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busybox/editors/diff.c
Denis Vlasenko cc3f20b9bd fix breakage found by randomconfig
2008-06-23 22:31:52 +00:00

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/* vi: set sw=4 ts=4: */
/*
* Mini diff implementation for busybox, adapted from OpenBSD diff.
*
* Copyright (C) 2006 by Robert Sullivan <cogito.ergo.cogito@hotmail.com>
* Copyright (c) 2003 Todd C. Miller <Todd.Miller@courtesan.com>
*
* Sponsored in part by the Defense Advanced Research Projects
* Agency (DARPA) and Air Force Research Laboratory, Air Force
* Materiel Command, USAF, under agreement number F39502-99-1-0512.
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include "libbb.h"
// #define FSIZE_MAX 32768
/* NOINLINEs added to prevent gcc from merging too much into diffreg()
* (it bites more than it can (efficiently) chew). */
/*
* Output flags
*/
enum {
/* Print a header/footer between files */
/* D_HEADER = 1, - unused */
/* Treat file as empty (/dev/null) */
D_EMPTY1 = 2 * ENABLE_FEATURE_DIFF_DIR,
D_EMPTY2 = 4 * ENABLE_FEATURE_DIFF_DIR,
};
/*
* Status values for print_status() and diffreg() return values
* Guide:
* D_SAME - files are the same
* D_DIFFER - files differ
* D_BINARY - binary files differ
* D_COMMON - subdirectory common to both dirs
* D_ONLY - file only exists in one dir
* D_ISDIR1 - path1 a dir, path2 a file
* D_ISDIR2 - path1 a file, path2 a dir
* D_ERROR - error occurred
* D_SKIPPED1 - skipped path1 as it is a special file
* D_SKIPPED2 - skipped path2 as it is a special file
*/
#define D_SAME 0
#define D_DIFFER (1 << 0)
#define D_BINARY (1 << 1)
#define D_COMMON (1 << 2)
/*#define D_ONLY (1 << 3) - unused */
#define D_ISDIR1 (1 << 4)
#define D_ISDIR2 (1 << 5)
#define D_ERROR (1 << 6)
#define D_SKIPPED1 (1 << 7)
#define D_SKIPPED2 (1 << 8)
/* Command line options */
#define FLAG_a (1 << 0)
#define FLAG_b (1 << 1)
#define FLAG_d (1 << 2)
#define FLAG_i (1 << 3)
#define FLAG_L (1 << 4)
#define FLAG_N (1 << 5)
#define FLAG_q (1 << 6)
#define FLAG_r (1 << 7)
#define FLAG_s (1 << 8)
#define FLAG_S (1 << 9)
#define FLAG_t (1 << 10)
#define FLAG_T (1 << 11)
#define FLAG_U (1 << 12)
#define FLAG_w (1 << 13)
struct cand {
int x;
int y;
int pred;
};
struct line {
int serial;
int value;
};
/*
* The following struct is used to record change information
* doing a "context" or "unified" diff. (see routine "change" to
* understand the highly mnemonic field names)
*/
struct context_vec {
int a; /* start line in old file */
int b; /* end line in old file */
int c; /* start line in new file */
int d; /* end line in new file */
};
#define g_read_buf bb_common_bufsiz1
struct globals {
bool anychange;
smallint exit_status;
int opt_U_context;
size_t max_context; /* size of context_vec_start */
USE_FEATURE_DIFF_DIR(int dl_count;)
USE_FEATURE_DIFF_DIR(char **dl;)
char *opt_S_start;
const char *label1;
const char *label2;
int *J; /* will be overlaid on class */
int clen;
int pref, suff; /* length of prefix and suffix */
int nlen[2];
int slen[2];
int clistlen; /* the length of clist */
struct cand *clist; /* merely a free storage pot for candidates */
long *ixnew; /* will be overlaid on nfile[1] */
long *ixold; /* will be overlaid on klist */
struct line *nfile[2];
struct line *sfile[2]; /* shortened by pruning common prefix/suffix */
struct context_vec *context_vec_start;
struct context_vec *context_vec_end;
struct context_vec *context_vec_ptr;
char *tempname1, *tempname2;
struct stat stb1, stb2;
};
#define G (*ptr_to_globals)
#define anychange (G.anychange )
#define exit_status (G.exit_status )
#define opt_U_context (G.opt_U_context )
#define max_context (G.max_context )
#define dl_count (G.dl_count )
#define dl (G.dl )
