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minix/commands/sed/sedexec.c
Ben Gras aa8206941c New sed
2006-11-02 16:48:15 +00:00

819 lines
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/* sedexec.c -- axecute compiled form of stream editor commands
Copyright (C) 1995-2003 Eric S. Raymond
Copyright (C) 2004-2006 Rene Rebe
The single entry point of this module is the function execute(). It
may take a string argument (the name of a file to be used as text) or
the argument NULL which tells it to filter standard input. It executes
the compiled commands in cmds[] on each line in turn.
The function command() does most of the work. match() and advance()
are used for matching text against precompiled regular expressions and
dosub() does right-hand-side substitution. Getline() does text input;
readout() and memcmp() are output and string-comparison utilities.
*/
#include <stdlib.h> /* exit */
#include <stdio.h> /* {f}puts, {f}printf, getc/putc, f{re}open, fclose */
#include <ctype.h> /* for isprint(), isdigit(), toascii() macros */
#include <string.h> /* for memcmp(3) */
#include "sed.h" /* command type structures & miscellaneous constants */
/***** shared variables imported from the main ******/
/* main data areas */
extern char linebuf[]; /* current-line buffer */
extern sedcmd cmds[]; /* hold compiled commands */
extern long linenum[]; /* numeric-addresses table */
/* miscellaneous shared variables */
extern int nflag; /* -n option flag */
extern int eargc; /* scratch copy of argument count */
extern sedcmd *pending; /* ptr to command waiting to be executed */
extern int last_line_used; /* last line address ($) used */
/***** end of imported stuff *****/
#define MAXHOLD MAXBUF /* size of the hold space */
#define GENSIZ MAXBUF /* maximum genbuf size */
static char LTLMSG[] = "sed: line too long\n";
static char *spend; /* current end-of-line-buffer pointer */
static long lnum = 0L; /* current source line number */
/* append buffer maintenance */
static sedcmd *appends[MAXAPPENDS]; /* array of ptrs to a,i,c commands */
static sedcmd **aptr = appends; /* ptr to current append */
/* genbuf and its pointers */
static char genbuf[GENSIZ];
static char *loc1;
static char *loc2;
static char *locs;
/* command-logic flags */
static int lastline; /* do-line flag */
static int line_with_newline; /* line had newline */
static int jump; /* jump to cmd's link address if set */
static int delete; /* delete command flag */
static int needs_advance; /* needs inc after substitution */
/* ugly HACK - neds REWORK */
/* tagged-pattern tracking */
static char *bracend[MAXTAGS]; /* tagged pattern start pointers */
static char *brastart[MAXTAGS]; /* tagged pattern end pointers */
/* prototypes */
static char *getline(char *buf, int max);
static char *place(char* asp, char* al1, char* al2);
static int advance(char* lp, char* ep, char** eob);
static int match(char *expbuf, int gf);
static int selected(sedcmd *ipc);
static int substitute(sedcmd *ipc);
static void command(sedcmd *ipc);
static void dosub(char *rhsbuf);
static void dumpto(char *p1, FILE *fp);
static void listto(char *p1, FILE *fp);
static void readout(void);
static void truncated(int h);
/* execute the compiled commands in cmds[] on a file
file: name of text source file to be filtered */
void execute(char* file)
{
register sedcmd *ipc; /* ptr to current command */
char *execp; /* ptr to source */
if (file != NULL) /* filter text from a named file */
if (freopen(file, "r", stdin) == NULL)
fprintf(stderr, "sed: can't open %s\n", file);
if (pending) /* there's a command waiting */
{
ipc = pending; /* it will be first executed */
pending = FALSE; /* turn off the waiting flag */
