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freebsd/usr.bin/m4/eval.c
Pedro F. Giffuni 8a16b7a18f General further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
2017-11-20 19:49:47 +00:00

1017 lines
21 KiB
C

/* $OpenBSD: eval.c,v 1.74 2015/02/05 12:59:57 millert Exp $ */
/* $NetBSD: eval.c,v 1.7 1996/11/10 21:21:29 pk Exp $ */
/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Ozan Yigit at York University.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* eval.c
* Facility: m4 macro processor
* by: oz
*/
#include <sys/types.h>
#include <err.h>
#include <errno.h>
#include <limits.h>
#include <unistd.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <fcntl.h>
#include "mdef.h"
#include "stdd.h"
#include "extern.h"
#include "pathnames.h"
static void dodefn(const char *);
static void dopushdef(const char *, const char *);
static void dodump(const char *[], int);
static void dotrace(const char *[], int, int);
static void doifelse(const char *[], int);
static int doincl(const char *);
static int dopaste(const char *);
static void dochq(const char *[], int);
static void dochc(const char *[], int);
static void dom4wrap(const char *);
static void dodiv(int);
static void doundiv(const char *[], int);
static void dosub(const char *[], int);
static void map(char *, const char *, const char *, const char *);
static const char *handledash(char *, char *, const char *);
static void expand_builtin(const char *[], int, int);
static void expand_macro(const char *[], int);
static void dump_one_def(const char *, struct macro_definition *);
unsigned long expansion_id;
/*
* eval - eval all macros and builtins calls
* argc - number of elements in argv.
* argv - element vector :
* argv[0] = definition of a user
* macro or NULL if built-in.
* argv[1] = name of the macro or
* built-in.
* argv[2] = parameters to user-defined
* . macro or built-in.
* .
*
* A call in the form of macro-or-builtin() will result in:
* argv[0] = nullstr
* argv[1] = macro-or-builtin
* argv[2] = nullstr
*
* argc is 3 for macro-or-builtin() and 2 for macro-or-builtin
*/
void
eval(const char *argv[], int argc, int td, int is_traced)
{
size_t mark = SIZE_MAX;
expansion_id++;
if (td & RECDEF)
m4errx(1, "expanding recursive definition for %s.", argv[1]);
if (is_traced)
mark = trace(argv, argc, infile+ilevel);
if (td == MACRTYPE)
expand_macro(argv, argc);
else
expand_builtin(argv, argc, td);
if (mark != SIZE_MAX)
finish_trace(mark);
}
/*
* expand_builtin - evaluate built-in macros.
*/
void
expand_builtin(const char *argv[], int argc, int td)
{
int c, n;
int ac;
static int sysval = 0;
#ifdef DEBUG
printf("argc = %d\n", argc);
for (n = 0; n < argc; n++)
printf("argv[%d] = %s\n", n, argv[n]);
fflush(stdout);
#endif
/*
* if argc == 3 and argv[2] is null, then we
* have macro-or-builtin() type call. We adjust
* argc to avoid further checking..
*/
/* we keep the initial value for those built-ins that differentiate
* between builtin() and builtin.
*/
ac = argc;
if (argc == 3 && !*(argv[2]) && !mimic_gnu)
argc--;
switch (td & TYPEMASK) {
case DEFITYPE:
if (argc > 2)
dodefine(argv[2], (argc > 3) ? argv[3] : null);
break;
case PUSDTYPE:
if (argc > 2)
dopushdef(argv[2], (argc > 3) ? argv[3] : null);
break;
case DUMPTYPE:
dodump(argv, argc);
break;
case TRACEONTYPE:
dotrace(argv, argc, 1);
break;
case TRACEOFFTYPE:
dotrace(argv, argc, 0);
break;
case EXPRTYPE:
/*
* doexpr - evaluate arithmetic
* expression
*/
{
int base = 10;
int maxdigits = 0;
const char *errstr;
if (argc > 3) {
base = strtonum(argv[3], 2, 36, &errstr);
if (errstr) {
m4errx(1, "expr: base %s invalid.", argv[3]);
}
}
if (argc > 4) {
maxdigits = strtonum(argv[4], 0, INT_MAX, &errstr);
if (errstr) {
m4errx(1, "expr: maxdigits %s invalid.", argv[4]);
}
}
if (argc > 2)
pbnumbase(expr(argv[2]), base, maxdigits);
break;
}
case IFELTYPE:
if (argc > 4)
doifelse(argv, argc);
break;
case IFDFTYPE:
/*
* doifdef - select one of two
* alternatives based on the existence of
* another definition
*/
if (argc > 3) {
if (lookup_macro_definition(argv[2]) != NULL)
pbstr(argv[3]);
else if (argc > 4)
pbstr(argv[4]);
}
break;
case LENGTYPE:
/*
* dolen - find the length of the
* argument
*/
pbnum((argc > 2) ? strlen(argv[2]) : 0);
break;
case INCRTYPE:
/*
* doincr - increment the value of the
* argument
*/
if (argc > 2)
pbnum(atoi(argv[2]) + 1);
break;
case DECRTYPE:
/*
* dodecr - decrement the value of the
* argument
*/
if (argc > 2)
pbnum(atoi(argv[2]) - 1);
break;
case SYSCTYPE:
/*
* dosys - execute system command
*/
if (argc > 2) {
fflush(stdout);
sysval = system(argv[2]);
}
break;
case SYSVTYPE:
/*
* dosysval - return value of the last
* system call.
