Rewrite scan procedure with a FSM. This improves code readability by
making clear transits between different states, and avoids bug with handling repeated $'s. Reviewed by: bapt Differential Revision: https://reviews.freebsd.org/D3221
This commit is contained in:
Xin LI
parent
43bc87c459
commit
7d477dc35a
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=285923
@ -1,5 +1,6 @@
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/*-
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* Copyright (c) 2015 Baptiste Daroussin <bapt@FreeBSD.org>
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* Copyright (c) 2015 Xin LI <delphij@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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@ -38,68 +39,23 @@ __FBSDID("$FreeBSD$");
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#include <unistd.h>
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#include <xlocale.h>
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static bool
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parse_id(FILE *fp, struct sbuf *buf, locale_t l)
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{
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int c;
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bool isid = false;
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bool subversion = false;
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sbuf_putc(buf, '$');
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while ((c = fgetc(fp)) != EOF) {
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sbuf_putc(buf, c);
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if (!isid) {
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if (c == '$') {
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sbuf_clear(buf);
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sbuf_putc(buf, '$');
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continue;
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}
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if (c == ':') {
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c = fgetc(fp);
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/* accept :: for subversion compatibility */
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if (c == ':') {
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subversion = true;
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sbuf_putc(buf, c);
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c = fgetc(fp);
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}
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if (c == ' ') {
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sbuf_putc(buf, c);
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isid = true;
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continue;
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}
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return (false);
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}
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if (!isalpha_l(c, l))
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return (false);
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} else {
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if (c == '\n')
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return (false);
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if (c == '$') {
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sbuf_finish(buf);
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/* should end with a space */
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c = sbuf_data(buf)[sbuf_len(buf) - 2];
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if (!subversion) {
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if (c != ' ')
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return (0);
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} else if (subversion) {
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if (c != ' ' && c != '#')
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return (0);
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}
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printf(" %s\n", sbuf_data(buf));
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return (true);
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}
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}
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}
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return (false);
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}
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typedef enum {
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/* state condition to transit to next state */
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INIT, /* '$' */
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DELIM_SEEN, /* letter */
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KEYWORD, /* punctuation mark */
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PUNC_SEEN, /* ':' -> _SVN; space -> TEXT */
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PUNC_SEEN_SVN, /* space */
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TEXT
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} analyzer_states;
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static int
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scan(FILE *fp, const char *name, bool quiet)
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{
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int c;
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bool hasid = false;
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bool subversion = false;
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analyzer_states state = INIT;
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struct sbuf *id = sbuf_new_auto();
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locale_t l;
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@ -109,10 +65,123 @@ scan(FILE *fp, const char *name, bool quiet)
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printf("%s:\n", name);
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while ((c = fgetc(fp)) != EOF) {
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if (c == '$') {
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sbuf_clear(id);
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if (parse_id(fp, id, l))
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hasid = true;
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switch (state) {
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case INIT:
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if (c == '$') {
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/* Transit to DELIM_SEEN if we see $ */
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state = DELIM_SEEN;
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} else {
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/* Otherwise, stay in INIT state */
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continue;
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}
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break;
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case DELIM_SEEN:
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if (isalpha_l(c, l)) {
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/* Transit to KEYWORD if we see letter */
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sbuf_clear(id);
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sbuf_putc(id, '$');
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sbuf_putc(id, c);
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state = KEYWORD;
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continue;
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} else if (c == '$') {
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/* Or, stay in DELIM_SEEN if more $ */
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continue;
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} else {
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/* Otherwise, transit back to INIT */
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state = INIT;
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}
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break;
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case KEYWORD:
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sbuf_putc(id, c);
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if (isalpha_l(c, l)) {
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/*
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* Stay in KEYWORD if additional letter is seen
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*/
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continue;
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} else if (c == ':') {
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/*
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* See ':' for the first time, transit to
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* PUNC_SEEN.
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*/
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state = PUNC_SEEN;
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subversion = false;
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} else if (c == '$') {
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/*
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* Incomplete ident. Go back to DELIM_SEEN
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* state because we see a '$' which could be
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* the beginning of a keyword.
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*/
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state = DELIM_SEEN;
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} else {
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/*
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* Go back to INIT state otherwise.
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*/
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state = INIT;
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}
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break;
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case PUNC_SEEN:
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case PUNC_SEEN_SVN:
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sbuf_putc(id, c);
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switch (c) {
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case ':':
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/*
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* If we see '::' (seen : in PUNC_SEEN),
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* activate subversion treatment and transit
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* to PUNC_SEEN_SVN state.
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*
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* If more than two :'s were seen, the ident
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* is invalid and we would therefore go back
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* to INIT state.
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*/
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if (state == PUNC_SEEN) {
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state = PUNC_SEEN_SVN;
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subversion = true;
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} else {
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state = INIT;
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}
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break;
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case ' ':
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/*
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* A space after ':' or '::' indicates we are at the
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* last component of potential ident.
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*/
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state = TEXT;
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break;
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default:
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/* All other characters are invalid */
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state = INIT;
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break;
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}
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break;
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case TEXT:
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sbuf_putc(id, c);
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if (iscntrl_l(c, l)) {
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/* Control characters are not allowed in this state */
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state = INIT;
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} else if (c == '$') {
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sbuf_finish(id);
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/*
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* valid ident should end with a space.
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*
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* subversion extension uses '#' to indicate that
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* the keyword expansion have exceeded the fixed
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* width, so it is also permitted if we are in
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* subversion mode. No length check is enforced
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* because GNU RCS ident(1) does not do it either.
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*/
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c = sbuf_data(id)[sbuf_len(id) - 2];
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if (c == ' ' || (subversion && c == '#')) {
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printf(" %s\n", sbuf_data(id));
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hasid = true;
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}
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state = INIT;
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}
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/* Other characters: stay in the state */
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break;
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}
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}
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sbuf_delete(id);
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