tor-browser

glat.cc (15304B)

---

// Copyright (c) 2009-2017 The OTS 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 "glat.h"

#include "gloc.h"
#include "mozilla/Compression.h"
#include <list>
#include <memory>

namespace ots {

// -----------------------------------------------------------------------------
// OpenTypeGLAT_v1
// -----------------------------------------------------------------------------

bool OpenTypeGLAT_v1::Parse(const uint8_t* data, size_t length) {
 Buffer table(data, length);
 OpenTypeGLOC* gloc = static_cast<OpenTypeGLOC*>(
     GetFont()->GetTypedTable(OTS_TAG_GLOC));
 if (!gloc) {
   return DropGraphite("Required Gloc table is missing");
 }

 if (!table.ReadU32(&this->version) || this->version >> 16 != 1) {
   return DropGraphite("Failed to read version");
 }

 const std::vector<uint32_t>& locations = gloc->GetLocations();
 if (locations.empty()) {
   return DropGraphite("No locations from Gloc table");
 }
 std::list<uint32_t> unverified(locations.begin(), locations.end());
 while (table.remaining()) {
   GlatEntry entry(this);
   if (table.offset() > unverified.front()) {
     return DropGraphite("Offset check failed for a GlatEntry");
   }
   if (table.offset() == unverified.front()) {
     unverified.pop_front();
   }
   if (unverified.empty()) {
     return DropGraphite("Expected more locations");
   }
   if (!entry.ParsePart(table)) {
     return DropGraphite("Failed to read a GlatEntry");
   }
   this->entries.push_back(entry);
 }

 if (unverified.size() != 1 || unverified.front() != table.offset()) {
   return DropGraphite("%zu location(s) could not be verified", unverified.size());
 }
 if (table.remaining()) {
   return Warning("%zu bytes unparsed", table.remaining());
 }
 return true;
}

bool OpenTypeGLAT_v1::Serialize(OTSStream* out) {
 assert(ShouldSerialize());
 if (!out->WriteU32(this->version) ||
     !SerializeParts(this->entries, out)) {
   return Error("Failed to write table");
 }
 return true;
}

bool OpenTypeGLAT_v1::GlatEntry::ParsePart(Buffer& table) {
 if (!table.ReadU8(&this->attNum)) {
   return parent->Error("GlatEntry: Failed to read attNum");
 }
 if (!table.ReadU8(&this->num)) {
   return parent->Error("GlatEntry: Failed to read num");
 }

 //this->attributes.resize(this->num);
 for (int i = 0; i < this->num; ++i) {
   this->attributes.emplace_back();
   if (!table.ReadS16(&this->attributes[i])) {
     return parent->Error("GlatEntry: Failed to read attribute %u", i);
   }
 }
 return true;
}

bool OpenTypeGLAT_v1::GlatEntry::SerializePart(OTSStream* out) const {
 if (!out->WriteU8(this->attNum) ||
     !out->WriteU8(this->num) ||
     !SerializeParts(this->attributes, out)) {
   return parent->Error("GlatEntry: Failed to write");
 }
 return true;
}

// -----------------------------------------------------------------------------
// OpenTypeGLAT_v2
// -----------------------------------------------------------------------------

bool OpenTypeGLAT_v2::Parse(const uint8_t* data, size_t length) {
 Buffer table(data, length);
 OpenTypeGLOC* gloc = static_cast<OpenTypeGLOC*>(
     GetFont()->GetTypedTable(OTS_TAG_GLOC));
 if (!gloc) {
   return DropGraphite("Required Gloc table is missing");
 }

 if (!table.ReadU32(&this->version) || this->version >> 16 != 1) {
   return DropGraphite("Failed to read version");
 }

 const std::vector<uint32_t>& locations = gloc->GetLocations();
 if (locations.empty()) {
   return DropGraphite("No locations from Gloc table");
 }
 std::list<uint32_t> unverified(locations.begin(), locations.end());
 while (table.remaining()) {
   GlatEntry entry(this);
   if (table.offset() > unverified.front()) {
     return DropGraphite("Offset check failed for a GlatEntry");
   }
   if (table.offset() == unverified.front()) {
     unverified.pop_front();
   }
   if (unverified.empty()) {
     return DropGraphite("Expected more locations");
   }
   if (!entry.ParsePart(table)) {
     return DropGraphite("Failed to read a GlatEntry");
   }
   this->entries.push_back(entry);
 }

