.h>
+#include <limits>
+#include "./buffer.h"
+#include "./store_bytes.h"
+
+namespace woff2 {
+
+static const int32_t kFLAG_ONCURVE = 1;
+static const int32_t kFLAG_XSHORT = 1 << 1;
+static const int32_t kFLAG_YSHORT = 1 << 2;
+static const int32_t kFLAG_REPEAT = 1 << 3;
+static const int32_t kFLAG_XREPEATSIGN = 1 << 4;
+static const int32_t kFLAG_YREPEATSIGN = 1 << 5;
+static const int32_t kFLAG_ARG_1_AND_2_ARE_WORDS = 1 << 0;
+static const int32_t kFLAG_WE_HAVE_A_SCALE = 1 << 3;
+static const int32_t kFLAG_MORE_COMPONENTS = 1 << 5;
+static const int32_t kFLAG_WE_HAVE_AN_X_AND_Y_SCALE = 1 << 6;
+static const int32_t kFLAG_WE_HAVE_A_TWO_BY_TWO = 1 << 7;
+static const int32_t kFLAG_WE_HAVE_INSTRUCTIONS = 1 << 8;
+
+bool ReadCompositeGlyphData(Buffer* buffer, Glyph* glyph) {
+  glyph->have_instructions = false;
+  glyph->composite_data = buffer->buffer() + buffer->offset();
+  size_t start_offset = buffer->offset();
+  uint16_t flags = kFLAG_MORE_COMPONENTS;
+  while (flags & kFLAG_MORE_COMPONENTS) {
+    if (!buffer->ReadU16(&flags)) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    glyph->have_instructions |= (flags & kFLAG_WE_HAVE_INSTRUCTIONS) != 0;
+    size_t arg_size = 2;  // glyph index
+    if (flags & kFLAG_ARG_1_AND_2_ARE_WORDS) {
+      arg_size += 4;
+    } else {
+      arg_size += 2;
+    }
+    if (flags & kFLAG_WE_HAVE_A_SCALE) {
+      arg_size += 2;
+    } else if (flags & kFLAG_WE_HAVE_AN_X_AND_Y_SCALE) {
+      arg_size += 4;
+    } else if (flags & kFLAG_WE_HAVE_A_TWO_BY_TWO) {
+      arg_size += 8;
+    }
+    if (!buffer->Skip(arg_size)) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+  }
+  if (buffer->offset() - start_offset > std::numeric_limits<uint32_t>::max()) {
+    return FONT_COMPRESSION_FAILURE();
+  }
+  glyph->composite_data_size = buffer->offset() - start_offset;
+  return true;
+}
+
+bool ReadGlyph(const uint8_t* data, size_t len, Glyph* glyph) {
+  Buffer buffer(data, len);
+
+  int16_t num_contours;
+  if (!buffer.ReadS16(&num_contours)) {
+    return FONT_COMPRESSION_FAILURE();
+  }
+
+  // Read the bounding box.
+  if (!buffer.ReadS16(&glyph->x_min) ||
+      !buffer.ReadS16(&glyph->y_min) ||
+      !buffer.ReadS16(&glyph->x_max) ||
+      !buffer.ReadS16(&glyph->y_max)) {
+    return FONT_COMPRESSION_FAILURE();
+  }
+
+  if (num_contours == 0) {
+    // Empty glyph.
+    return true;
+  }
+
+  if (num_contours > 0) {
+    // Simple glyph.
+    glyph->contours.resize(num_contours);
+
+    // Read the number of points per contour.
+    uint16_t last_point_index = 0;
+    for (int i = 0; i < num_contours; ++i) {
+      uint16_t point_index;
+      if (!buffer.ReadU16(&point_index)) {
+        return FONT_COMPRESSION_FAILURE();
+      }
+      uint16_t num_points = point_index - last_point_index + (i == 0 ? 1 : 0);
+      glyph->contours[i].resize(num_points);
+      last_point_index = point_index;
+    }
+
+    // Read the instructions.
+    if (!buffer.ReadU16(&glyph->instructions_size)) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    glyph->instructions_data = data + buffer.offset();
+    if (!buffer.Skip(glyph->instructions_size)) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+
+    // Read the run-length coded flags.
