annotate mpffs/find.c @ 378:82fb5a70c9fd

compal/audio: results of simple experiments
author Mychaela Falconia <falcon@freecalypso.org>
date Sat, 09 Oct 2021 23:20:00 +0000
parents 95f61c3b430a
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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34
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1 /*
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2 * This module contains the code for searching the FFS tree structure
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3 * for a specified absolute pathname.
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4 */
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5
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6 #include <sys/types.h>
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7 #include <ctype.h>
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8 #include <stdio.h>
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9 #include <string.h>
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10 #include <strings.h>
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11 #include <stdlib.h>
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12 #include <unistd.h>
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13 #include "types.h"
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14 #include "struct.h"
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15
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16 extern int root_node_no;
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17
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18 /*
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19 * The following function iterates through the descendants of a directory
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20 * object looking for a specific directory-member filename.
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21 *
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22 * Arguments:
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23 * - index # of the first descendant (descendant pointer from the dir object)
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24 * - filename to search for
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25 *
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26 * Returns: index # of the sought descendant object if found, 0 otherwise.
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27 */
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28 find_dir_member(first_descend, srchname)
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29 char *srchname;
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30 {
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31 int ent;
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32 struct objinfo obj;
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33
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34 for (ent = first_descend; ent != 0xFFFF; ent = obj.sibling) {
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35 obj.entryno = ent;
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36 get_index_entry(&obj);
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37 if (!obj.type) /* skip deleted objects w/o further looking */
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38 continue;
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39 validate_chunk(&obj);
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40 validate_obj_name(&obj);
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41 if (!strcmp(obj.dataptr, srchname))
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42 return(ent);
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43 }
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44 return(0);
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45 }
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46
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47 /*
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48 * The following function searches for a pathname from the root down.
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49 * Returns the index # if found, otherwise exits with an error message
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50 * indicating which step failed.
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51 *
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52 * Warning: the pathname in the argument buffer will be destroyed:
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53 * 0s put in place of the slashes.
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54 */
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55 find_pathname(pathname)
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56 char *pathname;
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57 {
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58 char *cur, *next;
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59 int idx;
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60 struct objinfo dir;
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61
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62 cur = pathname;
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63 if (*cur == '/')
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64 cur++;
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65 for (idx = root_node_no; cur; cur = next) {
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66 if (!*cur)
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67 break;
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68 next = index(cur, '/');
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69 if (next == cur) {
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70 fprintf(stderr,
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71 "malformed pathname: multiple adjacent slashes\n");
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72 exit(1);
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73 }
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74 if (next)
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75 *next++ = '\0';
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76 dir.entryno = idx;
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77 get_index_entry(&dir);
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78 if (dir.type != 0xF2) {
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79 fprintf(stderr,
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80 "pathname search error: encountered a non-directory\n");
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81 exit(1);
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82 }
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83 idx = find_dir_member(dir.descend, cur);
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84 if (!idx) {
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85 fprintf(stderr,
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86 "pathname search error: component name not found\n");
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87 exit(1);
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88 }
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89 }
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90 return(idx);
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91 }