inz

anagrep.c (raw)

#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdlib.h>
 
static void calcchars(int *counts, const char *buf)
{
	for (; *buf; buf++)
		if ((*buf & ~0x20) >= 'A' &&
		    (*buf & ~0x20) <= 'Z')
			counts[(*buf & ~0x20) - 'A']++;
}
 
static int calccmp(int *target, int *candidate)
{
	int i;
	for (i = 0; i <= 'Z' - 'A'; i++)
		if (target[i] < candidate[i])
			return false;
	return true;
}
 
struct result {
	char *str;
	size_t sl;
};
 
int rescmp(const void *a, const void *b)
{
	const struct result *ar = a;
	const struct result *br = b;
 
	if (ar->sl - br->sl)
		return br->sl - ar->sl;
	return strcmp(ar->str, br->str);
}
 
static void processfd(int *counts, int fd)
{
	char buffer[8192];
	size_t used = 0;
	int r;
	struct result *results = NULL;
	size_t nres = 0;
 
	while ((r = read(fd, buffer + used, sizeof(buffer) - used)) > 0) {
		char *nlp;
		used += r;
		while ((nlp = memchr(buffer, '\n', used))) {
			int lcounts['Z' - 'A' + 1] = { 0 };
			int cmp;
			*nlp = '\0';
			calcchars(lcounts, buffer);
			if (calccmp(counts, lcounts)) {
				results = realloc(results, ++nres * sizeof(*results));
				results[nres - 1].str = strdup(buffer);
				results[nres - 1].sl = nlp - buffer;
			}
			memmove(buffer, nlp + 1, used - (nlp - buffer) - 1);
			used -= (nlp - buffer) + 1;
		}
	}
	qsort(results, nres, sizeof(*results), rescmp);
	for (r = 0; r < nres; r++) {
		results[r].str[results[r].sl] = '\n';
		write(STDOUT_FILENO, results[r].str, results[r].sl + 1);
		free(results[r].str);
	}
	free(results);
}
 
int main(int argc, char **argv)
{
	int what['Z' - 'A' + 1] = { 0 };
	int i;
 
	calcchars(what, argv[1]);
	if (argc > 2) {
		for (i = 2; i < argc; i++) {
			int fd = open(argv[i], O_RDONLY);
			if (fd >= 0) {
				processfd(what, fd);
				close(fd);
			}
		}
	} else {
		processfd(what, STDIN_FILENO);
	}
 
	return 0;
}