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 basename component.
  62 // Example input -> output:
  63 //     c:\full\path\to\file.ext -> file.ext
  64 //     file.ext -> file.ext
  65 // Note: |size| is the number of characters in |path| not including the string
  66 // terminator.
  67 const wchar_t* GetNameFromPathExt(const wchar_t* path, size_t size);
  68 wchar_t* GetNameFromPathExt(wchar_t* path, size_t size);
  69
  70 // A string class that manages a fixed size buffer on the stack.
  71 // The methods in the class are based on the above string methods and the
  72 // class additionally is careful about proper buffer termination.
  73 template <size_t kCapacity>
  74 class StackString {
  75  public:
  76   StackString() {
  77     COMPILE_ASSERT(kCapacity != 0, invalid_buffer_size);
  78     buffer_[kCapacity] = L'\0';  // We always reserve 1 more than asked for.
  79     clear();
  80   }
  81
  82   // We do not expose a constructor that accepts a string pointer on purpose.
  83   // We expect the caller to call assign() and handle failures.
  84
  85   // Returns the number of reserved characters in this buffer, _including_
  86   // the reserved char for the terminator.
  87   size_t capacity() const {
  88     return kCapacity;
  89   }
  90
  91   wchar_t* get() {
  92     return buffer_;
  93   }
  94
  95   bool assign(const wchar_t* str) {
  96     return SafeStrCopy(buffer_, kCapacity, str);
  97   }
  98
  99   bool append(const wchar_t* str) {
 100     return SafeStrCat(buffer_, kCapacity, str);
 101   }
 102
 103   void clear() {
 104     buffer_[0] = L'\0';
 105   }
 106
 107   size_t length() const {
 108     return SafeStrLen(buffer_, kCapacity);
 109   }
 110
 111   // Does a case insensitive search for a substring.
 112   const wchar_t* findi(const wchar_t* find) const {
 113     return SearchStringI(buffer_, find);
 114   }
 115
 116   // Case insensitive string compare.
 117   int comparei(const wchar_t* str) const {
 118     return lstrcmpiW(buffer_, str);
 119   }
 120
 121   // Case sensitive string compare.
 122   int compare(const wchar_t* str) const {
 123     return lstrcmpW(buffer_, str);
 124   }
 125
 126   // Terminates the string at the specified location.
 127   // Note: this method has no effect if this object's length is less than
 128   // |location|.
 129   bool truncate_at(size_t location) {
 130     if (location >= kCapacity)
 131       return false;
 132     buffer_[location] = L'\0';
 133     return true;
 134   }
 135
 136  protected:
 137   // We reserve 1 more than what is asked for as a safeguard against
 138   // off-by-one errors.
 139   wchar_t buffer_[kCapacity + 1];
 140
 141  private:
 142   StackString(const StackString&);
 143   StackString& operator=(const StackString&);
 144 };
 145
 146 }  // namespace mini_installer
 147
 148 #endif  // CHROME_INSTALLER_MINI_INSTALLER_MINI_STRING_H_