outline basic sorting

1 files changed, 86 insertions, 4 deletions

diff --git a/sort.c b/sort.c
index 05cbbf3..eff1f0d 100644
--- a/sort.c
+++ b/sort.c
@@ -28,6 +28,7 @@
 #include <locale.h>
 #include <stdint.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
@@ -35,10 +36,16 @@
 #define LINE_MAX _POSIX_LINE_MAX
 #endif
 
+struct line {
+	FILE *file;
+	fpos_t pos;
+};
+
 static int sort_check(const char *input, char sep, const char *key, unsigned int flags)
 {
 	(void)sep;
 	(void)key;
+	(void)flags;
 
 	char prev[LINE_MAX] = "";
 	char cur[LINE_MAX] = "";
@@ -68,6 +75,78 @@ static int sort_check(const char *input, char sep, const char *key, unsigned int
 	return 0;
 }
 
+static void sort_add_pos(struct line **lines, size_t *nlines, FILE *f)
+{
+	struct line *tmp = realloc(*lines, (*nlines + 1) * sizeof(**lines));
+	if (tmp == NULL) {
+		perror("sort");
+		exit(1);
+	}
+	*lines = tmp;
+	(*lines)[*nlines].file = f;
+	fgetpos(f, &((*lines)[*nlines].pos));
+}
+
+static int sort_read(const char *path, struct line **lines, size_t *nlines)
+{
+	FILE *f = stdin;
+	if (strcmp(path, "-")) {
+		f = fopen(path, "r");
+	}
+	if (f == NULL) {
+		fprintf(stderr, "sort: %s: %s\n", path, strerror(errno));
+		return 1;
+	}
+
+	char cur[LINE_MAX] = "";
+
+	sort_add_pos(lines, nlines, f);
+	while (fgets(cur, sizeof(cur), f) != NULL) {
+	}
+
+	/* ignore EOF position */
+	(*nlines)--;
+
+	/* do *NOT* close f */
+	return 0;
+}
+
+static int sort_compar(const void *a, const void *b)
+{
+	const struct line *l1 = a;
+	const struct line *l2 = b;
+	char line1[LINE_MAX] = "";
+	char line2[LINE_MAX] = "";
+
+	fsetpos(l1->file, &l1->pos);
+	fgets(line1, sizeof(line1), l1->file);
+
+	fsetpos(l2->file, &l2->pos);
+	fgets(line2, sizeof(line2), l2->file);
+
+	return strcoll(line1, line2);
+}
+
+static int sort_sort(char *files[], int nfiles, char sep, const char *key, unsigned int flags)
+{
+	(void)sep;
+	(void)key;
+	(void)flags;
+
+	struct line *lines = NULL;
+	size_t nlines = 0;
+
+	for (int i = 0; i < nfiles; i++) {
+		if (sort_read(files[i], &lines, &nlines) != 0) {
+			return 1;
+		}
+	}
+
+	qsort(lines, nlines, sizeof(*lines), sort_compar);
+
+	return 0;
+}
+
 int main(int argc, char *argv[])
 {
 	setlocale(LC_ALL, "");
@@ -124,9 +203,12 @@ int main(int argc, char *argv[])
 		return sort_check(argv[optind], separator, key, flags);
 	}
 
-	/* add lines from all inputs */
-	/* sort */
-	/* print */
+	#if 0
+	if (mode == MERGE) {
+		/* optimize to assume sorted input */
+		return sort_merge(argv + optind, argc - optind, separator, key, flags);
+	}
+	#endif
 
-	return 0;
+	return sort_sort(argv + optind, argc - optind, separator, key, flags);
 }