#define opt_S_start (G.opt_S_start )
#define label1 (G.label1 )
#define label2 (G.label2 )
#define J (G.J )
#define clen (G.clen )
#define pref (G.pref )
#define suff (G.suff )
#define nlen (G.nlen )
#define slen (G.slen )
#define clistlen (G.clistlen )
#define clist (G.clist )
#define ixnew (G.ixnew )
#define ixold (G.ixold )
#define nfile (G.nfile )
#define sfile (G.sfile )
#define context_vec_start (G.context_vec_start )
#define context_vec_end (G.context_vec_end )
#define context_vec_ptr (G.context_vec_ptr )
#define stb1 (G.stb1 )
#define stb2 (G.stb2 )
#define tempname1 (G.tempname1 )
#define tempname2 (G.tempname2 )
#define INIT_G() do { \
SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
opt_U_context = 3; \
max_context = 64; \
} while (0)
#if ENABLE_FEATURE_DIFF_DIR
static void print_only(const char *path, const char *entry)
{
printf("Only in %s: %s\n", path, entry);
}
#endif
static void print_status(int val, char *_path1, char *_path2)
{
/*const char *const _entry = entry ? entry : "";*/
/*char *const _path1 = entry ? concat_path_file(path1, _entry) : path1;*/
/*char *const _path2 = entry ? concat_path_file(path2, _entry) : path2;*/
switch (val) {
/* case D_ONLY:
print_only(path1, entry);
break;
*/
case D_COMMON:
printf("Common subdirectories: %s and %s\n", _path1, _path2);
break;
case D_BINARY:
printf("Binary files %s and %s differ\n", _path1, _path2);
break;
case D_DIFFER:
if (option_mask32 & FLAG_q)
printf("Files %s and %s differ\n", _path1, _path2);
break;
case D_SAME:
if (option_mask32 & FLAG_s)
printf("Files %s and %s are identical\n", _path1, _path2);
break;
case D_ISDIR1:
printf("File %s is a %s while file %s is a %s\n",
_path1, "directory", _path2, "regular file");
break;
case D_ISDIR2:
printf("File %s is a %s while file %s is a %s\n",
_path1, "regular file", _path2, "directory");
break;
case D_SKIPPED1:
printf("File %s is not a regular file or directory and was skipped\n",
_path1);
break;
case D_SKIPPED2:
printf("File %s is not a regular file or directory and was skipped\n",
_path2);
break;
}
/*
if (entry) {
free(_path1);
free(_path2);
}
*/
}
/* Read line, return its nonzero hash. Return 0 if EOF.
*
* Hash function taken from Robert Sedgewick, Algorithms in C, 3d ed., p 578.
*/
static ALWAYS_INLINE int fiddle_sum(int sum, int t)
{
return sum * 127 + t;
}
static int readhash(FILE *fp)
{
int i, t, space;
int sum;
sum = 1;
space = 0;
i = 0;
if (!(option_mask32 & (FLAG_b | FLAG_w))) {
while ((t = getc(fp)) != '\n') {
if (t == EOF) {
if (i == 0)
return 0;
break;
}
sum = fiddle_sum(sum, t);
i = 1;
}
} else {
while (1) {
switch (t = getc(fp)) {
case '\t':
case '\r':
case '\v':
case '\f':
case ' ':
space = 1;
continue;
default:
if (space && !(option_mask32 & FLAG_w)) {
i = 1;
space = 0;
}
sum = fiddle_sum(sum, t);
i = 1;
continue;
case EOF:
if (i == 0)
return 0;
/* FALLTHROUGH */
case '\n':
break;
}
break;
}
}
/*
* There is a remote possibility that we end up with a zero sum.
* Zero is used as an EOF marker, so return 1 instead.
*/
return (sum == 0 ? 1 : sum);
}
/* Our diff implementation is using seek.
* When we meet non-seekable file, we must make a temp copy.
*/
static char *make_temp(FILE *f, struct stat *sb)
{
char *name;
int fd;
if (S_ISREG(sb->st_mode) || S_ISBLK(sb->st_mode))
return NULL;
name = xstrdup("/tmp/difXXXXXX");
fd = mkstemp(name);
if (fd < 0)
bb_perror_msg_and_die("mkstemp");
if (bb_copyfd_eof(fileno(f), fd) < 0) {
clean_up:
unlink(name);
xfunc_die(); /* error message is printed by bb_copyfd_eof */
}
fstat(fd, sb);
close(fd);
if (freopen(name, "r+", f) == NULL) {
bb_perror_msg("freopen");
goto clean_up;
}
return name;
}
/*
* Check to see if the given files differ.
* Returns 0 if they are the same, 1 if different, and -1 on error.
