Move public headers into a separate include/woff2 directory

This is a first step to make WOFF2 a shared library. Public headers are moved
in their own directory to make the public API clearer. This is similar to
the c/include/brotli/ directory in Brotli. "using" commands are also removed
from the public headers, so that callers won't have unexpected side effect
when including the files.

include/woff2/decode.h

@@ -0,0 +1,36 @@
+/* Copyright 2014 Google Inc. All Rights Reserved.
+
+   Distributed under MIT license.
+   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
+*/
+
+/* Library for converting WOFF2 format font files to their TTF versions. */
+
+#ifndef WOFF2_WOFF2_DEC_H_
+#define WOFF2_WOFF2_DEC_H_
+
+#include <stddef.h>
+#include <inttypes.h>
+#include <woff2/output.h>
+
+namespace woff2 {
+
+// Compute the size of the final uncompressed font, or 0 on error.
+size_t ComputeWOFF2FinalSize(const uint8_t *data, size_t length);
+
+// Decompresses the font into the target buffer. The result_length should
+// be the same as determined by ComputeFinalSize(). Returns true on successful
+// decompression.
+// DEPRECATED; please prefer the version that takes a WOFF2Out*
+bool ConvertWOFF2ToTTF(uint8_t *result, size_t result_length,
+                       const uint8_t *data, size_t length);
+
+// Decompresses the font into out. Returns true on success.
+// Works even if WOFF2Header totalSfntSize is wrong.
+// Please prefer this API.
+bool ConvertWOFF2ToTTF(const uint8_t *data, size_t length,
+                       WOFF2Out* out);
+
+} // namespace woff2
+
+#endif  // WOFF2_WOFF2_DEC_H_

include/woff2/encode.h

@@ -0,0 +1,43 @@
+/* Copyright 2014 Google Inc. All Rights Reserved.
+
+   Distributed under MIT license.
+   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
+*/
+
+/* Library for converting WOFF2 format font files to their TTF versions. */
+
+#ifndef WOFF2_WOFF2_ENC_H_
+#define WOFF2_WOFF2_ENC_H_
+
+#include <stddef.h>
+#include <inttypes.h>
+#include <string>
+
+namespace woff2 {
+
+struct WOFF2Params {
+  WOFF2Params() : extended_metadata(""), brotli_quality(11),
+                  allow_transforms(true) {}
+
+  std::string extended_metadata;
+  int brotli_quality;
+  bool allow_transforms;
+};
+
+// Returns an upper bound on the size of the compressed file.
+size_t MaxWOFF2CompressedSize(const uint8_t* data, size_t length);
+size_t MaxWOFF2CompressedSize(const uint8_t* data, size_t length,
+                              const std::string& extended_metadata);
+
+// Compresses the font into the target buffer. *result_length should be at least
+// the value returned by MaxWOFF2CompressedSize(), upon return, it is set to the
+// actual compressed size. Returns true on successful compression.
+bool ConvertTTFToWOFF2(const uint8_t *data, size_t length,
+                       uint8_t *result, size_t *result_length);
+bool ConvertTTFToWOFF2(const uint8_t *data, size_t length,
+                       uint8_t *result, size_t *result_length,
+                       const WOFF2Params& params);
+
+} // namespace woff2
+
+#endif  // WOFF2_WOFF2_ENC_H_

include/woff2/output.h

@@ -0,0 +1,86 @@
+/* Copyright 2016 Google Inc. All Rights Reserved.
+
+   Distributed under MIT license.
+   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
+*/
+
+/* Output buffer for WOFF2 decompression. */
+
+#ifndef WOFF2_WOFF2_OUT_H_
+#define WOFF2_WOFF2_OUT_H_
+
+#include <algorithm>
+#include <cstring>
+#include <memory>
+#include <string>
+
+namespace woff2 {
+
+// Suggested max size for output.
+const size_t kDefaultMaxSize = 30 * 1024 * 1024;
+
+/**
+ * Output interface for the woff2 decoding.
+ *
+ * Writes to arbitrary offsets are supported to facilitate updating offset
+ * table and checksums after tables are ready. Reading the current size is
+ * supported so a 'loca' table can be built up while writing glyphs.
+ *
+ * By default limits size to kDefaultMaxSize.
+ */
+class WOFF2Out {
+ public:
+  virtual ~WOFF2Out(void) {}
+
+  // Append n bytes of data from buf.
+  // Return true if all written, false otherwise.
+  virtual bool Write(const void *buf, size_t n) = 0;
+
+  // Write n bytes of data from buf at offset.
+  // Return true if all written, false otherwise.
+  virtual bool Write(const void *buf, size_t offset, size_t n) = 0;
+
+  virtual size_t Size() = 0;
+};
+
+/**
+ * Expanding memory block for woff2 out. By default limited to kDefaultMaxSize.
+ */
+class WOFF2StringOut : public WOFF2Out {
+ public:
+  // Create a writer that writes its data to buf.
+  // buf->size() will grow to at most max_size
+  // buf may be sized (e.g. using EstimateWOFF2FinalSize) or empty.
+  explicit WOFF2StringOut(std::string* buf);
+
+  bool Write(const void *buf, size_t n) override;
+  bool Write(const void *buf, size_t offset, size_t n) override;
+  size_t Size() override { return offset_; }
+  size_t MaxSize() { return max_size_; }
+  void SetMaxSize(size_t max_size);
+ private:
+  std::string* buf_;
+  size_t max_size_;
+  size_t offset_;
+};
+
+/**
+ * Fixed memory block for woff2 out.
+ */
+class WOFF2MemoryOut : public WOFF2Out {
+ public:
+  // Create a writer that writes its data to buf.
+  WOFF2MemoryOut(uint8_t* buf, size_t buf_size);
+
+  bool Write(const void *buf, size_t n) override;
+  bool Write(const void *buf, size_t offset, size_t n) override;
+  size_t Size() override { return offset_; }
+ private:
+  uint8_t* buf_;
+  size_t buf_size_;
+  size_t offset_;
+};
+
+} // namespace woff2
+
+#endif  // WOFF2_WOFF2_OUT_H_