goto doit; /* go to execute it immediately */
}
/* here's the main command-execution loop */
for(;;)
{
/* get next line to filter */
if ((execp = getline(linebuf, MAXBUF+1)) == BAD)
return;
spend = execp;
/* loop through compiled commands, executing them */
for(ipc = cmds; ipc->command; )
{
/* address command to select? - If not address
but allbut then invert, that is skip, the commmand */
if (ipc->addr1 || ipc->flags.allbut) {
if (!ipc->addr1 || !selected(ipc)) {
ipc++; /* not selected, next cmd */
continue;
}
}
doit:
command(ipc); /* execute the command pointed at */
if (delete) /* if delete flag is set */
break; /* don't exec rest of compiled cmds */
if (jump) /* if jump set, follow cmd's link */
{
jump = FALSE;
if ((ipc = ipc->u.link) == 0)
{
ipc = cmds;
break;
}
}
else /* normal goto next command */
ipc++;
}
/* we've now done all modification commands on the line */
/* here's where the transformed line is output */
if (!nflag && !delete)
{
fwrite(linebuf, spend - linebuf, 1, stdout);
if (line_with_newline)
putc('\n', stdout);
}
/* if we've been set up for append, emit the text from it */
if (aptr > appends)
readout();
delete = FALSE; /* clear delete flag; about to get next cmd */
}
}
/* is current command selected */
static int selected(sedcmd *ipc)
{
register char *p1 = ipc->addr1; /* point p1 at first address */
register char *p2 = ipc->addr2; /* and p2 at second */
unsigned char c;
int selected = FALSE;
if (ipc->flags.inrange)
{
selected = TRUE;
if (*p2 == CEND)
;
else if (*p2 == CLNUM)
{
c = p2[1];
if (lnum >= linenum[c])
ipc->flags.inrange = FALSE;
}
else if (match(p2, 0))
ipc->flags.inrange = FALSE;
}
else if (*p1 == CEND)
{
if (lastline)
selected = TRUE;
}
else if (*p1 == CLNUM)
{
c = p1[1];
if (lnum == linenum[c]) {
selected = TRUE;
if (p2)
ipc->flags.inrange = TRUE;
}
}
else if (match(p1, 0))
{
selected = TRUE;
if (p2)
ipc->flags.inrange = TRUE;
}
return ipc->flags.allbut ? !selected : selected;
}
/* match RE at expbuf against linebuf; if gf set, copy linebuf from genbuf */
static int match(char *expbuf, int gf) /* uses genbuf */
{
char *p1, *p2, c;
if (gf)
{
if (*expbuf)
return(FALSE);
p1 = linebuf; p2 = genbuf;
while ((*p1++ = *p2++));
if (needs_advance) {
loc2++;
}
locs = p1 = loc2;
}
else
{
p1 = linebuf + needs_advance;
locs = FALSE;
}
needs_advance = 0;
p2 = expbuf;
if (*p2++)
{
loc1 = p1;
if(*p2 == CCHR && p2[1] != *p1) /* 1st char is wrong */
return(FALSE); /* so fail */
return(advance(p1, p2, NULL)); /* else try to match rest */
}
/* quick check for 1st character if it's literal */
if (*p2 == CCHR)
{
c = p2[1]; /* pull out character to search for */
do {
if (*p1 != c)
continue; /* scan the source string */
if (advance(p1, p2,NULL)) /* found it, match the rest */
return(loc1 = p1, 1);
} while
(*p1++);
return(FALSE); /* didn't find that first char */
}
/* else try for unanchored match of the pattern */
do {
if (advance(p1, p2, NULL))
return(loc1 = p1, 1);
} while
(*p1++);
/* if got here, didn't match either way */
return(FALSE);
}
/* attempt to advance match pointer by one pattern element
lp: source (linebuf) ptr
ep: regular expression element ptr */
static int advance(char* lp, char* ep, char** eob)
{
char *curlp; /* save ptr for closures */
char c; /* scratch character holder */
char *bbeg;
int ct;
signed int bcount = -1;
for (;;)
switch (*ep++)
{
case CCHR: /* literal character */
if (*ep++ == *lp++) /* if chars are equal */
continue; /* matched */
return(FALSE); /* else return false */
case CDOT: /* anything but newline */
if (*lp++) /* first NUL is at EOL */
continue; /* keep going if didn't find */
return(FALSE); /* else return false */
case CNL: /* start-of-line */
