comparison: databuffer.h
databuffer.h
- changeset 32
- d11a034aabfd
- child 34
- 0a9a5902beaa
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| 1 /* | |
| 2 * botc source code | |
| 3 * Copyright (C) 2012 Santeri `Dusk` Piippo | |
| 4 * All rights reserved. | |
| 5 * | |
| 6 * Redistribution and use in source and binary forms, with or without | |
| 7 * modification, are permitted provided that the following conditions are met: | |
| 8 * | |
| 9 * 1. Redistributions of source code must retain the above copyright notice, | |
| 10 * this list of conditions and the following disclaimer. | |
| 11 * 2. Redistributions in binary form must reproduce the above copyright notice, | |
| 12 * this list of conditions and the following disclaimer in the documentation | |
| 13 * and/or other materials provided with the distribution. | |
| 14 * 3. Neither the name of the developer nor the names of its contributors may | |
| 15 * be used to endorse or promote products derived from this software without | |
| 16 * specific prior written permission. | |
| 17 * 4. Redistributions in any form must be accompanied by information on how to | |
| 18 * obtain complete source code for the software and any accompanying | |
| 19 * software that uses the software. The source code must either be included | |
| 20 * in the distribution or be available for no more than the cost of | |
| 21 * distribution plus a nominal fee, and must be freely redistributable | |
| 22 * under reasonable conditions. For an executable file, complete source | |
| 23 * code means the source code for all modules it contains. It does not | |
| 24 * include source code for modules or files that typically accompany the | |
| 25 * major components of the operating system on which the executable file | |
| 26 * runs. | |
| 27 * | |
| 28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | |
| 29 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE | |
| 32 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
| 33 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
| 34 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
| 35 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
| 36 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 37 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| 38 * POSSIBILITY OF SUCH DAMAGE. | |
| 39 */ | |
| 40 | |
| 41 #ifndef __DATABUFFER_H__ | |
| 42 #define __DATABUFFER_H__ | |
| 43 #include <stdio.h> | |
| 44 #include <string.h> | |
| 45 #include "common.h" | |
| 46 | |
| 47 // ============================================================================ | |
| 48 // DataBuffer: A dynamic data buffer. | |
| 49 class DataBuffer { | |
| 50 public: | |
| 51 // The actual buffer | |
| 52 unsigned char* buffer; | |
| 53 | |
| 54 // Allocated size of the buffer | |
| 55 unsigned int allocsize; | |
| 56 | |
| 57 // Written size of the buffer | |
| 58 unsigned int writesize; | |
| 59 | |
| 60 // METHODS | |
| 61 DataBuffer (unsigned int size=128) { | |
| 62 writesize = 0; | |
| 63 | |
| 64 buffer = new unsigned char[size]; | |
| 65 allocsize = size; | |
| 66 } | |
| 67 | |
| 68 ~DataBuffer () { | |
| 69 delete buffer; | |
| 70 } | |
| 71 | |
| 72 template<class T> void Write(T stuff) { | |
| 73 if (sizeof (char) != 1) { | |
| 74 error ("DataBuffer: sizeof(char) must be 1!\n"); | |
| 75 } | |
| 76 | |
| 77 // Out of space, must resize | |
| 78 if (writesize + sizeof(T) >= allocsize) { | |
| 79 // First, store the old buffer temporarily | |
| 80 char* copy = new char[allocsize]; | |
| 81 memcpy (copy, buffer, allocsize); | |
| 82 | |
| 83 // Remake the buffer with the new size. | |
| 84 // Have a bit of leeway so we don't have to | |
| 85 // resize immediately again. | |
| 86 size_t newsize = allocsize + sizeof (T) + 128; | |
| 87 delete buffer; | |
| 88 buffer = new unsigned char[newsize]; | |
| 89 allocsize = newsize; | |
| 90 | |
| 91 // Now, copy the new stuff over. | |
| 92 memcpy (buffer, copy, allocsize); | |
| 93 | |
| 94 // Nuke the copy now as it's no longer needed | |
| 95 delete copy; | |
| 96 } | |
| 97 | |
| 98 // Write the new stuff one byte at a time | |
| 99 for (unsigned int x = 0; x < sizeof (T); x++) { | |
| 100 if (writesize >= allocsize) | |
| 101 error ("DataBuffer: written size exceeds allocated size!\n"); | |
| 102 buffer[writesize] = CharByte<T> (stuff, x); | |
| 103 writesize++; | |
| 104 } | |
| 105 } | |
| 106 | |
| 107 private: | |
| 108 template <class T> unsigned char CharByte (T a, unsigned int b) { | |
| 109 if (b >= sizeof (T)) | |
| 110 error ("CharByte: tried to get byte %u out of a %u-byte %s\n", | |
| 111 b, sizeof (T), typeid(T).name()); | |
| 112 | |
| 113 unsigned long p1 = pow<unsigned long> (256, b); | |
| 114 unsigned long p2 = pow<unsigned long> (256, b+1); | |
| 115 unsigned long r = (a % p2) / p1; | |
| 116 | |
| 117 if (r > 256) | |
| 118 error ("result %lu too big!", r); | |
| 119 | |
| 120 unsigned char ur = static_cast<unsigned char> (r); | |
| 121 return ur; | |
| 122 } | |
| 123 }; | |
| 124 | |
| 125 #endif // __DATABUFFER_H__ |
