/*!@file
\brief lexical analyzer implementation for APC
- \details this lexer scans a root directory given from the command line
- for subdirectories and files structured for the APC grammar.
+ \details The lexer manages two FIFO stacks. One for maintaining tokens, the
+ other for maintaining a list of files to be scanned. During
+ execution, the lexer will return a token from its token queue if any
+ are present. If not, the lexer will will pop an element from its
+ file queue to 'scanner' to be tokenized. If the file queue is empty,
+ the lexer will instead call 'parsedir' to traverse the directory tree
+ and tokenize the results. If 'parsedir' does not generate any new
+ tokens, we are done.
\author Jordan Lavatai
\date Aug 2016
----------------------------------------------------------------------------*/
-//stdc
+/* Standard */
#include <stdio.h>
#include <string.h>
#include <errno.h>
-//posix
+/* Posix */
#include <unistd.h>
#include <stdlib.h>
-//bison
-#include "fileparser.tab.h"
-#define TOKEN_BUF_SIZE 1024
-#define DIRP_STACK_SIZE 512
+#include <limits.h> //realpath, NAME_MAX, PATH_MAX
+#include <dirent.h>
+/* Local */
+#include "parser.tab.h"
+#ifndef DE_STACKSIZE
+#define DE_STACKSIZE 1024
+#endif
+#ifndef TK_STACKSIZE
+#define TK_STACKSIZE 1024
+#endif
+/* Public */
+int lexer_init(void);
+int lexer(void);
+int lexer_lexfile(const char*);
+void lexer_pushtok(int, YYSTYPE);
+char const* lexer_get_current_filepath(void);
+struct dirent* lexer_direntpa[DE_STACKSIZE],** lexer_direntpp,** lexer_direntpb;
+/* Private */
+extern //lexer_lex.rl
+int lexer_lex(const char*);
+extern //scanner.c
+int scanner_init(void);
+extern //scanner.c
+int scanner(void);
+static inline
+int dredge_current_depth(void);
+extern //bison
+YYSTYPE yylval;
+static
+char const* current_filename;
+static
+struct tok
+{ YYSTYPE lval; //token val
+ int tok_t; //token type
+} token_stack[TK_STACKSIZE], *tsp, *tsx;
-int lexer_init(void);
-int lexer(void);
+/* Directory Entity Array/Stack
+ Simple array for keeping track of dirents yet to be processed by the scanner.
+ If this list is empty and there are no tokens, the lexer is done.
+ This array is populated by the scanner as an array, and popped locally by the
+ lexer as a stack, and is popped as a FIFO stack.
+*/
+#define DE_STACK (lexer_direntpa)
+#define DE_STACKP (lexer_direntpp)
+#define DE_STACKB (lexer_direntpb)
+#define DE_LEN() (DE_STACKP - DE_STACKB)
+#define DE_INIT() (DE_STACKP = DE_STACKB = DE_STACK)
+#define DE_POP() (*DE_STACKB++)
-static
-int lexer_scan(void);
+/* Token Stack
+ This is a FIFO stack whose pointers are a union of either a pointer to an
+ integer, or a pointer to two integers (a struct tok). This way, integers may
+ be added or removed from the stack either singularly (IPUSH/IPOP), or as a
+ full token of two integers (PUSH/POP).
+ An alignment error will occur if IPOP or IPUSH are used a non-even number of
+ times in a sequence!
+*/
+#define TK_STACK (token_stack)
+#define TK_STACKP (tsp)
+#define TK_STACKX (tsx)
+#define TK_LEN() (TK_STACKX - TK_STACKP)
+#define TK_INIT() (TK_STACKP = TK_STACKX = TK_STACK)
+#define TK_POP() (*TK_STACKP++)
+#define TK_PUSH(T,L) (*TK_STACKX++ = (struct tok){L,T})
-static
-int token_buf[TOKEN_BUF_SIZE], *tbp, *tbx;
-static
-DIR* dirp_stack[DIRP_STACK_SIZE], *dsp;
+/* Initializer
+ The initializer returns boolean true if an error occurs, which may be handled
+ with standard errno.
+*/
+int lexer_init
+()
+{ TK_INIT();
+ DE_INIT();
+ current_filename = NULL;
+ return scanner_init();
+}
-/* Initialize pointers */
-int
-lexer_init()
-{ tbp = tbx = token_buf;
- dsp = dirp_stack;
+/* Lexer
+ If the token buffer is empty, 'lexer' will initialize the token buffer and
+ call 'lexer_scandir'. If SCAN_ERROR is returned, an error is printed
+ before sending a null return to bison. If 0 tokens are generated, the error
+ printing is skipped. In all other cases, 'yylval' is set, and the token's
+ integer representation is returned.
