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#ifndef lint |
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static const char RCSid[] = "$Id: genbranch.c,v 2.6 2003/06/08 12:03:09 schorsch Exp $"; |
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#endif |
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/* |
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* genbranch.c - program to generate 3D Christmas tree branches. |
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* |
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* 8/23/86 |
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*/ |
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|
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#include <stdio.h> |
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|
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#include <stdlib.h> |
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|
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#include <math.h> |
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|
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#include "random.h" |
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|
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#define errf() (var*(0.5-frandom())) |
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|
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double bstart[3] = {0.0, 0.0, 0.0}; /* start of branch */ |
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double bend[3] = {28.0, 8.0, 0.0}; /* end of branch */ |
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double bthick = .6; /* branch radius at base */ |
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double bnarrow = .4; /* ratio of tip radius to base */ |
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double bratio = .4; /* ratio of limb to branch */ |
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char *branchmat = "m_bark"; /* bark material */ |
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|
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char *leafmat = "m_leaf"; /* leaf material */ |
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|
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int nshoots = 7; /* number of offshoots */ |
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int rdepth = 3; /* recursion depth */ |
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|
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double var = 0.3; /* variability */ |
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|
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|
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static void |
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stick(mat, beg, end, rad) /* output a branch or leaf */ |
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char *mat; |
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double beg[3], end[3]; |
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double rad; |
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{ |
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static int nsticks = 0; |
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|
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printf("\n%s cone s%d\n", mat, nsticks); |
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printf("0\n0\n8\n"); |
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printf("\t%18.12g\t%18.12g\t%18.12g\n", beg[0], beg[1], beg[2]); |
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printf("\t%18.12g\t%18.12g\t%18.12g\n", end[0], end[1], end[2]); |
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printf("\t%18.12g\t%18.12g\n", rad, bnarrow*rad); |
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|
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printf("\n%s sphere e%d\n", mat, nsticks); |
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printf("0\n0\n4"); |
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printf("\t%18.12g\t%18.12g\t%18.12g\t%18.12g\n", |
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end[0], end[1], end[2], bnarrow*rad); |
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|
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nsticks++; |
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} |
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|
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|
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static void |
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branch(beg, end, rad, lvl) /* generate branch recursively */ |
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double beg[3], end[3]; |
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double rad; |
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int lvl; |
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{ |
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double sqrt(); |
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double newbeg[3], newend[3]; |
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double t; |
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int i, j; |
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|
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if (lvl == 0) { |
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stick(leafmat, beg, end, rad); |
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return; |
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} |
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|
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stick(branchmat, beg, end, rad); |
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|
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for (i = 1; i <= nshoots; i++) { |
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/* right branch */ |
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t = (i+errf())/(nshoots+2); |
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t = (t + sqrt(t))/2.0; |
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for (j = 0; j < 3; j++) { |
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newbeg[j] = newend[j] = (end[j]-beg[j])*t + beg[j]; |
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newend[j] += (end[j]-beg[j])*(1+errf())/(nshoots+2); |
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} |
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newend[0] += (end[2]-newbeg[2])*bratio*(1+errf()); |
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newend[1] += (end[1]-newbeg[1])*bratio*(1+errf()); |
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newend[2] -= (end[0]-newbeg[0])*bratio*(1+errf()); |
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branch(newbeg, newend, |
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(1-(1-bnarrow)*t)*(1+2*bratio)/3*rad, lvl-1); |
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|
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/* left branch */ |
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t = (i+errf())/(nshoots+2); |
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t = (t + sqrt(t))/2.0; |
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for (j = 0; j < 3; j++) { |
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newbeg[j] = newend[j] = (end[j]-beg[j])*t + beg[j]; |
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newend[j] += (end[j]-beg[j])*(1+errf())/(nshoots+2); |
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} |
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newend[0] -= (end[2]-newbeg[2])*bratio*(1+errf()); |
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newend[1] += (end[1]-newbeg[1])*bratio*(1+errf()); |
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newend[2] += (end[0]-newbeg[0])*bratio*(1+errf()); |
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branch(newbeg, newend, |
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(1-(1-bnarrow)*t)*(1+2*bratio)/3*rad, lvl-1); |
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} |
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} |
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|
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|
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void |
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printhead(ac, av) /* print command header */ |
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register int ac; |
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register char **av; |
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{ |
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putchar('#'); |
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while (ac--) { |
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putchar(' '); |
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fputs(*av++, stdout); |
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} |
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putchar('\n'); |
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} |
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|
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|
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int |
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main(argc, argv) |
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int argc; |
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char *argv[]; |
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{ |
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int i, j; |
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|
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for (i = 1; i < argc && argv[i][0] == '-'; i++) |
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switch (argv[i][1]) { |
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case 'b': /* branch */ |
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switch (argv[i][2]) { |
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case 's': /* start */ |
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bstart[0] = atof(argv[++i]); |
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bstart[1] = atof(argv[++i]); |
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bstart[2] = atof(argv[++i]); |
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break; |
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case 'e': /* end */ |
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bend[0] = atof(argv[++i]); |
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bend[1] = atof(argv[++i]); |
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bend[2] = atof(argv[++i]); |
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break; |
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case 't': /* thickness */ |
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bthick = atof(argv[++i]); |
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break; |
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case 'n': /* narrow */ |
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bnarrow = atof(argv[++i]); |
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break; |
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case 'r': /* ratio */ |
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bratio = atof(argv[++i]); |
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break; |
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case 'm': /* material */ |
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branchmat = argv[++i]; |
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break; |
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default: |
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goto unkopt; |
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} |
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break; |
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case 'l': /* leaf */ |
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switch (argv[i][2]) { |
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case 'm': /* material */ |
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leafmat = argv[++i]; |
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break; |
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default: |
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goto unkopt; |
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} |
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break; |
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case 'n': /* number of offshoots */ |
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nshoots = atoi(argv[++i]); |
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break; |
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case 'r': /* recursion depth */ |
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rdepth = atoi(argv[++i]); |
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break; |
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case 's': /* seed */ |
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j = atoi(argv[++i]); |
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while (j-- > 0) |
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frandom(); |
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break; |
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case 'v': /* variability */ |
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var = atof(argv[++i]); |
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break; |
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default:; |
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unkopt: fprintf(stderr, "%s: unknown option: %s\n", |
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argv[0], argv[i]); |
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exit(1); |
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} |
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|
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if (i != argc) { |
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fprintf(stderr, "%s: bad argument\n", argv[0]); |
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exit(1); |
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} |
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printhead(argc, argv); |
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|
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branch(bstart, bend, bthick, rdepth); |
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|
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return(0); |
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} |
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|
