/[cvs]/joko/Uni/BSArch/04/bmp_fractal.c
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Annotation of /joko/Uni/BSArch/04/bmp_fractal.c

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Revision 1.3 - (hide annotations)
Sat Jul 1 11:45:35 2006 UTC (18 years, 2 months ago) by joko
Branch: MAIN
Changes since 1.2: +162 -38 lines
File MIME type: text/plain
now using MMF (Memory Mapped Files)

1 joko 1.1 /* Betriebssystem & Middleware
2     *
3     * Betriebssystemarchitektur SS 2006
4     *
5     * Uebung 4.4
6     */
7 joko 1.3
8     // $Id$
9    
10     #include <windows.h>
11 joko 1.1 #include <stdio.h>
12     #include <errno.h>
13    
14     #define XSIZE 500
15     #define YSIZE 500
16     #include "algorithm.h"
17    
18 joko 1.3
19 joko 1.2 /* BMP Header */
20 joko 1.1 unsigned char header[54]={0x42,0x4d, // signature BM
21     0xe6,0x71,0x0b,0x0, // filesize 750054
22     0x0,0x0,0x0,0x0, // reserved
23     0x36,0x0,0x0,0x0, // image offset 54
24     0x28,0x0,0x0,0x0, // size of header follows 40
25     0xf4,0x1,0x0,0x0, // with of image 500
26     0xf4,0x1,0x0,0x0, // height of image 500
27     0x1,0x0, // number of planes 1
28     0x18,0x0, // number of pixel 24
29     0x0,0x0,0x0,0x0, // compression
30     0xb0,0x71,0x0b,0x0, // size of image 750000
31     0x0,0x0,0x0,0x0, // xres
32     0x0,0x0,0x0,0x0, // yres
33     0x0,0x0,0x0,0x0, // number of colortables
34     0x0,0x0,0x0,0x0 // number of important colors
35     };
36    
37 joko 1.3
38     void printErrorAndExit(const char *msg, DWORD err) {
39     LPSTR lpMsgBuf;
40     if(FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER|
41     FORMAT_MESSAGE_FROM_SYSTEM |
42     FORMAT_MESSAGE_IGNORE_INSERTS,
43     NULL,
44     err,
45     MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
46     (LPTSTR) &lpMsgBuf,
47     0,
48     NULL ))
49     {
50     fprintf(stderr,"%s : %s\n",msg,lpMsgBuf);
51     LocalFree(lpMsgBuf);
52     }
53     else
54     {
55     fprintf(stderr,"Error at FormatMesage: %d\n",err=GetLastError());
56     }
57     exit(err);
58     }
59    
60    
61     void write_blank_file(char *filename) {
62    
63     FILE *fd;
64     int len, i, img_size;
65    
66     // open file handle
67     fd = fopen(filename, "wb+");
68     if (NULL == fd) {
69     perror("open");
70     exit(1);
71     }
72    
73     // write bmp header to file
74     len = fwrite(header, 1, sizeof(header), fd);
75    
76     // error checking
77     if (-1 == len || len != sizeof(header)) {
78     perror("write");
79     exit(2);
80     }
81    
82     // write three null-bytes for each pixel to file to create a black picture
83     img_size = XSIZE * YSIZE;
84     for (i = 0; i < img_size; i++) {
85     len = fwrite("\0\0\0", 1, 3, fd);
86     if (-1 == len || len != 3) {
87     perror("write");
88     exit(4);
89 joko 1.1 }
90 joko 1.3 }
91    
92     // close file handle
93     fclose(fd);
94     }
95    
96    
97     int main(int argc, char *argv[]) {
98     int len,x,y;
99     char bgr[3];
100     short svalue;
101     int lvalue;
102    
103     HANDLE hMap, hFile;
104     DWORD err, size;
105     int elems;
106    
107     LPVOID pData;
108     unsigned char *pDataBitmap, *pDataBitmapCurrent;
109    
110     int offset;
111    
112     // create empty file (black background)
113     write_blank_file("test.bmp");
114    
115    
116     /* open file for reading and writing */
117     hFile = CreateFile("test.bmp", GENERIC_WRITE|GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
118     if (INVALID_HANDLE_VALUE == hFile) {
119     err = GetLastError();
120     printErrorAndExit("Error at CreateFile",err);
121     }
122    
123     /* create the file mapping object */
124     hMap = CreateFileMapping(hFile, NULL, PAGE_READWRITE, 0, 0, NULL);
125     if (NULL == hMap) {
126     printErrorAndExit("Error at CreateFileMapping", GetLastError());
127     }
128    
129     /* map the whole file into the process context */
130     pData = MapViewOfFile(hMap, FILE_MAP_WRITE, 0, 0, 0);
131     if (NULL == pData) {
132     printErrorAndExit("Error at MapViewOfFile", GetLastError());
133     }
134    
135    
136     // calculate pointer to beginning of bitmap
137     pDataBitmap = (unsigned char *)((INT_PTR)pData + sizeof(header));
138    
139     // debugging
140     printf("pos. of file: %p\n", pData);
141     printf("pos. of bitmap: %p\n", pDataBitmap);
142    
143     // pointer to current pixel
144     pDataBitmapCurrent = pDataBitmap;
145    
146     /*
147     // turn bitmap into white wand
148     for (offset = 0; offset < 500 * 500 * 3; offset++) {
149     //pDataBitmap[offset] = 255;
150     *pDataBitmapCurrent = 255;
151     pDataBitmapCurrent++;
152     }
153     */
154    
155     // calculate fractal
156     for (y=YSIZE-1; y>=0; y--) {
157     for (x=0; x<XSIZE; x++) {
158     getColorValuesAt(x * (2.0 / XSIZE) - 1.5, y * (2.0 / YSIZE) - 1.0, &bgr[2], &bgr[1], &bgr[0]);
159    
160     // debugging
161     //printf("pointer: %p\n", pDataBitmapCurrent);
162    
163     // transfer color values to current pixel
164     //*pDataBitmapCurrent = (unsigned char *)bgr;
165     pDataBitmapCurrent[0] = bgr[0];
166     pDataBitmapCurrent[1] = bgr[1];
167     pDataBitmapCurrent[2] = bgr[2];
168    
169     // move pointer to next pixel
170     pDataBitmapCurrent += 3;
171    
172     }
173     //no padding required because 1500%4 =0
174     }
175    
176    
177     /* write the result into the file */
178     if (!FlushViewOfFile(pData, 0)) {
179     err = GetLastError();
180     printErrorAndExit("Error at UnmapViewOfFile", err);
181     }
182    
183     /* remove the mapped file */
184     if (!UnmapViewOfFile(pData)) {
185     err = GetLastError();
186     printErrorAndExit("Error at UnmapViewOfFile", err);
187     exit(err);
188     }
189    
190     /* cleanup handles */
191     if (!CloseHandle(hMap) || !CloseHandle(hFile) ) {
192     err = GetLastError();
193     printErrorAndExit("Error at CloseHandle", err);
194     }
195 joko 1.1
196     }

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