*
*/
pbnum(sysval);
break;
case ESYSCMDTYPE:
if (argc > 2)
doesyscmd(argv[2]);
break;
case INCLTYPE:
if (argc > 2) {
if (!doincl(argv[2])) {
if (mimic_gnu) {
warn("%s at line %lu: include(%s)",
CURRENT_NAME, CURRENT_LINE, argv[2]);
exit_code = 1;
} else
err(1, "%s at line %lu: include(%s)",
CURRENT_NAME, CURRENT_LINE, argv[2]);
}
}
break;
case SINCTYPE:
if (argc > 2)
(void) doincl(argv[2]);
break;
#ifdef EXTENDED
case PASTTYPE:
if (argc > 2)
if (!dopaste(argv[2]))
err(1, "%s at line %lu: paste(%s)",
CURRENT_NAME, CURRENT_LINE, argv[2]);
break;
case SPASTYPE:
if (argc > 2)
(void) dopaste(argv[2]);
break;
case FORMATTYPE:
doformat(argv, argc);
break;
#endif
case CHNQTYPE:
dochq(argv, ac);
break;
case CHNCTYPE:
dochc(argv, argc);
break;
case SUBSTYPE:
/*
* dosub - select substring
*
*/
if (argc > 3)
dosub(argv, argc);
break;
case SHIFTYPE:
/*
* doshift - push back all arguments
* except the first one (i.e. skip
* argv[2])
*/
if (argc > 3) {
for (n = argc - 1; n > 3; n--) {
pbstr(rquote);
pbstr(argv[n]);
pbstr(lquote);
pushback(COMMA);
}
pbstr(rquote);
pbstr(argv[3]);
pbstr(lquote);
}
break;
case DIVRTYPE:
if (argc > 2 && (n = atoi(argv[2])) != 0)
dodiv(n);
else {
active = stdout;
oindex = 0;
}
break;
case UNDVTYPE:
doundiv(argv, argc);
break;
case DIVNTYPE:
/*
* dodivnum - return the number of
* current output diversion
*/
pbnum(oindex);
break;
case UNDFTYPE:
/*
* doundefine - undefine a previously
* defined macro(s) or m4 keyword(s).
*/
if (argc > 2)
for (n = 2; n < argc; n++)
macro_undefine(argv[n]);
break;
case POPDTYPE:
/*
* dopopdef - remove the topmost
* definitions of macro(s) or m4
* keyword(s).
*/
if (argc > 2)
for (n = 2; n < argc; n++)
macro_popdef(argv[n]);
break;
case MKTMTYPE:
/*
* dotemp - create a temporary file
*/
if (argc > 2) {
int fd;
char *temp;
temp = xstrdup(argv[2]);
fd = mkstemp(temp);
if (fd == -1)
err(1,
"%s at line %lu: couldn't make temp file %s",
CURRENT_NAME, CURRENT_LINE, argv[2]);
close(fd);
pbstr(temp);
free(temp);
}
break;
case TRNLTYPE:
/*
* dotranslit - replace all characters in
* the source string that appears in the
* "from" string with the corresponding
* characters in the "to" string.