case CDOL: /* end-of-line */
if (*lp == 0) /* found that first NUL? */
continue; /* yes, keep going */
return(FALSE); /* else return false */
case CEOF: /* end-of-address mark */
loc2 = lp; /* set second loc */
return(TRUE); /* return true */
case CCL: /* a closure */
c = *lp++ & 0177;
if (ep[c>>3] & bits(c & 07)) /* is char in set? */
{
ep += 16; /* then skip rest of bitmask */
continue; /* and keep going */
}
return(FALSE); /* else return false */
case CBRA: /* start of tagged pattern */
brastart[(unsigned char)*ep++] = lp; /* mark it */
continue; /* and go */
case CKET: /* end of tagged pattern */
bcount = *ep;
if (eob) {
*eob = lp;
return (TRUE);
}
else
bracend[(unsigned char)*ep++] = lp; /* mark it */
continue; /* and go */
case CBACK: /* match back reference */
bbeg = brastart[(unsigned char)*ep];
ct = bracend[(unsigned char)*ep++] - bbeg;
if (memcmp(bbeg, lp, ct) == 0)
{
lp += ct;
continue;
}
return(FALSE);
case CBRA|STAR: /* \(...\)* */
{
char *lastlp;
curlp = lp;
if (*ep > bcount)
brastart[(unsigned char)*ep] = bracend[(unsigned char)*ep] = lp;
while (advance(lastlp=lp, ep+1, &lp)) {
if (*ep > bcount && lp != lastlp) {
bracend[(unsigned char)*ep] = lp; /* mark it */
brastart[(unsigned char)*ep] = lastlp;
}
if (lp == lastlp) break;
}
ep++;
/* FIXME: scan for the brace end */
while (*ep != CKET)
ep++;
ep+=2;
needs_advance = 1;
if (lp == curlp) /* 0 matches */
continue;
lp++;
goto star;
}
case CBACK|STAR: /* \n* */
bbeg = brastart[(unsigned char)*ep];
ct = bracend[(unsigned char)*ep++] - bbeg;
curlp = lp;
while(memcmp(bbeg, lp, ct) == 0)
lp += ct;
while(lp >= curlp)
{
if (advance(lp, ep, eob))
return(TRUE);
lp -= ct;
}
return(FALSE);
case CDOT|STAR: /* match .* */
curlp = lp; /* save closure start loc */
while (*lp++); /* match anything */
goto star; /* now look for followers */
case CCHR|STAR: /* match <literal char>* */
curlp = lp; /* save closure start loc */
while (*lp++ == *ep); /* match many of that char */
ep++; /* to start of next element */
goto star; /* match it and followers */
case CCL|STAR: /* match [...]* */
curlp = lp; /* save closure start loc */
do {
c = *lp++ & 0x7F; /* match any in set */
} while
(ep[c>>3] & bits(c & 07));
ep += 16; /* skip past the set */
goto star; /* match followers */
star: /* the recursion part of a * or + match */
needs_advance = 1;
if (--lp == curlp) { /* 0 matches */
continue;
}
#if 0
if (*ep == CCHR)
{
c = ep[1];
do {
if (*lp != c)
continue;
if (advance(lp, ep, eob))
return(TRUE);
} while
(lp-- > curlp);
return(FALSE);
}
if (*ep == CBACK)
{
c = *(brastart[ep[1]]);
do {
if (*lp != c)
continue;
if (advance(lp, ep, eob))
return(TRUE);
} while
(lp-- > curlp);
return(FALSE);
}
#endif
/* match followers, try shorter match, if needed */
do {
if (lp == locs)
break;
if (advance(lp, ep, eob))
return(TRUE);
} while
(lp-- > curlp);
return(FALSE);
default:
fprintf(stderr, "sed: internal RE error, %o\n", *--ep);
exit (2);
}
}
/* perform s command
ipc: ptr to s command struct */
static int substitute(sedcmd *ipc)
{
unsigned int n = 1;
/* find a match */
/* the needs_advance code got a bit tricky - might needs a clean
refactoring */
while (match(ipc->u.lhs, 0)) {
/* nth 0 is implied 1 */
if (!ipc->nth || n == ipc->nth) {
dosub(ipc->rhs); /* perform it once */
n++; /* mark for return */
break;
}
needs_advance = n++;
}
if (n == 1)
return(FALSE); /* command fails */
if (ipc->flags.global) /* if global flag enabled */
do { /* cycle through possibles */
if (match(ipc->u.lhs, 1)) { /* found another */
dosub(ipc->rhs); /* so substitute */
}
else /* otherwise, */
break; /* we're done */
} while (*loc2);
return(TRUE); /* we succeeded */
}
/* generate substituted right-hand side (of s command)
