util: introduce escape() and use it in Component::toUri()
Change-Id: Ie476ca0fc909fb275631c60195fb1aa5640cff10
Refs: #4484
diff --git a/src/util/string-helper.cpp b/src/util/string-helper.cpp
index 8be94d0..642b238 100644
--- a/src/util/string-helper.cpp
+++ b/src/util/string-helper.cpp
@@ -1,6 +1,6 @@
/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
- * Copyright (c) 2013-2017 Regents of the University of California.
+ * Copyright (c) 2013-2018 Regents of the University of California.
*
* This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
*
@@ -77,19 +77,6 @@
return toHex(buffer.data(), buffer.size(), wantUpperCase);
}
-int
-fromHexChar(char c)
-{
- if (c >= '0' && c <= '9')
- return c - '0';
- else if (c >= 'A' && c <= 'F')
- return c - 'A' + 0xA;
- else if (c >= 'a' && c <= 'f')
- return c - 'a' + 0xA;
- else
- return -1;
-}
-
shared_ptr<Buffer>
fromHex(const std::string& hexString)
{
@@ -107,31 +94,64 @@
}
std::string
+escape(const std::string& str)
+{
+ std::ostringstream os;
+ escape(os, str.data(), str.size());
+ return os.str();
+}
+
+void
+escape(std::ostream& os, const char* str, size_t len)
+{
+ for (size_t i = 0; i < len; ++i) {
+ auto c = str[i];
+ // Unreserved characters don't need to be escaped.
+ if ((c >= 'a' && c <= 'z') ||
+ (c >= 'A' && c <= 'Z') ||
+ (c >= '0' && c <= '9') ||
+ c == '-' || c == '.' ||
+ c == '_' || c == '~') {
+ os << c;
+ }
+ else {
+ os << '%';
+ os << toHexChar((c & 0xf0) >> 4);
+ os << toHexChar(c & 0xf);
+ }
+ }
+}
+
+std::string
unescape(const std::string& str)
{
- std::ostringstream result;
+ std::ostringstream os;
+ unescape(os, str.data(), str.size());
+ return os.str();
+}
- for (size_t i = 0; i < str.size(); ++i) {
- if (str[i] == '%' && i + 2 < str.size()) {
+void
+unescape(std::ostream& os, const char* str, size_t len)
+{
+ for (size_t i = 0; i < len; ++i) {
+ if (str[i] == '%' && i + 2 < len) {
int hi = fromHexChar(str[i + 1]);
int lo = fromHexChar(str[i + 2]);
if (hi < 0 || lo < 0)
// Invalid hex characters, so just keep the escaped string.
- result << str[i] << str[i + 1] << str[i + 2];
+ os << str[i] << str[i + 1] << str[i + 2];
else
- result << static_cast<char>((hi << 4) | lo);
+ os << static_cast<char>((hi << 4) | lo);
// Skip ahead past the escaped value.
i += 2;
}
else {
// Just copy through.
- result << str[i];
+ os << str[i];
}
}
-
- return result.str();
}
} // namespace ndn
diff --git a/src/util/string-helper.hpp b/src/util/string-helper.hpp
index 403c25e..a34fdb7 100644
--- a/src/util/string-helper.hpp
+++ b/src/util/string-helper.hpp
@@ -1,6 +1,6 @@
/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2013-2017 Regents of the University of California.
+/*
+ * Copyright (c) 2013-2018 Regents of the University of California.
*
* This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
*
@@ -142,12 +142,6 @@
toHex(const Buffer& buffer, bool wantUpperCase = true);
/**
- * @brief Convert the hex character to an integer from 0 to 15, or -1 if not a hex character
- */
-int
-fromHexChar(char c);
-
-/**
* @brief Convert the hex string to buffer
* @param hexString sequence of pairs of hex numbers (lower and upper case can be mixed)
* without any whitespace separators (e.g., "48656C6C6F2C20776F726C6421")
@@ -157,6 +151,51 @@
fromHex(const std::string& hexString);
/**
+ * @brief Convert (the least significant nibble of) @p n to the corresponding hex character
+ */
+constexpr char
+toHexChar(unsigned int n, bool wantUpperCase = true) noexcept
+{
+ return wantUpperCase ?
+ "0123456789ABCDEF"[n & 0xf] :
+ "0123456789abcdef"[n & 0xf];
+}
+
+/**
+ * @brief Convert the hex character @p c to an integer in [0, 15], or -1 if it's not a hex character
+ */
+constexpr int
+fromHexChar(char c) noexcept
+{
+ return (c >= '0' && c <= '9') ? int(c - '0') :
+ (c >= 'A' && c <= 'F') ? int(c - 'A' + 10) :
+ (c >= 'a' && c <= 'f') ? int(c - 'a' + 10) :
+ -1;
+}
+
+/**
+ * @brief Percent-encode a string
+ * @see RFC 3986 section 2
+ *
+ * This function will encode all characters that are not one of the following:
+ * ALPHA ("a" to "z" and "A" to "Z") / DIGIT (0 to 9) / "-" / "." / "_" / "~"
+ *
+ * The hex encoding uses the numbers 0-9 and the uppercase letters A-F.
+ *
+ * Examples:
+ *
+ * @code
+ * escape("hello world") == "hello%20world"
+ * escape("100%") == "100%25"
+ * @endcode
+ */
+std::string
+escape(const std::string& str);
+
+void
+escape(std::ostream& os, const char* str, size_t len);
+
+/**
* @brief Decode a percent-encoded string
* @see RFC 3986 section 2
*
@@ -172,6 +211,9 @@
std::string
unescape(const std::string& str);
+void
+unescape(std::ostream& os, const char* str, size_t len);
+
} // namespace ndn
#endif // NDN_UTIL_STRING_HELPER_HPP