+    std::vector<std::vector<uint8_t> > flags(num_contours);
+    {
+      uint8_t flag = 0;
+      uint8_t flag_repeat = 0;
+      for (int i = 0; i < num_contours; ++i) {
+        flags[i].resize(glyph->contours[i].size());
+        for (size_t j = 0; j < glyph->contours[i].size(); ++j) {
+          if (flag_repeat == 0) {
+            if (!buffer.ReadU8(&flag)) {
+              return FONT_COMPRESSION_FAILURE();
+            }
+            if (flag & kFLAG_REPEAT) {
+              if (!buffer.ReadU8(&flag_repeat)) {
+                return FONT_COMPRESSION_FAILURE();
+              }
+            }
+          } else {
+            flag_repeat--;
+          }
+          flags[i][j] = flag;
+          glyph->contours[i][j].on_curve = flag & kFLAG_ONCURVE;
+        }
+      }
+    }
+
+    // Read the x coordinates.
+    int prev_x = 0;
+    for (int i = 0; i < num_contours; ++i) {
+      for (size_t j = 0; j < glyph->contours[i].size(); ++j) {
+        uint8_t flag = flags[i][j];
+        if (flag & kFLAG_XSHORT) {
+          // single byte x-delta coord value
+          uint8_t x_delta;
+          if (!buffer.ReadU8(&x_delta)) {
+            return FONT_COMPRESSION_FAILURE();
+          }
+          int sign = (flag & kFLAG_XREPEATSIGN) ? 1 : -1;
+          glyph->contours[i][j].x = prev_x + sign * x_delta;
+        } else {
+          // double byte x-delta coord value
+          int16_t x_delta = 0;
+          if (!(flag & kFLAG_XREPEATSIGN)) {
+            if (!buffer.ReadS16(&x_delta)) {
+              return FONT_COMPRESSION_FAILURE();
+            }
+          }
+          glyph->contours[i][j].x = prev_x + x_delta;
+        }
+        prev_x = glyph->contours[i][j].x;
+      }
+    }
+
+    // Read the y coordinates.
+    int prev_y = 0;
+    for (int i = 0; i < num_contours; ++i) {
+      for (size_t j = 0; j < glyph->contours[i].size(); ++j) {
+        uint8_t flag = flags[i][j];
+        if (flag & kFLAG_YSHORT) {
+          // single byte y-delta coord value
+          uint8_t y_delta;
+          if (!buffer.ReadU8(&y_delta)) {
+            return FONT_COMPRESSION_FAILURE();
+          }
+          int sign = (flag & kFLAG_YREPEATSIGN) ? 1 : -1;
+          glyph->contours[i][j].y = prev_y + sign * y_delta;
+        } else {
+          // double byte y-delta coord value
+          int16_t y_delta = 0;
+          if (!(flag & kFLAG_YREPEATSIGN)) {
+            if (!buffer.ReadS16(&y_delta)) {
+              return FONT_COMPRESSION_FAILURE();
+            }
+          }
+          glyph->contours[i][j].y = prev_y + y_delta;
+        }
+        prev_y = glyph->contours[i][j].y;
+      }
+    }
+  } else if (num_contours == -1) {
+    // Composite glyph.
+    if (!ReadCompositeGlyphData(&buffer, glyph)) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    // Read the instructions.
+    if (glyph->have_instructions) {
+      if (!buffer.ReadU16(&glyph->instructions_size)) {
+        return FONT_COMPRESSION_FAILURE();
+      }
+      glyph->instructions_data = data + buffer.offset();
+      if (!buffer.Skip(glyph->instructions_size)) {
+        return FONT_COMPRESSION_FAILURE();
+      }
+    } else {
+      glyph->instructions_size = 0;
+    }
+  } else {
+    return FONT_COMPRESSION_FAILURE();
+  }
+  return true;
+}
+
+namespace {
+
+void StoreBbox(const Glyph& glyph, size_t* offset, uint8_t* dst) {
+  Store16(glyph.x_min, offset, dst);
+  Store16(glyph.y_min, offset, dst);
+  Store16(glyph.x_max, offset, dst);
+  Store16(glyph.y_max, offset, dst);
+}
+
+void StoreInstructions(const Glyph& glyph, size_t* offset, uint8_t* dst) {
+  Store16(glyph.instructions_size, offset, dst);
+  StoreBytes(glyph.instructions_data, glyph.instructions_size, offset, dst);
+}
+
+bool StoreEndPtsOfContours(const Glyph& glyph, size_t* offset, uint8_t* dst) {
+  int end_point = -1;
+  for (const auto& contour : glyph.contours) {
+    end_point += contour.size();
+    if (contour.size() > std::numeric_limits<uint16_t>::max() ||
+        end_point > std::numeric_limits<uint16_t>::max()) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    Store16(end_point, offset, dst);
+  }
+  return true;
+}
+
+bool StorePoints(const Glyph& glyph, size_t* offset,
+                 uint8_t* dst, size_t dst_size) {
+  int last_flag = -1;
+  int repeat_count = 0;
+  int last_x = 0;
+  int last_y = 0;
+  size_t x_bytes = 0;
+  size_t y_bytes = 0;
+
+  // Store the flags and calculate the total size of the x and y coordinates.