+*/
+int lexer
+#define $($)#$
+#define SCAN_ERROR -1
+#define TK_EMPTY (TK_STACKP == TK_STACKX)
+#define FAIL(...) \
+ do { \
+ fprintf(stderr,__VA_ARGS__); \
+ goto done; \
+ } while (0)
+()
+{ struct tok token;
+ start:
+ while (DE_LEN() > 0) //lex any directory entries in our stack
+ if (lexer_lexfile(DE_POP()->d_name) == 0)
+ FAIL("Lexer failed to tokenize [%s]\n",(*DE_STACKB)->d_name);
+ if (TK_EMPTY) //if there are no tokens,
+ { TK_INIT(); //initialize the token stack back to 0
+ switch (scanner())
+ { case SCAN_ERROR: //if an error occurred,
+ FAIL("Scanner error\n");
+ case 0: //if the the scanner finds no dirents,
+ goto done; //then we are done
+ default: //if we found some elements to scan,
+ goto start; //start over and lex them
+ }
+ }
+ token = TK_POP();
+ yylval = token.lval;
+ return token.tok_t;
+ done:
+ yylval.val = 0;
return 0;
}
-/* Returns a token identifier and sets yylval */
-int
-lexer()
-{ if (lexer_scan() == 0)
- return 0;
- yylval = *tbp++;
- return *tbp++;
-}
-/* Scanner
- Scans a filename from its alphabetically ordered list of file elements
- and tokenizes the result. If the file list is empty, then the stack of
- directory elements will be popped and processed as they are encountered.
+/* Token Receiver
+ This receiver takes a struct tok and pushes it to the FIFO stack.
+*/
+void lexer_pushtok
+#define $($)#$ //stringifier
+#define ERR_TK "Fatal: Generated over " $(TK_STACKSIZE) " tokens in one pass."
+( int tok, YYSTYPE lval )
+{ if (TK_LEN() >= TK_STACKSIZE)
+ { fprintf(stderr, ERR_TK);
+ exit(EXIT_FAILURE);
+ }
+ TK_PUSH(tok, lval);
+}
- Returns the number of tokens generated.
+/* Lexical analysis of a file
+ Strips a filename to its base name, then sends it to lexer_lex
*/
-#define MAX_ENTITIES 256
-static
-int lexer_scan()
-{ static struct dirent* entity;
- static struct dirent* files[MAX_ENTITIES];
- static struct dirent* dirs = files + MAX_ENTITIES - 1;
- static int num_files = 0;
- static int num_dirs = 0;
+int lexer_lexfile
+#define HIDDEN_WARNING "%s is hidden and will not be parsed!\n", filename
+( const char *filename
+)
+{ static char fname[NAME_MAX];
+ char *last_period = NULL, *iter;
- //sort out files and directories, grow directories from bottom up
- while ((entity = readdir(dirp)) != NULL)
- { switch (entity->d_type)
- { case DT_LNK:
- case DT_REG:
- files[num_files++] = entity;
- break;
- case DT_DIR:
- *(dirs - num_dirs++) = entity;
- break;
- case DT_UNKNOWN:
- default:
- printf("Ignoring unknown file: %s\n", entity->d_name);
- break;
- }
- }
- if (errno)
- perror("readdir");
- qsort(&files[0], num_files, sizeof struct dirent*, qalpha);
- num_ents = scandirat(dirfd, ".", &namelist, scanfilter, scancompar);
- if (num_ents < 0)
- { perror("scandirat");
- return -1;
+ if (*filename == '.')
+ { fprintf (stderr, HIDDEN_WARNING);
+ return 0;
}
- //process files
-
- //recurse into directories
+ /* Copy the filename and remove its suffix */
+ strncpy(fname,filename,NAME_MAX);
+ last_period = NULL;
+ for (iter = fname; *iter; iter++) //find the last '.' char
+ if (*iter == '.')
+ last_period = iter;
+ if (last_period) //if we found one,
+ *last_period = '\0'; //truncate the string there
+ /* Register the current_filename */
+ current_filename = filename;
+
+ return lexer_lex(fname);
+}
+char const* lexer_get_current_filepath
+()
+{ static char current_path[PATH_MAX];
+ static char const* last_filename;
+ if ((!last_filename || last_filename != current_filename) &&
+ (realpath(current_filename, current_path) != current_path))
+ { perror("realpath: ");
+ return NULL;
+ }
+ return (const char*)current_path;
}
projects / henge / webcc.git / blobdiff