blarson%skat.usc.edu@oberon.usc.edu (Bob Larson) (01/07/88)
Comp.sources.misc: Volume 2, Issue 1
Archive-Name: pd-diff
Submitted-By: blarson@skat.usc.edu (Bob Larson)
Comp.sources.misc: Volume 2, Issue 1
Archive-Name: pd-diff
Submitted-By: blarson@skat.usc.edu (Bob Larson)
#!/bin/sh
# manually generated shar
cat <<SHAR_EOF >README
Here's a public domain diff with the -b and -c options. (4.2bsd style
contex diffs.) I wasn't aware that these wern't present in all unix
versions of diff, so I didn't think posting it was a priority. It's
large, slow, and many of the comments are no longer true, but it does
work. (except when it runs out of memory) The one case I know of
where its output is incompatable with patch does seem to be pretty
rare. No makefile is included, the 4.2bsd diff is better on the unix
system I use. If you don't know how to compile and load a single C
program, this probably isn't the tool for you anyway. I'd be grateful
to anyone who cleans this up and documents it properly. It does
appear to have been separate files at some point, I'm presenting it in
a form similar to how I got it: mail headers and outdated documentation
in comments and all. I just banged on it enough to get it doing what
I wanted.
SHAR_EOF
cat <<SHAR_EOF >diff.c
/*
* Last Hacked by Robert A. Larson, blarson@ecla.usc.edu, Nov 29 86
* OSK support (except for error routines).
* Real context diffs, with a couple of minor problems:
* If the first change is deleting leading lines, and the second
* such that the context overlaps the deleted lines, the deleted
* lines are output as context. This is consistant with other
* cases of overlapping context, but patch doesn't like it. It's
* not hard to manually fix the diff in this (rare?) case.
* File modifacation times are not output.
* At most 9 lines of context is output.
*
* Previously Hacked by John Gilmore, hoptoad!gnu, 26Sep86.
* Compiles and runs under Unix. Much faster since it doesn't reallocate
* every data structure in the inner loop(!). Compatible with Unix diff
* output format, though it occasionally finds different sets of changed
* lines (both are valid). -c option needs work. Also, ftell's in
* <check> should be dumped when possible.
*
From: EVERHART%ARISIA%rca.com@CSNET-RELAY.ARPA
Message-Id: <8608201845.AA15181@lll-crg.ARPA>
Date: Wed, 20 Aug 86 10:34 EDT
To: hoptoad!gnu@LLL-CRG.ARPA
Subject: Decus C DIFF (partially moved to Amiga) source.
*/
/*
* D I F F
*/
/* For VMS:
)BUILD $(TKBOPTIONS) = {
TASK = ...DIF
}
*/
/*
* OSK changes: since OSK doesn't have realloc, put the size
* allocated in the head of each allocated region. This code
* assumes int is a maximally alligned type. There is AMIGA
* code to avoid realloc, but it is broken.
*/
#ifdef DOCUMENTATION
title diff Differential File Comparison
index Differential File Comparison
synopsis
diff [option] file1 file2
description
Diff compares two files, showing what must be changed to make
them identical. Either file1 or file2 (but not both) may refer
to directories. If that is the case, a file in the directory
whose name is the same as the other file argument will be used.
The standard input may be used for one of the files by replacing
the argument by "-". Except for the standard input, both files
must be on disk devices.
.s
Options:
.lm +8
.s.i -8;-b Remove trailing whitespace (blanks and tabs)
and compress all other strings of whitespace to a single blank.
.s.i -8;-c Print some context -- matching lines before
and after the non-match section. Mark non-matched sections
with "|".
.s.i -8;-i Ignore lower/upper case distinctions.
.s.i -8;-e Output is in an "editor script" format which
is compatible with the Unix 'ed' editor.
.s.lm -8
All information needed to compare the files is maintained in main
memory. This means that very large files (or fairly large files with
many differences) will cause the program to abort with an "out
of space" message. Main memory requirements (in words) are
approximately:
.s
2 * (length of file1 + length of file2)
.br
+ 3 * (number of changes)
.s
(Where "length" is the number of lines of data in each file.)
.s
The algorithm reads each file twice, once to build hash tables and once
to check for fortuitous matches (two lines that are in fact different,
but which have the same hash value). CPU time requirements include
sorting the hash tables and randomly searching memory tables for
equivalence classes. For example, on a time-shared VAX-11/780,
comparing two 1000 line files required about 30 seconds (elapsed
clock time) and about 10,000 bytes of working storage. About 90
per-cent of the time was taken up by file I/O.
diagnostics
.lm +8
.s.i -8;Warning, bad option 'x'
.s
The option is ignored.
.s.i -8;Usage ...
.s
Two input files were not specified.
.s.i -8;Can't open input file "filename". Can't continue.
.s.i -8;Out of space
.s
The program ran out of memory while comparing the two files.
.s.i -8;Can't read line nnn at xxx in file[A/B]
.s
This indicates an I/O error when seeking to the specific line.
It should not happen.
.s.i -8;Spurious match, output is not optimal.
.s
Two lines that were different yielded the same hash value. This is
harmless except that the difference output is not the minimum set of
differences between the two files. For example, instead of the output:
.s
lines 1 to 5 were changed to ...
.s
the program will print
.s
lines 1 to 3 were changed to ...
.br
lines 4 to 5 were changed to ...
.s
The program uses a CRC16 hash code. The likelihood of this error is
quite small.
.lm -8
author
The diff algorithm was developed by J. W. Hunt and M. D. McIlroy,
using a central algorithm defined by H. S. Stone.
It was published in:
.s.lm +4.nf
Hunt, J. W., and McIlroy, M. D.,
An Algorithm for Differential File Comparison,
Computing Science Technical Report #41,
Bell Laboratories, Murray Hill, NJ 07974
.s.lm -4.f
bugs
On RSX and DECUS C on VMS systems, diff may fail if the both
files are not "variable-length, implied carriage control"
format. The scopy program can be used to convert files
to this format if problems arise.
When compiled under VAX C, diff handles STREAM_LF files
properly (in addition to the canonical variable-length implied
carriage control files). Other variations should work, but
have not been tested.
When compiled under VAX C, diff is quite slow for unknown reasons
which ought to be investigated. On the other hand, it has access to
effectively unlimited memory.
Output in a form suitable for ed - the -e option - seems rather
pointless; the analogue on DEC systems is SLP (SUMSLP on VMS).
It would be simple to provide SLP-compatible output. The question
is, why bother - since the various DEC file comparison utilities
already produce it.
