toys/posix/cut.c - third_party/toybox - Git at Google

 /* cut.c - Cut from a file.
  *
  * Copyright 2012 Ranjan Kumar <ranjankumar.bth@gmail.com>, Kyungwan Han <asura321@gamil.com>
  *
  * http://pubs.opengroup.org/onlinepubs/9699919799/utilities/cut.html
  *
 USE_CUT(NEWTOY(cut, "b:c:f:d:sn", TOYFLAG_BIN))

 config CUT
   bool "cut"
   default y
   help
     usage: cut OPTION... [FILE]...
     Print selected parts of lines from each FILE to standard output.
       -b LIST    select only these bytes from LIST.
       -c LIST    select only these characters from LIST.
       -f LIST    select only these fields.
       -d DELIM  use DELIM instead of TAB for field delimiter.
       -s    do not print lines not containing delimiters.
       -n    don't split multibyte characters (Ignored).
 */
 #define FOR_cut
 #include "toys.h"

 typedef struct _slist {
   int start_position;
   int end_position;
   struct _slist *next;
 }SLIST;

 GLOBALS(
   char *delim;
   char *flist;
   char *clist;
   char *blist;
   struct _slist *slist_head;
   unsigned nelem;
 )

 #define BEGINOFLINE  0
 #define ENDOFLINE INT_MAX
 #define NORANGE -1

 static int get_user_options(void);
 void (*do_cut)(int);
 static void do_fcut(int fd);
 static void do_bccut(int fd);
 static void free_list(void);

 /*
  * add items in the slist.
  */
 static void add_to_list(int start, int end)
 {
   SLIST *current, *head_ref, *temp1_node;

   head_ref = TT.slist_head;
   temp1_node = (SLIST *)xzalloc(sizeof(SLIST));
   temp1_node->start_position = start;
   temp1_node->end_position = end;
   temp1_node->next = NULL;

   /* Special case for the head end */
   if (head_ref == NULL || (head_ref)->start_position >= start) {
       temp1_node->next = head_ref;
       head_ref = temp1_node;
   }
   else {
     /* Locate the node before the point of insertion */
     current = head_ref;
     while (current->next!=NULL && current->next->start_position < temp1_node->start_position)
         current = current->next;
     temp1_node->next = current->next;
     current->next = temp1_node;
   }
   TT.slist_head = head_ref;
   return;
 }

 /*
  * parse list and add to slist.
  */
 static void parse_list(char *list)
 {
   char *ctoken, *dtoken;
   int  start = 0, end = 0;
   while((ctoken = strsep(&list, ",")) != NULL) {
     if(!ctoken[0]) continue;

     //Get start position.
     dtoken = strsep(&ctoken, "-");
     if(!dtoken[0]) start = BEGINOFLINE;
     else {
       start = get_int_value(dtoken, 0, INT_MAX);
       start = (start?(start-1):start);
     }
     //Get end position.
     if(ctoken == NULL) end = NORANGE; //case e.g. 1,2,3
     else if(!ctoken[0]) end = ENDOFLINE; //case e.g. N-
     else {//case e.g. N-M
       end = get_int_value(ctoken, 0, INT_MAX);
       end = (end?end:ENDOFLINE);
             end--;
       if(end == start) end = NORANGE;
     }
     add_to_list(start, end);
     TT.nelem++;
   }
   //if list is missing in command line.
   if(TT.nelem == 0) error_exit("missing positions list:");
   return;
 }

 /*
  * retrive data from the file/s.
  */
 static void get_data(void)
 {
   char **argv = toys.optargs; //file name.
   toys.exitval = EXIT_SUCCESS;

   if(!*argv) do_cut(0); //for stdin
   else {
     for(; *argv; ++argv) {
       if(strcmp(*argv, "-") == 0) do_cut(0); //for stdin
       else {
         int fd = open(*argv, O_RDONLY, 0);
         if(fd < 0) {//if file not present then continue with other files.
           perror_msg(*argv);
           toys.exitval = EXIT_FAILURE;
           continue;
         }
         do_cut(fd);
         xclose(fd);
       }
     }
   }
   return;
 }

 /*
  * cut main function.
 */
 void cut_main(void)
 {
   char delimiter = '\t'; //default delimiter.
   int  num_of_options = 0;
   char *list;

   TT.nelem = 0;
   TT.slist_head = NULL;
   //verify the number of options provided by user.
   num_of_options = get_user_options();
   if(num_of_options == 0) error_exit("specify a list of bytes, characters, or fields");
   else if(num_of_options > 1) error_exit("only one type of list may be specified");