rhsbuf: where to put the result */
static void dosub(char *rhsbuf) /* uses linebuf, genbuf, spend */
{
char *lp, *sp, *rp;
int c;
/* copy linebuf to genbuf up to location 1 */
lp = linebuf; sp = genbuf;
while (lp < loc1) *sp++ = *lp++;
for (rp = rhsbuf; (c = *rp++); )
{
if (c & 0200 && (c & 0177) == '0')
{
sp = place(sp, loc1, loc2);
continue;
}
else if (c & 0200 && (c &= 0177) >= '1' && c < MAXTAGS+'1')
{
sp = place(sp, brastart[c-'1'], bracend[c-'1']);
continue;
}
*sp++ = c & 0177;
if (sp >= genbuf + MAXBUF)
fprintf(stderr, LTLMSG);
}
lp = loc2;
loc2 = sp - genbuf + linebuf;
while ((*sp++ = *lp++))
if (sp >= genbuf + MAXBUF)
fprintf(stderr, LTLMSG);
lp = linebuf; sp = genbuf;
while ((*lp++ = *sp++));
spend = lp-1;
}
/* place chars at *al1...*(al1 - 1) at asp... in genbuf[] */
static char *place(char* asp, char* al1, char* al2) /* uses genbuf */
{
while (al1 < al2)
{
*asp++ = *al1++;
if (asp >= genbuf + MAXBUF)
fprintf(stderr, LTLMSG);
}
return(asp);
}
/* list the pattern space in visually unambiguous form *p1... to fp
p1: the source
fp: output stream to write to */
static void listto(char *p1, FILE *fp)
{
for (; p1<spend; p1++)
if (isprint(*p1))
putc(*p1, fp); /* pass it through */
else
{
putc('\\', fp); /* emit a backslash */
switch(*p1)
{
case '\b': putc('b', fp); break; /* BS */
case '\t': putc('t', fp); break; /* TAB */
case '\n': putc('n', fp); break; /* NL */
case '\r': putc('r', fp); break; /* CR */
case '\033': putc('e', fp); break; /* ESC */
default: fprintf(fp, "%02x", *p1);
}
}
putc('\n', fp);
}
/* write a hex dump expansion of *p1... to fp
p1: source
fp: output */
static void dumpto(char *p1, FILE *fp)
{
for (; p1<spend; p1++)
fprintf(fp, "%02x", *p1);
fprintf(fp, "%02x", '\n');
putc('\n', fp);
}
static void truncated(int h)
{
static long last = 0L;
if (lnum == last) return;
last = lnum;
fprintf(stderr, "sed: ");
fprintf(stderr, h ? "hold space" : "line %ld", lnum);
fprintf(stderr, " truncated to %d characters\n", MAXBUF);
}
/* execute compiled command pointed at by ipc */
static void command(sedcmd *ipc)
{
static int didsub; /* true if last s succeeded */
static char holdsp[MAXHOLD]; /* the hold space */
static char *hspend = holdsp; /* hold space end pointer */
register char *p1, *p2;
char *execp;
needs_advance = 0;
switch(ipc->command)
{
case ACMD: /* append */
*aptr++ = ipc;
if (aptr >= appends + MAXAPPENDS)
fprintf(stderr,
"sed: too many appends after line %ld\n",
lnum);
*aptr = 0;
break;
case CCMD: /* change pattern space */
delete = TRUE;
if (!ipc->flags.inrange || lastline)
printf("%s\n", ipc->u.lhs);
break;
case DCMD: /* delete pattern space */
delete++;
break;
case CDCMD: /* delete a line in hold space */
p1 = p2 = linebuf;
while(*p1 != '\n')
if ((delete = (*p1++ == 0)))
return;
p1++;
while((*p2++ = *p1++)) continue;
spend = p2-1;
jump++;
break;
case EQCMD: /* show current line number */
fprintf(stdout, "%ld\n", lnum);
break;
case GCMD: /* copy hold space to pattern space */
p1 = linebuf; p2 = holdsp; while((*p1++ = *p2++));
spend = p1-1;
break;
case CGCMD: /* append hold space to pattern space */
*spend++ = '\n';
p1 = spend; p2 = holdsp;
do {
if (p1 > linebuf + MAXBUF) {
truncated(FALSE);
p1[-1] = 0;
break;
}
} while((*p1++ = *p2++));
spend = p1-1;
break;
case HCMD: /* copy pattern space to hold space */
p1 = holdsp; p2 = linebuf; while((*p1++ = *p2++));
hspend = p1-1;
break;
case CHCMD: /* append pattern space to hold space */
*hspend++ = '\n';
p1 = hspend; p2 = linebuf;
do {
if (p1 > holdsp + MAXBUF) {
truncated(TRUE);
p1[-1] = 0;
break;
}
} while((*p1++ = *p2++));
hspend = p1-1;
break;
case ICMD: /* insert text */
printf("%s\n", ipc->u.lhs);
break;
case BCMD: /* branch to label */