#endif
/*
* Diff maintains all information needed to compare the two files in main
* memory. This means that very large files (or fairly large files with
* many differences) will cause the program to abort with an "out of space"
* error. Main memory requirements (in words) are approximately:
*
* 2 * (length of file1 + length of file2) + (3 * number of changes)
*
* The diff algorithm reads each file twice (once to build hash tables and
* a second time to check for fortuitous matches), then reads the differences
* by seeking randomly within the files. CPU time requirements include
* sorting the two hash vectors and randomly searching memory tables for
* equivalence classes. For example, running in Vax compatibility
* mode, two 1000 line files with a fair number of differences took
* about 25 seconds (elapsed wall clock time) for processing. Most of this
* time was spent in the file read routines. This test required slightly
* more than 6000 words of memory for internal tables.
*
* The diff algorithm was developed by J. W. Hunt and M. D. McIlroy,
* using a central algorithm defined by H. S. Stone. The algorithm
* was described in:
*
* Hunt, J. W., and McIlroy, M. D.,
* An Algorithm for Differential File Comparison,
* Computing Science Technical Report #41,
* Bell Laboratories, Murray Hill, NJ 07974
*
* The following description is summarized from that document. While
* it has been slightly modified to correspond to the program source, the
* algorithm is essentially identical.
*
* 1. Read the input files, building two vectors containing the
* line number (serial) and hash value (hash) of each line.
* Data for fileA will be in a vector pointed to by fileA[],
* while data for fileB will be pointed to by fileB[]. The
* lengths (number of lines) of the files will be represented
* by lenA and lenB respectively. [This is slightly different
* from the published algorithm.]
*
* 2. Note initial and final sequences that have identical
* hash values to shorten subsequent processing. Note that
* the "jackpot" phase (step 9.) will examine all lines in
* the file. Next, sort each file using hash as the primary
* key and serial as the secondary key.
*
* 3. Construct an array of equivalence classes (member[1..lenB])
* where each element contains the line number in fileB and a
* flag which is True if the indicated line is the first member
* of an equivalence class. (An equivalence class is a set of
* lines which all hash to the same value. The lines themselves
* are not necessarily identical.)
*
* 4. Construct an array, class[1..lenA], where each element, I, is set to
* the index of a line, J, in fileB if member[J] is the first
* element in an equivalence class and the hash code of line[I] in
* fileA is the same as the hash code of line[J] in fileB. Class[I]
* is set to zero if no such line exists.
*
* If non-zero, class[I] now points in member[] to the beginning of
* the class of lines in fileB equivalent to line[I] in fileA.
*
* The next two steps implement the longest common subsequence algorithm.
*
* 5. Structure CANDIDATE { a, b, previous }, where a and b are line
* numbers and previous a reference to a candidate, will store
* candidate lists as they are constructed.
*
* Vector clist[] stores references to candidates. It is dimensioned
* (0..min(lenA, lenB) + 1)
*
* Initialize
* clist[0] = CANDIDATE { 0, 0, -1 };
* clist[1] = CANDIDATE { A+1, B+1, -1 };
* ktop = 1;
*
* clist[1] is a fence beyond the last usefully filled element
* and -1 is an out-of-range clist index. Ktop is the index of the
* fence. Note, because of the memory allocation used, clist[]
* is actually composed of two vectors, clist[] containing the
* candidate reference, and klist[] containing pointers to clist.
*
* 6. For (A = 1 to lenA) {
* I = class[A]; -- the index in member[]: beginning of
* -- the class of lines in fileB equivalent
* -- to this line in fileA.
* if (I is non-zero) {
* Merge each member into the candidate list
* as discussed below.
* }
*
* Unravel the chain of candidates, getting a vector of common subsequences:
*
* 7. Set all elements of match[0..lenA] to zero.
*
* 8. clist[ktop-1] points to the subsequence chain head. For each element
* in the chain, let A and B be the line number entries. Then, set
*
* match[A] = B;
*
* The non-zero elements of match[] now pick out a longest common
* subsequence chain, possibly including spurious matches due to
* hash coincidences. The pairings between the two files are:
*
* if (match[A] is non-zero) {
* line A in fileA matches line match[A] in fileB;
* }
*
* Now, read each line of fileA and fileB to check for jackpots:
*
* 9. for (A = 1 to lenA) {
* if (match[A] is nonzero) {
* if (fileA[A] is not identical to fileB[match[A]])
* match[A] = 0; -- Hash congruence
* }
* }
*
* Ignoring "squish" complications, the merge step may be defined as follows:
*
* Entry:
* clist[] Candidate pointer array
* ktop Fence beyond last filled index
* A Current index in fileA
* member[] Equivalence vector
* I The index in member[] of the first element
* of the class of lines in fileB that are
* equivalent to line[A] in fileA.
*
* 1. Let clist[R] be "an r-candidate" and C a reference to
* the last candidate found, which will always be an r-candidate.
* clist[R] will be updated with this reference once the previous
* value of clist[R] is no longer needed. Initialize:
*
* R = 0;
* C = clist[0];
*
* 2. Do steps 3 through 6 repeatedly:
*
* 3. set B to the line number in member[I];
* search clist[R..ktop] for an element, clist[S], such that
*
* clist[S-1].b < B and clist[S].b >= B
*
* Note that clist[] is ordered on clist[].b so that binary
* search will work. The search algorithm used requires the
* two "fence" entries described above.
*
* If such an element is found, perform steps 4. and 5.
*
* 4. Extend the longest common subsequence chain:
*
* If (clist[S].b > B) {
* clist[R] = C;
* R = S;
* C = candidate(A, B, clist[S - 1]);
* }
*
* 5. Extend the number of subsequences, moving the fence:
*
* If (S == ktop) {
* clist[ktop + 1] = clist[ktop]
* ktop = ktop + 1;
* break out of step 2's loop;
* }
*
* 6. I = I + 1;
* if (member[I] is the first element in another class) {
* break out of step 2's loop;
* }
* else {
* continue at step 2.
* }
*
* 7. clist[R] = C;
* exit merge subroutine.