   //Get list and assign the function.
   if(toys.optflags & FLAG_f) {
     list = TT.flist;
     do_cut = do_fcut;
   }
   else if(toys.optflags & FLAG_c) {
     list = TT.clist;
     do_cut = do_bccut;
   }
   else {
     list = TT.blist;
     do_cut = do_bccut;
   }

   if(toys.optflags & FLAG_d) {
     //delimiter must be 1 char.
     if(TT.delim[0] && TT.delim[1]) perror_exit("the delimiter must be a single character");
     delimiter = TT.delim[0];
   }

   if(!(toys.optflags & FLAG_d) && (toys.optflags & FLAG_f)) {
     TT.delim = (char *)xzalloc(2);
     TT.delim[0] = delimiter;
   }

   //when field is not specified, cutting has some special handling.
   if(!(toys.optflags & FLAG_f)) {
     if(toys.optflags & FLAG_s) perror_exit("suppressing non-delimited lines operating on fields");
     if(delimiter != '\t') perror_exit("an input delimiter may be specified only when operating on fields");
   }

   parse_list(list);
   get_data();
   if(!(toys.optflags & FLAG_d) && (toys.optflags & FLAG_f)) {
     free(TT.delim);
     TT.delim = NULL;
   }
   free_list();
   return;
 }

 /*
  * perform cut operation on the given delimiter.
  */
 static void do_fcut(int fd)
 {
   char *buff;
   char *delimiter = TT.delim;
   while((buff = get_line(fd)) != NULL) {
     //does line have any delimiter?.
     if(strrchr(buff, (int)delimiter[0]) == NULL) {
       //if not then print whole line and move to next line.
       if(!(toys.optflags & FLAG_s)) xputs(buff);
       continue;
     }

     unsigned cpos = 0;
     int start, ndelimiters = -1;
     int  nprinted_fields = 0;
     char *pfield = xzalloc(strlen(buff) + 1);
     SLIST *temp_node = TT.slist_head;

     if(temp_node != NULL) {
       //process list on each line.
       while(cpos < TT.nelem && buff) {
         if(!temp_node) break;
         start = temp_node->start_position;
         do {
           char *field = NULL;
           //count number of delimeters per line.
           while(buff) {
             if(ndelimiters < start) {
               ndelimiters++;
               field = strsep(&buff, delimiter);
             }
             else break;
           }
           //print field (if not yet printed).
           if(!pfield[ndelimiters]) {
             if(ndelimiters == start) {
               //put delimiter.
               if(nprinted_fields++ > 0) xputc(delimiter[0]);
               if(field) fputs(field, stdout);
               //make sure this field won't print again.
               pfield[ndelimiters] = (char) 0x23; //put some char at this position.
             }
           }
           start++;
           if((temp_node->end_position == NORANGE) || (!buff)) break;
         }while(start <= temp_node->end_position);
         temp_node = temp_node->next;
         cpos++;
       }
     }
     xputc('\n');
     free(pfield);
     pfield = NULL;
   }//End of while loop.
   return;
 }

 /*
  * perform cut operation char or byte.
  */
 static void do_bccut(int fd)
 {
   char *buff;
   while((buff = get_line(fd)) != NULL) {
     unsigned cpos = 0;
     int buffln = strlen(buff);
     char *pfield = xzalloc(buffln + 1);
     SLIST *temp_node = TT.slist_head;
     if(temp_node != NULL) {
       while(cpos < TT.nelem) {
         int start;
         if(!temp_node) break;
         start = temp_node->start_position;
         while(start < buffln) {
           //to avoid duplicate field printing.
           if(pfield[start]) {
               if(++start <= temp_node->end_position) continue;
               temp_node = temp_node->next;
               break;
           }
           else {
             //make sure this field won't print again.
             pfield[start] = (char) 0x23; //put some char at this position.
             xputc(buff[start]);
           }
           if(++start > temp_node->end_position) {
             temp_node = temp_node->next;
             break;
           }
         }
         cpos++;
       }
       xputc('\n');
     }
     free(pfield);
     pfield = NULL;
   }
   return;
 }

 /*
  * used to verify "c", "b" and "f" options are present in command line.
  * As cut command can only except any of them at a time.
 */
 static int get_user_options(void)
 {
   int i = 3, flag = 0;
   for(; i<6; i++) {//verify 3rd, 4th and 5th bit is set.
     int mask = 1;
     mask = mask << i;
     if(toys.optflags & mask) flag++;
   }
   return flag;
 }