*/
if (argc > 3) {
char *temp;
temp = xalloc(strlen(argv[2])+1, NULL);
if (argc > 4)
map(temp, argv[2], argv[3], argv[4]);
else
map(temp, argv[2], argv[3], null);
pbstr(temp);
free(temp);
} else if (argc > 2)
pbstr(argv[2]);
break;
case INDXTYPE:
/*
* doindex - find the index of the second
* argument string in the first argument
* string. -1 if not present.
*/
pbnum((argc > 3) ? indx(argv[2], argv[3]) : -1);
break;
case ERRPTYPE:
/*
* doerrp - print the arguments to stderr
* file
*/
if (argc > 2) {
for (n = 2; n < argc; n++)
fprintf(stderr, "%s ", argv[n]);
fprintf(stderr, "\n");
}
break;
case DNLNTYPE:
/*
* dodnl - eat-up-to and including
* newline
*/
while ((c = gpbc()) != '\n' && c != EOF)
;
break;
case M4WRTYPE:
/*
* dom4wrap - set up for
* wrap-up/wind-down activity
*/
if (argc > 2)
dom4wrap(argv[2]);
break;
case EXITTYPE:
/*
* doexit - immediate exit from m4.
*/
killdiv();
exit((argc > 2) ? atoi(argv[2]) : 0);
break;
case DEFNTYPE:
if (argc > 2)
for (n = 2; n < argc; n++)
dodefn(argv[n]);
break;
case INDIRTYPE: /* Indirect call */
if (argc > 2)
doindir(argv, argc);
break;
case BUILTINTYPE: /* Builtins only */
if (argc > 2)
dobuiltin(argv, argc);
break;
case PATSTYPE:
if (argc > 2)
dopatsubst(argv, argc);
break;
case REGEXPTYPE:
if (argc > 2)
doregexp(argv, argc);
break;
case LINETYPE:
doprintlineno(infile+ilevel);
break;
case FILENAMETYPE:
doprintfilename(infile+ilevel);
break;
case SELFTYPE:
pbstr(rquote);
pbstr(argv[1]);
pbstr(lquote);
break;
default:
m4errx(1, "eval: major botch.");
break;
}
}
/*
* expand_macro - user-defined macro expansion
*/
void
expand_macro(const char *argv[], int argc)
{
const char *t;
const char *p;
int n;
int argno;
t = argv[0]; /* defn string as a whole */
p = t;
while (*p)
p++;
p--; /* last character of defn */
while (p > t) {
if (*(p - 1) != ARGFLAG)
PUSHBACK(*p);
else {
switch (*p) {
case '#':
pbnum(argc - 2);
break;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
if ((argno = *p - '0') < argc - 1)
pbstr(argv[argno + 1]);
break;
case '*':
if (argc > 2) {
for (n = argc - 1; n > 2; n--) {
pbstr(argv[n]);
pushback(COMMA);
}
pbstr(argv[2]);
}
break;
case '@':
if (argc > 2) {
for (n = argc - 1; n > 2; n--) {
pbstr(rquote);
pbstr(argv[n]);
pbstr(lquote);
pushback(COMMA);
}
pbstr(rquote);
pbstr(argv[2]);
pbstr(lquote);
}
break;
default:
PUSHBACK(*p);
PUSHBACK('$');
break;
}
p--;
}
p--;
}
if (p == t) /* do last character */
PUSHBACK(*p);
}
/*
* dodefine - install definition in the table
*/
void
dodefine(const char *name, const char *defn)
{
if (!*name && !mimic_gnu)
m4errx(1, "null definition.");
else
macro_define(name, defn);
}
/*
* dodefn - push back a quoted definition of
* the given name.
*/
static void
dodefn(const char *name)
{
struct macro_definition *p;
if ((p = lookup_macro_definition(name)) != NULL) {
if ((p->type & TYPEMASK) == MACRTYPE) {
pbstr(rquote);
pbstr(p->defn);
pbstr(lquote);
} else {
pbstr(p->defn);
pbstr(BUILTIN_MARKER);
}
}
}
/*
* dopushdef - install a definition in the hash table
* without removing a previous definition. Since
* each new entry is entered in *front* of the
* hash bucket, it hides a previous definition from
* lookup.
