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qpdf/include/qpdf/QUtil.hh

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7.8 KiB
C++

// Copyright (c) 2005-2018 Jay Berkenbilt
//
// This file is part of qpdf.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Versions of qpdf prior to version 7 were released under the terms
// of version 2.0 of the Artistic License. At your option, you may
// continue to consider qpdf to be licensed under those terms. Please
// see the manual for additional information.
#ifndef QUTIL_HH
#define QUTIL_HH
#include <qpdf/DLL.h>
#include <qpdf/Types.h>
#include <string>
#include <list>
#include <stdexcept>
#include <stdio.h>
#include <time.h>
class RandomDataProvider;
namespace QUtil
{
// This is a collection of useful utility functions that don't
// really go anywhere else.
QPDF_DLL
std::string int_to_string(long long, int length = 0);
QPDF_DLL
std::string int_to_string_base(long long, int base, int length = 0);
QPDF_DLL
std::string double_to_string(double, int decimal_places = 0);
// These string to number methods throw std::runtime_error on
// underflow/overflow.
QPDF_DLL
long long string_to_ll(char const* str);
QPDF_DLL
int string_to_int(char const* str);
// Pipeline's write method wants unsigned char*, but we often have
// some other type of string. These methods do combinations of
// const_cast and reinterpret_cast to give us an unsigned char*.
// They should only be used when it is known that it is safe.
// None of the pipelines in qpdf modify the data passed to them,
// so within qpdf, it should always be safe.
QPDF_DLL
unsigned char* unsigned_char_pointer(std::string const& str);
QPDF_DLL
unsigned char* unsigned_char_pointer(char const* str);
// Throw std::runtime_error with a string formed by appending to
// "description: " the standard string corresponding to the
// current value of errno.
QPDF_DLL
void throw_system_error(std::string const& description);
// The status argument is assumed to be the return value of a
// standard library call that sets errno when it fails. If status
// is -1, convert the current value of errno to a
// std::runtime_error that includes the standard error string.
// Otherwise, return status.
QPDF_DLL
int os_wrapper(std::string const& description, int status);
// If the open fails, throws std::runtime_error. Otherwise, the
// FILE* is returned.
QPDF_DLL
FILE* safe_fopen(char const* filename, char const* mode);
// The FILE* argument is assumed to be the return of fopen. If
// null, throw std::runtime_error. Otherwise, return the FILE*
// argument.
QPDF_DLL
FILE* fopen_wrapper(std::string const&, FILE*);
// Wrap around off_t versions of fseek and ftell if available
QPDF_DLL
int seek(FILE* stream, qpdf_offset_t offset, int whence);
QPDF_DLL
qpdf_offset_t tell(FILE* stream);
QPDF_DLL
bool same_file(char const* name1, char const* name2);
QPDF_DLL
char* copy_string(std::string const&);
// Returns lower-case hex-encoded version of the string, treating
// each character in the input string as unsigned. The output
// string will be twice as long as the input string.
QPDF_DLL
std::string hex_encode(std::string const&);
// Returns a string that is the result of decoding the input
// string. The input string may consist of mixed case hexadecimal
// digits. Any characters that are not hexadecimal digits will be
// silently ignored. If there are an odd number of hexadecimal
// digits, a trailing 0 will be assumed.
QPDF_DLL
std::string hex_decode(std::string const&);
// Set stdin, stdout to binary mode
QPDF_DLL
void binary_stdout();
QPDF_DLL
void binary_stdin();
// Set stdout to line buffered
QPDF_DLL
void setLineBuf(FILE*);
// May modify argv0
QPDF_DLL
char* getWhoami(char* argv0);
// Get the value of an environment variable in a portable fashion.
// Returns true iff the variable is defined. If `value' is
// non-null, initializes it with the value of the variable.
QPDF_DLL
bool get_env(std::string const& var, std::string* value = 0);
QPDF_DLL
time_t get_current_time();
// Return a string containing the byte representation of the UTF-8
// encoding for the unicode value passed in.
QPDF_DLL
std::string toUTF8(unsigned long uval);
// Return a string containing the byte representation of the
// UTF-16 BE encoding for the unicode value passed in.
// Unrepresentable code points are converted to U+FFFD.
QPDF_DLL
std::string toUTF16(unsigned long uval);
// If secure random number generation is supported on your
// platform and qpdf was not compiled with insecure random number
// generation, this returns a cryptographically secure random
// number. Otherwise it falls back to random from stdlib and
// calls srandom automatically the first time it is called.
QPDF_DLL
long random();
// Wrapper around srandom from stdlib. Seeds the standard library
// weak random number generator, which is not used if secure
// random number generation is being used. You never need to call
// this method as it is called automatically if needed.
QPDF_DLL
void srandom(unsigned int seed);
// Initialize a buffer with random bytes. By default, qpdf tries
// to use a secure random number source. It can be configured at
// compile time to use an insecure random number source (from
// stdlib). You can also call setRandomDataProvider with a
// RandomDataProvider, in which case this method will get its
// random bytes from that.
QPDF_DLL
void initializeWithRandomBytes(unsigned char* data, size_t len);
// Supply a random data provider. If not supplied, depending on
// compile time options, qpdf will either use the operating
// system's secure random number source or an insecure random
// source from stdlib. The caller is responsible for managing the
// memory for the RandomDataProvider. This method modifies a
// static variable. If you are providing your own random data
// provider, you should call this at the beginning of your program
// before creating any QPDF objects. Passing a null to this
// method will reset the library back to whichever of the built-in
// random data handlers is appropriate based on how qpdf was
// compiled.
QPDF_DLL
void setRandomDataProvider(RandomDataProvider*);
// This returns the random data provider that would be used the
// next time qpdf needs random data. It will never return null.
// If no random data provider has been provided and the library
// was not compiled with any random data provider available, an
// exception will be thrown.
QPDF_DLL
RandomDataProvider* getRandomDataProvider();
QPDF_DLL
std::list<std::string> read_lines_from_file(char const* filename);
QPDF_DLL
std::list<std::string> read_lines_from_file(std::istream&);
QPDF_DLL
int strcasecmp(char const *, char const *);
// These routines help the tokenizer recognize certain character
// classes without using ctype, which we avoid because of locale
// considerations.
QPDF_DLL
bool is_hex_digit(char);
QPDF_DLL
bool is_space(char);
QPDF_DLL
bool is_digit(char);
QPDF_DLL
bool is_number(char const*);
};
#endif // QUTIL_HH