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-rw-r--r--src/utils/encoding.cpp254
1 files changed, 254 insertions, 0 deletions
diff --git a/src/utils/encoding.cpp b/src/utils/encoding.cpp
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+++ b/src/utils/encoding.cpp
@@ -0,0 +1,254 @@
+#include <utils/encoding.hpp>
+
+#include <utils/scopeguard.hpp>
+
+#include <stdexcept>
+
+#include <cassert>
+#include <string.h>
+#include <iconv.h>
+#include <cerrno>
+
+#include <map>
+#include <bitset>
+
+/**
+ * The UTF-8-encoded character used as a place holder when a character conversion fails.
+ * This is U+FFFD � "replacement character"
+ */
+static const char* invalid_char = "\xef\xbf\xbd";
+static const size_t invalid_char_len = 3;
+
+namespace utils
+{
+ /**
+ * Based on http://en.wikipedia.org/wiki/UTF-8#Description
+ */
+ std::size_t get_next_codepoint_size(const unsigned char c)
+ {
+ if ((c & 0b11111000) == 0b11110000) // 4 bytes: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
+ return 4;
+ else if ((c & 0b11110000) == 0b11100000) // 3 bytes: 1110xxx 10xxxxxx 10xxxxxx
+ return 3;
+ else if ((c & 0b11100000) == 0b11000000) // 2 bytes: 110xxxxx 10xxxxxx
+ return 2;
+ return 1; // 1 byte: 0xxxxxxx
+ }
+
+ bool is_valid_utf8(const char* s)
+ {
+ if (!s)
+ return false;
+
+ const unsigned char* str = reinterpret_cast<const unsigned char*>(s);
+
+ while (*str)
+ {
+ const auto codepoint_size = get_next_codepoint_size(str[0]);
+ if (codepoint_size == 4)
+ {
+ if (!str[1] || !str[2] || !str[3]
+ || ((str[1] & 0b11000000) != 0b10000000)
+ || ((str[2] & 0b11000000) != 0b10000000)
+ || ((str[3] & 0b11000000) != 0b10000000))
+ return false;
+ }
+ else if (codepoint_size == 3)
+ {
+ if (!str[1] || !str[2]
+ || ((str[1] & 0b11000000) != 0b10000000)
+ || ((str[2] & 0b11000000) != 0b10000000))
+ return false;
+ }
+ else if (codepoint_size == 2)
+ {
+ if (!str[1] ||
+ ((str[1] & 0b11000000) != 0b10000000))
+ return false;
+ }
+ else if ((str[0] & 0b10000000) != 0)
+ return false;
+ str += codepoint_size;
+ }
+ return true;
+ }
+
+ std::string remove_invalid_xml_chars(const std::string& original)
+ {
+ // The given string MUST be a valid utf-8 string
+ std::vector<char> res(original.size(), '\0');
+
+ // pointer where we write valid chars
+ char* r = res.data();
+
+ const char* str = original.c_str();
+ std::bitset<20> codepoint;
+
+ while (*str)
+ {
+ // 4 bytes: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
+ if ((str[0] & 0b11111000) == 0b11110000)
+ {
+ codepoint = ((str[0] & 0b00000111) << 18);
+ codepoint |= ((str[1] & 0b00111111) << 12);
+ codepoint |= ((str[2] & 0b00111111) << 6 );
+ codepoint |= ((str[3] & 0b00111111) << 0 );
+ if (codepoint.to_ulong() <= 0x10FFFF)
+ {
+ ::memcpy(r, str, 4);
+ r += 4;
+ }
+ str += 4;
+ }
+ // 3 bytes: 1110xxx 10xxxxxx 10xxxxxx
+ else if ((str[0] & 0b11110000) == 0b11100000)
+ {
+ codepoint = ((str[0] & 0b00001111) << 12);
+ codepoint |= ((str[1] & 0b00111111) << 6);
+ codepoint |= ((str[2] & 0b00111111) << 0 );
+ if (codepoint.to_ulong() <= 0xD7FF ||
+ (codepoint.to_ulong() >= 0xE000 && codepoint.to_ulong() <= 0xFFFD))
+ {
+ ::memcpy(r, str, 3);
+ r += 3;
+ }
+ str += 3;
+ }
+ // 2 bytes: 110xxxxx 10xxxxxx
+ else if (((str[0]) & 0b11100000) == 0b11000000)
+ {
+ // All 2 bytes char are valid, don't even bother calculating