*
* To illustrate vector contents, here is a sample run:
*
* File A:
* line 1
* line 2
* line 3
* line 4
* line 5 gets deleted
* line 6
*
* File B:
* line 1
* line 1.5 inserted
* line 2
* line 3 changed
* line 4
* line 6
*
* (For clarity, the "squish" step is omitted from the following)
*
* On entry to equiv() (after readin and sorting), the file[] vector is
* as follows (the first entry in each pair is the line number, the
* second is the hash value. Entries are sorted on hash value):
*
* FileA[] (1..lines in fileA):
* line hash
* 3 042400 6 043300 5 050026 1 102201 2 102701 4 103501
* FileB[] (1..lines in fileB):
* 6 043300 2 045600 1 102201 3 102701 5 103501 4 147166
*
*
* After Equiv has processed file[]:
*
* FileA[] (1..lines in fileA):
* line value
* 3 0 6 1 5 0 1 3 2 4 4 5
* Member[] (0..lines in fileB)
* 0 -6 -2 -1 -3 -5 -4
*
*
* After unsort() has unwound fileB:
*
* Class[] (1 .. lines in fileA):
* 3 4 0 5 0 1
*
* Within unravel(), match is built in the following order:
*
* match[6] := 6
* match[4] := 5
* match[2] := 3
* match[1] := 1
*
* Match[] (0 .. lines in fileA):
*
* 0 1 3 0 5 0 6
*
* Output is as follows:
*
* 1a2
* > line 1.5 inserted
* 3c4
* < line 3
* ---
* > line 3 changed
* 5d5
* < line 5 gets deleted
*
*
*/
#include <stdio.h>
#include <ctype.h>
#ifdef vms
#include <ssdef.h>
#include <stsdef.h>
#define IO_SUCCESS (SS$_NORMAL | STS$M_INHIB_MSG)
#define IO_ERROR SS$_ABORT
#endif
/*
* Note: IO_SUCCESS and IO_ERROR are defined in the Decus C stdio.h file
*/
#ifndef IO_SUCCESS
#define IO_SUCCESS 0
#endif
#ifndef IO_ERROR
#define IO_ERROR 1
#endif
#define EOS 0
#ifdef unix
char temfile[L_tmpnam];
char *tmpnam();
#define TEMPFILE (temfile[0]? temfile: (tmpnam(temfile), temfile))
#else
#define TEMPFILE "diff.tmp"
#endif
#define TRUE 1
#define FALSE 0
#ifdef pdp11
#define short int
#endif
typedef struct candidate {
int b; /* Line in fileB */
int a; /* Line in fileA */
int link; /* Previous candidate */
} CANDIDATE;
typedef struct line {
unsigned short hash; /* Hash value etc. */
short serial; /* Line number */
} LINE;
LINE *file[2]; /* Hash/line for total file */
#define fileA file[0]
#define fileB file[1]
LINE *sfile[2]; /* Hash/line after prefix */
#define sfileA sfile[0]
#define sfileB sfile[1]
int len[2]; /* Actual lines in each file */
#define lenA len[0]
#define lenB len[1]
int slen[2]; /* Squished lengths */
#define slenA slen[0]
#define slenB slen[1]
int prefix; /* Identical lines at start */
int suffix; /* Identical lenes at end */
FILE *infd[2] = { NULL, NULL }; /* Input file identifiers */
FILE *tempfd; /* Temp for input redirection */
extern long ftell();
extern FILE *fopen();
extern char *malloc();
char *fgetss();
unsigned short hash();
#ifdef AMIGA
/* Define these types for Amiga C */
char *savptr;
int savsiz;
char *wrk;
char *wrk2;
int cpysiz;
#endif
/*
* The following vectors overlay the area defined by fileA
*/
short *class; /* Unsorted line numbers */
int *klist; /* Index of element in clist */
CANDIDATE *clist; /* Storage pool for candidates */
int clength = 0; /* Number of active candidates */
#define CSIZE_INC 50 /* How many to allocate each time we have to */
int csize = CSIZE_INC; /* Current size of storage pool */
int *match; /* Longest subsequence */
long *oldseek; /* Seek position in file A */
/*
* The following vectors overlay the area defined by fileB
*/
short *member; /* Concatenated equiv. classes */
long *newseek; /* Seek position in file B */
char *textb; /* Input from file2 for check */
/*
* Global variables
*/
int eflag = FALSE; /* Edit script requested */
int bflag = FALSE; /* Blank supress requested */
int cflag = FALSE; /* Context printout */
int iflag = FALSE; /* Ignore case requested */
char text[257]; /* Input line from file1 */
extern char *myalloc(); /* Storage allocator */
extern char *compact(); /* Storage compactor */
#ifdef DEBUG
#ifndef OSK
#define TIMING
#endif
#endif
#ifdef TIMING
extern long time();
extern char *$$mend;
long totaltime;
long sectiontime;
char *mstart;
#endif
main(argc, argv)
int argc;
char **argv;
/*
* Diff main program
*/
{
register int i;
register char *ap;
#ifdef OSK
extern int _memmins;
_memmins = 16 * 1024; /* tell OSK we will malloc a lot */
#endif
#ifdef TIMING
sectiontime = time(&totaltime);
#endif
#ifdef vms
argc = getredirection(argc,argv);
#endif
while (argc > 1 && *(ap = argv[1]) == '-' && *++ap != EOS) {
while (*ap != EOS) {
switch ((*ap++)) {
case 'b':
bflag++;
break;
case 'c':
if (*ap > '0' && *ap <= '9') cflag = *ap++ - '0';
else cflag = 3;
break;
case 'e':
eflag++;
break;
case 'i':
iflag++;
break;
default:
fprintf(stderr,
"Warning, bad option '%c'\n",
ap[-1]);
break;
}
}
argc--;
argv++;
}
if (argc != 3)
error("Usage: diff [-options] file1 file2");
if (cflag && eflag) {
fprintf(stderr,
"Warning, -c and -e are incompatible, -c supressed.\n");
cflag = FALSE;
}
argv++;
for (i = 0; i <= 1; i++) {
if (argv[i][0] == '-' && argv[i][1] == EOS) {
infd[i] = stdin;
if ((tempfd = fopen(TEMPFILE, "w")) == NULL)
cant(TEMPFILE, "work", 1);
}
else {
infd[i] = fopen(argv[i], "r");
if (!infd[i]) cant(argv[i], "input", 2); /* Fatal error */
}
}
if (infd[0] == stdin && infd[1] == stdin)
error("Can't diff two things both on standard input.");
if (infd[0] == NULL && infd[1] == NULL) {
cant(argv[0], "input", 0);
cant(argv[1], "input", 1);
}
#ifdef vms
else if (infd[1] == NULL)
opendir(1, &argv[1], infd[0]);
else if (infd[0] == NULL)
opendir(0, &argv[0], infd[1]);
#endif
/*
* Read input, building hash tables.
