Add an encoder/decoder for quoted-printable.

chrome/browser/net/quoted_printable.cc

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/net/quoted_printable.h"
+
+#include "base/logging.h"
+
+namespace {
+
+const int kMaxCharPerLine = 76;
+const char* const kEOL = "\r\n";
+
+const char kHexTable[] = {

[tfarina, 2011/02/28 18:38:21]

You can simplify this as:

const char kHexTable[] = "0123456789ABCDEF";

[Jay Civelli, 2011/02/28 19:25:53]

Done.

+  '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
+};
+
+// Returns the value of |c| as it reads in hexa, -1 if |c| is not a valid hexa
+// char.
+int HexASCIICharToInt(char c) {

[brettw, 2011/02/28 17:33:14]

You should be able to use HexDigitToInt in string_util instead of writing this.

[Jay Civelli, 2011/02/28 19:25:53]

Done.

+  if (c >= 48 && c <=57)  // '0' to '9'.
+    return c - 48;
+
+  if (c >= 65 && c <= 70)  // 'A' to 'F'.
+    return c - 65 + 10;
+
+  if (c >= 97 && c <= 102)  // 'a' to 'f'.
+    return c - 97 + 10;
+
+  return -1;
+}
+
+}  // namespace
+
+namespace chrome_browser_net {
+
+void QuotedPrintableEncode(const std::string& input, std::string* output) {
+  // The number of characters in the current line.
+  int char_count = 0;
+  for (std::string::const_iterator iter = input.begin();
+       iter!= input.end(); ++iter) {

[brettw, 2011/02/28 17:33:14]

Space before the !

[Jay Civelli, 2011/02/28 19:25:53]

Done.

+    bool last_char = (iter + 1 == input.end());
+    char c = *iter;
+    // Whether this character can be inserted without encoding.
+    bool as_is = false;
+    // All printable ASCII characters can be included as is (but for =).
+    if (c >= 33 && c <= 126 && c != 61) {

[tfarina, 2011/02/28 18:32:44]

Is there a reason for not using the letters instead? I think they will make the
code more easy to read. Same thing for the other occurrences below.

[Jay Civelli, 2011/02/28 19:25:53]

Done.

+      as_is = true;
+    }
+
+    // Space and tab characters can be included as is if they don't appear at
+    // the end of a line or at then end of the input.
+    if (!as_is && (c == 9 || c == 32) && !last_char &&
+        !IsEOL(iter + 1, input)) {
+      as_is = true;
+    }
+
+    // End of line should be converted to CR-LF sequences.
+    if (!last_char) {
+      int eol_len = IsEOL(iter, input);
+      if (eol_len > 0) {
+        output->append(kEOL);
+        char_count = 0;
+        iter += (eol_len - 1);  // -1 because we'll ++ in the for() above.
+        continue;
+      }
+    }
+
+    // Insert a soft line break if necessary.
+    int min_chars_needed = as_is ? kMaxCharPerLine - 2 : kMaxCharPerLine - 4;
+    if (!last_char && char_count > min_chars_needed) {
+      output->append("=");
+      output->append(kEOL);
+      char_count = 0;
+    }
+
+    // Finally, insert the actual character(s).
+    if (as_is) {
+      output->append(1, c);
+      char_count++;
+    } else {
+      output->append("=");
+      output->append(1, kHexTable[static_cast<int>((c >> 4) & 0xF)]);
+      output->append(1, kHexTable[static_cast<int>(c & 0x0F)]);
+      char_count += 3;
+    }
+  }
+}
+
+bool QuotedPrintableDecode(const std::string& input, std::string* output) {
+  bool success = true;
+  for (std::string::const_iterator iter = input.begin();
+       iter!= input.end(); ++iter) {
+    char c = *iter;
+    if (c != '=') {
+      output->append(1, c);
+      continue;
+    }
+    if (input.end() - iter < 3) {
+      LOG(ERROR) << "unfinished = sequence in input string.";
+      success = false;
+      output->append(1, c);
+      continue;
+    }
+    char c2 = *(++iter);
+    char c3 = *(++iter);
+    if (c2 == 13 && c3 == 10) {
+      // Soft line break, ignored.
+      continue;
+    }
+
+    int i1 = HexASCIICharToInt(c2);
+    int i2 = HexASCIICharToInt(c3);
+    if (i1 == -1 || i2 == -1) {
+      LOG(ERROR) << "invalid = sequence, = followed by non hexa digit " <<
+          "chars: " << c2 << " " << c3;
+      success = false;
+      // Just insert the chars as is.
+      output->append("=");
+      output->append(1, c2);
+      output->append(1, c3);
+      continue;
+    }
+
+    char r = static_cast<char>((i1 << 4 & 0xF0) | (i2 &0x0F));

[brettw, 2011/02/28 17:33:14]

Can you use an extra set of parens around the first part, I'm not sure of the
order pf operations for << and &.

Space after the second &

[Jay Civelli, 2011/02/28 19:25:53]

Done.

+    output->append(1, r);
+  }
+  return success;
+}
+
+int IsEOL(const std::string::const_iterator& iter, const std::string& input) {
+  if (*iter == 10)
+    return 1;  // Single LF.
+
+  if (*iter == 13) {
+    if ((iter + 1) == input.end() || *(iter + 1) != 10)
+      return 1;  // Single CR (Commodore and Old Macs).
+    return 2;  // CR-LF.
+  }
+
+  return 0;
+}
+
+}  // chrome_browser_net