Hi
This is a braindead and incomplete implementation of tr that only
works for one-byte encodings. Do you think it makes sense to use this
implementation as some kind of stopgap-measure until we have a more
robust version of tr?
If you you would rather not take this version, what approach would
you take for the character set mapping when using UTF-8? A hashmap-,
or B-tree-based solution or something else entirely?
Cheers,
Silvan
-- >8 --- (use git am -c)
The taken approach works only for one-byte encodings and is rather slow.
---
Makefile | 1 +
tr.c | 117 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 118 insertions(+)
create mode 100644 tr.c
diff --git a/Makefile b/Makefile
index 2a72a1c..b78ad2c 100644
--- a/Makefile
+++ b/Makefile
@@ -81,6 +81,7 @@ SRC = \
tee.c \
test.c \
touch.c \
+ tr.c \
true.c \
tty.c \
uname.c \
diff --git a/tr.c b/tr.c
new file mode 100644
index 0000000..0053a52
--- /dev/null
+++ b/tr.c
@@ -0,0 +1,117 @@
+/* See LICENSE file for copyright and license details. */
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "text.h"
+#include "util.h"
+
+static void
+usage(void)
+{
+ eprintf("usage: tr set1 [set2]\n");
+}
+
+void
+handle_escapes(char *s)
+{
+ switch(*s) {
+ case 'n':
+ *s = '\x0A';
+ break;
+ case 't':
+ *s = '\x09';
+ break;
+ case '\\':
+ *s = '\x5c';
+ break;
+ }
+}
+
+void
+parse_mapping(char *set1, char *set2, char *mappings)
+{
+ char *s;
+ size_t n = 0;
+ size_t lset2;
+
+ if(set2) {
+ lset2 = strnlen(set2, 255);
+ } else {
+ set2 = (char*) &set1[0];
+ lset2 = 0;
+ }
+
+ for(s = set1; *s; s++) {
+ if(*s == '\\') {
+ handle_escapes(++s);
+ ++n;
+ }
+
+ mappings[(int) *s] = set2[n];
+ if(n < (lset2 - 1))
+ n++;
+ }
+}
+
+void
+map_to_null(const char *mappings, char *in)
+{
+ const char *s;
+
+ for(s = in; *s; s++) {
+ if(!mappings[(int) *s])
+ putchar((int) *s);
+ }
+}
+
+void
+map_to_set(const char *mappings, char *in)
+{
+ const char *s;
+
+ for(s = in; *s; s++) {
+ if(!mappings[(int) *s]) {
+ putchar((int) *s);
+ } else {
+ putchar((int) mappings[(int) *s]);
+ }
+ }
+}
+
+int
+main(int argc, char *argv[])
+{
+ char mappings[255];
+ char *buf = NULL;
+ size_t size = 0;
+ void (*mapfunc) (const char*, char*);
+
+ memset(mappings, 0, 255);
+
+ ARGBEGIN {
+ default:
+ usage();
+ } ARGEND;
+
+ if(!argc)
+ usage();
+
+ if(argc >= 2) {
+ parse_mapping(argv[0], argv[1], mappings);
+ mapfunc = map_to_set;
+ } else {
+ parse_mapping(argv[0], NULL, mappings);
+ mapfunc = map_to_null;
+ }
+
+ while(afgets(&buf, &size, stdin))
+ mapfunc(mappings, buf);
+
+ if (ferror(stdin)) {
+ eprintf("<stdin>: read error:");
+ return EXIT_FAILURE;
+ }
+
+ return EXIT_SUCCESS;
+}
--
1.8.4.2
