rlz/lib/string_utils.cc

   1 // Copyright (c) 2012 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 // String manipulation functions used in the RLZ library.
   6
   7 #include "rlz/lib/string_utils.h"
   8
   9 #include "rlz/lib/assert.h"
  10
  11 namespace rlz_lib {
  12
  13 bool IsAscii(unsigned char letter) {
  14   return letter < 0x80;
  15 }
  16
  17 bool GetHexValue(char letter, int* value) {
  18   if (!value) {
  19     ASSERT_STRING("GetHexValue: Invalid output paramter");
  20     return false;
  21   }
  22   *value = 0;
  23
  24   if (letter >= '0' && letter <= '9')
  25     *value = letter - '0';
  26   else if (letter >= 'a' && letter <= 'f')
  27     *value = (letter - 'a') + 0xA;
  28   else if (letter >= 'A' && letter <= 'F')
  29     *value = (letter - 'A') + 0xA;
  30   else
  31     return false;
  32
  33   return true;
  34 }
  35
  36 int HexStringToInteger(const char* text) {
  37   if (!text) {
  38     ASSERT_STRING("HexStringToInteger: text is NULL.");
  39     return 0;
  40   }
  41
  42   int idx = 0;
  43   // Ignore leading whitespace.
  44   while (text[idx] == '\t' || text[idx] == ' ')
  45     idx++;
  46
  47   if ((text[idx] == '0') &&
  48       (text[idx + 1] == 'X' || text[idx + 1] == 'x'))
  49     idx +=2;  // String is of the form 0x...
  50
  51   int number = 0;
  52   int digit = 0;
  53   for (; text[idx] != '\0'; idx++) {
  54     if (!GetHexValue(text[idx], &digit)) {
  55       // Ignore trailing whitespaces, but assert on other trailing characters.
  56       bool only_whitespaces = true;
  57       while (only_whitespaces && text[idx])
  58         only_whitespaces = (text[idx++] == ' ');
  59       if (!only_whitespaces)
  60         ASSERT_STRING("HexStringToInteger: text contains non-hex characters.");
  61       return number;
  62     }
  63     number = (number << 4) | digit;
  64   }
  65
  66   return number;
  67 }
  68
  69 bool BytesToString(const unsigned char* data,
  70                    int data_len,
  71                    std::string* string) {
  72   if (!string)
  73     return false;
  74
  75   string->clear();
  76   if (data_len < 1 || !data)
  77     return false;
  78
  79   static const char kHex[] = "0123456789ABCDEF";
  80
  81   // Fix the buffer size to begin with to avoid repeated re-allocation.
  82   string->resize(data_len * 2);
  83   int index = data_len;
  84   while (index--) {
  85     string->at(2 * index) = kHex[data[index] >> 4];  // high digit
  86     string->at(2 * index + 1) = kHex[data[index] & 0x0F];  // low digit
  87   }
  88
  89   return true;
  90 }
  91
  92 }  // namespace rlz_lib