src/variables.c

   1 /*******************************************************************************
   2  * Reverse Polish Notation calculator.                                         *
   3  * Copyright (c) 2007-2008, Samuel Fredrickson <kinghajj@gmail.com>            *
   4  * All rights reserved.                                                        *
   5  *                                                                             *
   6  * Redistribution and use in source and binary forms, with or without          *
   7  * modification, are permitted provided that the following conditions are met: *
   8  *     * Redistributions of source code must retain the above copyright        *
   9  *       notice, this list of conditions and the following disclaimer.         *
  10  *     * Redistributions in binary form must reproduce the above copyright     *
  11  *       notice, this list of conditions and the following disclaimer in the   *
  12  *       documentation and/or other materials provided with the distribution.  *
  13  *                                                                             *
  14  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER ``AS IS'' AND ANY EXPRESS *
  15  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED           *
  16  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE      *
  17  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY        *
  18  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES  *
  19  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR          *
  20  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER  *
  21  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT          *
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY   *
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH *
  24  * DAMAGE.                                                                     *
  25  ******************************************************************************/
  26
  27 /*******************************************************************************
  28  * variables.c - implements the variables table.                               *
  29  ******************************************************************************/
  30
  31 #include "rpn.h"
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35
  36 //! Creates a new, empty variables table.
  37 /**
  38  * @return The new, empty variables table.
  39  */
  40 RPNVariables *RPN_newVariables()
  41 {
  42         RPNVariables *variables = new(RPNVariables);
  43         if(!variables)
  44                 RPN_error("could not allocate memory for a variables table.");
  45         // uthash.h requires that an empty table hash be set to NULL.
  46         variables->table = NULL;
  47         RPN_dprintf("allocated variable table %p", variables);
  48         return variables;
  49 }
  50
  51 //! Creates a new variable.
  52 /**
  53  * @param name The string representation of the variable.
  54  * @param value The value of the variable.
  55  * @return The new variable.
  56  */
  57 RPNVariable *RPN_newVariable(char *name, RPNValue value)
  58 {
  59         RPNVariable *var = new(RPNVariable);
  60         if(!var)
  61                 RPN_error("could not allocate memory for a variable.");
  62         var->name = name;
  63         var->value = value;
  64         RPN_dprintf("allocated variable %p", var);
  65         return var;
  66 }
  67
  68 //! Adds a variable to a variable table.
  69 /**
  70  * @param variables The variable table.
  71  * @param name The string representation of the variable.
  72  * @param value The value of the variable.
  73  * @return true if succeeds.
  74  */
  75 bool RPN_addVariable(RPNVariables *variables, char *name, RPNValue value)
  76 {
  77         RPNVariable *var;
  78
  79         if(!variables)
  80                 RPN_error("tried to push variable to a NULL stack.");
  81         var = RPN_newVariable(name, value);
  82         // name of hash header, name of hash table, name of key, length of key,
  83         // structure to add
  84         HASH_ADD_KEYPTR( hh, variables->table, name, strlen(name), var );
  85         RPN_dprintf("added variable %p to table %p", var, variables);
  86         return true;
  87 }
  88
  89 //! Finds a variable by its string representation.
  90 /**
  91  * @param variables The variable table.
  92  * @param name The string representation of the variable.
  93  * @return The variable if found, else NULL.
  94  */
  95 RPNVariable *RPN_findVariable(RPNVariables *variables, char *name)
  96 {
  97         RPNVariable *var = NULL;
  98         if(!variables)
  99                 RPN_error("tried to find variable in NULL stack.");
 100         if(!name)
 101                 RPN_error("tried to find a variable with a NULL name.");
 102         HASH_FIND_STR( variables->table, name, var);
 103         return var;
 104 }
 105
 106 //! Gets the value of a variable by its string representation.
 107 /**
 108  * @param variables The variable table.
 109  * @param name The string representation of the variable.
 110  * @return The value if found, else 0.
 111  */
 112 RPNValue RPN_getVariableValue(RPNVariables *variables, char *name)
 113 {
 114         RPNVariable *var = RPN_findVariable(variables, name);
 115         RPNValue value = 0;
 116
 117         if(!variables)
 118                 RPN_error("tried to find variable in a NULL variable table.");
 119         if(var)
 120                 value = var->value;
 121
 122         return value;
 123 }
 124
 125 //! Frees a variable and its string representation.
