diff options
Diffstat (limited to 'modules/woff2/src/glyph.cc')
| -rw-r--r-- | modules/woff2/src/glyph.cc | 383 |
1 files changed, 383 insertions, 0 deletions
diff --git a/modules/woff2/src/glyph.cc b/modules/woff2/src/glyph.cc new file mode 100644 index 0000000000..5b4948679c --- /dev/null +++ b/modules/woff2/src/glyph.cc @@ -0,0 +1,383 @@ +/* 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 |