annotate circbuffer.c @ 611:870c63519757

Change comparison to be more paranoid (and perhaps avoid Klocwork false positive). Does not change behaviour.
author Matt Johnston <matt@ucc.asn.au>
date Thu, 07 Apr 2011 11:18:35 +0000
parents a98a2138364a
children 4222a1039b06
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1 /*
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2 * Dropbear SSH
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3 *
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4 * Copyright (c) 2002-2004 Matt Johnston
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5 * All rights reserved.
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6 *
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7 * Permission is hereby granted, free of charge, to any person obtaining a copy
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8 * of this software and associated documentation files (the "Software"), to deal
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9 * in the Software without restriction, including without limitation the rights
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10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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11 * copies of the Software, and to permit persons to whom the Software is
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12 * furnished to do so, subject to the following conditions:
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13 *
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14 * The above copyright notice and this permission notice shall be included in
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15 * all copies or substantial portions of the Software.
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16 *
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17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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20 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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23 * SOFTWARE. */
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24
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25 #include "includes.h"
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26 #include "dbutil.h"
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27 #include "circbuffer.h"
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28
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29 #define MAX_CBUF_SIZE 100000000
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30
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31 circbuffer * cbuf_new(unsigned int size) {
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32
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33 circbuffer *cbuf = NULL;
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34
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35 if (size > MAX_CBUF_SIZE) {
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36 dropbear_exit("Bad cbuf size");
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37 }
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38
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39 cbuf = (circbuffer*)m_malloc(sizeof(circbuffer));
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40 cbuf->data = (unsigned char*)m_malloc(size);
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41 cbuf->used = 0;
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42 cbuf->readpos = 0;
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43 cbuf->writepos = 0;
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44 cbuf->size = size;
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45
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46 return cbuf;
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47 }
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48
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49 void cbuf_free(circbuffer * cbuf) {
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50
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51 m_free(cbuf->data);
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52 m_free(cbuf);
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53 }
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54
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55 unsigned int cbuf_getused(circbuffer * cbuf) {
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56
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57 return cbuf->used;
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58
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59 }
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60
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61 unsigned int cbuf_getavail(circbuffer * cbuf) {
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62
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63 return cbuf->size - cbuf->used;
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64
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65 }
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66
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67 unsigned int cbuf_readlen(circbuffer *cbuf) {
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68
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69 dropbear_assert(((2*cbuf->size)+cbuf->writepos-cbuf->readpos)%cbuf->size == cbuf->used%cbuf->size);
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70 dropbear_assert(((2*cbuf->size)+cbuf->readpos-cbuf->writepos)%cbuf->size == (cbuf->size-cbuf->used)%cbuf->size);
108
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71
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72 if (cbuf->used == 0) {
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73 TRACE(("cbuf_readlen: unused buffer"))
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74 return 0;
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75 }
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76
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77 if (cbuf->readpos < cbuf->writepos) {
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78 return cbuf->writepos - cbuf->readpos;
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79 }
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80
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81 return cbuf->size - cbuf->readpos;
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82 }
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83
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84 unsigned int cbuf_writelen(circbuffer *cbuf) {
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85
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86 dropbear_assert(cbuf->used <= cbuf->size);
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87 dropbear_assert(((2*cbuf->size)+cbuf->writepos-cbuf->readpos)%cbuf->size == cbuf->used%cbuf->size);
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88 dropbear_assert(((2*cbuf->size)+cbuf->readpos-cbuf->writepos)%cbuf->size == (cbuf->size-cbuf->used)%cbuf->size);
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89
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90 if (cbuf->used == cbuf->size) {
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91 TRACE(("cbuf_writelen: full buffer"))
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92 return 0; /* full */
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93 }
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94
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95 if (cbuf->writepos < cbuf->readpos) {
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96 return cbuf->readpos - cbuf->writepos;
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97 }
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98
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99 return cbuf->size - cbuf->writepos;
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100 }
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101
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102 unsigned char* cbuf_readptr(circbuffer *cbuf, unsigned int len) {
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103 if (len > cbuf_readlen(cbuf)) {
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104 dropbear_exit("Bad cbuf read");
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105 }
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106
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107 return &cbuf->data[cbuf->readpos];
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108 }
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109
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110 unsigned char* cbuf_writeptr(circbuffer *cbuf, unsigned int len) {
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111
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112 if (len > cbuf_writelen(cbuf)) {
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113 dropbear_exit("Bad cbuf write");
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114 }
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115
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116 return &cbuf->data[cbuf->writepos];
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117 }
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118
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119 void cbuf_incrwrite(circbuffer *cbuf, unsigned int len) {
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120 if (len > cbuf_writelen(cbuf)) {
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121 dropbear_exit("Bad cbuf write");
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122 }
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123
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124 cbuf->used += len;
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125 dropbear_assert(cbuf->used <= cbuf->size);
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126 cbuf->writepos = (cbuf->writepos + len) % cbuf->size;
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127 }
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128
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129
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130 void cbuf_incrread(circbuffer *cbuf, unsigned int len) {
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131 if (len > cbuf_readlen(cbuf)) {
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132 dropbear_exit("Bad cbuf read");
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133 }
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134
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135 dropbear_assert(cbuf->used >= len);
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136 cbuf->used -= len;
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137 cbuf->readpos = (cbuf->readpos + len) % cbuf->size;
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138 }