I have made a implementation of the 'csplit' command in about 160 lines of code.
The implementation is mostly POSIX compliment, but it is missing a few things
It works as a Read-Eval-Print loop, where it prints to a file that changes
based on context. So doing negative offsets would require it to print lines it
doesn't accumulate yet.
The other main one is the fact it doesn't do "[LINE] {[NUMBER]}" cleanly yet.
It also includes the GNU extension "{*}" argument
The other breaks from POSIX are mostly insignificant, like the fact it doesn't
check locale environment variables or uses "%lu" for file size instead of "%d".
From 96c08c5c50715b4a8dce492667972751bf91af9c Mon Sep 17 00:00:00 2001
From: Oliver Webb <aquahobby...@proton.me>
Date: Mon, 11 Sep 2023 23:53:55 -0500
Subject: [PATCH] Implementation of csplit command
---
toys/pending/csplit.c | 164 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 164 insertions(+)
create mode 100644 toys/pending/csplit.c
diff --git a/toys/pending/csplit.c b/toys/pending/csplit.c
new file mode 100644
index 00000000..85db576e
--- /dev/null
+++ b/toys/pending/csplit.c
@@ -0,0 +1,164 @@
+/* csplit.c - split files on context
+ *
+ * Copyright 2023 Oliver Webb <aquahobby...@proton.me>
+ *
+ * See https://pubs.opengroup.org/onlinepubs/9699919799/utilities/csplit.html
+ * Deviations From POSIX:
+ * Does not use %d for file size output
+ * Doesn't do negitive offsets
+ * GNU Extension: "{*}"
+ *
+
+USE_CSPLIT(NEWTOY(csplit, "<2skf:n#", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_MAYFORK))
+
+config CSPLIT
+ bool "csplit"
+ default n
+ help
+ usage: csplit [-ks] [-f PREFIX] [-n INTEGER] file arg...
+
+ Split files into multiple files based on list of rules
+
+ -k Does not delete Files on error
+ -s No file output size messages
+ -f [PREFIX] Use [PREFIX] as filename prefix instead of "xx"
+ -n [INTEGER] Make all filename numbers [INTEGER] characters long
+
+ Valid Rules:
+ /regexp/[INTEGER] Break file before line that regexp matches,
+ %regexp%[INTEGER] Break file after line that regexp matches,
+ If a offset is specified for these rules, the break will happen [INTEGER]
+ lines after the regexp match
+ if a offset is specified, it will break at [INTEGER] lines after the offset
+ [INTEGER] Break file at line before [INTEGER]
+ {INTEGER} Repeat Previous Pattern INTEGER Number of times if INTEGER is *
+ The pattern repeats forever
+
+*/
+
+#define FOR_csplit
+#include "toys.h"
+
+GLOBALS(
+ long n;
+ char *f;
+)
+
+size_t indx = 1, findx = 0, lineno = 1, btc = 0;
+char *filefmt, *flname, *prefix;
+int eg = 0, offset = -1;
+
+// This is only int so we can exit cleanly in ternary operators
+int abort_csplit(char *err) {
+ // Cycle down through index instead of keeping track of what files we made
+ if (!FLAG(k)) for (; indx>=1; indx--)
+ remove(xmprintf(filefmt, prefix, findx));
+ error_exit("%s\n", err);
+ return 1;
+}
+
+int rgmatch(char *rxrl, char *line, char *fmt) {
+ regex_t rxp;
+ sscanf(rxrl,fmt, toybuf, &offset);
+ xregcomp(&rxp, toybuf, 0);
+ int rr = regexec(&rxp, line, 0, 0, 0);
+ if (!rr) return 1;
+ else if (rr == REG_NOMATCH) return 0;
+ return abort_csplit("bad regex");
+}
+
+int cntxt(char *line, char *rule) {
+ if (eg) return 0;
+
+ if (offset < 0);
+ else if (offset == 0) {
+ offset = -1;
+ return 1;
+ } else {
+ offset--;
+ return 0;
+ }
+
+ switch (rule[0]) {
+
+ case '/':
+ return rgmatch(rule, line, "/%[^/%]/%d");
+ break;
+ case '%':
+ offset++;
+ return rgmatch(rule, line, "%%%[^/%]%%%d");
+ break;
+
+ case '{':
+ // GNU extention: {*}
+ if (!strcmp(rule,"{*}"))
+ btc = -1;
+ else if (!sscanf(rule,"{%lu}",&btc))
+ abort_csplit("bad rule");
+
+ if (cntxt(line, toys.optargs[indx-1])) {
+ // Manipulate the rule then return to it later so we create a
+ // new file but are still on the same rule. This is the only
+ // reason why we differentiate between rule and file Index
+ if (btc != 1) {
+ toys.optargs[indx] = xmprintf("{%lu}",btc-1);
+ indx--;
+ }
+ return 1;
+ }
+ return 0;
+ break;
+
+ default:
+ offset = ((size_t)atoll(rule)) ? (atoll(rule)) : abort_csplit("bad rule");
+ return (lineno > offset) ? abort_csplit("bad rule order") :
+ (lineno == offset);
+ break;
+ }
+
+ // The code should never get to this point without returning something
+ perror_exit("Error");
+ return 1;
+}
+
+void csplit_main(void)
+{
+ FILE *fin = (*toys.optargs[0] != '-') ? xfopen(toys.optargs[0], "r") : stdin;
+
+ struct stat st;
+
+ // -f and -n formatting
+ filefmt = xmprintf("%%s%%0%dd", TT.n ? (int)TT.n : 2);
+ prefix = TT.f ? TT.f : "xx";
+
+ flname = xmprintf(filefmt, prefix, findx);
+ FILE *actvfile = xfopen(flname, "w+");
+ for (char *line; (line = xgetline(fin)); free(line)) {
+ lineno++;
+ if (cntxt(line, toys.optargs[indx])) {
+
+ fclose(actvfile);
+ if (!FLAG(s)) {
+ stat(flname, &st);
+ printf("%ld\n", st.st_size);
+ }
+
+ indx++;
+ findx++;
+ flname = xmprintf(filefmt, prefix, findx);
+ actvfile = xfopen(flname, "w+");
+
+ if (indx == toys.optc) eg = 1;
+ }
+ fprintf(actvfile, "%s\n", line);
+ }
+
+ fclose(actvfile);
+ if (!FLAG(s)) {
+ stat(flname, &st);
+ printf("%ld\n", st.st_size);
+ }
+
+ // Abort Case: Not All Rules Processed
+ if (indx < toys.optc-1) abort_csplit("Rules not processed");
+}
--
2.34.1
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