src/lexer.c

   1 /*!@file
   2   \brief   lexical analyzer implementation for APC
   3   \details lexer for tokenizing filenames from a directory root
   4   \author  Jordan Lavatai
   5   \date    Aug 2016
   6   ----------------------------------------------------------------------------*/
   7 //stdc
   8 #include <stdio.h>
   9 #include <string.h>
  10 #include <errno.h>
  11 //posix
  12 #include <unistd.h>
  13 #include <dirent.h>
  14 //bison
  15 #include "fileparser.tab.h"
  16
  17 int lexer_init(void);
  18 int lexer();
  19
  20 #define BUF_SIZE 256
  21 #define STACK_BUF_SIZE (BUF_SIZE >> 2)
  22 static DIR*  dp_stack_buf[STACK_BUF_SIZE];
  23 static char  path_buf[BUF_SIZE];
  24 static char  storage_buf[BUF_SIZE];
  25
  26 /* Setup stack and first directory to read from */
  27 int
  28 lexer_init()
  29 { char cwd_buf[MAX_TOK_LEN];
  30
  31   dsp = dp_stack_base;
  32   getcwd(path_buf, MAX_TOK_LEN);
  33   printf("|------cwd is %s------|\n", path_buf);
  34   if(!(*dsp = opendir(path_buf)))
  35     printf("opendir(cwd) failed in linit()\n");
  36
  37   *dsp = dp;
  38   printf("dp_stack is %x, dsp is %x size is %d\n",*dp_stack, *dsp, sizeof dp);
  39
  40   return 0;
  41 }
  42
  43 /* Returns token identifier and sets yylval */
  44 int
  45 lexer()
  46 { static DIR** dsp = &dp_stack_buf;
  47   int tok_t;
  48   char buf[MAX_TOK_LEN];
  49   char* file_name;
  50
  51   printf("|------in yylex(), calling tok_dir------|\n");
  52   if((tok_t = tok_dir(*dsp, yylval.str)) == -1)
  53     printf("tok_dir returned -1, something is broken\n");
  54   printf("|------in yylex(), returning tok_t = %d | err = %s------|\n", tok_t, strerror(errno));
  55   return tok_t;
  56 }
  57
  58 #define DSP_PUSH(_val) *++dsp = (_val)
  59
  60 int
  61 tok_dir(DIR* dp, char buf[])
  62 {
  63   struct dirent* de; /* directory entry */
  64   static DIR *tmp_dp;
  65   char *tmp_path;
  66   int path_len;
  67
  68
  69 tok_start:
  70   if((*dsp == NULL) || (de = readdir(*dsp)) == NULL)
  71     {
  72       if(errno)
  73         {  printf("Error:%s in tok_dir\n", strerror(errno));
  74           return errno;
  75         }
  76       if( (dsp - dp_stack) >= 0)
  77         {
  78           printf("Current directory is null, pop one off ");
  79 #define DSP_POP() *dsp--
  80
  81           dp = DSP_POP();
  82
  83           /* Remove directory that was popped from path */
  84 #define SUB_PATH() tmp_path = strrchr(path, '/'); \
  85           path_len = strlen(tmp_path);            \
  86           memset(tmp_path, 0, path_len)
  87
  88           SUB_PATH();
  89
  90           goto tok_start;
  91         }
  92       return 0; /* Done */
  93     }
  94
  95   else if(de->d_type == DT_REG)
  96     { printf("|------dir_ent is a file, "\
  97              "setting yylval to %s------|\n", de->d_name);
  98       memmove(buf, de->d_name, MAX_TOK_LEN);
  99       return FDAT;
 100     }
 101   else if (de->d_type == DT_DIR )
 102     { if ((dsp - dp_stack) >= MAX_DIR_DEP) /* We've opened to many directories */
 103         {
 104           printf("Too many directories!\n");
 105           return 1;
 106         }
 107       if(strcmp(de->d_name,".") == 0 || strcmp(de->d_name,"..") == 0)
 108         {
 109           printf("directory is %s \n", de->d_name);
 110           goto tok_start;
 111         }
 112
 113       printf("|------ dir_ent is directory %s, "\
 114              "cwd = %s, path = %s ------|\n", de->d_name, get_current_dir_name(), path);
 115
 116
 117       /* Add directory name to path */
 118 #define ADD_PATH(_name) strcat(path, "/");      \
 119                         strcat(path, _name)
 120
 121       ADD_PATH(de->d_name);
 122
 123       tmp_dp = opendir(path);
 124       if(tmp_dp == 0)
 125         { printf("opening the directory failed,"\
 126                  "errno = %s\n", strerror(errno));
 127           return -1;
 128         }
 129
 130       DSP_PUSH(tmp_dp);
 131
 132       goto tok_start;
 133
 134     }
 135   else
 136     {
 137       printf("A file that is not a diretory or a regular file is unable to be tokenized: %s\n", de->d_name);
 138       return -1;
 139     }
 140
 141
 142
 143 }