*/
input(0);
input(1);
squish();
#ifdef DEBUG
printf("before sort\n");
for (i = 1; i <= slenA; i++)
printf("sfileA[%d] = %6d %06o\n",
i, sfileA[i].serial, sfileA[i].hash);
for (i = 1; i <= slenB; i++)
printf("sfileB[%d] = %6d %06o\n",
i, sfileB[i].serial, sfileB[i].hash);
#endif
sort(sfileA, slenA);
sort(sfileB, slenB);
#ifdef TIMING
ptime("input");
#endif
#ifdef DEBUG
printf("after sort\n");
for (i = 1; i <= slenA; i++)
printf("sfileA[%d] = %6d %06o\n",
i, sfileA[i].serial, sfileB[i].hash);
for (i = 1; i <= slenB; i++)
printf("sfileB[%d] = %6d %06o\n",
i, sfileB[i].serial, sfileB[i].hash);
#endif
/*
* Build equivalence classes.
*/
member = (short *)fileB;
equiv();
member = (short *)compact((char *)member, (slenB + 2) * sizeof (int),
"squeezing member vector");
/*
* Reorder equivalence classes into array class[]
*/
class = (short *)fileA;
unsort();
class = (short *)compact((char *)class, (slenA + 2) * sizeof (int),
"compacting class vector");
#ifdef TIMING
ptime("equiv/unsort");
#endif
/*
* Find longest subsequences
*/
klist = (int *)myalloc((slenA + 2) * sizeof (int), "klist");
clist = (CANDIDATE *)myalloc(csize * sizeof (CANDIDATE), "clist");
i = subseq();
#ifndef OSK
free((char *)member);
free((char *)class);
#else
free((char *)member - sizeof(int));
free((char *)class - sizeof(int));
#endif
match = (int *)myalloc((lenA + 2) * sizeof (int), "match");
unravel(klist[i]);
#ifndef OSK
free((char *)clist);
free((char *)klist);
#else
free((char *)clist - sizeof(int));
free((char *)klist - sizeof(int));
#endif
#ifdef TIMING
ptime("subsequence/unravel");
#endif
/*
* Check for fortuitous matches and output differences
*/
oldseek = (long *)myalloc((lenA + 2) * sizeof (* oldseek), "oldseek");
newseek = (long *)myalloc((lenB + 2) * sizeof (* newseek), "newseek");
textb = myalloc(sizeof text, "textbuffer");
if (check(argv[0], argv[1]))
fprintf(stderr, "Spurious match, output is not optimal\n");
#ifdef TIMING
ptime("check");
#endif
output(argv[0], argv[1]);
#ifdef TIMING
ptime("output");
printf("%ld seconds required\n", sectiontime - totaltime);
#endif
if (tempfd != NULL) {
fclose(tempfd);
#ifdef unix
unlink(TEMPFILE);
#else
#ifdef OSK
unlink(TEMPFILE);
#else
remove(TEMPFILE);
#endif
#endif
}
}
input(which)
int which; /* 0 or 1 to redefine infd[] */
/*
* Read the file, building hash table
*/
{
register LINE *lentry;
register int linect = 0;
FILE *fd;
#define LSIZE_INC 200 /* # of line entries to alloc at once */
int lsize = LSIZE_INC;
lentry = (LINE *)myalloc(sizeof(LINE) * (lsize+3), "line");
fd = infd[which];
while (!getline(fd, text)) {
if (++linect >= lsize) {
lsize += 200;
lentry = (LINE *)compact((char *)lentry,
(lsize + 3) * sizeof(LINE),
"extending line vector");
}
lentry[linect].hash = hash(text);
}
/*
* If input was from stdin ("-" command), finish off the temp file.
*/
if (fd == stdin) {
fclose(tempfd);
tempfd = infd[which] = fopen(TEMPFILE, "r");
}
/* If we wanted to be stingy with memory, we could realloc lentry down
* to its exact size (+3 for some odd reason) here. No need? */
len[which] = linect;
file[which] = lentry;
}
squish()
/*
* Look for initial and trailing sequences that have identical hash values.
* Don't bother building them into the candidate vector.
*/
{
register int i;
register LINE *ap;
register LINE *bp;
int j;
int k;
/*
* prefix -> first line (from start) that doesn't hash identically
*/
i = 0; ap = &fileA[1]; bp = &fileB[1];
while (i < lenA && i < lenB && ap->hash == bp->hash) {
i++; ap++; bp++;
}
prefix = i;
/*
* suffix -> first line (from end) that doesn't hash identically
*/
j = lenA - i;
k = lenB - i;
ap = &fileA[lenA];
bp = &fileB[lenB];
i = 0;
while (i < j && i < k && ap->hash == bp->hash) {
i++; ap--; bp--;
}
suffix = i;
/*
* Tuck the counts away
*/
for (k = 0; k <= 1; k++) {
sfile[k] = file[k] + prefix;
j = slen[k] = len[k] - prefix - suffix;
for (i = 0, ap = sfile[k]; i <= slen[k]; i++, ap++) {
ap->serial = i;
}
}
}
sort(vector, vecsize)
LINE *vector; /* What to sort */
int vecsize; /* How many to sort */
/*
* Sort hash entries
*/
{
register int j;
register LINE *aim;
register LINE *ai;
int mid;
int k;
LINE work;
for (j = 1; j <= vecsize; j *= 2);
mid = (j - 1);
while ((mid /= 2) != 0) {
k = vecsize - mid;
for (j = 1; j <= k; j++) {
for (ai = &vector[j]; ai > vector; ai -= mid) {
aim = &ai[mid];
if (aim < ai)
break; /* ?? Why ?? */
if (aim->hash > ai->hash ||
aim->hash == ai->hash &&
aim->serial > ai->serial)
break;
work.hash = ai->hash;
ai->hash = aim->hash;
aim->hash = work.hash;
work.serial = ai->serial;
ai->serial = aim->serial;
aim->serial = work.serial;
}
}
}
}
equiv()
/*
* Build equivalence class vector
*/
{
register LINE *ap;
register union {
LINE *bp;
short *mp;
} r;
register int j;
LINE *atop;
#ifdef DEBUG
printf("equiv entry\n");
for (j = 1; j <= slenA; j++)
printf("sfileA[%d] = %6d %06o\n",
j, sfileA[j].serial, sfileA[j].hash);
