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1 /* ----------------------------------------------------------------------------
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2 * File : input.c
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3 * Purpose : input routine to create a Tree from an input file
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4 * ----------------------------------------------------------------------------
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5 */
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6
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7 #include <ctype.h>
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8 #include <string.h>
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9 #include "defs.h"
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10 #include "tree.h"
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11 #include "input.h"
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12
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13 char *EnvNm; /* Stores name of current Envir file */
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14 static int tokDepth = 0; /* Depth in tree of current token */
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15 static int prevTokDepth; /* Depth in tree of prev token */
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16
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17 static void SaveSubtree();
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18
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19 /* ----------------------------------------------------------------------------
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20 *
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21 * GetNextToken() reads the next token from the file indicated by 'fp' and
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22 * returns a token. If the token is TOKEN_LABEL, the lexeme is returned
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23 * in 'lexeme'. If memory could not be allocated for 'lexeme', it is NULL.
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24 *
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25 * The following tokens are supported:
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26 *
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27 * - TOKEN_LABEL: a string of characters, up to 'TOKEN-MAXSIZ'
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28 * characters, delimited by number of leading spaces and newlines.
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29 * If a label has more than this number of characters, the rest are
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30 * ignored.
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31 * - TOKEN_EOF
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32 *
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33 * ----------------------------------------------------------------------------
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34 */
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35
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36 int
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37 GetNextToken(fp, lexeme)
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38 FILE *fp;
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39 char **lexeme;
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40 {
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41 static char lexbuf[INPUT_BUFSIZ];
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42 register char *curbuf = lexbuf;
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43 register int charct = 0;
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44 register int c;
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45 int done = FALSE;
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46
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47 prevTokDepth = tokDepth;
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48 tokDepth = 0;
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49
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50 c = getc(fp);
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51
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52 /* skip over leading whitespace */
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53 while (c == ' ')
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54 {
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55 tokDepth++;
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56 c = getc(fp);
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57 }
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58 tokDepth /= 2;
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59
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60 while (1)
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61 {
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62 switch (c)
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63 {
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64 case EOF:
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65 return (TOKEN_EOF);
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66 case '\n':
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67 *curbuf = '\0';
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68 *lexeme = strdup(lexbuf);
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69 return (TOKEN_LABEL);
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70 break;
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71 default:
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72 *curbuf++ = c;
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73 charct++;
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74 /* check for buffer overflow */
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75 if (charct >= TOKEN_MAXSIZ)
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76 {
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77 *curbuf = '\0';
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78 *lexeme = strdup(lexbuf);
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79 /* since buffer is full, skip over remaining chars */
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80 c = getc(fp);
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81 while (c != '\n' && c != EOF)
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82 c = getc(fp);
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83 if (c == EOF)
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84 ungetc(c, fp);
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85 return (TOKEN_LABEL);
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86 }
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87 else
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88 c = getc(fp);
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89 }
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90 }
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91 }
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92
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93
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94 /* ----------------------------------------------------------------------------
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95 *
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96 * SetNodeLabelAndValue() sets the label text of the specified node and
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97 * stores any string value following the label and preceded by a "^^"
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98 * delimiter.
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99 *
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100 * ----------------------------------------------------------------------------
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101 */
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102
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103 void
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104 SetNodeLabelAndValue(node, label_and_value)
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105 Tree *node;
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106 char *label_and_value;
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107 {
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108 char* val;
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109
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110 if (val = strstr(label_and_value, "^^"))
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111 {
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112 /* Set node value to string following ^^ delimiter. */
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113 node->value = val+2;
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114 /* Erase value from input string, leaving only label. */
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115 *val = '\0';
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116 }
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117 else
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118 { node->value = NULL; }
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119 SetNodeLabel(node, label_and_value);
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120 }
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121
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122
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123 /* ----------------------------------------------------------------------------
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124 *
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125 * ReadTreeFromFile() takes a filename argument and constructs
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126 * a Tree from the labels in the file. If a tree could be constructed,
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127 * even partially, it is returned by the function. NULL is returned if
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128 * the file could not be opened or there was insufficient memory for
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129 * creating the tree.
