icuSources/layout/LETableReference.h

   1 /*
   2  * -*- c++ -*-
   3  *
   4  * (C) Copyright IBM Corp. and others 2013 - All Rights Reserved
   5  *
   6  * Range checking
   7  *
   8  */
   9
  10 #ifndef __LETABLEREFERENCE_H
  11 #define __LETABLEREFERENCE_H
  12
  13 #include "LETypes.h"
  14 #include "LEFontInstance.h"
  15
  16
  17 #define kQuestionmarkTableTag  0x3F3F3F3FUL
  18 #define kTildeTableTag  0x7e7e7e7eUL
  19 #ifdef __cplusplus
  20
  21 // internal - interface for range checking
  22 U_NAMESPACE_BEGIN
  23
  24 #if LE_ASSERT_BAD_FONT
  25 class LETableReference; // fwd
  26 /**
  27  *  defined in OpenTypeUtilities.cpp
  28  * @internal
  29  */
  30 extern void _debug_LETableReference(const char *f, int l, const char *msg, const LETableReference *what, const void *ptr, size_t len);
  31
  32 #define LE_DEBUG_TR(x) _debug_LETableReference(__FILE__, __LINE__, x, this, NULL, 0);
  33 #define LE_DEBUG_TR3(x,y,z) _debug_LETableReference(__FILE__, __LINE__, x, this, (const void*)y, (size_t)z);
  34 #if 0
  35 #define LE_TRACE_TR(x) _debug_LETableReference(__FILE__, __LINE__, x, this, NULL, 0);
  36 #else
  37 #define LE_TRACE_TR(x)
  38 #endif
  39
  40 #else
  41 #define LE_DEBUG_TR(x)
  42 #define LE_DEBUG_TR3(x,y,z)
  43 #define LE_TRACE_TR(x)
  44 #endif
  45
  46 /**
  47  * @internal
  48  */
  49 class LETableReference {
  50 public:
  51 /**
  52  * @internal
  53  * Construct from a specific tag
  54  */
  55   LETableReference(const LEFontInstance* font, LETag tableTag, LEErrorCode &success) :
  56     fFont(font), fTag(tableTag), fParent(NULL), fStart(NULL),fLength(LE_UINTPTR_MAX) {
  57       loadTable(success);
  58     LE_TRACE_TR("INFO: new table load")
  59   }
  60
  61   LETableReference(const LETableReference &parent, LEErrorCode &success) : fFont(parent.fFont), fTag(parent.fTag), fParent(&parent), fStart(parent.fStart), fLength(parent.fLength) {
  62     if(LE_FAILURE(success)) {
  63       clear();
  64     }
  65     LE_TRACE_TR("INFO: new clone")
  66   }
  67
  68    LETableReference(const le_uint8* data, size_t length = LE_UINTPTR_MAX) :
  69     fFont(NULL), fTag(kQuestionmarkTableTag), fParent(NULL), fStart(data), fLength(length) {
  70     LE_TRACE_TR("INFO: new raw")
  71   }
  72   LETableReference() :
  73     fFont(NULL), fTag(kQuestionmarkTableTag), fParent(NULL), fStart(NULL), fLength(0) {
  74     LE_TRACE_TR("INFO: new empty")
  75   }
  76
  77   ~LETableReference() {
  78     fTag=kTildeTableTag;
  79     LE_TRACE_TR("INFO: new dtor")
  80   }
  81
  82   /**
  83    * @internal
  84    * @param length  if LE_UINTPTR_MAX means "whole table"
  85    * subset
  86    */
  87   LETableReference(const LETableReference &parent, size_t offset, size_t length,
  88                    LEErrorCode &err) :
  89     fFont(parent.fFont), fTag(parent.fTag), fParent(&parent),
  90     fStart((parent.fStart)+offset), fLength(length) {
  91     if(LE_SUCCESS(err)) {
  92       if(isEmpty()) {
  93         //err = LE_MISSING_FONT_TABLE_ERROR;
  94         clear(); // it's just empty. Not an error.