 if (unverified.size() != 1 || unverified.front() != table.offset()) {
   return DropGraphite("%zu location(s) could not be verified", unverified.size());
 }
 if (table.remaining()) {
   return Warning("%zu bytes unparsed", table.remaining());
 }
 return true;
}

bool OpenTypeGLAT_v2::Serialize(OTSStream* out) {
 assert(ShouldSerialize());
 if (!out->WriteU32(this->version) ||
     !SerializeParts(this->entries, out)) {
   return Error("Failed to write table");
 }
 return true;
}

bool OpenTypeGLAT_v2::GlatEntry::ParsePart(Buffer& table) {
 if (!table.ReadS16(&this->attNum)) {
   return parent->Error("GlatEntry: Failed to read attNum");
 }
 if (!table.ReadS16(&this->num) || this->num < 0) {
   return parent->Error("GlatEntry: Failed to read valid num");
 }

 //this->attributes.resize(this->num);
 for (int i = 0; i < this->num; ++i) {
   this->attributes.emplace_back();
   if (!table.ReadS16(&this->attributes[i])) {
     return parent->Error("GlatEntry: Failed to read attribute %u", i);
   }
 }
 return true;
}

bool OpenTypeGLAT_v2::GlatEntry::SerializePart(OTSStream* out) const {
 if (!out->WriteS16(this->attNum) ||
     !out->WriteS16(this->num) ||
     !SerializeParts(this->attributes, out)) {
   return parent->Error("GlatEntry: Failed to write");
 }
 return true;
}

// -----------------------------------------------------------------------------
// OpenTypeGLAT_v3
// -----------------------------------------------------------------------------

bool OpenTypeGLAT_v3::Parse(const uint8_t* data, size_t length,
                           bool prevent_decompression) {
 Buffer table(data, length);
 OpenTypeGLOC* gloc = static_cast<OpenTypeGLOC*>(
     GetFont()->GetTypedTable(OTS_TAG_GLOC));
 if (!gloc) {
   return DropGraphite("Required Gloc table is missing");
 }

 if (!table.ReadU32(&this->version) || this->version >> 16 != 3) {
   return DropGraphite("Failed to read version");
 }
 if (!table.ReadU32(&this->compHead)) {
   return DropGraphite("Failed to read compression header");
 }
 switch ((this->compHead & SCHEME) >> 27) {
   case 0:  // uncompressed
     break;
   case 1: {  // lz4
     if (prevent_decompression) {
       return DropGraphite("Illegal nested compression");
     }
     size_t decompressed_size = this->compHead & FULL_SIZE;
     if (decompressed_size < length) {
       return DropGraphite("Decompressed size is less than compressed size");
     }
     if (decompressed_size == 0) {
       return DropGraphite("Decompressed size is set to 0");
     }
     // decompressed table must be <= OTS_MAX_DECOMPRESSED_TABLE_SIZE
     if (decompressed_size > OTS_MAX_DECOMPRESSED_TABLE_SIZE) {
       return DropGraphite("Decompressed size exceeds %gMB: %gMB",
                           OTS_MAX_DECOMPRESSED_TABLE_SIZE / (1024.0 * 1024.0),
                           decompressed_size / (1024.0 * 1024.0));
     }
     std::unique_ptr<uint8_t> decompressed(new uint8_t[decompressed_size]());
     size_t outputSize = 0;
     bool ret = mozilla::Compression::LZ4::decompressPartial(
         reinterpret_cast<const char*>(data + table.offset()),
         table.remaining(),  // input buffer size (input size + padding)
         reinterpret_cast<char*>(decompressed.get()),
         decompressed_size,  // target output size
         &outputSize);  // return output size
     if (!ret || outputSize != decompressed_size) {
       return DropGraphite("Decompression failed");
     }
     return this->Parse(decompressed.get(), decompressed_size, true);
   }
   default:
     return DropGraphite("Unknown compression scheme");
 }
 if (this->compHead & RESERVED) {
   Warning("Nonzero reserved");
 }

