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#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
enum {
SEP_DEFAULT = -1,
};
void freq(FILE *f, int field);
struct count {
char *name;
int freq;
};
struct count *cs;
size_t cs_len = 0;
char sep;
size_t
get_index(char *name) {
for (size_t i = 0; i < cs_len; i++) {
if (strcmp(cs[i].name, name) == 0)
return i;
}
return -1;
}
/* can only increase freqs */
void
update_record(char *name) {
int i = get_index(name);
if (i == -1) {
/* create record */
cs_len++;
cs = realloc(cs, sizeof(struct count) * cs_len);
if (cs == NULL) {
perror("realloc");
exit(1);
}
cs[cs_len - 1].name = strdup(name);
cs[cs_len - 1].freq = 1;
} else {
/* add 1 to freq */
cs[i].freq++;
}
}
void
free_freqs(void) {
for (size_t i = 0; i < cs_len; i++)
free(cs[i].name);
free(cs);
}
void
print_freqs(void) {
for (size_t i = 0; i < cs_len; i++)
printf("%d\t%s\n", cs[i].freq, cs[i].name);
}
int
is_sep(int c) {
if (sep == SEP_DEFAULT)
return isspace(c);
else
return (c == sep);
}
int
main (int argc, char **argv) {
int c, field = 1;
sep = SEP_DEFAULT;
while ((c = getopt(argc, argv, ":d:k:")) != -1) {
switch (c) {
case 'd':
sep = optarg[0];
break;
case 'k':
field = atoi(optarg);
break;
case '?':
fprintf(stderr, "usage: %s [-d delim] [-k fieldnum] [file...]\n", argv[0]);
return 1;
}
}
argc -= optind;
argv += optind - 1;
if (argc == 0)
freq(stdin, field);
else while (*++argv) {
FILE *f = stdin;
if (strcmp(*argv, "-") != 0) {
f = fopen(*argv, "r");
if (f == NULL) {
perror(*argv);
continue;
}
}
freq(f, field);
if (f != stdin)
fclose(f);
}
print_freqs();
free_freqs();
return 0;
}
void
freq(FILE *f, int field) {
char *field_start, *line = NULL;
size_t linelen = 0;
ssize_t n, i;
int cur_field, in_word, linenum;
linenum = 0;
while ((n = getline(&line, &linelen, f)) != -1) {
if (line[n-1] == '\n') {
line[n-1] = '\0'; /* remove the '\n' */
n--;
}
linenum++;
i = 0;
field_start = line;
if (field == 0)
goto field_found;
in_word = 0;
cur_field = 1;
/* eat up whitespace at front */
while (is_sep(line[i]))
i++;
for (; i < n; i++) {
if (is_sep(line[i])) {
if (in_word) {
if (cur_field == field) {
line[i] = '\0';
goto field_found;
}
field_start = (char *)-1;
cur_field++;
in_word = 0;
}
} else {
if (!in_word)
field_start = line + i;
in_word = 1;
}
}
if (cur_field != field) {
/* didn't find the specified field */
fprintf(stderr, "freq: warning: field %d not found on line %d\n", field, linenum);
continue;
}
if (field_start == (char *)-1) {
fprintf(stderr, "freq: warning: empty field %d on line %d\n", field, linenum);
continue;
}
field_found:
//fprintf(stderr, "found '%s'\n", field_start);
update_record(field_start);
}
free(line);
}
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