  95       } else if(offset >= fParent->fLength) {
  96         LE_DEBUG_TR3("offset out of range: (%p) +%d", NULL, offset);
  97         err = LE_INDEX_OUT_OF_BOUNDS_ERROR;
  98         clear();
  99       } else {
 100         if(fLength == LE_UINTPTR_MAX &&
 101            fParent->fLength != LE_UINTPTR_MAX) {
 102           fLength = (fParent->fLength) - offset; // decrement length as base address is incremented
 103         }
 104         if(fLength != LE_UINTPTR_MAX) {  // if we have bounds:
 105           if(offset+fLength > fParent->fLength) {
 106             LE_DEBUG_TR3("offset+fLength out of range: (%p) +%d", NULL, offset+fLength);
 107             err = LE_INDEX_OUT_OF_BOUNDS_ERROR; // exceeded
 108             clear();
 109           }
 110         }
 111       }
 112     } else {
 113       clear();
 114     }
 115     LE_TRACE_TR("INFO: new subset")
 116   }
 117
 118   const void* getAlias() const { return (const void*)fStart; }
 119   const void* getAliasRAW() const { LE_DEBUG_TR("getAliasRAW()"); return (const void*)fStart; }
 120   le_bool isEmpty() const { return fStart==NULL || fLength==0; }
 121   le_bool isValid() const { return !isEmpty(); }
 122   le_bool hasBounds() const { return fLength!=LE_UINTPTR_MAX; }
 123   void clear() { fLength=0; fStart=NULL; }
 124   size_t getLength() const { return fLength; }
 125   const LEFontInstance* getFont() const { return fFont; }
 126   LETag getTag() const { return fTag; }
 127   const LETableReference* getParent() const { return fParent; }
 128
 129   void addOffset(size_t offset, LEErrorCode &success) {
 130     if(hasBounds()) {
 131       if(offset > fLength) {
 132         LE_DEBUG_TR("addOffset off end");
 133         success = LE_INDEX_OUT_OF_BOUNDS_ERROR;
 134         return;
 135       } else {
 136         fLength -= offset;
 137       }
 138     }
 139     fStart += offset;
 140   }
 141
 142   size_t ptrToOffset(const void *atPtr, LEErrorCode &success) const {
 143     if(atPtr==NULL) return 0;
 144     if(LE_FAILURE(success)) return LE_UINTPTR_MAX;
 145     if((atPtr < fStart) ||
 146        (hasBounds() && (atPtr > fStart+fLength))) {
 147       LE_DEBUG_TR3("ptrToOffset args out of range: %p", atPtr, 0);
 148       success = LE_INDEX_OUT_OF_BOUNDS_ERROR;
 149       return LE_UINTPTR_MAX;
 150     }
 151     return ((const le_uint8*)atPtr)-fStart;
 152   }
 153
 154   /**
 155    * Clamp down the length, for range checking.
 156    */
 157   size_t contractLength(size_t newLength) {
 158     if(fLength!=LE_UINTPTR_MAX&&newLength>0&&newLength<=fLength) {
 159       fLength = newLength;
 160     }
 161     return fLength;
 162   }
 163
 164   /**
 165    * Throw an error if offset+length off end
 166    */
 167 public:
 168   size_t verifyLength(size_t offset, size_t length, LEErrorCode &success) {
 169     if(isValid()&&
 170        LE_SUCCESS(success) &&
 171        fLength!=LE_UINTPTR_MAX && length!=LE_UINTPTR_MAX && offset!=LE_UINTPTR_MAX &&
 172        (offset+length)>fLength) {
 173       LE_DEBUG_TR3("verifyLength failed (%p) %d",NULL, offset+length);
 174       success = LE_INDEX_OUT_OF_BOUNDS_ERROR;
 175 #if LE_ASSERT_BAD_FONT
 176       fprintf(stderr, "offset=%lu, len=%lu, would be at %p, (%lu) off end. End at %p\n", offset,length, fStart+offset+length, (offset+length-fLength), (offset+length-fLength)+fStart);
 177 #endif
 178     }
 179     return fLength;
 180   }
 181
 182   /**
 183    * Change parent link to another
 184    */
 185   LETableReference &reparent(const LETableReference &base) {
 186     fParent = &base;
 187     return *this;
 188   }
 189
 190   /**
 191    * remove parent link. Factory functions should do this.
 192    */
 193   void orphan(void) {
 194     fParent=NULL;
 195   }
 196
 197 protected:
 198   const LEFontInstance* fFont;
 199   LETag  fTag;
 200   const LETableReference *fParent;
 201   const le_uint8 *fStart; // keep as 8 bit internally, for pointer math
 202   size_t fLength;
 203
 204   void loadTable(LEErrorCode &success) {
 205     if(LE_SUCCESS(success)) {
 206       fStart = (const le_uint8*)(fFont->getFontTable(fTag, fLength)); // note - a null table is not an error.