 const std::vector<uint32_t>& locations = gloc->GetLocations();
 if (locations.empty()) {
   return DropGraphite("No locations from Gloc table");
 }
 std::list<uint32_t> unverified(locations.begin(), locations.end());
 //this->entries.resize(locations.size() - 1, this);
 for (size_t i = 0; i < locations.size() - 1; ++i) {
   this->entries.emplace_back(this);
   if (table.offset() != unverified.front()) {
     return DropGraphite("Offset check failed for a GlyphAttrs");
   }
   unverified.pop_front();
   if (!this->entries[i].ParsePart(table,
                                   unverified.front() - table.offset())) {
       // unverified.front() is guaranteed to exist because of the number of
       // iterations of this loop
     return DropGraphite("Failed to read a GlyphAttrs");
   }
 }

 if (unverified.size() != 1 || unverified.front() != table.offset()) {
   return DropGraphite("%zu location(s) could not be verified", unverified.size());
 }
 if (table.remaining()) {
   return Warning("%zu bytes unparsed", table.remaining());
 }
 return true;
}

bool OpenTypeGLAT_v3::Serialize(OTSStream* out) {
 assert(ShouldSerialize());
 if (!out->WriteU32(this->version) ||
     !out->WriteU32(this->compHead) ||
     !SerializeParts(this->entries, out)) {
   return Error("Failed to write table");
 }
 return true;
}

bool OpenTypeGLAT_v3::GlyphAttrs::ParsePart(Buffer& table, const size_t size) {
 size_t init_offset = table.offset();
 if (parent->compHead & OCTABOXES && !octabox.ParsePart(table)) {
   // parent->flags & 0b1: octaboxes are present flag
   return parent->Error("GlyphAttrs: Failed to read octabox");
 }

 while (table.offset() < init_offset + size) {
   GlatEntry entry(parent);
   if (!entry.ParsePart(table)) {
     return parent->Error("GlyphAttrs: Failed to read a GlatEntry");
   }
   this->entries.push_back(entry);
 }
 return true;
}

bool OpenTypeGLAT_v3::GlyphAttrs::SerializePart(OTSStream* out) const {
 if ((parent->compHead & OCTABOXES && !octabox.SerializePart(out)) ||
     !SerializeParts(this->entries, out)) {
   return parent->Error("GlyphAttrs: Failed to write");
 }
 return true;
}

bool OpenTypeGLAT_v3::GlyphAttrs::
OctaboxMetrics::ParsePart(Buffer& table) {
 if (!table.ReadU16(&this->subbox_bitmap)) {
   return parent->Error("OctaboxMetrics: Failed to read subbox_bitmap");
 }
 if (!table.ReadU8(&this->diag_neg_min)) {
   return parent->Error("OctaboxMetrics: Failed to read diag_neg_min");
 }
 if (!table.ReadU8(&this->diag_neg_max) ||
     this->diag_neg_max < this->diag_neg_min) {
   return parent->Error("OctaboxMetrics: Failed to read valid diag_neg_max");
 }
 if (!table.ReadU8(&this->diag_pos_min)) {
   return parent->Error("OctaboxMetrics: Failed to read diag_pos_min");
 }
 if (!table.ReadU8(&this->diag_pos_max) ||
     this->diag_pos_max < this->diag_pos_min) {
   return parent->Error("OctaboxMetrics: Failed to read valid diag_pos_max");
 }

 unsigned subboxes_len = 0;  // count of 1's in this->subbox_bitmap
 for (uint16_t i = this->subbox_bitmap; i; i >>= 1) {
   if (i & 0b1) {
     ++subboxes_len;
   }
 }
 //this->subboxes.resize(subboxes_len, parent);
 for (unsigned i = 0; i < subboxes_len; i++) {
   this->subboxes.emplace_back(parent);
   if (!this->subboxes[i].ParsePart(table)) {
     return parent->Error("OctaboxMetrics: Failed to read subbox[%u]", i);
   }
 }
 return true;
}

bool OpenTypeGLAT_v3::GlyphAttrs::
OctaboxMetrics::SerializePart(OTSStream* out) const {
 if (!out->WriteU16(this->subbox_bitmap) ||
     !out->WriteU8(this->diag_neg_min) ||
     !out->WriteU8(this->diag_neg_max) ||
     !out->WriteU8(this->diag_pos_min) ||
     !out->WriteU8(this->diag_pos_max) ||
     !SerializeParts(this->subboxes, out)) {
   return parent->Error("OctaboxMetrics: Failed to write");
 }
 return true;
}

