1 // Copyright (c) 2008, Google Inc. 2 // All rights reserved. 3 // 4 // Redistribution and use in source and binary forms, with or without 5 // modification, are permitted provided that the following conditions are 6 // met: 7 // 8 // * Redistributions of source code must retain the above copyright 9 // notice, this list of conditions and the following disclaimer. 10 // * Redistributions in binary form must reproduce the above 11 // copyright notice, this list of conditions and the following disclaimer 12 // in the documentation and/or other materials provided with the 13 // distribution. 14 // * Neither the name of Google Inc. nor the names of its 15 // contributors may be used to endorse or promote products derived from 16 // this software without specific prior written permission. 17 // 18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 30 // --- 31 // Author: Sanjay Ghemawat 32 // 33 // A printf() wrapper that writes into a fixed length buffer. 34 // Useful in low-level code that does not want to use allocating 35 // routines like StringPrintf(). 36 // 37 // The implementation currently uses vsnprintf(). This seems to 38 // be fine for use in many low-level contexts, but we may need to 39 // rethink this decision if we hit a problem with it calling 40 // down into malloc() etc. 41 42 #ifndef BASE_RAW_PRINTER_H_ 43 #define BASE_RAW_PRINTER_H_ 44 45 #include <config.h> 46 #include "base/basictypes.h" 47 48 namespace base { 49 50 class RawPrinter { 51 public: 52 // REQUIRES: "length > 0" 53 // Will printf any data added to this into "buf[0,length-1]" and 54 // will arrange to always keep buf[] null-terminated. 55 RawPrinter(char* buf, int length); 56 57 // Return the number of bytes that have been appended to the string 58 // so far. Does not count any bytes that were dropped due to overflow. 59 int length() const { return (ptr_ - base_); } 60 61 // Return the number of bytes that can be added to this. 62 int space_left() const { return (limit_ - ptr_); } 63 64 // Format the supplied arguments according to the "format" string 65 // and append to this. Will silently truncate the output if it does 66 // not fit. 67 void Printf(const char* format, ...) 68 #ifdef HAVE___ATTRIBUTE__ 69 __attribute__ ((__format__ (__printf__, 2, 3))) 70 #endif 71 ; 72 73 private: 74 // We can write into [ptr_ .. limit_-1]. 75 // *limit_ is also writable, but reserved for a terminating \0 76 // in case we overflow. 77 // 78 // Invariants: *ptr_ == \0 79 // Invariants: *limit_ == \0 80 char* base_; // Initial pointer 81 char* ptr_; // Where should we write next 82 char* limit_; // One past last non-\0 char we can write 83 84 DISALLOW_COPY_AND_ASSIGN(RawPrinter); 85 }; 86 87 } 88 89 #endif // BASE_RAW_PRINTER_H_ 90
