X-Git-Url: https://git.saurik.com/apple/icu.git/blobdiff_plain/efa1e6592fb03ce23b15276b2b91d885a3ee7da5..57a6839dcb3bba09e8228b822b290604668416fe:/icuSources/layout/LETableReference.h

diff --git a/icuSources/layout/LETableReference.h b/icuSources/layout/LETableReference.h
new file mode 100644
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+++ b/icuSources/layout/LETableReference.h
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+/*
+ * -*- c++ -*-
+ *
+ * (C) Copyright IBM Corp. and others 2013 - All Rights Reserved
+ *
+ * Range checking
+ *
+ */
+
+#ifndef __LETABLEREFERENCE_H
+#define __LETABLEREFERENCE_H
+
+#include "LETypes.h"
+#include "LEFontInstance.h"
+
+
+#define kQuestionmarkTableTag  0x3F3F3F3FUL
+#define kTildeTableTag  0x7e7e7e7eUL
+#ifdef __cplusplus
+
+// internal - interface for range checking
+U_NAMESPACE_BEGIN
+
+#if LE_ASSERT_BAD_FONT
+class LETableReference; // fwd
+/**
+ *  defined in OpenTypeUtilities.cpp
+ * @internal
+ */
+extern void _debug_LETableReference(const char *f, int l, const char *msg, const LETableReference *what, const void *ptr, size_t len);
+
+#define LE_DEBUG_TR(x) _debug_LETableReference(__FILE__, __LINE__, x, this, NULL, 0);
+#define LE_DEBUG_TR3(x,y,z) _debug_LETableReference(__FILE__, __LINE__, x, this, (const void*)y, (size_t)z);
+#if 0
+#define LE_TRACE_TR(x) _debug_LETableReference(__FILE__, __LINE__, x, this, NULL, 0);
+#else
+#define LE_TRACE_TR(x)
+#endif
+
+#else
+#define LE_DEBUG_TR(x)
+#define LE_DEBUG_TR3(x,y,z)
+#define LE_TRACE_TR(x)
+#endif
+
+/**
+ * @internal
+ */
+class LETableReference {
+public:
+/**
+ * @internal
+ * Construct from a specific tag
+ */
+  LETableReference(const LEFontInstance* font, LETag tableTag, LEErrorCode &success) :
+    fFont(font), fTag(tableTag), fParent(NULL), fStart(NULL),fLength(LE_UINTPTR_MAX) {
+      loadTable(success);
+    LE_TRACE_TR("INFO: new table load")
+  }
+
+  LETableReference(const LETableReference &parent, LEErrorCode &success) : fFont(parent.fFont), fTag(parent.fTag), fParent(&parent), fStart(parent.fStart), fLength(parent.fLength) {
+    if(LE_FAILURE(success)) {
+      clear();
+    }
+    LE_TRACE_TR("INFO: new clone")
+  }
+
+   LETableReference(const le_uint8* data, size_t length = LE_UINTPTR_MAX) :
+    fFont(NULL), fTag(kQuestionmarkTableTag), fParent(NULL), fStart(data), fLength(length) {
+    LE_TRACE_TR("INFO: new raw")
+  }
+  LETableReference() :
+    fFont(NULL), fTag(kQuestionmarkTableTag), fParent(NULL), fStart(NULL), fLength(0) {
+    LE_TRACE_TR("INFO: new empty")
+  }
+
+  ~LETableReference() {
+    fTag=kTildeTableTag;
+    LE_TRACE_TR("INFO: new dtor")
+  }
+
+  /**
+   * @internal
+   * @param length  if LE_UINTPTR_MAX means "whole table"
+   * subset
+   */
+  LETableReference(const LETableReference &parent, size_t offset, size_t length,
+                   LEErrorCode &err) :
+    fFont(parent.fFont), fTag(parent.fTag), fParent(&parent),
+    fStart((parent.fStart)+offset), fLength(length) {
+    if(LE_SUCCESS(err)) {
+      if(isEmpty()) {
+        //err = LE_MISSING_FONT_TABLE_ERROR;
+        clear(); // it's just empty. Not an error.