for (j = 1; j <= slenB; j++)
printf("sfileB[%d] = %6d %06o\n",
j, sfileB[j].serial, sfileB[j].hash);
#endif
j = 1;
ap = &sfileA[1];
r.bp = &sfileB[1];
atop = &sfileA[slenA];
while (ap <= atop && j <= slenB) {
if (ap->hash < r.bp->hash) {
ap->hash = 0;
ap++;
}
else if (ap->hash == r.bp->hash) {
ap->hash = j;
ap++;
}
else {
r.bp++;
j++;
}
}
while (ap <= atop) {
ap->hash = 0;
ap++;
}
sfileB[slenB + 1].hash = 0;
#ifdef DEBUG
printf("equiv exit\n");
for (j = 1; j <= slenA; j++)
printf("sfileA[%d] = %6d %06o\n",
j, sfileA[j].serial, sfileA[j].hash);
for (j = 1; j <= slenB; j++)
printf("sfileB[%d] = %6d %06o\n",
j, sfileB[j].serial, sfileB[j].hash);
#endif
ap = &sfileB[0];
atop = &sfileB[slenB];
r.mp = &member[0];
while (++ap <= atop) {
r.mp++;
*r.mp = -(ap->serial);
while (ap[1].hash == ap->hash) {
ap++;
r.mp++;
*r.mp = ap->serial;
}
}
r.mp[1] = -1;
#ifdef DEBUG
for (j = 0; j <= slenB; j++)
printf("member[%d] = %d\n", j, member[j]);
#endif
}
unsort()
/*
* Build class vector
*/
{
register int *temp;
register int *tp;
register union {
LINE *ap;
short *cp;
} u;
LINE *evec;
short *eclass;
#ifdef DEBUG
int i;
#endif
temp = (int *)myalloc((slenA + 1) * sizeof(int), "unsort scratch");
u.ap = &sfileA[1];
evec = &sfileA[slenA];
while (u.ap <= evec) {
#ifdef DEBUG
printf("temp[%2d] := %06o\n", u.ap->serial, u.ap->hash);
#endif
temp[u.ap->serial] = u.ap->hash;
u.ap++;
}
/*
* Copy into class vector and free work space
*/
u.cp = &class[1];
eclass = &class[slenA];
tp = &temp[1];
while (u.cp <= eclass)
*u.cp++ = *tp++;
#ifndef OSK
free((char *) temp);
#else
free((char *)temp - sizeof(int));
#endif
#ifdef DEBUG
printf("unsort exit\n");
for (i = 1; i <= slenA; i++)
printf("class[%d] = %d %06o\n", i, class[i], class[i]);
#endif
}
subseq()
/*
* Generate maximum common subsequence chain in clist[]
*/
{
int a;
register unsigned ktop;
register int b;
register int s;
unsigned r;
int i;
int cand;
klist[0] = newcand(0, 0, -1);
klist[1] = newcand(slenA + 1, slenB + 1, -1);
ktop = 1; /* -> guard entry */
for (a = 1; a <= slenA; a++) {
/*
* For each non-zero element in fileA ...
*/
if ((i = class[a]) == 0)
continue;
cand = klist[0]; /* No candidate now */
r = 0; /* Current r-candidate */
do {
#ifdef DEBUG
printf("a = %d, i = %d, b = %d\n", a, i, member[i]);
#endif
/*
* Perform the merge algorithm
*/
if ((b = member[i]) < 0)
b = -b;
#ifdef DEBUG
printf("search(%d, %d, %d) -> %d\n",
r, ktop, b, search(r, ktop, b));
#endif
if ((s = search(r, ktop, b)) != 0) {
if (clist[klist[s]].b > b) {
klist[r] = cand;
r = s;
cand = newcand(a, b, klist[s-1]);
#ifdef DEBUG
dumpklist(ktop, "klist[s-1]->b > b");
#endif
}
if (s >= ktop) {
klist[ktop + 1] = klist[ktop];
ktop++;
#ifdef DEBUG
klist[r] = cand;
dumpklist(ktop, "extend");
#endif
break;
}
}
} while (member[++i] > 0);
klist[r] = cand;
}
#ifdef DEBUG
printf("last entry = %d\n", ktop - 1);
#endif
return(ktop - 1); /* Last entry found */
}
int
newcand(a, b, pred)
int a; /* Line in fileA */
int b; /* Line in fileB */
int pred; /* Link to predecessor, index in cand[] */
{
register CANDIDATE *new;
clength++;
if (++clength >= csize) {
csize += CSIZE_INC;
clist = (CANDIDATE *)compact((char *)clist,
csize * sizeof (CANDIDATE),
"extending clist");
}
new = &clist[clength - 1];
new->a = a;
new->b = b;
new->link = pred;
return(clength - 1);
}
search(low, high, b)
register unsigned low;
register unsigned high;
register int b;
/*
* Search klist[low..top] (inclusive) for b. If klist[low]->b >= b,
* return zero. Else return s such that klist[s-1]->b < b and
* klist[s]->b >= b. Note that the algorithm presupposes the two
* preset "fence" elements, (0, 0) and (slenA, slenB).
*/
{
register int temp;
register unsigned mid;
if (clist[klist[low]].b >= b)
return(0);
while ((mid = (low + high) / 2) > low) {
if ((temp = clist[klist[mid]].b) > b)
high = mid;
else if (temp < b)
low = mid;
else {
return(mid);
}
}
return(mid + 1);
}
unravel(k)
register int k;
{
register int i;
register CANDIDATE *cp;
int first_trailer;
int difference;
first_trailer = lenA - suffix;
difference = lenB - lenA;
#ifdef DEBUG
printf("first trailer = %d, difference = %d\n",
first_trailer, difference);
#endif
for (i = 0; i <= lenA; i++) {
match[i] = (i <= prefix) ? i
: (i > first_trailer) ? i + difference
: 0;
}
#ifdef DEBUG
printf("unravel\n");
#endif
while (k != -1) {
cp = &clist[k];
#ifdef DEBUG
if (k < 0 || k >= clength)
error("Illegal link -> %d", k);
printf("match[%d] := %d\n", cp->a + prefix, cp->b + prefix);
#endif
match[cp->a + prefix] = cp->b + prefix;
k = cp->link;
}
}
/*
* Check for hash matches (jackpots) and collect random access indices to
* the two files.
*
* It should be possible to avoid doing most of the ftell's by noticing
* that we are not doing a context diff and noticing that if a line
* compares equal to the other file, we will not ever need to know its
* file position. FIXME.