*/
static NOINLINE int files_differ(FILE *f1, FILE *f2)
{
size_t i, j;
/* Prevent making copies for "/dev/null" (too common) */
/* Deal with input from pipes etc */
tempname1 = make_temp(f1, &stb1);
tempname2 = make_temp(f2, &stb2);
if (stb1.st_size != stb2.st_size) {
return 1;
}
while (1) {
i = fread(g_read_buf, 1, COMMON_BUFSIZE/2, f1);
j = fread(g_read_buf + COMMON_BUFSIZE/2, 1, COMMON_BUFSIZE/2, f2);
if (i != j)
return 1;
if (i == 0)
return (ferror(f1) || ferror(f2)) ? -1 : 0;
if (memcmp(g_read_buf,
g_read_buf + COMMON_BUFSIZE/2, i) != 0)
return 1;
}
}
static void prepare(int i, FILE *fp /*, off_t filesize*/)
{
struct line *p;
int h;
size_t j, sz;
rewind(fp);
/*sz = (filesize <= FSIZE_MAX ? filesize : FSIZE_MAX) / 25;*/
/*if (sz < 100)*/
sz = 100;
p = xmalloc((sz + 3) * sizeof(p[0]));
j = 0;
while ((h = readhash(fp)) != 0) { /* while not EOF */
if (j == sz) {
sz = sz * 3 / 2;
p = xrealloc(p, (sz + 3) * sizeof(p[0]));
}
p[++j].value = h;
}
nlen[i] = j;
nfile[i] = p;
}
static void prune(void)
{
int i, j;
for (pref = 0; pref < nlen[0] && pref < nlen[1] &&
nfile[0][pref + 1].value == nfile[1][pref + 1].value; pref++)
continue;
for (suff = 0; suff < nlen[0] - pref && suff < nlen[1] - pref &&
nfile[0][nlen[0] - suff].value == nfile[1][nlen[1] - suff].value;
suff++)
continue;
for (j = 0; j < 2; j++) {
sfile[j] = nfile[j] + pref;
slen[j] = nlen[j] - pref - suff;
for (i = 0; i <= slen[j]; i++)
sfile[j][i].serial = i;
}
}
static void equiv(struct line *a, int n, struct line *b, int m, int *c)
{
int i, j;
i = j = 1;
while (i <= n && j <= m) {
if (a[i].value < b[j].value)
a[i++].value = 0;
else if (a[i].value == b[j].value)
a[i++].value = j;
else
j++;
}
while (i <= n)
a[i++].value = 0;
b[m + 1].value = 0;
j = 0;
while (++j <= m) {
c[j] = -b[j].serial;
while (b[j + 1].value == b[j].value) {
j++;
c[j] = b[j].serial;
}
}
c[j] = -1;
}
static int isqrt(int n)
{
int y, x;
if (n == 0)
return 0;
x = 1;
do {
y = x;
x = n / x;
x += y;
x /= 2;
} while ((x - y) > 1 || (x - y) < -1);
return x;
}
static int newcand(int x, int y, int pred)
{
struct cand *q;
if (clen == clistlen) {
clistlen = clistlen * 11 / 10;
clist = xrealloc(clist, clistlen * sizeof(struct cand));
}
q = clist + clen;
q->x = x;
q->y = y;
q->pred = pred;
return clen++;
}
static int search(int *c, int k, int y)
{
int i, j, l, t;
if (clist[c[k]].y < y) /* quick look for typical case */
return k + 1;
i = 0;
j = k + 1;
while (1) {
l = i + j;
if ((l >>= 1) <= i)
break;
t = clist[c[l]].y;
if (t > y)
j = l;
else if (t < y)
i = l;
else
return l;
}
return l + 1;
}
static int stone(int *a, int n, int *b, int *c)
{
int i, k, y, j, l;
int oldc, tc, oldl;
unsigned int numtries;
#if ENABLE_FEATURE_DIFF_MINIMAL
const unsigned int bound =
(option_mask32 & FLAG_d) ? UINT_MAX : MAX(256, isqrt(n));
#else
const unsigned int bound = MAX(256, isqrt(n));
#endif
k = 0;
c[0] = newcand(0, 0, 0);
for (i = 1; i <= n; i++) {
j = a[i];
if (j == 0)
continue;
y = -b[j];
oldl = 0;
oldc = c[0];
numtries = 0;
do {
if (y <= clist[oldc].y)
continue;
l = search(c, k, y);
if (l != oldl + 1)
oldc = c[l - 1];
if (l <= k) {
if (clist[c[l]].y <= y)
continue;
tc = c[l];
c[l] = newcand(i, y, oldc);
oldc = tc;
oldl = l;
numtries++;
} else {
c[l] = newcand(i, y, oldc);
k++;
break;
}
} while ((y = b[++j]) > 0 && numtries < bound);
}
return k;
}
static void unravel(int p)
{
struct cand *q;
int i;
for (i = 0; i <= nlen[0]; i++)
J[i] = i <= pref ? i : i > nlen[0] - suff ? i + nlen[1] - nlen[0] : 0;
for (q = clist + p; q->y != 0; q = clist + q->pred)
J[q->x + pref] = q->y + pref;
}
static void unsort(struct line *f, int l, int *b)
{
int *a, i;
a = xmalloc((l + 1) * sizeof(int));
for (i = 1; i <= l; i++)
a[f[i].serial] = f[i].value;
for (i = 1; i <= l; i++)
b[i] = a[i];
free(a);
}
static int skipline(FILE *f)
{
int i, c;
for (i = 1; (c = getc(f)) != '\n' && c != EOF; i++)
continue;
return i;
}
/*
* Check does double duty:
* 1. ferret out any fortuitous correspondences due
* to confounding by hashing (which result in "jackpot")
* 2. collect random access indexes to the two files
*/
static NOINLINE void check(FILE *f1, FILE *f2)
{
int i, j, jackpot, c, d;
long ctold, ctnew;
rewind(f1);
rewind(f2);
j = 1;
ixold[0] = ixnew[0] = 0;
jackpot = 0;
ctold = ctnew = 0;
for (i = 1; i <= nlen[0]; i++) {
if (J[i] == 0) {
ixold[i] = ctold += skipline(f1);
continue;
}
while (j < J[i]) {
ixnew[j] = ctnew += skipline(f2);
j++;
}
if (option_mask32 & (FLAG_b | FLAG_w | FLAG_i)) {
while (1) {
c = getc(f1);
d = getc(f2);
/*
* GNU diff ignores a missing newline
* in one file if bflag || wflag.
