Revert of Update OTS to revision 6d2e08b

third_party/ots/include/opentype-sanitiser.h

Index: third_party/ots/include/opentype-sanitiser.h
diff --git a/third_party/ots/include/opentype-sanitiser.h b/third_party/ots/include/opentype-sanitiser.h
index 285a438979ca704e712625e9225378c52f02c58d..1c445ae00e42af577f8a13ffc318a07d12e5b617 100644
--- a/third_party/ots/include/opentype-sanitiser.h
+++ b/third_party/ots/include/opentype-sanitiser.h
@@ -29,9 +29,6 @@
 #include <cstddef>
 #include <cstring>
 
-#define OTS_TAG(c1,c2,c3,c4) ((uint32_t)((((uint8_t)(c1))<<24)|(((uint8_t)(c2))<<16)|(((uint8_t)(c3))<<8)|((uint8_t)(c4))))
-#define OTS_UNTAG(tag)       ((uint8_t)((tag)>>24)), ((uint8_t)((tag)>>16)), ((uint8_t)((tag)>>8)), ((uint8_t)(tag))
-
 namespace ots {
 
 // -----------------------------------------------------------------------------
@@ -40,7 +37,9 @@
 // -----------------------------------------------------------------------------
 class OTSStream {
  public:
-  OTSStream() : chksum_(0) {}
+  OTSStream() {
+    ResetChecksum();
+  }
 
   virtual ~OTSStream() {}
 
@@ -52,15 +51,20 @@
 
     const size_t orig_length = length;
     size_t offset = 0;
-
-    size_t chksum_offset = Tell() & 3;
-    if (chksum_offset) {
-      const size_t l = std::min(length, static_cast<size_t>(4) - chksum_offset);
-      uint32_t tmp = 0;
-      std::memcpy(reinterpret_cast<uint8_t *>(&tmp) + chksum_offset, data, l);
+    if (chksum_buffer_offset_) {
+      const size_t l =
+        std::min(length, static_cast<size_t>(4) - chksum_buffer_offset_);
+      std::memcpy(chksum_buffer_ + chksum_buffer_offset_, data, l);
+      chksum_buffer_offset_ += l;
+      offset += l;
+      length -= l;
+    }
+
+    if (chksum_buffer_offset_ == 4) {
+      uint32_t tmp;
+      std::memcpy(&tmp, chksum_buffer_, 4);
       chksum_ += ntohl(tmp);
-      length -= l;
-      offset += l;
+      chksum_buffer_offset_ = 0;
     }
 
     while (length >= 4) {
@@ -73,11 +77,11 @@
     }
 
     if (length) {
+      if (chksum_buffer_offset_ != 0) return false;  // not reached
       if (length > 4) return false;  // not reached
-      uint32_t tmp = 0;
-      std::memcpy(&tmp,
-                  reinterpret_cast<const uint8_t*>(data) + offset, length);
-      chksum_ += ntohl(tmp);
+      std::memcpy(chksum_buffer_,
+             reinterpret_cast<const uint8_t*>(data) + offset, length);
+      chksum_buffer_offset_ = length;
     }
 
     return WriteRaw(data, orig_length);
@@ -138,16 +142,41 @@
   }
 
   void ResetChecksum() {
-    assert((Tell() & 3) == 0);
     chksum_ = 0;
+    chksum_buffer_offset_ = 0;
   }
 
   uint32_t chksum() const {
+    assert(chksum_buffer_offset_ == 0);
     return chksum_;
+  }
+
+  struct ChecksumState {
+    uint32_t chksum;
+    uint8_t chksum_buffer[4];
+    unsigned chksum_buffer_offset;
+  };
+
+  ChecksumState SaveChecksumState() const {
+    ChecksumState s;
+    s.chksum = chksum_;
+    s.chksum_buffer_offset = chksum_buffer_offset_;
+    std::memcpy(s.chksum_buffer, chksum_buffer_, 4);
+
+    return s;
+  }
+
+  void RestoreChecksum(const ChecksumState &s) {
+    assert(chksum_buffer_offset_ == 0);
+    chksum_ += s.chksum;
+    chksum_buffer_offset_ = s.chksum_buffer_offset;
+    std::memcpy(chksum_buffer_, s.chksum_buffer, 4);
   }
 
  protected:
   uint32_t chksum_;
+  uint8_t chksum_buffer_[4];
+  unsigned chksum_buffer_offset_;
 };
 
 #ifdef __GCC__
@@ -189,6 +218,9 @@
     virtual TableAction GetTableAction(uint32_t tag) { return ots::TABLE_ACTION_DEFAULT; }
 };
 
+// For backward compatibility - remove once Chrome switches over to the new API.
+bool Process(OTSStream *output, const uint8_t *input, size_t length);
+
 }  // namespace ots
 
 #endif  // OPENTYPE_SANITISER_H_