*/
check(fileAname, fileBname)
char *fileAname;
char *fileBname;
{
register int a; /* Current line in file A */
register int b; /* Current line in file B */
int jackpot;
/*
* The VAX C ftell() returns the address of the CURRENT record, not the
* next one (as in DECUS C or, effectively, other C's). Hence, the values
* are "off by one" in the array. OFFSET compensates for this.
*/
#ifdef vms
#define OFFSET (-1)
#else
#define OFFSET 0
#endif
b = 1;
rewind(infd[0]);
rewind(infd[1]);
/*
* See above; these would be over-written on VMS anyway.
*/
#ifndef vms
oldseek[0] = ftell(infd[0]);
newseek[0] = ftell(infd[1]);
#endif
jackpot = 0;
#ifdef DEBUG
printf("match vector\n");
for (a = 0; a <= lenA; a++)
printf("match[%d] = %d\n", a, match[a]);
#endif
for (a = 1; a <= lenA; a++) {
if (match[a] == 0) {
/* Unique line in A */
oldseek[a+OFFSET] = ftell(infd[0]);
getline(infd[0], text);
continue;
}
while (b < match[a]) {
/* Skip over unique lines in B */
newseek[b+OFFSET] = ftell(infd[1]);
getline(infd[1], textb);
b++;
}
/*
* Compare the two, supposedly matching, lines.
* Unless we are going to print these lines, don't bother to
* remember where they are. We only print matching lines
* if a context diff is happening, or if a jackpot occurs.
*/
if (cflag) {
oldseek[a+OFFSET] = ftell(infd[0]);
newseek[b+OFFSET] = ftell(infd[1]);
}
getline(infd[0], text);
getline(infd[1], textb);
if (!streq(text, textb)) {
fprintf(stderr, "Spurious match:\n");
fprintf(stderr, "line %d in %s, \"%s\"\n",
a, fileAname, text);
fprintf(stderr, "line %d in %s, \"%s\"\n",
b, fileBname, textb);
match[a] = 0;
jackpot++;
}
b++;
}
for (; b <= lenB; b++) {
newseek[b+OFFSET] = ftell(infd[1]);
getline(infd[1], textb);
}
/*
* The logical converse to the code up above, for NON-VMS systems, to
* store away an fseek() pointer at the beginning of the file. For VMS,
* we need one at EOF...
*/
#ifdef vms
oldseek[lenA] = ftell(infd[0]);
getline(infd[0],text); /* Will hit EOF... */
newseek[lenB] = ftell(infd[1]);
getline(infd[1],textb); /* Will hit EOF... */
#endif
return(jackpot);
}
output(fileAname, fileBname)
char *fileAname, *fileBname;
{
register int astart;
register int aend = 0;
int bstart;
register int bend;
rewind(infd[0]);
rewind(infd[1]);
match[0] = 0;
match[lenA+1] = lenB + 1;
if (!eflag) {
if (cflag) {
/*
* Should include ctime style dates after the file names, but
* this would be non-trivial on OSK. Perhaps there should be
* a special case for stdin.
*/
printf("*** %s\n--- %s\n", fileAname, fileBname);
}
/*
* Normal printout
*/
for (astart = 1; astart <= lenA; astart = aend + 1) {
/*
* New subsequence, skip over matching stuff
*/
while (astart <= lenA
&& match[astart] == (match[astart - 1] + 1))
astart++;
/*
* Found a difference, setup range and print it
*/
bstart = match[astart - 1] + 1;
aend = astart - 1;
while (aend < lenA && match[aend + 1] == 0)
aend++;
bend = match[aend + 1] - 1;
match[aend] = bend;
change(astart, aend, bstart, bend);
}
}
else {
/*
* Edit script output -- differences are output "backwards"
* for the benefit of a line-oriented editor.
*/
for (aend = lenA; aend >= 1; aend = astart - 1) {
while (aend >= 1
&& match[aend] == (match[aend + 1] - 1)
&& match[aend] != 0)
aend--;
bend = match[aend + 1] - 1;
astart = aend + 1;
while (astart > 1 && match[astart - 1] == 0)
astart--;
bstart = match[astart - 1] + 1;
match[astart] = bstart;
change(astart, aend, bstart, bend);
}
}
if (lenA == 0)
change(1, 0, 1, lenB);
}
/*
* Output a change entry: fileA[astart..aend] changed to fileB[bstart..bend]
*/
change(astart, aend, bstart, bend)
int astart;
int aend;
int bstart;
int bend;
{
char c;
/*
* This catches a "dummy" last entry
*/
if (astart > aend && bstart > bend)
return;
c = (astart > aend) ? 'a' : (bstart > bend) ? 'd' : 'c';
if (cflag) fputs("**************\n*** ", stdout);
if (c == 'a' && !cflag)
range(astart-1, astart-1, 0); /* Addition: just print one odd # */
else
range(astart, aend, 0); /* Print both, if different */
if (!cflag) {
putchar(c);
if (!eflag) {
if (c == 'd')
range(bstart-1, bstart-1, 1); /* Deletion: just print one odd # */
else
range(bstart, bend, 1); /* Print both, if different */
}
}
putchar('\n');
if (!eflag) {
fetch(oldseek, astart, aend, lenA, infd[0],
cflag ? (c=='d' ? "- " : "! ") : "< ");
if (cflag) {
fputs("--- ", stdout);
range(bstart, bend, 1);
fputs(" -----\n", stdout);
} else if (astart <= aend && bstart <= bend)
printf("---\n");
}
fetch(newseek, bstart, bend, lenB, infd[1],
cflag ? (c=='a' ? "+ " : "! ") : (eflag ? "" : "> "));
if (eflag && bstart <= bend)
printf(".\n");
}
range(from, to, w)
int from;
int to;
int w;
/*
* Print a range
*/
{
if (cflag) {
if((from -= cflag) <= 0) from = 1;
if((to += cflag) > len[w]) to = len[w];
}
if (to > from) {
printf("%d,%d", from, to);
} else if (to < from) {
printf("%d,%d", to, from);
} else {
printf("%d", from);
}
}
fetch(seekvec, start, end, trueend, fd, pfx)
long *seekvec;
register int start;
register int end;
int trueend;
FILE *fd;
char *pfx;
/*
* Print the appropriate text
*/
{
register int i;
register int first;
register int last;
if (cflag) {
if((first = start - cflag) <= 0) first = 1;
if((last = end + cflag) > trueend) last = trueend;
} else {
first = start;
last = end;
}
if (fseek(fd, seekvec[first], 0) != 0) {
printf("?Can't read line %d at %08lx (hex) in file%c\n",
start, seekvec[first],
(fd == infd[0]) ? 'A' : 'B');
}
else {
for (i = first; i <= last; i++) {
if (fgetss(text, sizeof text, fd) == NULL) {
printf("** Unexpected end of file\n");
break;
}
#ifdef DEBUG
printf("%5d: %s%s\n", i, pfx, text);
#else
fputs((cflag && (i<start || i>end)) ? " " : pfx, stdout);
fputs(text, stdout);
putchar('\n');
#endif
}
}
}
/*
* Input routine, read one line to buffer[], return TRUE on eof, else FALSE.
