CEP/C/db.c

   1 /*
   2  * db: functions to retrieve data from the database file.
   3  *
   4  * The database is a CSV list, each line has the following format
   5  * (pt_BR for now):
   6  *
   7  * CEP;UF;Cidade;Bairro;Rua
   8  *
   9  * A line is called an entry, each value in the line is called
  10  * an info.
  11  *
  12  * This file is licensed under the GPLv2 license.
  13  *
  14  * Luiz Fernando N. Capitulino
  15  * <lcapitulino@gmail.com>
  16  */
  17 #include <stdio.h>
  18 #include <string.h>
  19 #include <stdlib.h>
  20
  21 #include "db.h"
  22 #include "misc.h"
  23
  24 /* eof_info(): return 1 if 'c' is an end of info character,
  25  * otherwise return 0. */
  26 static int eof_info(FILE *db, char c)
  27 {
  28         if (c == ';' || c == '\n')
  29                 return 1;
  30
  31         if (c == '\r') {
  32                 /* remove trailing '\n' */
  33                 c = fgetc(db);
  34                 if (c != '\n')
  35                         fatal("DOS file seems corrupted");
  36                 return 1;
  37         }
  38
  39         return 0;
  40 }
  41
  42 /* read_info(): Return the next info from the 'db' file,
  43  * aborts program execution on error. */
  44 static char *read_info(FILE *db)
  45 {
  46         char *info;
  47
  48         info = read_chars(db, eof_info);
  49         if (!info)
  50                 fatal("didn't read expected EOF from db file");
  51
  52         return info;
  53 }
  54
  55
  56 /* read_buf(): read 'len' characters from 'db' file into 'buf',
  57  * the characters have to be part of an info (ie, they're
  58  * terminated by ';' or '\n') otherwise program execution is
  59  * aborted. */
  60 static void read_buf(FILE *db, char *buf, size_t len)
  61 {
  62         int c;
  63         size_t i;
  64
  65         for (i = 0; i < (len - 1); i++)
  66                 buf[i] = fgetc(db);
  67
  68         buf[i] = '\0';
  69
  70         c = fgetc(db);
  71         if (c != ';')
  72                 fatal("db file is corrupted");
  73 }
  74
  75 /* read_cep(): read CEP info from the 'db' file. */
  76 static unsigned int read_cep(FILE *db)
  77 {
  78         char cep_str[DB_CEP_LEN + 1];
  79
  80         read_buf(db, cep_str, sizeof(cep_str));
  81
  82         /* XXX: error check */
  83         return strtol(cep_str, NULL, 10);
  84 }
  85
  86 /* read_uf(): read UF info from the 'db' file. */
  87 static void read_uf(FILE *db, char *uf)
  88 {
  89         read_buf(db, uf, DB_UF_LEN);
  90 }
  91
  92 /* file_eof(): return 1 if next character from 'db' is EOF,
  93  * otherwise return 0. */
  94 static int file_eof(FILE *db)
  95 {
  96         int c;
  97
  98         c = fgetc(db);
  99         if (c == EOF)
 100                 return 1;
 101
 102         ungetc(c, db);
 103         return 0;
 104 }
 105
 106 /* db_next_entry(): return the next entry from 'db' file, if
 107  * EOF is found return NULL. */
 108 struct db_entry *db_next_entry(FILE *db)
 109 {
 110         struct db_entry *entry;
 111
 112         if (file_eof(db))
 113                 return NULL;
 114
 115         entry = malloc(sizeof(*entry));
 116         if (!entry)
 117                 fatal("cannot allocate memory");
 118
 119         entry->cep = read_cep(db);
 120         read_uf(db, entry->uf);
 121         entry->cidade = read_info(db);
 122         entry->bairro = read_info(db);
 123         entry->desc   = read_info(db);
 124
 125         return entry;
 126 }
 127
 128 /* db_free_entry(): free all the memory allocated by 'entry */
 129 void db_free_entry(struct db_entry **entry)
 130 {
 131         free((*entry)->cidade);
 132         free((*entry)->bairro);
 133         free((*entry)->desc);
 134         free(*entry);
 135 }
 136
 137 /* db_dump_entry(): dump 'entry' info in CSV format to stdout */
 138 void db_dump_entry(const struct db_entry *entry)
 139 {
 140         printf("%u;%s;%s;%s;%s\n", entry->cep, entry->uf,
 141                entry->cidade, entry->bairro, entry->desc);
 142 }
 143
 144 /* db_print_entry(): print 'entry' info in human readable format
 145  * to stdout */
 146 void db_print_entry(const struct db_entry *entry)
 147 {
 148         putchar('\n');
 149
 150         printf(
 151                "CEP:    %d\n"
 152                "UF:     %s\n"
 153                "Cidade: %s\n"
 154                "Bairro: %s\n"
 155                "Desc:   %s\n",
 156                entry->cep, entry->uf, entry->cidade,
 157                entry->bairro, entry->desc);
 158
 159         putchar('\n');
 160 }
 161
 162 /* db_dump_csv(): dump all entries in 'db' file in CSV format
 163  * to stdout */
 164 void db_dump_csv(FILE *db)
 165 {
 166         struct db_entry *entry;
 167
 168         for (;;) {
 169                 entry = db_next_entry(db);
 170                 if (!entry)
 171                         break;
 172
 173                 db_dump_entry(entry);
 174                 db_free_entry(&entry);
 175         }
 176 }
 177
 178 /* db_entries_match(): return 1 if ent1 == ent2, return
 179  * 0 otherwise */
 180 int db_entries_match(const struct db_entry *ent1,
 181                      const struct db_entry *ent2)
 182 {
 183         if (ent1->cep != ent2->cep)
 184                 return 0;
 185
 186         if (strcmp(ent1->uf, ent2->uf))
 187                 return 0;
 188
 189         if (strcmp(ent1->cidade, ent2->cidade))
 190                 return 0;
 191
 192         if (strcmp(ent1->bairro, ent2->bairro))
 193                 return 0;
 194
 195         if (strcmp(ent1->desc, ent2->desc))
 196                 return 0;
 197
 198         return 1;
 199 }