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130 *
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131 * ----------------------------------------------------------------------------
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132 */
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133
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134 Tree*
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135 ReadTreeFromFile(fname, error)
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136 char *fname;
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137 ErrCode *error;
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138 {
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139 FILE *infile;
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140 int inside_list = 0; /* for semantic checking */
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141 int first_child = TRUE;
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142
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143 int token;
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144 char *label;
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145
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146 Tree *tree = NULL; /* the return value of this function */
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147 Tree *parent = NULL; /* parent of 'node' */
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148 Tree *node; /* current node */
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149 Tree *new_node; /* new node to add after current node */
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150
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151 *error = ERR_NONE;
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152
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153 infile = fopen(fname, "r");
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154 if (infile == NULL)
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155 {
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156 *error = ERR_OPENFAIL;
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157 return (NULL);
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158 }
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159
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160 /* first line of file is Envir file name, save */
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161 token = GetNextToken(infile, &label);
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162 if (token == TOKEN_EOF)
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163 {
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164 *error = ERR_EMPTYFILE;
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165 fclose(infile);
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166 return (NULL);
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167 }
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168 else if (token == TOKEN_LABEL)
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169 {
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170 if (label == NULL)
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171 {
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172 *error = ERR_MEMALLOC;
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173 fclose(infile);
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174 return (NULL);
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175 }
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176 EnvNm = strdup(label);
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177 }
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178
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179 /* set up root node */
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180 token = GetNextToken(infile, &label);
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181 if (token == TOKEN_EOF)
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182 {
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183 *error = ERR_EMPTYFILE;
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184 fclose(infile);
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185 return (NULL);
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186 }
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187 else if (token == TOKEN_LABEL)
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188 {
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189 if (label == NULL)
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190 {
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191 *error = ERR_MEMALLOC;
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192 fclose(infile);
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193 return (NULL);
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194 }
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195 tree = MakeNode();
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196 if (tree == NULL)
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197 {
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198 *error = ERR_MEMALLOC;
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199 fclose(infile);
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200 free(label);
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201 return(NULL);
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202 }
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203 SetNodeLabelAndValue(tree, label);
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204 tree->parent = NULL;
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205 node = tree;
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206 }
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207 else
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208 {
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209 *error = ERR_NOROOT;
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210 fclose(infile);
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211 return (NULL);
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212 }
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213
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214 /* add children and siblings */
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215 while (1)
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216 {
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217 token = GetNextToken(infile, &label);
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218 if (token == TOKEN_EOF)
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219 break;
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220
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221 if (tokDepth > prevTokDepth) /* then new subtree */
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222 {
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223 inside_list++;
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224 first_child = TRUE;
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225 parent = node;
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226 }
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227 else if (tokDepth < prevTokDepth) /* then end of subtree */
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228 if (!inside_list)
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229 {
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230 *error = ERR_NOBEGIN;
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231 fclose(infile);
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232 return (tree);
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233 }
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234 else
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235 while (tokDepth < inside_list)
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236 {
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237 inside_list--;
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238 node = node->parent;
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239 parent = node->parent;
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240 }
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241
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242 if (label == NULL)
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243 {
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244 *error = ERR_MEMALLOC;
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245 fclose(infile);
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246 return (tree);
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247 }
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248 if (parent == NULL)
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249 {
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250 *error = ERR_MANYROOT;
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251 fclose(infile);
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252 free(label);
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253 return (tree);
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254 }
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255 else
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256 {
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257 new_node = MakeNode();
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258 if (new_node == NULL)
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259 {
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260 *error = ERR_MEMALLOC;
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261 fclose(infile);
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262 free(label);
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263 return (tree);
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264 }
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265 SetNodeLabelAndValue(new_node, label);
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266 new_node->parent = parent;
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267
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268 if (first_child)
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269 {
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270 new_node->parent->child = new_node;
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271 first_child = FALSE;
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272 }
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273 else
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274 node->sibling = new_node;
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275
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276 node = new_node;
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277 /*
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278 * printf("%3d tok: '%s'; tokDepth: %d; prevTokDepth: %d; inside_list: %d\n",
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279 * NumNodes, node->label.text, tokDepth, prevTokDepth, inside_list);
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280 */
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281 }
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282 }
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283 fclose(infile);
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284 return (tree);
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285 }
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286
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287
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288 /* ----------------------------------------------------------------------------
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289 *
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290 * SaveTreeToFile() takes a tree and saves it to a file specified by 'fname.'
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291 * If the file could not be opened for writing, False is returned. Otherwise,
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292 * True is returned.
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293 *
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294 * ----------------------------------------------------------------------------
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295 */
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296
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297 SaveTreeToFile(tree, fname)
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298 Tree *tree;
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299 char *fname;
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300 {
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301 FILE *outfile;
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302
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303 outfile = fopen(fname, "w");
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304 if (outfile == NULL)
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305 return (FALSE);
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306
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307 fprintf(outfile, "%s\n", EnvNm); /* Save Env File Name */
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308 fprintf(outfile, "%s\n", tree->label.text);
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309 if (tree->child)
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310 SaveSubtree(tree->child, 0, outfile);
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311
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312 fclose(outfile);
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313 return (TRUE);
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314 }
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315
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316
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317 /* ----------------------------------------------------------------------------
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318 *
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319 * SaveSubtree() is the recursive procedure that supports SaveTreeToFile().
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320 *
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321 * ----------------------------------------------------------------------------
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322 */
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323
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324 static void
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325 SaveSubtree(tree, level, fp)
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326 Tree *tree;
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327 int level;
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328 FILE *fp;
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329 {
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330 int i;
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331
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332 level++;
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333 for ( ; tree ; tree = tree->sibling)
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334 {
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335 for (i = 0 ; i < level ; i++)
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336 {
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337 putc(' ', fp);
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338 putc(' ', fp);
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339 }
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340 fprintf(fp, "%s\n", tree->label.text);
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341 if (tree->child)
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342 SaveSubtree(tree->child, level, fp);
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343 }
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344 level--;
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345 }
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346
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347
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