third_party/ots/include/opentype-sanitiser.h

   1 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef OPENTYPE_SANITISER_H_
   6 #define OPENTYPE_SANITISER_H_
   7
   8 #if defined(_WIN32)
   9 #include <stdlib.h>
  10 typedef signed char int8_t;
  11 typedef unsigned char uint8_t;
  12 typedef short int16_t;
  13 typedef unsigned short uint16_t;
  14 typedef int int32_t;
  15 typedef unsigned int uint32_t;
  16 typedef __int64 int64_t;
  17 typedef unsigned __int64 uint64_t;
  18 #define ntohl(x) _byteswap_ulong (x)
  19 #define ntohs(x) _byteswap_ushort (x)
  20 #define htonl(x) _byteswap_ulong (x)
  21 #define htons(x) _byteswap_ushort (x)
  22 #else
  23 #include <arpa/inet.h>
  24 #include <stdint.h>
  25 #endif
  26
  27 #include <algorithm>
  28 #include <cassert>
  29 #include <cstddef>
  30 #include <cstring>
  31
  32 #define OTS_TAG(c1,c2,c3,c4) ((uint32_t)((((uint8_t)(c1))<<24)|(((uint8_t)(c2))<<16)|(((uint8_t)(c3))<<8)|((uint8_t)(c4))))
  33 #define OTS_UNTAG(tag)       ((uint8_t)((tag)>>24)), ((uint8_t)((tag)>>16)), ((uint8_t)((tag)>>8)), ((uint8_t)(tag))
  34
  35 namespace ots {
  36
  37 // -----------------------------------------------------------------------------
  38 // This is an interface for an abstract stream class which is used for writing
  39 // the serialised results out.
  40 // -----------------------------------------------------------------------------
  41 class OTSStream {
  42  public:
  43   OTSStream() : chksum_(0) {}
  44
  45   virtual ~OTSStream() {}
  46
  47   // This should be implemented to perform the actual write.
  48   virtual bool WriteRaw(const void *data, size_t length) = 0;
  49
  50   bool Write(const void *data, size_t length) {
  51     if (!length) return false;
  52
  53     const size_t orig_length = length;
  54     size_t offset = 0;
  55
  56     size_t chksum_offset = Tell() & 3;
  57     if (chksum_offset) {
  58       const size_t l = std::min(length, static_cast<size_t>(4) - chksum_offset);
  59       uint32_t tmp = 0;
  60       std::memcpy(reinterpret_cast<uint8_t *>(&tmp) + chksum_offset, data, l);
  61       chksum_ += ntohl(tmp);
  62       length -= l;
  63       offset += l;
  64     }
  65
  66     while (length >= 4) {
  67       uint32_t tmp;
  68       std::memcpy(&tmp, reinterpret_cast<const uint8_t *>(data) + offset,
  69         sizeof(uint32_t));
  70       chksum_ += ntohl(tmp);
  71       length -= 4;
  72       offset += 4;
  73     }
  74
  75     if (length) {
  76       if (length > 4) return false;  // not reached
  77       uint32_t tmp = 0;
  78       std::memcpy(&tmp,
  79                   reinterpret_cast<const uint8_t*>(data) + offset, length);
  80       chksum_ += ntohl(tmp);
  81     }
  82
  83     return WriteRaw(data, orig_length);
  84   }
  85
  86   virtual bool Seek(off_t position) = 0;
  87   virtual off_t Tell() const = 0;
  88
  89   virtual bool Pad(size_t bytes) {
  90     static const uint32_t kZero = 0;
  91     while (bytes >= 4) {
  92       if (!WriteTag(kZero)) return false;
  93       bytes -= 4;
  94     }
  95     while (bytes) {
  96       static const uint8_t kZerob = 0;
  97       if (!Write(&kZerob, 1)) return false;
  98       bytes--;
  99     }
 100     return true;
 101   }
 102
 103   bool WriteU8(uint8_t v) {
 104     return Write(&v, sizeof(v));
 105   }
 106
 107   bool WriteU16(uint16_t v) {
 108     v = htons(v);
 109     return Write(&v, sizeof(v));
 110   }
 111
 112   bool WriteS16(int16_t v) {
 113     v = htons(v);
 114     return Write(&v, sizeof(v));
 115   }
 116
 117   bool WriteU24(uint32_t v) {
 118     v = htonl(v);
 119     return Write(reinterpret_cast<uint8_t*>(&v)+1, 3);
 120   }
 121
 122   bool WriteU32(uint32_t v) {
 123     v = htonl(v);
 124     return Write(&v, sizeof(v));
 125   }
 126
 127   bool WriteS32(int32_t v) {
 128     v = htonl(v);
 129     return Write(&v, sizeof(v));
 130   }
 131
 132   bool WriteR64(uint64_t v) {
 133     return Write(&v, sizeof(v));
 134   }
 135
 136   bool WriteTag(uint32_t v) {
 137     return Write(&v, sizeof(v));
 138   }
 139
 140   void ResetChecksum() {
 141     assert((Tell() & 3) == 0);
 142     chksum_ = 0;
 143   }
 144
 145   uint32_t chksum() const {
 146     return chksum_;
 147   }
 148
 149  protected:
 150   uint32_t chksum_;
 151 };
 152
 153 #ifdef __GCC__
 154 #define MSGFUNC_FMT_ATTR __attribute__((format(printf, 2, 3)))
 155 #else
 156 #define MSGFUNC_FMT_ATTR
 157 #endif
 158
 159 enum TableAction {
 160   TABLE_ACTION_DEFAULT,  // Use OTS's default action for that table
 161   TABLE_ACTION_SANITIZE, // Sanitize the table, potentially droping it
 162   TABLE_ACTION_PASSTHRU, // Serialize the table unchanged
 163   TABLE_ACTION_DROP      // Drop the table
 164 };
 165
 166 class OTSContext {
 167   public:
 168     OTSContext() {}
 169     virtual ~OTSContext() {}
 170
 171     // Process a given OpenType file and write out a sanitised version
 172     //   output: a pointer to an object implementing the OTSStream interface. The
 173     //     sanitisied output will be written to this. In the even of a failure,
 174     //     partial output may have been written.
 175     //   input: the OpenType file
 176     //   length: the size, in bytes, of |input|
 177     bool Process(OTSStream *output, const uint8_t *input, size_t length);
 178
 179     // This function will be called when OTS is reporting an error.
 180     //   level: the severity of the generated message:
 181     //     0: error messages in case OTS fails to sanitize the font.
 182     //     1: warning messages about issue OTS fixed in the sanitized font.
 183     virtual void Message(int level, const char *format, ...) MSGFUNC_FMT_ATTR {}
 184
 185     // This function will be called when OTS needs to decide what to do for a
 186     // font table.
 187     //   tag: table tag as an integer in big-endian byte order, independent of
 188     //   platform endianness
 189     virtual TableAction GetTableAction(uint32_t tag) { return ots::TABLE_ACTION_DEFAULT; }
 190 };
 191
 192 }  // namespace ots
 193
 194 #endif  // OPENTYPE_SANITISER_H_