jump = TRUE;
break;
case LCMD: /* list text */
listto(linebuf, (ipc->fout != NULL)?ipc->fout:stdout); break;
case CLCMD: /* dump text */
dumpto(linebuf, (ipc->fout != NULL)?ipc->fout:stdout); break;
case NCMD: /* read next line into pattern space */
if (!nflag)
puts(linebuf); /* flush out the current line */
if (aptr > appends)
readout(); /* do pending a, r commands */
if ((execp = getline(linebuf, MAXBUF+1)) == BAD)
{
pending = ipc;
delete = TRUE;
break;
}
spend = execp;
break;
case CNCMD: /* append next line to pattern space */
if (aptr > appends)
readout();
*spend++ = '\n';
if ((execp = getline(spend,
linebuf + MAXBUF+1 - spend)) == BAD)
{
pending = ipc;
delete = TRUE;
break;
}
spend = execp;
break;
case PCMD: /* print pattern space */
puts(linebuf);
break;
case CPCMD: /* print one line from pattern space */
cpcom: /* so s command can jump here */
for(p1 = linebuf; *p1 != '\n' && *p1 != '\0'; )
putc(*p1++, stdout);
putc('\n', stdout);
break;
case QCMD: /* quit the stream editor */
if (!nflag)
puts(linebuf); /* flush out the current line */
if (aptr > appends)
readout(); /* do any pending a and r commands */
exit(0);
case RCMD: /* read a file into the stream */
*aptr++ = ipc;
if (aptr >= appends + MAXAPPENDS)
fprintf(stderr,
"sed: too many reads after line %ld\n",
lnum);
*aptr = 0;
break;
case SCMD: /* substitute RE */
didsub = substitute(ipc);
if (ipc->flags.print && didsub)
{
if (ipc->flags.print == TRUE)
puts(linebuf);
else
goto cpcom;
}
if (didsub && ipc->fout)
fprintf(ipc->fout, "%s\n", linebuf);
break;
case TCMD: /* branch on last s successful */
case CTCMD: /* branch on last s failed */
if (didsub == (ipc->command == CTCMD))
break; /* no branch if last s failed, else */
didsub = FALSE;
jump = TRUE; /* set up to jump to assoc'd label */
break;
case CWCMD: /* write one line from pattern space */
for(p1 = linebuf; *p1 != '\n' && *p1 != '\0'; )
putc(*p1++, ipc->fout);
putc('\n', ipc->fout);
break;
case WCMD: /* write pattern space to file */
fprintf(ipc->fout, "%s\n", linebuf);
break;
case XCMD: /* exchange pattern and hold spaces */
p1 = linebuf; p2 = genbuf; while((*p2++ = *p1++)) continue;
p1 = holdsp; p2 = linebuf; while((*p2++ = *p1++)) continue;
spend = p2 - 1;
p1 = genbuf; p2 = holdsp; while((*p2++ = *p1++)) continue;
hspend = p2 - 1;
break;
case YCMD:
p1 = linebuf; p2 = ipc->u.lhs;
while((*p1 = p2[(unsigned char)*p1]))
p1++;
break;
}
}
/* get next line of text to be filtered
buf: where to send the input
max: max chars to read */
static char *getline(char *buf, int max)
{
if (fgets(buf, max, stdin) != NULL)
{
int c;
lnum++; /* note that we got another line */
/* find the end of the input and overwrite a possible '\n' */
while (*buf != '\n' && *buf != 0)
buf++;
line_with_newline = *buf == '\n';
*buf=0;
/* detect last line - but only if the address was used in a command */
if (last_line_used) {
if ((c = fgetc(stdin)) != EOF)
ungetc (c, stdin);
else {
if (eargc == 0) /* if no more args */
lastline = TRUE; /* set a flag */
}
}
return(buf); /* return ptr to terminating null */
}
else
{
return(BAD);
}
}
/* write file indicated by r command to output */
static void readout(void)
{
register int t; /* hold input char or EOF */
FILE *fi; /* ptr to file to be read */
aptr = appends - 1; /* arrange for pre-increment to work right */
while(*++aptr)
if ((*aptr)->command == ACMD) /* process "a" cmd */
printf("%s\n", (*aptr)->u.lhs);
else /* process "r" cmd */
{
if ((fi = fopen((*aptr)->u.lhs, "r")) == NULL)
continue;
while((t = getc(fi)) != EOF)
putc((char) t, stdout);
fclose(fi);
}
aptr = appends; /* reset the append ptr */
*aptr = 0;
}
/* sedexec.c ends here */
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