*/
static void
dopushdef(const char *name, const char *defn)
{
if (!*name && !mimic_gnu)
m4errx(1, "null definition.");
else
macro_pushdef(name, defn);
}
/*
* dump_one_def - dump the specified definition.
*/
static void
dump_one_def(const char *name, struct macro_definition *p)
{
if (!traceout)
traceout = stderr;
if (mimic_gnu) {
if ((p->type & TYPEMASK) == MACRTYPE)
fprintf(traceout, "%s:\t%s\n", name, p->defn);
else {
fprintf(traceout, "%s:\t<%s>\n", name, p->defn);
}
} else
fprintf(traceout, "`%s'\t`%s'\n", name, p->defn);
}
/*
* dodumpdef - dump the specified definitions in the hash
* table to stderr. If nothing is specified, the entire
* hash table is dumped.
*/
static void
dodump(const char *argv[], int argc)
{
int n;
struct macro_definition *p;
if (argc > 2) {
for (n = 2; n < argc; n++)
if ((p = lookup_macro_definition(argv[n])) != NULL)
dump_one_def(argv[n], p);
} else
macro_for_all(dump_one_def);
}
/*
* dotrace - mark some macros as traced/untraced depending upon on.
*/
static void
dotrace(const char *argv[], int argc, int on)
{
int n;
if (argc > 2) {
for (n = 2; n < argc; n++)
mark_traced(argv[n], on);
} else
mark_traced(NULL, on);
}
/*
* doifelse - select one of two alternatives - loop.
*/
static void
doifelse(const char *argv[], int argc)
{
cycle {
if (STREQ(argv[2], argv[3]))
pbstr(argv[4]);
else if (argc == 6)
pbstr(argv[5]);
else if (argc > 6) {
argv += 3;
argc -= 3;
continue;
}
break;
}
}
/*
* doinclude - include a given file.
*/
static int
doincl(const char *ifile)
{
if (ilevel + 1 == MAXINP)
m4errx(1, "too many include files.");
if (fopen_trypath(infile+ilevel+1, ifile) != NULL) {
ilevel++;
bbase[ilevel] = bufbase = bp;
return (1);
} else
return (0);
}
#ifdef EXTENDED
/*
* dopaste - include a given file without any
* macro processing.
*/
static int
dopaste(const char *pfile)
{
FILE *pf;
int c;
if ((pf = fopen(pfile, "r")) != NULL) {
if (synch_lines)
fprintf(active, "#line 1 \"%s\"\n", pfile);
while ((c = getc(pf)) != EOF)
putc(c, active);
(void) fclose(pf);
emit_synchline();
return (1);
} else
return (0);
}
#endif
/*
* dochq - change quote characters
*/
static void
dochq(const char *argv[], int ac)
{
if (ac == 2) {
lquote[0] = LQUOTE; lquote[1] = EOS;
rquote[0] = RQUOTE; rquote[1] = EOS;
} else {
strlcpy(lquote, argv[2], sizeof(lquote));
if (ac > 3) {
strlcpy(rquote, argv[3], sizeof(rquote));
} else {
rquote[0] = ECOMMT; rquote[1] = EOS;
}
}
}
/*
* dochc - change comment characters
*/
static void
dochc(const char *argv[], int argc)
{
/* XXX Note that there is no difference between no argument and a single
* empty argument.
*/
if (argc == 2) {
scommt[0] = EOS;
ecommt[0] = EOS;
} else {
strlcpy(scommt, argv[2], sizeof(scommt));
if (argc == 3) {
ecommt[0] = ECOMMT; ecommt[1] = EOS;
} else {
strlcpy(ecommt, argv[3], sizeof(ecommt));
}
}
}
/*
* dom4wrap - expand text at EOF
*/
static void
dom4wrap(const char *text)
{
if (wrapindex >= maxwraps) {
if (maxwraps == 0)
maxwraps = 16;
else
maxwraps *= 2;
m4wraps = xreallocarray(m4wraps, maxwraps, sizeof(*m4wraps),
"too many m4wraps");
}
m4wraps[wrapindex++] = xstrdup(text);
}
/*
* dodivert - divert the output to a temporary file
*/
static void
dodiv(int n)
{
int fd;
oindex = n;
if (n >= maxout) {
if (mimic_gnu)
resizedivs(n + 10);
else
n = 0; /* bitbucket */
}
if (n < 0)
n = 0; /* bitbucket */
if (outfile[n] == NULL) {
char fname[] = _PATH_DIVNAME;
if ((fd = mkstemp(fname)) < 0 ||
unlink(fname) == -1 ||
(outfile[n] = fdopen(fd, "w+")) == NULL)
err(1, "%s: cannot divert", fname);
}
active = outfile[n];
}
/*
* doundivert - undivert a specified output, or all
* other outputs, in numerical order.
