chrome/installer/mini_installer/mini_string.h

   1 // Copyright (c) 2011 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 CHROME_INSTALLER_MINI_INSTALLER_MINI_STRING_H_
   6 #define CHROME_INSTALLER_MINI_INSTALLER_MINI_STRING_H_
   7
   8 #ifndef COMPILE_ASSERT
   9 // COMPILE_ASSERT macro borrowed from basictypes.h
  10 template <bool>
  11 struct CompileAssert {};
  12 #define COMPILE_ASSERT(expr, msg) \
  13     typedef CompileAssert<(bool(expr))> msg[bool(expr) ? 1 : -1]
  14 #endif
  15
  16 namespace mini_installer {
  17
  18 // NOTE: Do not assume that these string functions support UTF encoding.
  19 // This is fine for the purposes of the mini_installer, but you have
  20 // been warned!
  21
  22 // Formats a sequence of |bytes| as hex.  The |str| buffer must have room for
  23 // at least 2*|size| + 1.
  24 bool HexEncode(const void* bytes, size_t size, wchar_t* str, size_t str_size);
  25
  26 // Counts the number of characters in the string up to a maximum of
  27 // alloc_size.  The highest return value from this function can therefore be
  28 // alloc_size - 1 since |alloc_size| includes the \0 terminator.
  29 size_t SafeStrLen(const wchar_t* str, size_t alloc_size);
  30
  31 // Simple replacement for CRT string copy method that does not overflow.
  32 // Returns true if the source was copied successfully otherwise returns false.
  33 // Parameter src is assumed to be NULL terminated and the NULL character is
  34 // copied over to string dest.
  35 bool SafeStrCopy(wchar_t* dest, size_t dest_size, const wchar_t* src);
  36
  37 // Simple replacement for CRT string copy method that does not overflow.
  38 // Returns true if the source was copied successfully otherwise returns false.
  39 // Parameter src is assumed to be NULL terminated and the NULL character is
  40 // copied over to string dest.  If the return value is false, the |dest|
  41 // string should be the same as it was before.
  42 bool SafeStrCat(wchar_t* dest, size_t dest_size, const wchar_t* src);
  43
  44 // Function to check if a string (specified by str) ends with another string
  45 // (specified by end_str).
  46 bool StrEndsWith(const wchar_t* str, const wchar_t* end_str);
  47
  48 // Function to check if a string (specified by str) starts with another string
  49 // (specified by start_str).
  50 bool StrStartsWith(const wchar_t* str, const wchar_t* start_str);
  51
  52 // Case insensitive search of the first occurrence of |find| in |source|.
  53 const wchar_t* SearchStringI(const wchar_t* source, const wchar_t* find);
  54
  55 // Searches for |tag| within |str|.  Returns true if |tag| is found and is
  56 // immediately followed by '-' or is at the end of the string.  If |position|
  57 // is non-NULL, the location of the tag is returned in |*position| on success.
  58 bool FindTagInStr(const wchar_t* str, const wchar_t* tag,
  59                   const wchar_t** position);
  60
  61 // Takes the path to file and returns a pointer to the filename component. For
  62 // example for input of c:\full\path\to\file.ext it returns pointer to file.ext.
  63 // It returns NULL if extension or path separator is not found.
  64 // |size| is the number of characters in |path| not including the string
  65 // terminator.
  66 wchar_t* GetNameFromPathExt(wchar_t* path, size_t size);
  67
  68 // A string class that manages a fixed size buffer on the stack.
  69 // The methods in the class are based on the above string methods and the
  70 // class additionally is careful about proper buffer termination.
  71 template <size_t kCapacity>
  72 class StackString {
  73  public:
  74   StackString() {
  75     COMPILE_ASSERT(kCapacity != 0, invalid_buffer_size);
  76     buffer_[kCapacity] = L'\0';  // We always reserve 1 more than asked for.
  77     clear();
  78   }
  79
  80   // We do not expose a constructor that accepts a string pointer on purpose.
  81   // We expect the caller to call assign() and handle failures.
  82
  83   // Returns the number of reserved characters in this buffer, _including_
  84   // the reserved char for the terminator.
  85   size_t capacity() const {
  86     return kCapacity;
  87   }
  88
  89   wchar_t* get() {
  90     return buffer_;
  91   }
  92
  93   bool assign(const wchar_t* str) {
  94     return SafeStrCopy(buffer_, kCapacity, str);
  95   }
  96
  97   bool append(const wchar_t* str) {
  98     return SafeStrCat(buffer_, kCapacity, str);
  99   }
 100
 101   void clear() {
 102     buffer_[0] = L'\0';
 103   }
 104
 105   size_t length() const {
 106     return SafeStrLen(buffer_, kCapacity);
 107   }
 108
 109   // Does a case insensitive search for a substring.
 110   const wchar_t* findi(const wchar_t* find) const {
 111     return SearchStringI(buffer_, find);
 112   }
 113
 114   // Case insensitive string compare.
 115   int comparei(const wchar_t* str) const {
 116     return lstrcmpiW(buffer_, str);
 117   }
 118
 119   // Case sensitive string compare.
 120   int compare(const wchar_t* str) const {
 121     return lstrcmpW(buffer_, str);
 122   }
 123
 124   // Terminates the string at the specified location.
 125   // Note: this method has no effect if this object's length is less than
 126   // |location|.
 127   bool truncate_at(size_t location) {
 128     if (location >= kCapacity)
 129       return false;
 130     buffer_[location] = L'\0';
 131     return true;
 132   }
 133
 134  protected:
 135   // We reserve 1 more than what is asked for as a safeguard against
 136   // off-by-one errors.
 137   wchar_t buffer_[kCapacity + 1];
 138
 139  private:
 140   StackString(const StackString&);
 141   StackString& operator=(const StackString&);
 142 };
 143
 144 }  // namespace mini_installer
 145
 146 #endif  // CHROME_INSTALLER_MINI_INSTALLER_MINI_STRING_H_