1 | #include "port_before.h" |
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2 | |
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3 | /*- |
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4 | * Copyright (c) 1990, 1993, 1994 |
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5 | * The Regents of the University of California. All rights reserved. |
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6 | * |
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7 | * This code is derived from software contributed to Berkeley by |
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8 | * Mike Olson. |
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9 | * |
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10 | * Redistribution and use in source and binary forms, with or without |
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11 | * modification, are permitted provided that the following conditions |
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12 | * are met: |
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13 | * 1. Redistributions of source code must retain the above copyright |
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14 | * notice, this list of conditions and the following disclaimer. |
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15 | * 2. Redistributions in binary form must reproduce the above copyright |
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16 | * notice, this list of conditions and the following disclaimer in the |
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17 | * documentation and/or other materials provided with the distribution. |
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18 | * 4. Neither the name of the University nor the names of its contributors |
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19 | * may be used to endorse or promote products derived from this software |
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20 | * without specific prior written permission. |
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21 | * |
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22 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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23 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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24 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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25 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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26 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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27 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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28 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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29 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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30 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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31 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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32 | * SUCH DAMAGE. |
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33 | */ |
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34 | |
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35 | #if defined(LIBC_SCCS) && !defined(lint) |
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36 | static char sccsid[] = "@(#)rec_delete.c 8.7 (Berkeley) 7/14/94"; |
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37 | #endif /* LIBC_SCCS and not lint */ |
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38 | #include <sys/cdefs.h> |
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39 | __FBSDID("$FreeBSD$"); |
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40 | |
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41 | #include <sys/types.h> |
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42 | |
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43 | #include <errno.h> |
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44 | #include <stdio.h> |
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45 | #include <string.h> |
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46 | |
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47 | #include <db.h> |
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48 | #include "recno.h" |
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49 | |
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50 | static int rec_rdelete(BTREE *, recno_t); |
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51 | |
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52 | /* |
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53 | * __REC_DELETE -- Delete the item(s) referenced by a key. |
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54 | * |
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55 | * Parameters: |
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56 | * dbp: pointer to access method |
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57 | * key: key to delete |
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58 | * flags: R_CURSOR if deleting what the cursor references |
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59 | * |
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60 | * Returns: |
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61 | * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. |
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62 | */ |
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63 | int |
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64 | __rec_delete(const DB *dbp, const DBT *key, u_int flags) |
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65 | { |
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66 | BTREE *t; |
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67 | recno_t nrec; |
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68 | int status; |
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69 | |
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70 | t = dbp->internal; |
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71 | |
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72 | /* Toss any page pinned across calls. */ |
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73 | if (t->bt_pinned != NULL) { |
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74 | mpool_put(t->bt_mp, t->bt_pinned, 0); |
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75 | t->bt_pinned = NULL; |
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76 | } |
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77 | |
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78 | switch(flags) { |
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79 | case 0: |
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80 | if ((nrec = *(recno_t *)key->data) == 0) |
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81 | goto einval; |
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82 | if (nrec > t->bt_nrecs) |
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83 | return (RET_SPECIAL); |
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84 | --nrec; |
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85 | status = rec_rdelete(t, nrec); |
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86 | break; |
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87 | case R_CURSOR: |
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88 | if (!F_ISSET(&t->bt_cursor, CURS_INIT)) |
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89 | goto einval; |
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90 | if (t->bt_nrecs == 0) |
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91 | return (RET_SPECIAL); |
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92 | status = rec_rdelete(t, t->bt_cursor.rcursor - 1); |
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93 | if (status == RET_SUCCESS) |
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94 | --t->bt_cursor.rcursor; |
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95 | break; |
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96 | default: |
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97 | einval: errno = EINVAL; |
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98 | return (RET_ERROR); |
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99 | } |
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100 | |
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101 | if (status == RET_SUCCESS) |
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102 | F_SET(t, B_MODIFIED | R_MODIFIED); |
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103 | return (status); |
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104 | } |
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105 | |
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106 | /* |
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107 | * REC_RDELETE -- Delete the data matching the specified key. |
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108 | * |
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109 | * Parameters: |
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110 | * tree: tree |
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111 | * nrec: record to delete |
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112 | * |
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113 | * Returns: |
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114 | * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found. |
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115 | */ |
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116 | static int |
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117 | rec_rdelete(BTREE *t, recno_t nrec) |
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118 | { |
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119 | EPG *e; |
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120 | PAGE *h; |
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121 | int status; |
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122 | |
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123 | /* Find the record; __rec_search pins the page. */ |
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124 | if ((e = __rec_search(t, nrec, SDELETE)) == NULL) |
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125 | return (RET_ERROR); |
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126 | |
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127 | /* Delete the record. */ |
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128 | h = e->page; |
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129 | status = __rec_dleaf(t, h, e->index); |
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130 | if (status != RET_SUCCESS) { |
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131 | mpool_put(t->bt_mp, h, 0); |
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132 | return (status); |
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133 | } |
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134 | mpool_put(t->bt_mp, h, MPOOL_DIRTY); |
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135 | return (RET_SUCCESS); |
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136 | } |
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137 | |
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138 | /* |
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139 | * __REC_DLEAF -- Delete a single record from a recno leaf page. |
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140 | * |
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141 | * Parameters: |
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142 | * t: tree |
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143 | * idx: index on current page to delete |
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144 | * |
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145 | * Returns: |
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146 | * RET_SUCCESS, RET_ERROR. |
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147 | */ |
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148 | int |
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149 | __rec_dleaf(BTREE *t, PAGE *h, u_int32_t idx) |
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150 | { |
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151 | RLEAF *rl; |
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152 | indx_t *ip, cnt, offset; |
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153 | u_int32_t nbytes; |
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154 | char *from; |
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155 | void *to; |
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156 | |
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157 | /* |
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158 | * Delete a record from a recno leaf page. Internal records are never |
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159 | * deleted from internal pages, regardless of the records that caused |
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160 | * them to be added being deleted. Pages made empty by deletion are |
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161 | * not reclaimed. They are, however, made available for reuse. |
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162 | * |
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163 | * Pack the remaining entries at the end of the page, shift the indices |
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164 | * down, overwriting the deleted record and its index. If the record |
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165 | * uses overflow pages, make them available for reuse. |
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166 | */ |
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167 | to = rl = GETRLEAF(h, idx); |
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168 | if (rl->flags & P_BIGDATA && __ovfl_delete(t, rl->bytes) == RET_ERROR) |
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169 | return (RET_ERROR); |
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170 | nbytes = NRLEAF(rl); |
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171 | |
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172 | /* |
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173 | * Compress the key/data pairs. Compress and adjust the [BR]LEAF |
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174 | * offsets. Reset the headers. |
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175 | */ |
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176 | from = (char *)h + h->upper; |
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177 | memmove(from + nbytes, from, (char *)to - from); |
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178 | h->upper += nbytes; |
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179 | |
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180 | offset = h->linp[idx]; |
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181 | for (cnt = &h->linp[idx] - (ip = &h->linp[0]); cnt--; ++ip) |
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182 | if (ip[0] < offset) |
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183 | ip[0] += nbytes; |
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184 | for (cnt = &h->linp[NEXTINDEX(h)] - ip; --cnt; ++ip) |
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185 | ip[0] = ip[1] < offset ? ip[1] + nbytes : ip[1]; |
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186 | h->lower -= sizeof(indx_t); |
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187 | --t->bt_nrecs; |
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188 | return (RET_SUCCESS); |
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189 | } |
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