+      } else if(offset >= fParent->fLength) {
+        LE_DEBUG_TR3("offset out of range: (%p) +%d", NULL, offset);
+        err = LE_INDEX_OUT_OF_BOUNDS_ERROR;
+        clear();
+      } else {
+        if(fLength == LE_UINTPTR_MAX &&
+           fParent->fLength != LE_UINTPTR_MAX) {
+          fLength = (fParent->fLength) - offset; // decrement length as base address is incremented
+        }
+        if(fLength != LE_UINTPTR_MAX) {  // if we have bounds:
+          if(offset+fLength > fParent->fLength) {
+            LE_DEBUG_TR3("offset+fLength out of range: (%p) +%d", NULL, offset+fLength);
+            err = LE_INDEX_OUT_OF_BOUNDS_ERROR; // exceeded
+            clear();
+          }
+        }
+      }
+    } else {
+      clear();
+    }
+    LE_TRACE_TR("INFO: new subset")
+  }
+
+  const void* getAlias() const { return (const void*)fStart; }
+  const void* getAliasRAW() const { LE_DEBUG_TR("getAliasRAW()"); return (const void*)fStart; }
+  le_bool isEmpty() const { return fStart==NULL || fLength==0; }
+  le_bool isValid() const { return !isEmpty(); }
+  le_bool hasBounds() const { return fLength!=LE_UINTPTR_MAX; }
+  void clear() { fLength=0; fStart=NULL; }
+  size_t getLength() const { return fLength; }
+  const LEFontInstance* getFont() const { return fFont; }
+  LETag getTag() const { return fTag; }
+  const LETableReference* getParent() const { return fParent; }
+
+  void addOffset(size_t offset, LEErrorCode &success) {
+    if(hasBounds()) {
+      if(offset > fLength) {
+        LE_DEBUG_TR("addOffset off end");
+        success = LE_INDEX_OUT_OF_BOUNDS_ERROR;
+        return;
+      } else {
+        fLength -= offset;
+      }
+    }
+    fStart += offset;
+  }
+
+  size_t ptrToOffset(const void *atPtr, LEErrorCode &success) const {
+    if(atPtr==NULL) return 0;
+    if(LE_FAILURE(success)) return LE_UINTPTR_MAX;
+    if((atPtr < fStart) ||
+       (hasBounds() && (atPtr > fStart+fLength))) {
+      LE_DEBUG_TR3("ptrToOffset args out of range: %p", atPtr, 0);
+      success = LE_INDEX_OUT_OF_BOUNDS_ERROR;
+      return LE_UINTPTR_MAX;
+    }
+    return ((const le_uint8*)atPtr)-fStart;
+  }
+
+  /**
+   * Clamp down the length, for range checking.
+   */
+  size_t contractLength(size_t newLength) {
+    if(fLength!=LE_UINTPTR_MAX&&newLength>0&&newLength<=fLength) {
+      fLength = newLength;
+    }
+    return fLength;
+  }
+
+  /**
+   * Throw an error if offset+length off end
+   */
+public:
+  size_t verifyLength(size_t offset, size_t length, LEErrorCode &success) {
+    if(isValid()&&
+       LE_SUCCESS(success) &&
+       fLength!=LE_UINTPTR_MAX && length!=LE_UINTPTR_MAX && offset!=LE_UINTPTR_MAX &&
+       (offset+length)>fLength) {
+      LE_DEBUG_TR3("verifyLength failed (%p) %d",NULL, offset+length);
+      success = LE_INDEX_OUT_OF_BOUNDS_ERROR;
+#if LE_ASSERT_BAD_FONT
+      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);
+#endif
+    }
+    return fLength;
+  }
+
+  /**
+   * Change parent link to another
+   */
+  LETableReference &reparent(const LETableReference &base) {
+    fParent = &base;
+    return *this;
+  }
+
+  /**
+   * remove parent link. Factory functions should do this.
+   */
+  void orphan(void) {
+    fParent=NULL;
+  }
+
+protected:
+  const LEFontInstance* fFont;
+  LETag  fTag;
+  const LETableReference *fParent;
+  const le_uint8 *fStart; // keep as 8 bit internally, for pointer math
+  size_t fLength;
+
+  void loadTable(LEErrorCode &success) {
+    if(LE_SUCCESS(success)) {
+      fStart = (const le_uint8*)(fFont->getFontTable(fTag, fLength)); // note - a null table is not an error.