 207     }
 208   }
 209
 210   void setRaw(const void *data, size_t length = LE_UINTPTR_MAX) {
 211     fFont = NULL;
 212     fTag = kQuestionmarkTableTag;
 213     fParent = NULL;
 214     fStart = (const le_uint8*)data;
 215     fLength = length;
 216   }
 217 };
 218
 219
 220 template<class T>
 221 class LETableVarSizer {
 222  public:
 223   inline static size_t getSize();
 224 };
 225
 226 // base definition- could override for adjustments
 227 template<class T> inline
 228 size_t LETableVarSizer<T>::getSize() {
 229   return sizeof(T);
 230 }
 231
 232 /**
 233  * \def LE_VAR_ARRAY
 234  * @param x Type (T)
 235  * @param y some member that is of length ANY_NUMBER
 236  * Call this after defining a class, for example:
 237  *   LE_VAR_ARRAY(FeatureListTable,featureRecordArray)
 238  * this is roughly equivalent to:
 239  *   template<> inline size_t LETableVarSizer<FeatureListTable>::getSize() { return sizeof(FeatureListTable) - (sizeof(le_uint16)*ANY_NUMBER); }
 240  * it's a specialization that informs the LETableReference subclasses to NOT include the variable array in the size.
 241  * dereferencing NULL is valid here because we never actually dereference it, just inside sizeof.
 242  */
 243 #define LE_VAR_ARRAY(x,y) template<> inline size_t LETableVarSizer<x>::getSize() { return sizeof(x) - (sizeof(((const x*)0)->y)); }
 244 /**
 245  * \def LE_CORRECT_SIZE
 246  * @param x type (T)
 247  * @param y fixed size for T
 248  */
 249 #define LE_CORRECT_SIZE(x,y) template<> inline size_t LETableVarSizer<x>::getSize() { return y; }
 250
 251 /**
 252  * Open a new entry based on an existing table
 253  */
 254
 255 /**
 256  * \def LE_UNBOUNDED_ARRAY
 257  * define an array with no *known* bound. Will trim to available size.
 258  * @internal
 259  */
 260 #define LE_UNBOUNDED_ARRAY LE_UINT32_MAX
 261
 262 template<class T>
 263 class LEReferenceToArrayOf : public LETableReference {
 264 public:
 265   LEReferenceToArrayOf(const LETableReference &parent, LEErrorCode &success, size_t offset, le_uint32 count)
 266     : LETableReference(parent, offset, LE_UINTPTR_MAX, success), fCount(count) {
 267     LE_TRACE_TR("INFO: new RTAO by offset")
 268     if(LE_SUCCESS(success)) {
 269       if(count == LE_UNBOUNDED_ARRAY) { // not a known length
 270         count = getLength()/LETableVarSizer<T>::getSize(); // fit to max size
 271       }
 272       LETableReference::verifyLength(0, LETableVarSizer<T>::getSize()*count, success);
 273     }
 274     if(LE_FAILURE(success)) {
 275       fCount=0;
 276       clear();
 277     }
 278   }
 279
 280   LEReferenceToArrayOf(const LETableReference &parent, LEErrorCode &success, const T* array, le_uint32 count)
 281     : LETableReference(parent, parent.ptrToOffset(array, success), LE_UINTPTR_MAX, success), fCount(count) {
 282 LE_TRACE_TR("INFO: new RTAO")
 283     if(LE_SUCCESS(success)) {
 284       if(count == LE_UNBOUNDED_ARRAY) { // not a known length
 285         count = getLength()/LETableVarSizer<T>::getSize(); // fit to max size
 286       }
 287       LETableReference::verifyLength(0, LETableVarSizer<T>::getSize()*count, success);
 288     }
 289     if(LE_FAILURE(success)) clear();
 290   }
 291  LEReferenceToArrayOf(const LETableReference &parent, LEErrorCode &success, const T* array, size_t offset, le_uint32 count)
 292    : LETableReference(parent, parent.ptrToOffset(array, success)+offset, LE_UINTPTR_MAX, success), fCount(count) {
 293 LE_TRACE_TR("INFO: new RTAO")
 294     if(LE_SUCCESS(success)) {
 295       if(count == LE_UNBOUNDED_ARRAY) { // not a known length
 296         count = getLength()/LETableVarSizer<T>::getSize(); // fit to max size
 297       }
 298       LETableReference::verifyLength(0, LETableVarSizer<T>::getSize()*count, success);
 299     }
 300     if(LE_FAILURE(success)) clear();
 301   }
 302
 303  LEReferenceToArrayOf() :LETableReference(), fCount(0) {}
 304
 305   le_uint32 getCount() const { return fCount; }
 306
 307   using LETableReference::getAlias;
 308
 309   const T *getAlias(le_uint32 i, LEErrorCode &success) const {
 310     return ((const T*)(((const char*)getAlias())+getOffsetFor(i, success)));
 311   }
 312
 313   const T *getAliasRAW() const { LE_DEBUG_TR("getAliasRAW<>"); return (const T*)fStart; }
 314
 315   const T& getObject(le_uint32 i, LEErrorCode &success) const {
 316     return *getAlias(i,success);
 317   }
 318
 319   const T& operator()(le_uint32 i, LEErrorCode &success) const {
 320     return *getAlias(i,success);
 321   }
 322
 323   size_t getOffsetFor(le_uint32 i, LEErrorCode &success) const {
 324     if(LE_SUCCESS(success)&&i<getCount()) {
 325       return LETableVarSizer<T>::getSize()*i;
 326     } else {
 327       success = LE_INDEX_OUT_OF_BOUNDS_ERROR;
 328     }
 329     return 0;
 330   }
 331
 332   LEReferenceToArrayOf<T> &reparent(const LETableReference &base) {
 333     fParent = &base;
 334     return *this;
 335   }
 336
 337  LEReferenceToArrayOf(const LETableReference& parent, LEErrorCode & success) : LETableReference(parent,0, LE_UINTPTR_MAX, success), fCount(0) {
 338     LE_TRACE_TR("INFO: null RTAO")
 339   }
 340
 341 private:
 342   le_uint32 fCount;
 343 };
 344
 345
 346 template<class T>
 347 class LEReferenceTo : public LETableReference {
 348 public:
 349   /**
 350    * open a sub reference.