*/
static void
doundiv(const char *argv[], int argc)
{
int ind;
int n;
if (argc > 2) {
for (ind = 2; ind < argc; ind++) {
const char *errstr;
n = strtonum(argv[ind], 1, INT_MAX, &errstr);
if (errstr) {
if (errno == EINVAL && mimic_gnu)
getdivfile(argv[ind]);
} else {
if (n < maxout && outfile[n] != NULL)
getdiv(n);
}
}
}
else
for (n = 1; n < maxout; n++)
if (outfile[n] != NULL)
getdiv(n);
}
/*
* dosub - select substring
*/
static void
dosub(const char *argv[], int argc)
{
const char *ap, *fc, *k;
int nc;
ap = argv[2]; /* target string */
#ifdef EXPR
fc = ap + expr(argv[3]); /* first char */
#else
fc = ap + atoi(argv[3]); /* first char */
#endif
nc = strlen(fc);
if (argc >= 5)
#ifdef EXPR
nc = min(nc, expr(argv[4]));
#else
nc = min(nc, atoi(argv[4]));
#endif
if (fc >= ap && fc < ap + strlen(ap))
for (k = fc + nc - 1; k >= fc; k--)
pushback(*k);
}
/*
* map:
* map every character of s1 that is specified in from
* into s3 and replace in s. (source s1 remains untouched)
*
* This is derived from the a standard implementation of map(s,from,to)
* function of ICON language. Within mapvec, we replace every character
* of "from" with the corresponding character in "to".
* If "to" is shorter than "from", than the corresponding entries are null,
* which means that those characters disappear altogether.
*/
static void
map(char *dest, const char *src, const char *from, const char *to)
{
const char *tmp;
unsigned char sch, dch;
static char frombis[257];
static char tobis[257];
int i;
char seen[256];
static unsigned char mapvec[256] = {
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,
36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52,
53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69,
70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86,
87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102,
103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115,
116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128,
129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141,
142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154,
155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167,
168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180,
181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193,
194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206,
207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219,
220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232,
233, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245,
246, 247, 248, 249, 250, 251, 252, 253, 254, 255
};
if (*src) {
if (mimic_gnu) {
/*
* expand character ranges on the fly
*/
from = handledash(frombis, frombis + 256, from);
to = handledash(tobis, tobis + 256, to);
}
tmp = from;
/*
* create a mapping between "from" and
* "to"
*/
for (i = 0; i < 256; i++)
seen[i] = 0;
while (*from) {
if (!seen[(unsigned char)(*from)]) {
mapvec[(unsigned char)(*from)] = (unsigned char)(*to);
seen[(unsigned char)(*from)] = 1;
}
from++;
if (*to)
to++;
}
while (*src) {
sch = (unsigned char)(*src++);
dch = mapvec[sch];
if ((*dest = (char)dch))
dest++;
}
/*
* restore all the changed characters
*/
while (*tmp) {
mapvec[(unsigned char)(*tmp)] = (unsigned char)(*tmp);
tmp++;
}
}
*dest = '\0';
}
/*
* handledash:
* use buffer to copy the src string, expanding character ranges
* on the way.
*/
static const char *
handledash(char *buffer, char *end, const char *src)
{
char *p;
p = buffer;
while(*src) {
if (src[1] == '-' && src[2]) {
unsigned char i;
if ((unsigned char)src[0] <= (unsigned char)src[2]) {
for (i = (unsigned char)src[0];
i <= (unsigned char)src[2]; i++) {
*p++ = i;
if (p == end) {
*p = '\0';
return buffer;
}
}
} else {
for (i = (unsigned char)src[0];
i >= (unsigned char)src[2]; i--) {
*p++ = i;
if (p == end) {
*p = '\0';
return buffer;
}
}
}
src += 3;
} else
*p++ = *src++;
if (p == end)
break;
}
*p = '\0';
return buffer;
}