*/
if ((option_mask32 & (FLAG_b | FLAG_w))
&& ((c == EOF && d == '\n') || (c == '\n' && d == EOF))
) {
break;
}
ctold++;
ctnew++;
if ((option_mask32 & FLAG_b) && isspace(c) && isspace(d)) {
do {
if (c == '\n')
break;
ctold++;
c = getc(f1);
} while (isspace(c));
do {
if (d == '\n')
break;
ctnew++;
d = getc(f2);
} while (isspace(d));
} else if (option_mask32 & FLAG_w) {
while (isspace(c) && c != '\n') {
c = getc(f1);
ctold++;
}
while (isspace(d) && d != '\n') {
d = getc(f2);
ctnew++;
}
}
if (c != d) {
jackpot++;
J[i] = 0;
if (c != '\n' && c != EOF)
ctold += skipline(f1);
if (d != '\n' && c != EOF)
ctnew += skipline(f2);
break;
}
if (c == '\n' || c == EOF)
break;
}
} else {
while (1) {
ctold++;
ctnew++;
c = getc(f1);
d = getc(f2);
if (c != d) {
J[i] = 0;
if (c != '\n' && c != EOF)
ctold += skipline(f1);
/* was buggy? "if (d != '\n' && c != EOF)" */
if (d != '\n' && d != EOF)
ctnew += skipline(f2);
break;
}
if (c == '\n' || c == EOF)
break;
}
}
ixold[i] = ctold;
ixnew[j] = ctnew;
j++;
}
for (; j <= nlen[1]; j++)
ixnew[j] = ctnew += skipline(f2);
}
/* shellsort CACM #201 */
static void sort(struct line *a, int n)
{
struct line *ai, *aim, w;
int j, m = 0, k;
if (n == 0)
return;
for (j = 1; j <= n; j *= 2)
m = 2 * j - 1;
for (m /= 2; m != 0; m /= 2) {
k = n - m;
for (j = 1; j <= k; j++) {
for (ai = &a[j]; ai > a; ai -= m) {
aim = &ai[m];
if (aim < ai)
break; /* wraparound */
if (aim->value > ai[0].value
|| (aim->value == ai[0].value && aim->serial > ai[0].serial)
) {
break;
}
w.value = ai[0].value;
ai[0].value = aim->value;
aim->value = w.value;
w.serial = ai[0].serial;
ai[0].serial = aim->serial;
aim->serial = w.serial;
}
}
}
}
static void uni_range(int a, int b)
{
if (a < b)
printf("%d,%d", a, b - a + 1);
else if (a == b)
printf("%d", b);
else
printf("%d,0", b);
}
static void fetch(long *f, int a, int b, FILE *lb, int ch)
{
int i, j, c, lastc, col, nc;
if (a > b)
return;
for (i = a; i <= b; i++) {
fseek(lb, f[i - 1], SEEK_SET);
nc = f[i] - f[i - 1];
if (ch != '\0') {
putchar(ch);
if (option_mask32 & FLAG_T)
putchar('\t');
}
col = 0;
for (j = 0, lastc = '\0'; j < nc; j++, lastc = c) {
c = getc(lb);
if (c == EOF) {
printf("\n\\ No newline at end of file\n");
return;
}
if (c == '\t' && (option_mask32 & FLAG_t)) {
do {
putchar(' ');
} while (++col & 7);
} else {
putchar(c);
col++;
}
}
}
}
#if ENABLE_FEATURE_DIFF_BINARY
static int asciifile(FILE *f)
{
int i, cnt;
if (option_mask32 & FLAG_a)
return 1;
rewind(f);
cnt = fread(g_read_buf, 1, COMMON_BUFSIZE, f);
for (i = 0; i < cnt; i++) {
if (!isprint(g_read_buf[i])
&& !isspace(g_read_buf[i])
) {
return 0;
}
}
return 1;
}
#else
#define asciifile(f) 1
#endif
/* dump accumulated "unified" diff changes */
static void dump_unified_vec(FILE *f1, FILE *f2)
{
struct context_vec *cvp = context_vec_start;
int lowa, upb, lowc, upd;
int a, b, c, d;
char ch;
if (context_vec_start > context_vec_ptr)
return;
b = d = 0; /* gcc */
lowa = MAX(1, cvp->a - opt_U_context);
upb = MIN(nlen[0], context_vec_ptr->b + opt_U_context);
lowc = MAX(1, cvp->c - opt_U_context);
upd = MIN(nlen[1], context_vec_ptr->d + opt_U_context);
printf("@@ -");
uni_range(lowa, upb);
printf(" +");
uni_range(lowc, upd);
printf(" @@\n");
/*
* Output changes in "unified" diff format--the old and new lines
* are printed together.