* The terminating newline is always removed. If "-b" was given, trailing
* whitespace (blanks and tabs) are removed and strings of blanks and
* tabs are replaced by a single blank. Getline() does all hacking for
* redirected input files.
*/
int
getline(fd, buffer)
FILE *fd;
char *buffer;
{
register char *top;
register char *fromp;
register char c;
if (fgetss(buffer, sizeof text, fd) == NULL) {
*buffer = EOS;
return(TRUE);
}
if (fd == stdin)
fputss(buffer, tempfd);
if (bflag || iflag) {
top = buffer;
fromp = buffer;
while ((c = *fromp++) != EOS) {
if (bflag && (c == ' ' || c == '\t')) {
c = ' ';
while (*fromp == ' ' || *fromp == '\t')
fromp++;
}
if (iflag)
c = tolower(c);
*top++ = c;
}
if (bflag && top[-1] == ' ')
top--;
*top = EOS;
}
return(FALSE);
}
static unsigned short crc16a[] = {
0000000, 0140301, 0140601, 0000500,
0141401, 0001700, 0001200, 0141101,
0143001, 0003300, 0003600, 0143501,
0002400, 0142701, 0142201, 0002100,
};
static unsigned short crc16b[] = {
0000000, 0146001, 0154001, 0012000,
0170001, 0036000, 0024000, 0162001,
0120001, 0066000, 0074000, 0132001,
0050000, 0116001, 0104001, 0043000,
};
unsigned short
hash(buffer)
char *buffer;
/*
* Return the CRC16 hash code for the buffer
* Algorithm from Stu Wecker (Digital memo 130-959-002-00).
*/
{
register unsigned short crc;
register char *tp;
register short temp;
crc = 0;
for (tp = buffer; *tp != EOS;) {
temp = *tp++ ^ crc; /* XOR crc with new char */
crc = (crc >> 8)
^ crc16a[(temp & 0017)]
^ crc16b[(temp & 0360) >> 4];
}
#ifdef DEBUG_ALL
printf("%06o: %s\n", (crc == 0) ? 1 : crc, buffer);
#endif
return((crc == 0) ? (unsigned short) 1 : crc);
}
#ifdef vms
opendir(which, arg, okfd)
int which; /* Which file to open (0 or 1) */
char **arg; /* File name argument, &argv[which] */
FILE *okfd; /* File name (already open) */
{
register char *tp;
register int c;
register char *newname;
fgetname(okfd, text);
/*
* Skip over device name
*/
for (tp = text; (c = *tp) && c != ':'; tp++);
if (c) tp++;
else tp = text;
/*
* Skip over [UIC] or [PPN] if present
*/
if (*tp == '[' || *tp == '(') {
while ((c = *tp++) && c != ']' && c != ')');
if (c == 0) {
fprintf(stderr, "?Bug: bad file name \"%s\"\n",
text);
tp--;
}
}
strcpy(text, tp);
/*
* Don't include version
*/
for (tp = text; (c = *tp) && c != ';'; tp++);
*tp = 0;
/*
* Now, text has the file name, tp - text, its length,
* and *arg the (possible) directory name. Create a new
* file name for opening.
*/
#ifndef OSK
if ((newname = malloc(tp - text + strlen(*arg) + 1)) == NULL)
error("Out of space at start");
#ifdef AMIGA
savsiz = tp - text + strlen(*arg) + 1;
savptr = newname;
#endif
#else
newname = myalloc(tp - text + strlen(*arg) + 1, "Out of space at start");
#endif
concat(newname, *arg, text, NULL);
if ((infd[which] = fopen(newname, "r")) == NULL)
cant(*arg, "constructed input", 1);
else
*arg = newname;
}
/* Amiga C doesn't have all these extensions for directory... */
#endif
char *
myalloc(amount, why)
int amount;
char *why;
/*
* Allocate or crash.
*/
{
register char *pointer;
#ifdef OSK
amount += sizeof(int);
#endif
if ((pointer = malloc((unsigned) amount)) == NULL)
noroom(why);
#ifdef OSK
*((int *)pointer) = amount;
pointer += sizeof(int);
#ifdef DEBUG
fprintf(stderr, "Myalloc: %d at %06o\n", amount, pointer);
#endif
#endif
#ifdef AMIGA
savsiz = amount;
savptr = pointer;
#endif
return (pointer);
}
/*
* Reallocate pointer, compacting storage
*
* The "compacting storage" part is probably not relevant any more.
* There used to be horrid code here that malloc'd one byte and freed
* it at magic times, to cause garbage collection of the freespace
* or something. It's safely gone now, you didn't have to see it.
* -- John Gilmore, Nebula Consultants, Sept 26, 1986
*/
char *
compact(pointer, new_amount, why)
char *pointer;
int new_amount;
char *why;
{
register char *new_pointer;
#ifndef AMIGA
#ifndef OSK
extern char *realloc();
if ((new_pointer = realloc(pointer, (unsigned) new_amount)) == NULL){
noroom(why);
}
#else
register int old_amount;
new_amount += sizeof(int);
if((new_pointer = malloc(new_amount)) == NULL) noroom(why);
*(int *)new_pointer = new_amount;
new_pointer += sizeof(int);
old_amount = *(((int *)pointer)-1);
/* _strass is like bcopy with the first two arguments reversted */
_strass(new_pointer, pointer, (new_amount <= old_amount ?
new_amount : old_amount) - sizeof(int));
#ifdef DEBUG
fprintf(stderr, "compact %d to %d from %06o to %06o\n",
old_amount, new_amount, pointer, new_pointer);
#endif
free(pointer - sizeof(int));
#endif
#else
/*
* This routine is heavily dependent on C storage allocator hacks
* For Amiga, we can't rely on storage being left alone "up to"
* the boundary of allocation as in VMS or RSX. Therefore we have
* to be different here and allocate a new larger segment, then
* free the old one. Messy but hopefully it will work.