 /*
  * free the slist.
 */
 static void free_list(void)
 {
   SLIST *temp;
   while(TT.slist_head != NULL) {
     temp = TT.slist_head->next;
     free(TT.slist_head);
     TT.slist_head = temp;
   }
   return;
 }
	/* cut.c - Cut from a file.
	*
	* Copyright 2012 Ranjan Kumar <ranjankumar.bth@gmail.com>, Kyungwan Han <asura321@gamil.com>
	*
	* http://pubs.opengroup.org/onlinepubs/9699919799/utilities/cut.html
	*
	USE_CUT(NEWTOY(cut, "b:c:f:d:sn", TOYFLAG_BIN))

	config CUT
	bool "cut"
	default y
	help
	usage: cut OPTION... [FILE]...
	Print selected parts of lines from each FILE to standard output.
	-b LIST select only these bytes from LIST.
	-c LIST select only these characters from LIST.
	-f LIST select only these fields.
	-d DELIM use DELIM instead of TAB for field delimiter.
	-s do not print lines not containing delimiters.
	-n don't split multibyte characters (Ignored).
	*/
	#define FOR_cut
	#include "toys.h"

	typedef struct _slist {
	int start_position;
	int end_position;
	struct _slist *next;
	}SLIST;

	GLOBALS(
	char *delim;
	char *flist;
	char *clist;
	char *blist;
	struct _slist *slist_head;
	unsigned nelem;
	)

	#define BEGINOFLINE 0
	#define ENDOFLINE INT_MAX
	#define NORANGE -1

	static int get_user_options(void);
	void (*do_cut)(int);
	static void do_fcut(int fd);
	static void do_bccut(int fd);
	static void free_list(void);

	/*
	* add items in the slist.
	*/
	static void add_to_list(int start, int end)
	{
	SLIST current, head_ref, *temp1_node;

	head_ref = TT.slist_head;
	temp1_node = (SLIST *)xzalloc(sizeof(SLIST));
	temp1_node->start_position = start;
	temp1_node->end_position = end;
	temp1_node->next = NULL;

	/* Special case for the head end */
	if (head_ref == NULL \|\| (head_ref)->start_position >= start) {
	temp1_node->next = head_ref;
	head_ref = temp1_node;
	}
	else {
	/* Locate the node before the point of insertion */
	current = head_ref;
	while (current->next!=NULL && current->next->start_position < temp1_node->start_position)
	current = current->next;
	temp1_node->next = current->next;
	current->next = temp1_node;
	}
	TT.slist_head = head_ref;
	return;
	}

	/*
	* parse list and add to slist.
	*/
	static void parse_list(char *list)
	{
	char ctoken, dtoken;
	int start = 0, end = 0;
	while((ctoken = strsep(&list, ",")) != NULL) {
	if(!ctoken[0]) continue;

	//Get start position.
	dtoken = strsep(&ctoken, "-");
	if(!dtoken[0]) start = BEGINOFLINE;
	else {
	start = get_int_value(dtoken, 0, INT_MAX);
	start = (start?(start-1):start);
	}
	//Get end position.
	if(ctoken == NULL) end = NORANGE; //case e.g. 1,2,3
	else if(!ctoken[0]) end = ENDOFLINE; //case e.g. N-
	else {//case e.g. N-M
	end = get_int_value(ctoken, 0, INT_MAX);
	end = (end?end:ENDOFLINE);
	end--;
	if(end == start) end = NORANGE;
	}
	add_to_list(start, end);
	TT.nelem++;
	}
	//if list is missing in command line.
	if(TT.nelem == 0) error_exit("missing positions list:");
	return;
	}

	/*
	* retrive data from the file/s.
	*/
	static void get_data(void)
	{
	char **argv = toys.optargs; //file name.
	toys.exitval = EXIT_SUCCESS;

	if(!*argv) do_cut(0); //for stdin
	else {
	for(; *argv; ++argv) {
	if(strcmp(*argv, "-") == 0) do_cut(0); //for stdin
	else {
	int fd = open(*argv, O_RDONLY, 0);
	if(fd < 0) {//if file not present then continue with other files.
	perror_msg(*argv);
	toys.exitval = EXIT_FAILURE;
	continue;
	}
	do_cut(fd);
	xclose(fd);
	}
	}
	}
	return;
	}

	/*
	* cut main function.
	*/
	void cut_main(void)
	{
	char delimiter = '\t'; //default delimiter.
	int num_of_options = 0;
	char *list;

	TT.nelem = 0;
	TT.slist_head = NULL;
	//verify the number of options provided by user.
	num_of_options = get_user_options();
	if(num_of_options == 0) error_exit("specify a list of bytes, characters, or fields");
	else if(num_of_options > 1) error_exit("only one type of list may be specified");

