#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <limits.h>
#include <unistd.h>
#include <sys/wait.h>
#include "common.h"

enum {
	Maxrange = 0x1fff,
};

Range *
getcharset(char *path, int *i, int pjwface)
{
	pid_t pid;
	Range *ranges;
	char t[32], *e, *p;
	int s, fds[2], n, r;
	unsigned long min, max, k;

	*i = 0;
	ranges = NULL;
	if(pipe(fds) < 0){
		perror("pipe");
		return NULL;
	}
	if((pid = fork()) == 0){
		if(dup2(fds[1], 1) < 0 || execlp("fc-query", "fc-query", "--format", "%{charset} ", path, NULL) < 0){
			perror("fc-query");
			exit(1);
		}
		exit(1);
	}

	close(fds[1]);
	if(pid > 0){
		for(n = 0;; n = strlen(t)){
			if((r = read(fds[0], t+n, sizeof(t)-n-1)) < 0){
				perror("charset read");
				goto err;
			}else if(r == 0 && n == 0)
				break;
			n += r;
			t[n] = 0;

			min = max = strtoul(t, &e, 16);
			if(e == t || min > UINT32_MAX){
formatting:
				fprintf(stderr, "fc-query: unexpected formatting\n");
				goto err;
			}
			if(*e == '-'){
				max = strtoul(p = e+1, &e, 16);
				if(e == p || max > UINT32_MAX)
					goto formatting;
			}else if(*e != ' ')
				goto formatting;
			e++;
			n = strlen(e);
			memmove(t, e, n);
			t[n] = 0;
			if(min == 0 && pjwface)
				min++;
			for(k = min; k <= max; k += Maxrange+1){
				ranges = realloc(ranges, (*i+1)*sizeof(*ranges));
				ranges[*i].min = k;
				ranges[*i].max = k+Maxrange<max ? k+Maxrange : max;
				(*i)++;
			}
		}

		waitpid(pid, &s, 0);
	}else{
		perror("fork");
		goto err;
	}
	close(fds[0]);

	return ranges;
err:
	close(fds[0]);
	free(ranges);
	return NULL;
}