+  for (const auto& contour : glyph.contours) {
+    for (const auto& point : contour) {
+      int flag = point.on_curve ? kFLAG_ONCURVE : 0;
+      int dx = point.x - last_x;
+      int dy = point.y - last_y;
+      if (dx == 0) {
+        flag |= kFLAG_XREPEATSIGN;
+      } else if (dx > -256 && dx < 256) {
+        flag |= kFLAG_XSHORT | (dx > 0 ? kFLAG_XREPEATSIGN : 0);
+        x_bytes += 1;
+      } else {
+        x_bytes += 2;
+      }
+      if (dy == 0) {
+        flag |= kFLAG_YREPEATSIGN;
+      } else if (dy > -256 && dy < 256) {
+        flag |= kFLAG_YSHORT | (dy > 0 ? kFLAG_YREPEATSIGN : 0);
+        y_bytes += 1;
+      } else {
+        y_bytes += 2;
+      }
+      if (flag == last_flag && repeat_count != 255) {
+        dst[*offset - 1] |= kFLAG_REPEAT;
+        repeat_count++;
+      } else {
+        if (repeat_count != 0) {
+          if (*offset >= dst_size) {
+            return FONT_COMPRESSION_FAILURE();
+          }
+          dst[(*offset)++] = repeat_count;
+        }
+        if (*offset >= dst_size) {
+          return FONT_COMPRESSION_FAILURE();
+        }
+        dst[(*offset)++] = flag;
+        repeat_count = 0;
+      }
+      last_x = point.x;
+      last_y = point.y;
+      last_flag = flag;
+    }
+  }
+  if (repeat_count != 0) {
+    if (*offset >= dst_size) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    dst[(*offset)++] = repeat_count;
+  }
+
+  if (*offset + x_bytes + y_bytes > dst_size) {
+    return FONT_COMPRESSION_FAILURE();
+  }
+
+  // Store the x and y coordinates.
+  size_t x_offset = *offset;
+  size_t y_offset = *offset + x_bytes;
+  last_x = 0;
+  last_y = 0;
+  for (const auto& contour : glyph.contours) {
+    for (const auto& point : contour) {
+      int dx = point.x - last_x;
+      int dy = point.y - last_y;
+      if (dx == 0) {
+        // pass
+      } else if (dx > -256 && dx < 256) {
+        dst[x_offset++] = std::abs(dx);
+      } else {
+        Store16(dx, &x_offset, dst);
+      }
+      if (dy == 0) {
+        // pass
+      } else if (dy > -256 && dy < 256) {
+        dst[y_offset++] = std::abs(dy);
+      } else {
+        Store16(dy, &y_offset, dst);
+      }
+      last_x += dx;
+      last_y += dy;
+    }
+  }
+  *offset = y_offset;
+  return true;
+}
+
+}  // namespace
+
+bool StoreGlyph(const Glyph& glyph, uint8_t* dst, size_t* dst_size) {
+  size_t offset = 0;
+  if (glyph.composite_data_size > 0) {
+    // Composite glyph.
+    if (*dst_size < ((10ULL + glyph.composite_data_size) +
+                     ((glyph.have_instructions ? 2ULL : 0) +
+                      glyph.instructions_size))) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    Store16(-1, &offset, dst);
+    StoreBbox(glyph, &offset, dst);
+    StoreBytes(glyph.composite_data, glyph.composite_data_size, &offset, dst);
+    if (glyph.have_instructions) {
+      StoreInstructions(glyph, &offset, dst);
+    }
+  } else if (glyph.contours.size() > 0) {
+    // Simple glyph.
+    if (glyph.contours.size() > std::numeric_limits<int16_t>::max()) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    if (*dst_size < ((12ULL + 2 * glyph.contours.size()) +
+                     glyph.instructions_size)) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    Store16(glyph.contours.size(), &offset, dst);
+    StoreBbox(glyph, &offset, dst);
+    if (!StoreEndPtsOfContours(glyph, &offset, dst)) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    StoreInstructions(glyph, &offset, dst);
+    if (!StorePoints(glyph, &offset, dst, *dst_size)) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+  }
+  *dst_size = offset;
+  return true;
+}
+
+} // namespace woff2