*/
for (; cvp <= context_vec_ptr; cvp++) {
a = cvp->a;
b = cvp->b;
c = cvp->c;
d = cvp->d;
/*
* c: both new and old changes
* d: only changes in the old file
* a: only changes in the new file
*/
if (a <= b && c <= d)
ch = 'c';
else
ch = (a <= b) ? 'd' : 'a';
#if 0
switch (ch) {
case 'c':
// fetch() seeks!
fetch(ixold, lowa, a - 1, f1, ' ');
fetch(ixold, a, b, f1, '-');
fetch(ixnew, c, d, f2, '+');
break;
case 'd':
fetch(ixold, lowa, a - 1, f1, ' ');
fetch(ixold, a, b, f1, '-');
break;
case 'a':
fetch(ixnew, lowc, c - 1, f2, ' ');
fetch(ixnew, c, d, f2, '+');
break;
}
#else
if (ch == 'c' || ch == 'd') {
fetch(ixold, lowa, a - 1, f1, ' ');
fetch(ixold, a, b, f1, '-');
}
if (ch == 'a')
fetch(ixnew, lowc, c - 1, f2, ' ');
if (ch == 'c' || ch == 'a')
fetch(ixnew, c, d, f2, '+');
#endif
lowa = b + 1;
lowc = d + 1;
}
fetch(ixnew, d + 1, upd, f2, ' ');
context_vec_ptr = context_vec_start - 1;
}
static void print_header(const char *file1, const char *file2)
{
if (label1)
printf("--- %s\n", label1);
else
printf("--- %s\t%s", file1, ctime(&stb1.st_mtime));
if (label2)
printf("+++ %s\n", label2);
else
printf("+++ %s\t%s", file2, ctime(&stb2.st_mtime));
}
/*
* Indicate that there is a difference between lines a and b of the from file
* to get to lines c to d of the to file. If a is greater than b then there
* are no lines in the from file involved and this means that there were
* lines appended (beginning at b). If c is greater than d then there are
* lines missing from the to file.
*/
static void change(char *file1, FILE *f1, char *file2, FILE *f2,
int a, int b, int c, int d)
{
if ((a > b && c > d) || (option_mask32 & FLAG_q)) {
anychange = 1;
return;
}
/*
* Allocate change records as needed.
*/
if (context_vec_ptr == context_vec_end - 1) {
ptrdiff_t offset = context_vec_ptr - context_vec_start;
max_context <<= 1;
context_vec_start = xrealloc(context_vec_start,
max_context * sizeof(struct context_vec));
context_vec_end = context_vec_start + max_context;
context_vec_ptr = context_vec_start + offset;
}
if (anychange == 0) {
/*
* Print the context/unidiff header first time through.
*/
print_header(file1, file2);
} else if (a > context_vec_ptr->b + (2 * opt_U_context) + 1
&& c > context_vec_ptr->d + (2 * opt_U_context) + 1
) {
/*
* If this change is more than 'context' lines from the
* previous change, dump the record and reset it.
*/
// dump_unified_vec() seeks!
dump_unified_vec(f1, f2);
}
context_vec_ptr++;
context_vec_ptr->a = a;
context_vec_ptr->b = b;
context_vec_ptr->c = c;
context_vec_ptr->d = d;
anychange = 1;
}
static void output(char *file1, FILE *f1, char *file2, FILE *f2)
{
/* Note that j0 and j1 can't be used as they are defined in math.h.