	//Get list and assign the function.
	if(toys.optflags & FLAG_f) {
	list = TT.flist;
	do_cut = do_fcut;
	}
	else if(toys.optflags & FLAG_c) {
	list = TT.clist;
	do_cut = do_bccut;
	}
	else {
	list = TT.blist;
	do_cut = do_bccut;
	}

	if(toys.optflags & FLAG_d) {
	//delimiter must be 1 char.
	if(TT.delim[0] && TT.delim[1]) perror_exit("the delimiter must be a single character");
	delimiter = TT.delim[0];
	}

	if(!(toys.optflags & FLAG_d) && (toys.optflags & FLAG_f)) {
	TT.delim = (char *)xzalloc(2);
	TT.delim[0] = delimiter;
	}

	//when field is not specified, cutting has some special handling.
	if(!(toys.optflags & FLAG_f)) {
	if(toys.optflags & FLAG_s) perror_exit("suppressing non-delimited lines operating on fields");
	if(delimiter != '\t') perror_exit("an input delimiter may be specified only when operating on fields");
	}

	parse_list(list);
	get_data();
	if(!(toys.optflags & FLAG_d) && (toys.optflags & FLAG_f)) {
	free(TT.delim);
	TT.delim = NULL;
	}
	free_list();
	return;
	}

	/*
	* perform cut operation on the given delimiter.
	*/
	static void do_fcut(int fd)
	{
	char *buff;
	char *delimiter = TT.delim;
	while((buff = get_line(fd)) != NULL) {
	//does line have any delimiter?.
	if(strrchr(buff, (int)delimiter[0]) == NULL) {
	//if not then print whole line and move to next line.
	if(!(toys.optflags & FLAG_s)) xputs(buff);
	continue;
	}

	unsigned cpos = 0;
	int start, ndelimiters = -1;
	int nprinted_fields = 0;
	char *pfield = xzalloc(strlen(buff) + 1);
	SLIST *temp_node = TT.slist_head;

	if(temp_node != NULL) {
	//process list on each line.
	while(cpos < TT.nelem && buff) {
	if(!temp_node) break;
	start = temp_node->start_position;
	do {
	char *field = NULL;
	//count number of delimeters per line.
	while(buff) {
	if(ndelimiters < start) {
	ndelimiters++;
	field = strsep(&buff, delimiter);
	}
	else break;
	}
	//print field (if not yet printed).
	if(!pfield[ndelimiters]) {
	if(ndelimiters == start) {
	//put delimiter.
	if(nprinted_fields++ > 0) xputc(delimiter[0]);
	if(field) fputs(field, stdout);
	//make sure this field won't print again.
	pfield[ndelimiters] = (char) 0x23; //put some char at this position.
	}
	}
	start++;
	if((temp_node->end_position == NORANGE) \|\| (!buff)) break;
	}while(start <= temp_node->end_position);
	temp_node = temp_node->next;
	cpos++;
	}
	}
	xputc('\n');
	free(pfield);
	pfield = NULL;
	}//End of while loop.
	return;
	}

	/*
	* perform cut operation char or byte.
	*/
	static void do_bccut(int fd)
	{
	char *buff;
	while((buff = get_line(fd)) != NULL) {
	unsigned cpos = 0;
	int buffln = strlen(buff);
	char *pfield = xzalloc(buffln + 1);
	SLIST *temp_node = TT.slist_head;
	if(temp_node != NULL) {
	while(cpos < TT.nelem) {
	int start;
	if(!temp_node) break;
	start = temp_node->start_position;
	while(start < buffln) {
	//to avoid duplicate field printing.
	if(pfield[start]) {
	if(++start <= temp_node->end_position) continue;
	temp_node = temp_node->next;
	break;
	}
	else {
	//make sure this field won't print again.
	pfield[start] = (char) 0x23; //put some char at this position.
	xputc(buff[start]);
	}
	if(++start > temp_node->end_position) {
	temp_node = temp_node->next;
	break;
	}
	}
	cpos++;
	}
	xputc('\n');
	}
	free(pfield);
	pfield = NULL;
	}
	return;
	}

	/*
	* used to verify "c", "b" and "f" options are present in command line.
	* As cut command can only except any of them at a time.
	*/
	static int get_user_options(void)
	{
	int i = 3, flag = 0;
	for(; i<6; i++) {//verify 3rd, 4th and 5th bit is set.
	int mask = 1;
	mask = mask << i;
	if(toys.optflags & mask) flag++;
	}
	return flag;
	}

	/*
	* free the slist.
	*/
	static void free_list(void)
	{
	SLIST *temp;
	while(TT.slist_head != NULL) {
	temp = TT.slist_head->next;
	free(TT.slist_head);
	TT.slist_head = temp;
	}
	return;
	}