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Diffstat (limited to 'utils/format/formatter.cpp')
| -rw-r--r-- | utils/format/formatter.cpp | 293 |
1 files changed, 293 insertions, 0 deletions
diff --git a/utils/format/formatter.cpp b/utils/format/formatter.cpp new file mode 100644 index 000000000000..99cfd40f03ab --- /dev/null +++ b/utils/format/formatter.cpp @@ -0,0 +1,293 @@ +// Copyright 2010 The Kyua Authors. +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above copyright +// notice, this list of conditions and the following disclaimer in the +// documentation and/or other materials provided with the distribution. +// * Neither the name of Google Inc. nor the names of its contributors +// may be used to endorse or promote products derived from this software +// without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +#include "utils/format/formatter.hpp" + +#include <memory> +#include <string> +#include <utility> + +#include "utils/format/exceptions.hpp" +#include "utils/sanity.hpp" +#include "utils/text/exceptions.hpp" +#include "utils/text/operations.ipp" + +namespace format = utils::format; +namespace text = utils::text; + + +namespace { + + +/// Finds the next placeholder in a string. +/// +/// \param format The original format string provided by the user; needed for +/// error reporting purposes only. +/// \param expansion The string containing the placeholder to look for. Any +/// '%%' in the string will be skipped, and they must be stripped later by +/// strip_double_percent(). +/// \param begin The position from which to start looking for the next +/// placeholder. +/// +/// \return The position in the string in which the placeholder is located and +/// the placeholder itself. If there are no placeholders left, this returns +/// the length of the string and an empty string. +/// +/// \throw bad_format_error If the input string contains a trailing formatting +/// character. We cannot detect any other kind of invalid formatter because +/// we do not implement a full parser for them. +static std::pair< std::string::size_type, std::string > +find_next_placeholder(const std::string& format, + const std::string& expansion, + std::string::size_type begin) +{ + begin = expansion.find('%', begin); + while (begin != std::string::npos && expansion[begin + 1] == '%') + begin = expansion.find('%', begin + 2); + if (begin == std::string::npos) + return std::make_pair(expansion.length(), ""); + if (begin == expansion.length() - 1) + throw format::bad_format_error(format, "Trailing %"); + + std::string::size_type end = begin + 1; + while (end < expansion.length() && expansion[end] != 's') + end++; + const std::string placeholder = expansion.substr(begin, end - begin + 1); + if (end == expansion.length() || + placeholder.find('%', 1) != std::string::npos) + throw format::bad_format_error(format, "Unterminated placeholder '" + + placeholder + "'"); + return std::make_pair(begin, placeholder); +} + + +/// Converts a string to an integer. +/// +/// \param format The format string; for error reporting purposes only. +/// \param str The string to conver. +/// \param what The name of the field this integer belongs to; for error +/// reporting purposes only. +/// +/// \return An integer representing the input string. +inline int +to_int(const std::string& format, const std::string& str, const char* what) +{ + try { + return text::to_type< int >(str); + } catch (const text::value_error& e) { + throw format::bad_format_error(format, "Invalid " + std::string(what) + + "specifier"); + } +} + + +/// Constructs an std::ostringstream based on a formatting placeholder. +/// +/// \param format The format placeholder; may be empty. +/// +/// \return A new std::ostringstream that is prepared to format a single +/// object in the manner specified by the format placeholder. +/// +/// \throw bad_format_error If the format string is bad. We do minimal +/// validation on this string though. +static std::ostringstream* +new_ostringstream(const std::string& format) +{ + std::auto_ptr< std::ostringstream > output(new std::ostringstream()); + + if (format.length() <= 2) { + // If the format is empty, we create a new stream so that we don't have + // to check for NULLs later on. We rarely should hit this condition + // (and when we do it's a bug in the caller), so this is not a big deal. + // + // Otherwise, if the format is a regular '%s', then we don't have to do + // any processing for additional formatters. So this is just a "fast + // path". + } else { + std::string partial = format.substr(1, format.length() - 2); + if (partial[0] == '0') { + output->fill('0'); + partial.erase(0, 1); + } + if (!partial.empty()) { + const std::string::size_type dot = partial.find('.'); + if (dot != 0) + output->width(to_int(format, partial.substr(0, dot), "width")); + if (dot != std::string::npos) { + output->setf(std::ios::fixed, std::ios::floatfield); + output->precision(to_int(format, partial.substr(dot + 1), + "precision")); + } + } + } + + return output.release(); +} + + +/// Replaces '%%' by '%' in a given string range. +/// +/// \param in The input string to be rewritten. +/// \param begin The position at which to start the replacement. +/// \param end The position at which to end the replacement. +/// +/// \return The modified string and the amount of characters removed. +static std::pair< std::string, int > +strip_double_percent(const std::string& in, const std::string::size_type begin, + std::string::size_type end) +{ + std::string part = in.substr(begin, end - begin); + + int removed = 0; + std::string::size_type pos = part.find("%%"); + while (pos != std::string::npos) { + part.erase(pos, 1); + ++removed; + pos = part.find("%%", pos + 1); + } + + return std::make_pair(in.substr(0, begin) + part + in.substr(end), removed); +} + + +} // anonymous namespace + + +/// Performs internal initialization of the formatter. +/// +/// This is separate from the constructor just because it is shared by different +/// overloaded constructors. +void +format::formatter::init(void) +{ + const std::pair< std::string::size_type, std::string > placeholder = + find_next_placeholder(_format, _expansion, _last_pos); + const std::pair< std::string, int > no_percents = + strip_double_percent(_expansion, _last_pos, placeholder.first); + + _oss = new_ostringstream(placeholder.second); + + _expansion = no_percents.first; + _placeholder_pos = placeholder.first - no_percents.second; + _placeholder = placeholder.second; +} + + +/// Constructs a new formatter object (internal). +/// +/// \param format The format string. +/// \param expansion The format string with any replacements performed so far. +/// \param last_pos The position from which to start looking for formatting +/// placeholders. This must be maintained in case one of the replacements +/// introduced a new placeholder, which must be ignored. Think, for +/// example, replacing a "%s" string with "foo %s". +format::formatter::formatter(const std::string& format, + const std::string& expansion, + const std::string::size_type last_pos) : + _format(format), + _expansion(expansion), + _last_pos(last_pos), + _oss(NULL) +{ + init(); +} + + +/// Constructs a new formatter object. +/// +/// \param format The format string. The formatters in the string are not +/// validated during construction, but will cause errors when used later if +/// they are invalid. +format::formatter::formatter(const std::string& format) : + _format(format), + _expansion(format), + _last_pos(0), + _oss(NULL) +{ + init(); +} + + +format::formatter::~formatter(void) +{ + delete _oss; +} + + +/// Returns the formatted string. +/// +/// \return A string representation of the formatted string. +const std::string& +format::formatter::str(void) const +{ + return _expansion; +} + + +/// Automatic conversion of formatter objects to strings. +/// +/// This is provided to allow painless injection of formatter objects into +/// streams, without having to manually call the str() method. +format::formatter::operator const std::string&(void) const +{ + return _expansion; +} + + +/// Specialization of operator% for booleans. +/// +/// \param value The boolean to inject into the format string. +/// +/// \return A new formatter that has one less format placeholder. +format::formatter +format::formatter::operator%(const bool& value) const +{ + (*_oss) << (value ? "true" : "false"); + return replace(_oss->str()); +} + + +/// Replaces the first formatting placeholder with a value. +/// +/// \param arg The replacement string. +/// +/// \return A new formatter in which the first formatting placeholder has been +/// replaced by arg and is ready to replace the next item. +/// +/// \throw utils::format::extra_args_error If there are no more formatting +/// placeholders in the input string, or if the placeholder is invalid. +format::formatter +format::formatter::replace(const std::string& arg) const +{ + if (_placeholder_pos == _expansion.length()) + throw format::extra_args_error(_format, arg); + + const std::string expansion = _expansion.substr(0, _placeholder_pos) + + arg + _expansion.substr(_placeholder_pos + _placeholder.length()); + return formatter(_format, expansion, _placeholder_pos + arg.length()); +} |