* This also allows the rather amusing variable 'j00'... */
int m, i0, i1, j00, j01;
rewind(f1);
rewind(f2);
m = nlen[0];
J[0] = 0;
J[m + 1] = nlen[1] + 1;
for (i0 = 1; i0 <= m; i0 = i1 + 1) {
while (i0 <= m && J[i0] == J[i0 - 1] + 1)
i0++;
j00 = J[i0 - 1] + 1;
i1 = i0 - 1;
while (i1 < m && J[i1 + 1] == 0)
i1++;
j01 = J[i1 + 1] - 1;
J[i1] = j01;
// change() seeks!
change(file1, f1, file2, f2, i0, i1, j00, j01);
}
if (m == 0) {
// change() seeks!
change(file1, f1, file2, f2, 1, 0, 1, nlen[1]);
}
if (anychange != 0 && !(option_mask32 & FLAG_q)) {
// dump_unified_vec() seeks!
dump_unified_vec(f1, f2);
}
}
/*
* The following code uses an algorithm due to Harold Stone,
* which finds a pair of longest identical subsequences in
* the two files.
*
* The major goal is to generate the match vector J.
* J[i] is the index of the line in file1 corresponding
* to line i in file0. J[i] = 0 if there is no
* such line in file1.
*
* Lines are hashed so as to work in core. All potential
* matches are located by sorting the lines of each file
* on the hash (called "value"). In particular, this
* collects the equivalence classes in file1 together.
* Subroutine equiv replaces the value of each line in
* file0 by the index of the first element of its
* matching equivalence in (the reordered) file1.
* To save space equiv squeezes file1 into a single
* array member in which the equivalence classes
* are simply concatenated, except that their first
* members are flagged by changing sign.
*
* Next the indices that point into member are unsorted into
* array class according to the original order of file0.
*
* The cleverness lies in routine stone. This marches
* through the lines of file0, developing a vector klist
* of "k-candidates". At step i a k-candidate is a matched
* pair of lines x,y (x in file0, y in file1) such that
* there is a common subsequence of length k
* between the first i lines of file0 and the first y
* lines of file1, but there is no such subsequence for
* any smaller y. x is the earliest possible mate to y
* that occurs in such a subsequence.
*
* Whenever any of the members of the equivalence class of
* lines in file1 matable to a line in file0 has serial number
* less than the y of some k-candidate, that k-candidate
* with the smallest such y is replaced. The new
* k-candidate is chained (via pred) to the current
* k-1 candidate so that the actual subsequence can
* be recovered. When a member has serial number greater
* that the y of all k-candidates, the klist is extended.
* At the end, the longest subsequence is pulled out
* and placed in the array J by unravel
*
* With J in hand, the matches there recorded are
* checked against reality to assure that no spurious
* matches have crept in due to hashing. If they have,
* they are broken, and "jackpot" is recorded--a harmless
* matter except that a true match for a spuriously
* mated line may now be unnecessarily reported as a change.
*
* Much of the complexity of the program comes simply
* from trying to minimize core utilization and
* maximize the range of doable problems by dynamically
* allocating what is needed and reusing what is not.
* The core requirements for problems larger than somewhat
* are (in words) 2*length(file0) + length(file1) +
* 3*(number of k-candidates installed), typically about
* 6n words for files of length n.
*/
/* NB: files can be not REGular. The only sure thing that they
* are not both DIRectories. */
static unsigned diffreg(char *file1, char *file2, int flags)
{
int *member; /* will be overlaid on nfile[1] */
int *class; /* will be overlaid on nfile[0] */
int *klist; /* will be overlaid on nfile[0] after class */
FILE *f1;
FILE *f2;
unsigned rval;
int i;
anychange = 0;
context_vec_ptr = context_vec_start - 1;
tempname1 = tempname2 = NULL;
/* Is any of them a directory? Then it's simple */
if (S_ISDIR(stb1.st_mode) != S_ISDIR(stb2.st_mode))
return (S_ISDIR(stb1.st_mode) ? D_ISDIR1 : D_ISDIR2);
/* None of them are directories */
rval = D_SAME;
if (flags & D_EMPTY1)
/* can't be stdin, but xfopen_stdin() is smaller code */
f1 = xfopen_stdin(bb_dev_null);
else
f1 = xfopen_stdin(file1);
if (flags & D_EMPTY2)
f2 = xfopen_stdin(bb_dev_null);
else
f2 = xfopen_stdin(file2);
/* NB: if D_EMPTY1/2 is set, other file is always a regular file,
* not pipe/fifo/chardev/etc - D_EMPTY is used by "diff -r" only,
* and it never diffs non-ordinary files in subdirs. */
if (!(flags & (D_EMPTY1 | D_EMPTY2))) {
/* Quick check whether they are different */
/* NB: copies non-REG files to tempfiles and fills tempname1/2 */
i = files_differ(f1, f2);
if (i != 1) { /* not different? */
if (i != 0) /* error? */
exit_status |= 2;
goto closem;
}
}
if (!asciifile(f1) || !asciifile(f2)) {
rval = D_BINARY;
exit_status |= 1;
goto closem;
}
// Rewind inside!
