diff options
Diffstat (limited to 'toys/posix')
| -rw-r--r-- | toys/posix/cut.c | 328 |
1 files changed, 328 insertions, 0 deletions
diff --git a/toys/posix/cut.c b/toys/posix/cut.c new file mode 100644 index 00000000..af4a1d9a --- /dev/null +++ b/toys/posix/cut.c @@ -0,0 +1,328 @@ +/* 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; +} |