*/
extern char *malloc();
/* No realloc(). Do a malloc and copy it. */
if ((new_pointer = malloc((unsigned) new_amount)) == NULL){
noroom(why);
}
/* This MUST assume the program calls compact using the old pointer as the
last call of malloc... Reason is that RSX version is really simpleminded */
cpysiz=savsiz;
/* Complain if deallocate area not same as last allocate area */
if (savptr != pointer) bogus(why);
wrk2=new_pointer;
for (wrk=pointer;cpysiz > 0;cpysiz--){
/* copy data to new area */
*wrk2++ = *wrk++;
}
/* when done, free old memory area. */
free(pointer);
#endif
#ifndef OSK
#ifdef DEBUG
if (new_pointer != pointer) {
fprintf(stderr, "moved from %06o to %06o\n",
pointer, new_pointer);
}
/* rdump(new_pointer, why);
*/
#endif
#endif
return (new_pointer);
}
noroom(why)
char *why;
{
fprintf(stderr, "?DIFF-F-out of room when %s\n", why);
exit(IO_ERROR);
}
#ifdef AMIGA
bogus(why)
char *why;
{
fprintf(stderr, "?DIFF-F-invalid compaction when %s\n", why);
exit(IO_ERROR);
}
#endif
#ifdef DEBUG
rdump(pointer, why)
int *pointer;
char *why;
/*
* Dump memory block
*/
{
int *last;
int count;
last = ((int **)pointer)[-1];
fprintf(stderr, "dump %s of %06o -> %06o, %d words",
why, pointer, last, last - pointer);
last = (int *)(((int) last) & ~1);
for (count = 0; pointer < last; ++count) {
if ((count & 07) == 0) {
fprintf(stderr, "\n%06o", pointer);
}
fprintf(stderr, "\t%06o", *pointer);
pointer++;
}
fprintf(stderr, "\n");
}
#endif
cant(filename, what, fatalflag)
char *filename;
char *what;
int fatalflag;
/*
* Can't open file message
*/
{
fprintf(stderr, "Can't open %s file \"%s\": ", what, filename);
#ifndef OSK
perror((char *)NULL);
#else
prerr(0, errno);
#endif
if (fatalflag) {
exit(fatalflag);
}
}
#ifdef DEBUG
dump(d_linep, d_len, d_which)
LINE *d_linep;
{
register int i;
printf("Dump of file%c, %d elements\n", "AB"[d_which], d_len);
printf("linep @ %06o\n", d_linep);
for (i = 0; i <= d_len; i++) {
printf("%3d %6d %06o\n", i,
d_linep[i].serial, d_linep[i].hash);
}
}
dumpklist(kmax, why)
int kmax;
char *why;
/*
* Dump klist
*/
{
register int i;
register CANDIDATE *cp;
register int count;
printf("\nklist[0..%d] %s, clength = %d\n", kmax, why, clength);
for (i = 0; i <= kmax; i++) {
cp = &clist[klist[i]];
printf("%2d %2d", i, klist[i]);
if (cp >= &clist[0] && cp < &clist[clength])
printf(" (%2d %2d -> %2d)\n", cp->a, cp->b, cp->link);
else if (klist[i] == -1)
printf(" End of chain\n");
else printf(" illegal klist element\n");
}
for (i = 0; i <= kmax; i++) {
count = -1;
for (cp = (CANDIDATE *)klist[i]; cp > &clist[0];
cp = (CANDIDATE *)&cp->link) {
if (++count >= 6) {
printf("\n ");
count = 0;
}
printf(" (%2d: %2d,%2d -> %d)",
cp-clist, cp->a, cp->b, cp->link);
}
printf("\n");
}
printf("*\n");
}
#endif
#ifdef TIMING
ptime(why)
char *why;
/*
* Dump time buffer
*/
{
long ttemp;
ttemp = time(NULL);
printf("%ld seconds for %s\n",
ttemp - sectiontime, why);
sectiontime = ttemp;
}
#endif
/*
* s t r e q . c
*/
/*)LIBRARY
*/
#ifdef DOCUMENTATION
title streq String Equality Test
index String equality test
synopsis
.s.nf
streq(a, b);
char *a;
char *b;
.s.f
Description
Return TRUE if the strings are equal.
Bugs
#endif
/* #define EOS 0
#define FALSE 0
#define TRUE 1
*/
int
streq(s1, s2)
register char *s1;
register char *s2;
/*
* TRUE if strings are identical
*/
{
while (*s1++ == *s2) {
if (*s2++ == EOS)
return (TRUE);
}
return (FALSE);
}
/*
* e r r o r . c
*/
/*)LIBRARY
*/
#ifdef DOCUMENTATION
title error Fatal Error Exit
index Fatal error exit
synopsis
.s.nf
_error()
error(format, args)
char *format;
.s.f
documentation
Fatal error exits. _error() halts, error() prints something
on stderr and then halts.
bugs
THIS DOES NOT WORK ON MANY SYSTEMS DUE TO EXTREMLY NON-PORTABLE CODE.
Why oh why can't people learn to use varargs properly? This code will
blow up on OSK. Fortunatly, it isn't used often...
#endif
/* VARARGS */
error(format, args)
char *format;
/*
* Error message before retiring.
*/
{
fprintf(stderr, format, &args);
putc('\n', stderr);
_error();
}
_error()
{
exit(1);
}
/* #include <stdio.h> */
fputss(s, iop)
register char *s;
register FILE *iop;
/*
* Like fput() except that it puts a newline at the end of the line.
*/
{
#ifndef OSK
/*
* Why wasn't this written like the OSK section? What's the difference between
* fputc and putc other than I've never heard of fputc?
*/
register c;
while (c = *s++)
fputc(c, iop);
fputc('\n', iop);
#else
fputs(s, iop);
putc('\n', iop);
#endif
}
/*
* Fgetss() is like fgets() except that the terminating newline
* is removed.
*/
char *fgetss(s, n, iop)
char *s;
register FILE *iop;
{
register c;
register char *cs;
cs = s;
/*
* The getc in the next line used to be an "fgetc". Change it back if
* getc doesn't work on your system, though that would be odd.
*/
while ((c = getc(iop))>=0 && --n>0) {
if (c=='\n')
break;
*cs++ = c;
}
if (c<0 && cs==s)
return((char *)NULL);
*cs = '\0'; /* Overwrite newline as null */
return(s);
}
SHAR_EOF
exit 0
Bob Larson Arpa: Blarson@Ecla.Usc.Edu blarson@skat.usc.edu
Uucp: {sdcrdcf,cit-vax}!oberon!skat!blarson
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