prepare(0, f1 /*, stb1.st_size*/);
prepare(1, f2 /*, stb2.st_size*/);
prune();
sort(sfile[0], slen[0]);
sort(sfile[1], slen[1]);
member = (int *) nfile[1];
equiv(sfile[0], slen[0], sfile[1], slen[1], member);
member = xrealloc(member, (slen[1] + 2) * sizeof(int));
class = (int *) nfile[0];
unsort(sfile[0], slen[0], class);
class = xrealloc(class, (slen[0] + 2) * sizeof(int));
klist = xmalloc((slen[0] + 2) * sizeof(int));
clen = 0;
clistlen = 100;
clist = xmalloc(clistlen * sizeof(struct cand));
i = stone(class, slen[0], member, klist);
free(member);
free(class);
J = xrealloc(J, (nlen[0] + 2) * sizeof(int));
unravel(klist[i]);
free(clist);
free(klist);
ixold = xrealloc(ixold, (nlen[0] + 2) * sizeof(long));
ixnew = xrealloc(ixnew, (nlen[1] + 2) * sizeof(long));
// Rewind inside!
check(f1, f2);
// Rewind inside!
output(file1, f1, file2, f2);
closem:
if (anychange) {
exit_status |= 1;
if (rval == D_SAME)
rval = D_DIFFER;
}
fclose_if_not_stdin(f1);
fclose_if_not_stdin(f2);
if (tempname1) {
unlink(tempname1);
free(tempname1);
}
if (tempname2) {
unlink(tempname2);
free(tempname2);
}
return rval;
}
#if ENABLE_FEATURE_DIFF_DIR
static void do_diff(char *dir1, char *path1, char *dir2, char *path2)
{
int flags = 0; /*D_HEADER;*/
int val;
char *fullpath1 = NULL; /* if -N */
char *fullpath2 = NULL;
if (path1)
fullpath1 = concat_path_file(dir1, path1);
if (path2)
fullpath2 = concat_path_file(dir2, path2);
if (!fullpath1 || stat(fullpath1, &stb1) != 0) {
flags |= D_EMPTY1;
memset(&stb1, 0, sizeof(stb1));
if (path2) {
free(fullpath1);
fullpath1 = concat_path_file(dir1, path2);
}
}
if (!fullpath2 || stat(fullpath2, &stb2) != 0) {
flags |= D_EMPTY2;
memset(&stb2, 0, sizeof(stb2));
stb2.st_mode = stb1.st_mode;
if (path1) {
free(fullpath2);
fullpath2 = concat_path_file(dir2, path1);
}
}
if (stb1.st_mode == 0)
stb1.st_mode = stb2.st_mode;
if (S_ISDIR(stb1.st_mode) && S_ISDIR(stb2.st_mode)) {
printf("Common subdirectories: %s and %s\n", fullpath1, fullpath2);
goto ret;
}
if (!S_ISREG(stb1.st_mode) && !S_ISDIR(stb1.st_mode))
val = D_SKIPPED1;
else if (!S_ISREG(stb2.st_mode) && !S_ISDIR(stb2.st_mode))
val = D_SKIPPED2;
else {
/* Both files are either REGular or DIRectories */
val = diffreg(fullpath1, fullpath2, flags);
}
print_status(val, fullpath1, fullpath2 /*, NULL*/);
ret:
free(fullpath1);
free(fullpath2);
}
#endif
#if ENABLE_FEATURE_DIFF_DIR
/* This function adds a filename to dl, the directory listing. */
static int add_to_dirlist(const char *filename,
struct stat *sb ATTRIBUTE_UNUSED,
void *userdata,
int depth ATTRIBUTE_UNUSED)
{
/* +2: with space for eventual trailing NULL */
dl = xrealloc(dl, (dl_count+2) * sizeof(dl[0]));
dl[dl_count] = xstrdup(filename + (int)(ptrdiff_t)userdata);
dl_count++;
return TRUE;
}
/* This returns a sorted directory listing. */
static char **get_recursive_dirlist(char *path)
{
dl_count = 0;
dl = xzalloc(sizeof(dl[0]));
/* We need to trim root directory prefix.
