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-rw-r--r--modules/woff2/src/glyph.cc383
1 files changed, 383 insertions, 0 deletions
diff --git a/modules/woff2/src/glyph.cc b/modules/woff2/src/glyph.cc
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+++ b/modules/woff2/src/glyph.cc
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+/* 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_OVERLAP_SIMPLE = 1 << 6;
+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;
+ }
+ }
+ }
+
+ if (!flags.empty() && !flags[0].empty()) {
+ glyph->overlap_simple_flag_set = (flags[0][0] & kFLAG_OVERLAP_SIMPLE);
+ }
+
+ // 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 previous_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;
+ if (previous_flag == -1 && glyph.overlap_simple_flag_set) {
+ // First flag needs to have overlap simple bit set.
+ flag = flag | kFLAG_OVERLAP_SIMPLE;
+ }
+ 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 == previous_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;
+ previous_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