gfx/ots/include/opentype-sanitiser.h

   1 // Copyright (c) 2009-2017 The OTS 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) || defined(__CYGWIN__)
   9   #define OTS_DLL_IMPORT __declspec(dllimport)
  10   #define OTS_DLL_EXPORT __declspec(dllexport)
  11 #else
  12   #if __GNUC__ >= 4
  13     #define OTS_DLL_IMPORT __attribute__((visibility ("default")))
  14     #define OTS_DLL_EXPORT __attribute__((visibility ("default")))
  15   #endif
  16 #endif
  17
  18 #ifdef OTS_DLL
  19   #ifdef OTS_DLL_EXPORTS
  20     #define OTS_API OTS_DLL_EXPORT
  21   #else
  22     #define OTS_API OTS_DLL_IMPORT
  23   #endif
  24 #else
  25   #define OTS_API
  26 #endif
  27
  28 #if defined(_WIN32)
  29 #include <stdlib.h>
  30 typedef signed char int8_t;
  31 typedef unsigned char uint8_t;
  32 typedef short int16_t;
  33 typedef unsigned short uint16_t;
  34 typedef int int32_t;
  35 typedef unsigned int uint32_t;
  36 typedef __int64 int64_t;
  37 typedef unsigned __int64 uint64_t;
  38 #define ots_ntohl(x) _byteswap_ulong (x)
  39 #define ots_ntohs(x) _byteswap_ushort (x)
  40 #define ots_htonl(x) _byteswap_ulong (x)
  41 #define ots_htons(x) _byteswap_ushort (x)
  42 #else
  43 #include <arpa/inet.h>
  44 #include <stdint.h>
  45 #define ots_ntohl(x) ntohl (x)
  46 #define ots_ntohs(x) ntohs (x)
  47 #define ots_htonl(x) htonl (x)
  48 #define ots_htons(x) htons (x)
  49 #endif
  50
  51 #include <sys/types.h>
  52
  53 #include <algorithm>
  54 #include <cassert>
  55 #include <cstddef>
  56 #include <cstring>
  57
  58 #define OTS_TAG(c1,c2,c3,c4) ((uint32_t)((((uint8_t)(c1))<<24)|(((uint8_t)(c2))<<16)|(((uint8_t)(c3))<<8)|((uint8_t)(c4))))
  59 #define OTS_UNTAG(tag)       ((char)((tag)>>24)), ((char)((tag)>>16)), ((char)((tag)>>8)), ((char)(tag))
  60
  61 #if defined(__GNUC__) && (__GNUC__ >= 4) || (__clang__)
  62 #define OTS_UNUSED __attribute__((unused))
  63 #elif defined(_MSC_VER)
  64 #define OTS_UNUSED __pragma(warning(suppress: 4100 4101))
  65 #else
  66 #define OTS_UNUSED
  67 #endif
  68
  69 namespace ots {
  70
  71 // -----------------------------------------------------------------------------
  72 // This is an interface for an abstract stream class which is used for writing
  73 // the serialised results out.
  74 // -----------------------------------------------------------------------------
  75 class OTSStream {
  76  public:
  77   OTSStream() : chksum_(0) {}
  78
  79   virtual ~OTSStream() {}
  80
  81   virtual size_t size() = 0;
  82
  83   // This should be implemented to perform the actual write.