+    }
+  }
+
+  void setRaw(const void *data, size_t length = LE_UINTPTR_MAX) {
+    fFont = NULL;
+    fTag = kQuestionmarkTableTag;
+    fParent = NULL;
+    fStart = (const le_uint8*)data;
+    fLength = length;
+  }
+};
+
+
+template<class T>
+class LETableVarSizer {
+ public:
+  inline static size_t getSize();
+};
+
+// base definition- could override for adjustments
+template<class T> inline
+size_t LETableVarSizer<T>::getSize() {
+  return sizeof(T);
+}
+
+/**
+ * \def LE_VAR_ARRAY
+ * @param x Type (T)
+ * @param y some member that is of length ANY_NUMBER
+ * Call this after defining a class, for example:
+ *   LE_VAR_ARRAY(FeatureListTable,featureRecordArray)
+ * this is roughly equivalent to:
+ *   template<> inline size_t LETableVarSizer<FeatureListTable>::getSize() { return sizeof(FeatureListTable) - (sizeof(le_uint16)*ANY_NUMBER); }
+ * it's a specialization that informs the LETableReference subclasses to NOT include the variable array in the size.
+ * dereferencing NULL is valid here because we never actually dereference it, just inside sizeof.
+ */
+#define LE_VAR_ARRAY(x,y) template<> inline size_t LETableVarSizer<x>::getSize() { return sizeof(x) - (sizeof(((const x*)0)->y)); }
+/**
+ * \def LE_CORRECT_SIZE
+ * @param x type (T)
+ * @param y fixed size for T
+ */
+#define LE_CORRECT_SIZE(x,y) template<> inline size_t LETableVarSizer<x>::getSize() { return y; }
+
+/**
+ * Open a new entry based on an existing table
+ */
+
+/**
+ * \def LE_UNBOUNDED_ARRAY
+ * define an array with no *known* bound. Will trim to available size.
+ * @internal
+ */
+#define LE_UNBOUNDED_ARRAY LE_UINT32_MAX
+
+template<class T>
+class LEReferenceToArrayOf : public LETableReference {
+public:
+  LEReferenceToArrayOf(const LETableReference &parent, LEErrorCode &success, size_t offset, le_uint32 count)
+    : LETableReference(parent, offset, LE_UINTPTR_MAX, success), fCount(count) {
+    LE_TRACE_TR("INFO: new RTAO by offset")
+    if(LE_SUCCESS(success)) {
+      if(count == LE_UNBOUNDED_ARRAY) { // not a known length
+        count = getLength()/LETableVarSizer<T>::getSize(); // fit to max size
+      }
+      LETableReference::verifyLength(0, LETableVarSizer<T>::getSize()*count, success);
+    }
+    if(LE_FAILURE(success)) {
+      fCount=0;
+      clear();
+    }
+  }
+
+  LEReferenceToArrayOf(const LETableReference &parent, LEErrorCode &success, const T* array, le_uint32 count)
+    : LETableReference(parent, parent.ptrToOffset(array, success), LE_UINTPTR_MAX, success), fCount(count) {
+LE_TRACE_TR("INFO: new RTAO")
+    if(LE_SUCCESS(success)) {
+      if(count == LE_UNBOUNDED_ARRAY) { // not a known length
+        count = getLength()/LETableVarSizer<T>::getSize(); // fit to max size
+      }
+      LETableReference::verifyLength(0, LETableVarSizer<T>::getSize()*count, success);
+    }
+    if(LE_FAILURE(success)) clear();
+  }
+ LEReferenceToArrayOf(const LETableReference &parent, LEErrorCode &success, const T* array, size_t offset, le_uint32 count)
+   : LETableReference(parent, parent.ptrToOffset(array, success)+offset, LE_UINTPTR_MAX, success), fCount(count) {
+LE_TRACE_TR("INFO: new RTAO")
+    if(LE_SUCCESS(success)) {
+      if(count == LE_UNBOUNDED_ARRAY) { // not a known length
+        count = getLength()/LETableVarSizer<T>::getSize(); // fit to max size
+      }
+      LETableReference::verifyLength(0, LETableVarSizer<T>::getSize()*count, success);
+    }
+    if(LE_FAILURE(success)) clear();
+  }
+
+ LEReferenceToArrayOf() :LETableReference(), fCount(0) {}
+
+  le_uint32 getCount() const { return fCount; }
+
+  using LETableReference::getAlias;
+
+  const T *getAlias(le_uint32 i, LEErrorCode &success) const {
+    return ((const T*)(((const char*)getAlias())+getOffsetFor(i, success)));
+  }
+
+  const T *getAliasRAW() const { LE_DEBUG_TR("getAliasRAW<>"); return (const T*)fStart; }
+
+  const T& getObject(le_uint32 i, LEErrorCode &success) const {
+    return *getAlias(i,success);
+  }
+  
+  const T& operator()(le_uint32 i, LEErrorCode &success) const {
+    return *getAlias(i,success);
+  }
+
+  size_t getOffsetFor(le_uint32 i, LEErrorCode &success) const {
+    if(LE_SUCCESS(success)&&i<getCount()) {
+      return LETableVarSizer<T>::getSize()*i;
+    } else {
+      success = LE_INDEX_OUT_OF_BOUNDS_ERROR;
+    }
+    return 0;
+  }
+
+  LEReferenceToArrayOf<T> &reparent(const LETableReference &base) {
+    fParent = &base;
+    return *this;
+  }
+
+ LEReferenceToArrayOf(const LETableReference& parent, LEErrorCode & success) : LETableReference(parent,0, LE_UINTPTR_MAX, success), fCount(0) {
+    LE_TRACE_TR("INFO: null RTAO")
+  }
+
+private:
+  le_uint32 fCount;
+};
+
+
+template<class T>
+class LEReferenceTo : public LETableReference {
+public:
+  /**
+   * open a sub reference.