bool OpenTypeGLAT_v3::GlyphAttrs::OctaboxMetrics::
SubboxEntry::ParsePart(Buffer& table) {
 if (!table.ReadU8(&this->left)) {
   return parent->Error("SubboxEntry: Failed to read left");
 }
 if (!table.ReadU8(&this->right) || this->right < this->left) {
   return parent->Error("SubboxEntry: Failed to read valid right");
 }
 if (!table.ReadU8(&this->bottom)) {
   return parent->Error("SubboxEntry: Failed to read bottom");
 }
 if (!table.ReadU8(&this->top) || this->top < this->bottom) {
   return parent->Error("SubboxEntry: Failed to read valid top");
 }
 if (!table.ReadU8(&this->diag_pos_min)) {
   return parent->Error("SubboxEntry: Failed to read diag_pos_min");
 }
 if (!table.ReadU8(&this->diag_pos_max) ||
     this->diag_pos_max < this->diag_pos_min) {
   return parent->Error("SubboxEntry: Failed to read valid diag_pos_max");
 }
 if (!table.ReadU8(&this->diag_neg_min)) {
   return parent->Error("SubboxEntry: Failed to read diag_neg_min");
 }
 if (!table.ReadU8(&this->diag_neg_max) ||
     this->diag_neg_max < this->diag_neg_min) {
   return parent->Error("SubboxEntry: Failed to read valid diag_neg_max");
 }
 return true;
}

bool OpenTypeGLAT_v3::GlyphAttrs::OctaboxMetrics::
SubboxEntry::SerializePart(OTSStream* out) const {
 if (!out->WriteU8(this->left) ||
     !out->WriteU8(this->right) ||
     !out->WriteU8(this->bottom) ||
     !out->WriteU8(this->top) ||
     !out->WriteU8(this->diag_pos_min) ||
     !out->WriteU8(this->diag_pos_max) ||
     !out->WriteU8(this->diag_neg_min) ||
     !out->WriteU8(this->diag_neg_max)) {
   return parent->Error("SubboxEntry: Failed to write");
 }
 return true;
}

bool OpenTypeGLAT_v3::GlyphAttrs::
GlatEntry::ParsePart(Buffer& table) {
 if (!table.ReadS16(&this->attNum)) {
   return parent->Error("GlatEntry: Failed to read attNum");
 }
 if (!table.ReadS16(&this->num) || this->num < 0) {
   return parent->Error("GlatEntry: Failed to read valid num");
 }

 //this->attributes.resize(this->num);
 for (int i = 0; i < this->num; ++i) {
   this->attributes.emplace_back();
   if (!table.ReadS16(&this->attributes[i])) {
     return parent->Error("GlatEntry: Failed to read attribute %u", i);
   }
 }
 return true;
}

bool OpenTypeGLAT_v3::GlyphAttrs::
GlatEntry::SerializePart(OTSStream* out) const {
 if (!out->WriteS16(this->attNum) ||
     !out->WriteS16(this->num) ||
     !SerializeParts(this->attributes, out)) {
   return parent->Error("GlatEntry: Failed to write");
 }
 return true;
}

// -----------------------------------------------------------------------------
// OpenTypeGLAT
// -----------------------------------------------------------------------------

bool OpenTypeGLAT::Parse(const uint8_t* data, size_t length) {
 Buffer table(data, length);
 uint32_t version;
 if (!table.ReadU32(&version)) {
   return DropGraphite("Failed to read version");
 }
 switch (version >> 16) {
   case 1:
     this->handler = new OpenTypeGLAT_v1(this->font, this->tag);
     break;
   case 2:
     this->handler = new OpenTypeGLAT_v2(this->font, this->tag);
     break;
   case 3: {
     this->handler = new OpenTypeGLAT_v3(this->font, this->tag);
     break;
   }
   default:
     return DropGraphite("Unsupported table version: %u", version >> 16);
 }
 return this->handler->Parse(data, length);
}

bool OpenTypeGLAT::Serialize(OTSStream* out) {
 if (!this->handler) {
   return Error("No Glat table parsed");
 }
 return this->handler->Serialize(out);
}

}  // namespace ots