 351    * @param parent parent reference
 352    * @param success error status
 353    * @param atPtr location of reference - if NULL, will be at offset zero (i.e. downcast of parent). Otherwise must be a pointer within parent's bounds.
 354    */
 355  inline LEReferenceTo(const LETableReference &parent, LEErrorCode &success, const void* atPtr)
 356     : LETableReference(parent, parent.ptrToOffset(atPtr, success), LE_UINTPTR_MAX, success) {
 357     verifyLength(0, LETableVarSizer<T>::getSize(), success);
 358     if(LE_FAILURE(success)) clear();
 359   }
 360   /**
 361    * ptr plus offset
 362    */
 363  inline LEReferenceTo(const LETableReference &parent, LEErrorCode &success, const void* atPtr, size_t offset)
 364     : LETableReference(parent, parent.ptrToOffset(atPtr, success)+offset, LE_UINTPTR_MAX, success) {
 365     verifyLength(0, LETableVarSizer<T>::getSize(), success);
 366     if(LE_FAILURE(success)) clear();
 367   }
 368  inline LEReferenceTo(const LETableReference &parent, LEErrorCode &success, size_t offset)
 369     : LETableReference(parent, offset, LE_UINTPTR_MAX, success) {
 370     verifyLength(0, LETableVarSizer<T>::getSize(), success);
 371     if(LE_FAILURE(success)) clear();
 372   }
 373  inline LEReferenceTo(const LETableReference &parent, LEErrorCode &success)
 374     : LETableReference(parent, 0, LE_UINTPTR_MAX, success) {
 375     verifyLength(0, LETableVarSizer<T>::getSize(), success);
 376     if(LE_FAILURE(success)) clear();
 377   }
 378  inline LEReferenceTo(const LEFontInstance *font, LETag tableTag, LEErrorCode &success)
 379    : LETableReference(font, tableTag, success) {
 380     verifyLength(0, LETableVarSizer<T>::getSize(), success);
 381     if(LE_FAILURE(success)) clear();
 382   }
 383  inline LEReferenceTo(const le_uint8 *data, size_t length = LE_UINTPTR_MAX) : LETableReference(data, length) {}
 384  inline LEReferenceTo(const T *data, size_t length = LE_UINTPTR_MAX) : LETableReference((const le_uint8*)data, length) {}
 385  inline LEReferenceTo() : LETableReference(NULL) {}
 386
 387  inline LEReferenceTo<T>& operator=(const T* other) {
 388     setRaw(other);
 389     return *this;
 390   }
 391
 392   LEReferenceTo<T> &reparent(const LETableReference &base) {
 393     fParent = &base;
 394     return *this;
 395   }
 396
 397   /**
 398    * roll forward by one <T> size.
 399    * same as addOffset(LETableVarSizer<T>::getSize(),success)
 400    */
 401   void addObject(LEErrorCode &success) {
 402     addOffset(LETableVarSizer<T>::getSize(), success);
 403   }
 404   void addObject(size_t count, LEErrorCode &success) {
 405     addOffset(LETableVarSizer<T>::getSize()*count, success);
 406   }
 407
 408   const T *operator->() const { return getAlias(); }
 409   const T *getAlias() const { return (const T*)fStart; }
 410   const T *getAliasRAW() const { LE_DEBUG_TR("getAliasRAW<>"); return (const T*)fStart; }
 411 };
 412
 413
 414 U_NAMESPACE_END
 415
 416 #endif
 417
 418 #endif