1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 | #ifndef STLPLUS_DPRINTF#define STLPLUS_DPRINTF//////////////////////////////////////////////////////////////////////////////////// Author: Andy Rushton// Copyright: (c) Southampton University 1999-2004// (c) Andy Rushton 2004 onwards// License: BSD License, see ../docs/license.html//// Provides an sprintf-like function acting on STL strings. The 'd' in dprintf// stands for "dynamic" in that the string is a dynamic string whereas a char*// buffer would be static (in size that is, not static in C terms).//// The obvious solution to the problem of in-memory formatted output is to use// sprintf(), but this is a potentially dangerous operation since it will quite// happily charge off the end of the string it is printing to and thereby// corrupt memory. This kind of buffer-overflow vulnerability is the source of// most security failures exploited by virus-writers. It means that sprintf// should *never* be used and should be made obsolete.//// In any case, using arbitrary-sized fixed-length buffers is not part of any// quality-orientated design philosophy.//// Most operating systems now have a safe version of sprintf, but this is// non-standard. The functions in this file are platform-independent interfaces// to the underlying safe implementation.//// I would like to make this set of functions obsolete too, since I believe the// C runtime should be deprecated in favour of C++ runtime which uses dynamic// strings and can handle exceptions. However, there is as yet no C++// equivalent functionality to some of the string-handling available through// the printf-like functions, so it has to stay for now.//// int dprintf (std::string& buffer, const char* format, ...);//// Formats the message by appending to the std::string buffer according to// the formatting codes in the format string. The return int is the number// of characters generated by this call, i.e. the increase in the length of// the std::string.//// int vdprintf (std::string& buffer, const char* format, va_list args);//// As above, but using a pre-initialised va_args argument list. Useful for// nesting dprintf calls within variable argument functions.//// std::string dformat (const char* format, ...);//// Similar to dprintf() above, except the result is formatted into a new// std::string which is returned by the function. Very useful for inline// calls within an iostream expression.//// e.g. cout << "Total: " << dformat("%6i",t) << endl;//// std::string vdformat (const char* format, va_list);//// As above, but using a pre-initialised va_args argument list. Useful for nesting// dformat calls within variable argument functions.//// The format string supports the following format codes as in the C runtime library://// % [ flags ] [ field ] [ . precision ] [ modifier ] [ conversion ]//// flags:// - - left justified// + - print sign for +ve numbers// ' ' - leading space where + sign would be// 0 - leading zeros to width of field// # - alternate format//// field:// a numeric argument specifying the field width - default = 0// * means take the next va_arg as the field width - if negative then left justify//// precision:// a numeric argument the meaning of which depends on the conversion -// - %s - max characters from a string - default = strlen()// - %e, %f - decimal places to be displayed - default = 6// - %g - significant digits to be displayed - default = 6// - all integer conversions - minimum digits to display - default = 0// * means take the next va_arg as the field width - if negative then left justify//// modifier:// h - short or unsigned short// l - long or unsigned long// L - long double//// conversions:// d, i - short/int/long as decimal// u - short/int/long as unsigned decimal// o - short/int/long as unsigned octal - # adds leading 0// x, X - short/int/long as unsigned hexadecimal - # adds leading 0x// c - char// s - char*// f - double/long double as fixed point// e, E - double/long double as floating point// g, G - double/long double as fixed point/floating point depending on value// p - void* as unsigned hexadecimal// % - literal %// n - int* as recipient of length of formatted string so far//////////////////////////////////////////////////////////////////////////////////#include "portability_fixes.hpp"#include <string>#include <stdexcept>#include <stdarg.h>namespace stlplus{ // format by appending to a string and return the increase in length // if there is an error, return a negative number and leave the string unchanged int dprintf (std::string& formatted, const char* format, ...); int vdprintf (std::string& formatted, const char* format, va_list args); // format into a new string and return the result // if there is an error, throw an exception // exceptions: std::invalid_argument std::string dformat (const char* format, ...) ; // exceptions: std::invalid_argument std::string vdformat (const char* format, va_list) ;}#endif |