+ // the codepoint
+ ::memcpy(r, str, 2);
+ r += 2;
+ str += 2;
+ }
+ // 1 byte: 0xxxxxxx
+ else if ((str[0] & 0b10000000) == 0)
+ {
+ codepoint = ((str[0] & 0b01111111));
+ if (codepoint.to_ulong() == 0x09 ||
+ codepoint.to_ulong() == 0x0A ||
+ codepoint.to_ulong() == 0x0D ||
+ codepoint.to_ulong() >= 0x20)
+ {
+ ::memcpy(r, str, 1);
+ r += 1;
+ }
+ str += 1;
+ }
+ else
+ throw std::runtime_error("Invalid UTF-8 passed to remove_invalid_xml_chars");
+ }
+ return {res.data(), static_cast<size_t>(r - res.data())};
+ }
+
+ std::string convert_to_utf8(const std::string& str, const char* charset)
+ {
+ std::string res;
+
+ const iconv_t cd = iconv_open("UTF-8", charset);
+ if (cd == (iconv_t)-1)
+ throw std::runtime_error("Cannot convert into UTF-8");
+
+ // Make sure cd is always closed when we leave this function
+ const auto sg = utils::make_scope_guard([&cd](){ iconv_close(cd); });
+
+ size_t inbytesleft = str.size();
+
+ // iconv will not attempt to modify this buffer, but some plateform
+ // require a char** anyway
+#ifdef ICONV_SECOND_ARGUMENT_IS_CONST
+ const char* inbuf_ptr = str.c_str();
+#else
+ char* inbuf_ptr = const_cast<char*>(str.c_str());
+#endif
+
+ size_t outbytesleft = str.size() * 4;
+ char* outbuf = new char[outbytesleft];
+ char* outbuf_ptr = outbuf;
+
+ // Make sure outbuf is always deleted when we leave this function
+ const auto sg2 = utils::make_scope_guard([outbuf](){ delete[] outbuf; });
+
+ bool done = false;
+ while (done == false)
+ {
+ size_t error = iconv(cd, &inbuf_ptr, &inbytesleft, &outbuf_ptr, &outbytesleft);
+ if ((size_t)-1 == error)
+ {
+ switch (errno)
+ {
+ case EILSEQ:
+ // Invalid byte found. Insert a placeholder instead of the
+ // converted character, jump one byte and continue
+ memcpy(outbuf_ptr, invalid_char, invalid_char_len);
+ outbuf_ptr += invalid_char_len;
+ inbytesleft--;
+ inbuf_ptr++;
+ break;
+ case EINVAL:
+ // A multibyte sequence is not terminated, but we can't
+ // provide any more data, so we just add a placeholder to
+ // indicate that the character is not properly converted,
+ // and we stop the conversion
+ memcpy(outbuf_ptr, invalid_char, invalid_char_len);
+ outbuf_ptr += invalid_char_len;
+ outbuf_ptr++;
+ done = true;
+ break;
+ case E2BIG: // This should never happen
+ default: // This should happen even neverer
+ done = true;
+ break;
+ }
+ }
+ else
+ {
+ // The conversion finished without any error, stop converting
+ done = true;
+ }
+ }
+ // Terminate the converted buffer, and copy that buffer it into the
+ // string we return
+ *outbuf_ptr = '\0';
+ res = outbuf;
+ return res;
+ }
+
+}
+
+namespace xep0106
+{
+ static const std::map<const char, const std::string> encode_map = {
+ {' ', "\\20"},
+ {'"', "\\22"},
+ {'&', "\\26"},
+ {'\'',"\\27"},
+ {'/', "\\2f"},
+ {':', "\\3a"},
+ {'<', "\\3c"},
+ {'>', "\\3e"},
+ {'@', "\\40"},
+ };
+
+ void decode(std::string& s)
+ {
+ std::string::size_type pos;
+ for (const auto& pair: encode_map)
+ while ((pos = s.find(pair.second)) != std::string::npos)
+ s.replace(pos, pair.second.size(),
+ 1, pair.first);
+ }
+
+ void encode(std::string& s)
+ {
+ std::string::size_type pos;
+ while ((pos = s.find_first_of(" \"&'/:<>@")) != std::string::npos)
+ {
+ auto it = encode_map.find(s[pos]);
+ assert(it != encode_map.end());
+ s.replace(pos, 1, it->second);
+ }
+ }
+}