+   * @param parent parent reference
+   * @param success error status
+   * @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.
+   */
+ inline LEReferenceTo(const LETableReference &parent, LEErrorCode &success, const void* atPtr)
+    : LETableReference(parent, parent.ptrToOffset(atPtr, success), LE_UINTPTR_MAX, success) {
+    verifyLength(0, LETableVarSizer<T>::getSize(), success);
+    if(LE_FAILURE(success)) clear();
+  }
+  /**
+   * ptr plus offset
+   */
+ inline LEReferenceTo(const LETableReference &parent, LEErrorCode &success, const void* atPtr, size_t offset)
+    : LETableReference(parent, parent.ptrToOffset(atPtr, success)+offset, LE_UINTPTR_MAX, success) {
+    verifyLength(0, LETableVarSizer<T>::getSize(), success);
+    if(LE_FAILURE(success)) clear();
+  }
+ inline LEReferenceTo(const LETableReference &parent, LEErrorCode &success, size_t offset)
+    : LETableReference(parent, offset, LE_UINTPTR_MAX, success) {
+    verifyLength(0, LETableVarSizer<T>::getSize(), success);
+    if(LE_FAILURE(success)) clear();
+  }
+ inline LEReferenceTo(const LETableReference &parent, LEErrorCode &success)
+    : LETableReference(parent, 0, LE_UINTPTR_MAX, success) {
+    verifyLength(0, LETableVarSizer<T>::getSize(), success);
+    if(LE_FAILURE(success)) clear();
+  }
+ inline LEReferenceTo(const LEFontInstance *font, LETag tableTag, LEErrorCode &success)
+   : LETableReference(font, tableTag, success) {
+    verifyLength(0, LETableVarSizer<T>::getSize(), success);
+    if(LE_FAILURE(success)) clear();
+  }
+ inline LEReferenceTo(const le_uint8 *data, size_t length = LE_UINTPTR_MAX) : LETableReference(data, length) {}
+ inline LEReferenceTo(const T *data, size_t length = LE_UINTPTR_MAX) : LETableReference((const le_uint8*)data, length) {}
+ inline LEReferenceTo() : LETableReference(NULL) {}
+
+ inline LEReferenceTo<T>& operator=(const T* other) {
+    setRaw(other);
+    return *this;
+  }
+
+  LEReferenceTo<T> &reparent(const LETableReference &base) {
+    fParent = &base;
+    return *this;
+  }
+
+  /**
+   * roll forward by one <T> size.
+   * same as addOffset(LETableVarSizer<T>::getSize(),success)
+   */
+  void addObject(LEErrorCode &success) {
+    addOffset(LETableVarSizer<T>::getSize(), success);
+  }
+  void addObject(size_t count, LEErrorCode &success) {
+    addOffset(LETableVarSizer<T>::getSize()*count, success);
+  }
+
+  const T *operator->() const { return getAlias(); }
+  const T *getAlias() const { return (const T*)fStart; }
+  const T *getAliasRAW() const { LE_DEBUG_TR("getAliasRAW<>"); return (const T*)fStart; }
+};
+
+
+U_NAMESPACE_END
+
+#endif
+
+#endif