  84   virtual bool WriteRaw(const void *data, size_t length) = 0;
  85
  86   bool Write(const void *data, size_t length) {
  87     if (!length) return false;
  88
  89     const size_t orig_length = length;
  90     size_t offset = 0;
  91
  92     size_t chksum_offset = Tell() & 3;
  93     if (chksum_offset) {
  94       const size_t l = std::min(length, static_cast<size_t>(4) - chksum_offset);
  95       uint32_t tmp = 0;
  96       std::memcpy(reinterpret_cast<uint8_t *>(&tmp) + chksum_offset, data, l);
  97       chksum_ += ots_ntohl(tmp);
  98       length -= l;
  99       offset += l;
 100     }
 101
 102     while (length >= 4) {
 103       uint32_t tmp;
 104       std::memcpy(&tmp, reinterpret_cast<const uint8_t *>(data) + offset,
 105         sizeof(uint32_t));
 106       chksum_ += ots_ntohl(tmp);
 107       length -= 4;
 108       offset += 4;
 109     }
 110
 111     if (length) {
 112       if (length > 4) return false;  // not reached
 113       uint32_t tmp = 0;
 114       std::memcpy(&tmp,
 115                   reinterpret_cast<const uint8_t*>(data) + offset, length);
 116       chksum_ += ots_ntohl(tmp);
 117     }
 118
 119     return WriteRaw(data, orig_length);
 120   }
 121
 122   virtual bool Seek(off_t position) = 0;
 123   virtual off_t Tell() const = 0;
 124
 125   virtual bool Pad(size_t bytes) {
 126     static const uint32_t kZero = 0;
 127     while (bytes >= 4) {
 128       if (!Write(&kZero, 4)) return false;
 129       bytes -= 4;
 130     }
 131     while (bytes) {
 132       static const uint8_t kZerob = 0;
 133       if (!Write(&kZerob, 1)) return false;
 134       bytes--;
 135     }
 136     return true;
 137   }
 138
 139   bool WriteU8(uint8_t v) {
 140     return Write(&v, sizeof(v));
 141   }
 142
 143   bool WriteU16(uint16_t v) {
 144     v = ots_htons(v);
 145     return Write(&v, sizeof(v));
 146   }
 147
 148   bool WriteS16(int16_t v) {
 149     v = ots_htons(v);
 150     return Write(&v, sizeof(v));
 151   }
 152
 153   bool WriteU24(uint32_t v) {
 154     v = ots_htonl(v);
 155     return Write(reinterpret_cast<uint8_t*>(&v)+1, 3);
 156   }
 157
 158   bool WriteU32(uint32_t v) {
 159     v = ots_htonl(v);
 160     return Write(&v, sizeof(v));
 161   }
 162
 163   bool WriteS32(int32_t v) {
 164     v = ots_htonl(v);
 165     return Write(&v, sizeof(v));
 166   }
 167
 168   bool WriteR64(uint64_t v) {
 169     return Write(&v, sizeof(v));
 170   }
 171
 172   void ResetChecksum() {
 173     assert((Tell() & 3) == 0);
 174     chksum_ = 0;
 175   }
 176
 177   uint32_t chksum() const {
 178     return chksum_;
 179   }
 180
 181  protected:
 182   uint32_t chksum_;
 183 };
 184
 185 #ifdef __GCC__
 186 #define MSGFUNC_FMT_ATTR __attribute__((format(printf, 2, 3)))
 187 #else
 188 #define MSGFUNC_FMT_ATTR
 189 #endif
 190
 191 enum TableAction {
 192   TABLE_ACTION_DEFAULT,  // Use OTS's default action for that table
 193   TABLE_ACTION_SANITIZE, // Sanitize the table, potentially dropping it
 194   TABLE_ACTION_PASSTHRU, // Serialize the table unchanged
 195   TABLE_ACTION_DROP      // Drop the table
 196 };
 197
 198 class OTS_API OTSContext {
 199   public:
 200     OTSContext() {}
 201     virtual ~OTSContext() {}
 202
 203     // Process a given OpenType file and write out a sanitized version
 204     //   output: a pointer to an object implementing the OTSStream interface. The
 205     //     sanitisied output will be written to this. In the even of a failure,
 206     //     partial output may have been written.
 207     //   input: the OpenType file
 208     //   length: the size, in bytes, of |input|
 209     //   index: if the input is a font collection and index is specified, then
 210     //     the corresponding font will be returned, otherwise the whole
 211     //     collection. Ignored for non-collection fonts.
 212     bool Process(OTSStream *output, const uint8_t *input, size_t length, uint32_t index = -1);
 213
 214     // This function will be called when OTS is reporting an error.
 215     //   level: the severity of the generated message:
 216     //     0: error messages in case OTS fails to sanitize the font.
 217     //     1: warning messages about issue OTS fixed in the sanitized font.
 218     virtual void Message(int level OTS_UNUSED, const char *format OTS_UNUSED, ...) MSGFUNC_FMT_ATTR {}
 219
 220     // This function will be called when OTS needs to decide what to do for a
 221     // font table.
 222     //   tag: table tag formed with OTS_TAG() macro
 223     virtual TableAction GetTableAction(uint32_t tag OTS_UNUSED) { return ots::TABLE_ACTION_DEFAULT; }
 224 };
 225
 226 }  // namespace ots
 227
 228 #endif  // OPENTYPE_SANITISER_H_