* Using void *userdata to specify its length,
* add_to_dirlist will remove it. */
if (option_mask32 & FLAG_r) {
recursive_action(path, ACTION_RECURSE|ACTION_FOLLOWLINKS,
add_to_dirlist, /* file_action */
NULL, /* dir_action */
(void*)(strlen(path) + 1),
0);
} else {
DIR *dp;
struct dirent *ep;
dp = warn_opendir(path);
while ((ep = readdir(dp))) {
if (!strcmp(ep->d_name, "..") || LONE_CHAR(ep->d_name, '.'))
continue;
add_to_dirlist(ep->d_name, NULL, (void*)(int)0, 0);
}
closedir(dp);
}
/* Sort dl alphabetically. */
qsort_string_vector(dl, dl_count);
dl[dl_count] = NULL;
return dl;
}
static void diffdir(char *p1, char *p2)
{
char **dirlist1, **dirlist2;
char *dp1, *dp2;
int pos;
/* Check for trailing slashes. */
dp1 = last_char_is(p1, '/');
if (dp1 != NULL)
*dp1 = '\0';
dp2 = last_char_is(p2, '/');
if (dp2 != NULL)
*dp2 = '\0';
/* Get directory listings for p1 and p2. */
dirlist1 = get_recursive_dirlist(p1);
dirlist2 = get_recursive_dirlist(p2);
/* If -S was set, find the starting point. */
if (opt_S_start) {
while (*dirlist1 != NULL && strcmp(*dirlist1, opt_S_start) < 0)
dirlist1++;
while (*dirlist2 != NULL && strcmp(*dirlist2, opt_S_start) < 0)
dirlist2++;
if ((*dirlist1 == NULL) || (*dirlist2 == NULL))
bb_error_msg(bb_msg_invalid_arg, "NULL", "-S");
}
/* Now that both dirlist1 and dirlist2 contain sorted directory
* listings, we can start to go through dirlist1. If both listings
* contain the same file, then do a normal diff. Otherwise, behaviour
* is determined by whether the -N flag is set. */
while (*dirlist1 != NULL || *dirlist2 != NULL) {
dp1 = *dirlist1;
dp2 = *dirlist2;
pos = dp1 == NULL ? 1 : (dp2 == NULL ? -1 : strcmp(dp1, dp2));
if (pos == 0) {
do_diff(p1, dp1, p2, dp2);
dirlist1++;
dirlist2++;
} else if (pos < 0) {
if (option_mask32 & FLAG_N)
do_diff(p1, dp1, p2, NULL);
else
print_only(p1, dp1);
dirlist1++;
} else {
if (option_mask32 & FLAG_N)
do_diff(p1, NULL, p2, dp2);
else
print_only(p2, dp2);
dirlist2++;
}
}
}
#endif
int diff_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int diff_main(int argc ATTRIBUTE_UNUSED, char **argv)
{
int gotstdin = 0;
char *f1, *f2;
llist_t *L_arg = NULL;
INIT_G();
/* exactly 2 params; collect multiple -L <label>; -U N */
opt_complementary = "=2:L::U+";
getopt32(argv, "abdiL:NqrsS:tTU:wu"
"p" /* ignored (for compatibility) */,
&L_arg, &opt_S_start, &opt_U_context);
/*argc -= optind;*/
argv += optind;
while (L_arg) {
if (label1 && label2)
bb_show_usage();
if (label1) /* then label2 is NULL */
label2 = label1;
label1 = llist_pop(&L_arg);
}
/*
* Do sanity checks, fill in stb1 and stb2 and call the appropriate
* driver routine. Both drivers use the contents of stb1 and stb2.
*/
f1 = argv[0];
f2 = argv[1];
if (LONE_DASH(f1)) {
fstat(STDIN_FILENO, &stb1);
gotstdin++;
} else
xstat(f1, &stb1);
if (LONE_DASH(f2)) {
fstat(STDIN_FILENO, &stb2);
gotstdin++;
} else
xstat(f2, &stb2);
if (gotstdin && (S_ISDIR(stb1.st_mode) || S_ISDIR(stb2.st_mode)))
bb_error_msg_and_die("can't compare stdin to a directory");
if (S_ISDIR(stb1.st_mode) && S_ISDIR(stb2.st_mode)) {
#if ENABLE_FEATURE_DIFF_DIR
diffdir(f1, f2);
return exit_status;
#else
bb_error_msg_and_die("no support for directory comparison");
#endif
}
if (S_ISDIR(stb1.st_mode)) { /* "diff dir file" */
/* NB: "diff dir dir2/dir3/file" must become
* "diff dir/file dir2/dir3/file" */
char *slash = strrchr(f2, '/');
f1 = concat_path_file(f1, slash ? slash + 1 : f2);
xstat(f1, &stb1);
}
if (S_ISDIR(stb2.st_mode)) {
char *slash = strrchr(f1, '/');
f2 = concat_path_file(f2, slash ? slash + 1 : f1);
xstat(f2, &stb2);
}
/* diffreg can get non-regular files here,
* they are not both DIRestories */
print_status((gotstdin > 1 ? D_SAME : diffreg(f1, f2, 0)),
f1, f2 /*, NULL*/);
return exit_status;
}
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