 126 /**
 127  * @param variable The variable to free.
 128  */
 129 void RPN_freeVariable(RPNVariable *variable)
 130 {
 131         if(!variable || !variable->name)
 132                 RPN_error("attempted to free a NULL variable.");
 133         RPN_free(variable->name);
 134         RPN_free(variable);
 135         RPN_dprintf("freed variable %p", variable);
 136 }
 137
 138 //! Removes a variable from a variable table, then frees it.
 139 /**
 140  * @param variables The variable table.
 141  * @param variable The variable to remove.
 142  */
 143 void RPN_removeVariable(RPNVariables *variables, RPNVariable *variable)
 144 {
 145         if(!variables)
 146                 RPN_error("attempted to remove a variable from a NULL variable table.");
 147         if(!variable)
 148                 RPN_error("attempted to remove a NULL variable.");
 149         HASH_DEL( variables->table, variable );
 150         RPN_freeVariable(variable);
 151         RPN_dprintf("removed variable %p from table %p", variable, variables);
 152 }
 153
 154 //! Frees a variable table and all its variables.
 155 /**
 156  * @param variables The variable table to free.
 157  */
 158 void RPN_freeVariables(RPNVariables *variables)
 159 {
 160         RPNVariable *variable, *next;
 161
 162         // go through every command and remove/free it.
 163         for(variable = variables->table; variable != NULL; variable = next) {
 164                 next = variable->hh.next;
 165                 RPN_removeVariable(variables, variable);
 166         }
 167
 168         RPN_free(variables);
 169         RPN_dprintf("freed variable table %p", variables);
 170 }
 171
 172 //! Prints the variables of a variable table.
 173 /**
 174  * @param variables The variable table to print.
 175  */
 176 void RPN_printVariables(RPNVariables *variables)
 177 {
 178         RPNVariable *var;
 179
 180         RPN_printf("[ ");
 181         for(var = variables->table; var != NULL; var = var->hh.next)
 182                 RPN_printf("%s = " RPN_VALUE_SHORT_FORMAT ", ", var->name, var->value);
 183         RPN_printf("]\n");
 184 }
 185
 186 //! Prints the variables of a variable table in more detail.
 187 /**
 188  * @param variables The variable table to print.
 189  */
 190 void RPN_printVariablesDetailed(RPNVariables *variables)
 191 {
 192         RPNVariable *var;
 193
 194         RPN_printf("[ ");
 195         for(var = variables->table; var != NULL; var = var->hh.next)
 196                 RPN_printf("%s = " RPN_VALUE_LONG_FORMAT ", ", var->name, var->value);
 197         RPN_printf("]\n");
 198 }
 199
 200 //! Returns a default variable table.
 201 /**
 202  * @return The default variable table.
 203  */
 204 RPNVariables *RPN_defaultVariables()
 205 {
 206         RPNVariables *variables = RPN_newVariables();
 207
 208         // Computer sizes.
 209         RPN_addVariable(variables, strdup("KB"),  1000);
 210         RPN_addVariable(variables, strdup("MB"),  1000 * 1000);
 211         RPN_addVariable(variables, strdup("GB"),  1000 * 1000 * 1000);
 212         RPN_addVariable(variables, strdup("KiB"), 1024);
 213         RPN_addVariable(variables, strdup("MiB"), 1024 * 1024);
 214         RPN_addVariable(variables, strdup("GiB"), 1024 * 1024 * 1024);
 215         RPN_addVariable(variables, strdup("Kib"), 1024 / 8);
 216         RPN_addVariable(variables, strdup("Mib"), 1024 * 1024 / 8);
 217         RPN_addVariable(variables, strdup("Gib"), 1024 * 1024 * 1024 / 8);
 218
 219         // Mathematical numbers.
 220         RPN_addVariable(variables, strdup("PI"), 3.1415926535897932385);
 221         RPN_addVariable(variables, strdup("E"),  2.72828182845904523536);
 222
 223         // Time sizes.
 224         RPN_addVariable(variables, strdup("HOURS"), 60 * 60);
 225         RPN_addVariable(variables, strdup("MINUTES"), 60);
 226
 227         return variables;
 228 }