/*
* Mini diff implementation for busybox, adapted from OpenBSD diff.
*
+ * Copyright (C) 2010 by Matheus Izvekov <mizvekov@gmail.com>
* Copyright (C) 2006 by Robert Sullivan <cogito.ergo.cogito@hotmail.com>
* Copyright (c) 2003 Todd C. Miller <Todd.Miller@courtesan.com>
*
* 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.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
-#include "libbb.h"
-
-#define FSIZE_MAX 32768
-
/*
- * Output flags
+ * 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.
*/
-#define D_HEADER 1 /* Print a header/footer between files */
-#define D_EMPTY1 2 /* Treat first file as empty (/dev/null) */
-#define D_EMPTY2 4 /* Treat second file as empty (/dev/null) */
-/*
- * 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_MISMATCH1 - path1 a dir, path2 a file
- * D_MISMATCH2 - 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
- */
+//config:config DIFF
+//config: bool "diff"
+//config: default y
+//config: help
+//config: diff compares two files or directories and outputs the
+//config: differences between them in a form that can be given to
+//config: the patch command.
+//config:
+//config:config FEATURE_DIFF_LONG_OPTIONS
+//config: bool "Enable long options"
+//config: default y
+//config: depends on DIFF && LONG_OPTS
+//config: help
+//config: Enable use of long options.
+//config:
+//config:config FEATURE_DIFF_DIR
+//config: bool "Enable directory support"
+//config: default y
+//config: depends on DIFF
+//config: help
+//config: This option enables support for directory and subdirectory
+//config: comparison.
+
+//kbuild:lib-$(CONFIG_DIFF) += diff.o
+
+//applet:IF_DIFF(APPLET(diff, BB_DIR_USR_BIN, BB_SUID_DROP))
+
+//usage:#define diff_trivial_usage
+//usage: "[-abBdiNqrTstw] [-L LABEL] [-S FILE] [-U LINES] FILE1 FILE2"
+//usage:#define diff_full_usage "\n\n"
+//usage: "Compare files line by line and output the differences between them.\n"
+//usage: "This implementation supports unified diffs only.\n"
+//usage: "\n -a Treat all files as text"
+//usage: "\n -b Ignore changes in the amount of whitespace"
+//usage: "\n -B Ignore changes whose lines are all blank"
+//usage: "\n -d Try hard to find a smaller set of changes"
+//usage: "\n -i Ignore case differences"
+//usage: "\n -L Use LABEL instead of the filename in the unified header"
+//usage: "\n -N Treat absent files as empty"
+//usage: "\n -q Output only whether files differ"
+//usage: "\n -r Recurse"
+//usage: "\n -S Start with FILE when comparing directories"
+//usage: "\n -T Make tabs line up by prefixing a tab when necessary"
+//usage: "\n -s Report when two files are the same"
+//usage: "\n -t Expand tabs to spaces in output"
+//usage: "\n -U Output LINES lines of context"
+//usage: "\n -w Ignore all whitespace"
-#define D_SAME 0
-#define D_DIFFER (1<<0)
-#define D_BINARY (1<<1)
-#define D_COMMON (1<<2)
-#define D_ONLY (1<<3)
-#define D_MISMATCH1 (1<<4)
-#define D_MISMATCH2 (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)
-
-#define g_read_buf bb_common_bufsiz1
+#include "libbb.h"
-struct cand {
- int x;
- int y;
- int pred;
-};
+#if 0
+# define dbg_error_msg(...) bb_error_msg(__VA_ARGS__)
+#else
+# define dbg_error_msg(...) ((void)0)
+#endif
-struct line {
- int serial;
- int value;
+enum { /* print_status() and diffreg() return values */
+ STATUS_SAME, /* files are the same */
+ STATUS_DIFFER, /* files differ */
+ STATUS_BINARY, /* binary files differ */
};
-/*
- * 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 */
+enum { /* Commandline flags */
+ FLAG_a,
+ FLAG_b,
+ FLAG_d,
+ FLAG_i,
+ FLAG_L, /* never used, handled by getopt32 */
+ FLAG_N,
+ FLAG_q,
+ FLAG_r,
+ FLAG_s,
+ FLAG_S, /* never used, handled by getopt32 */
+ FLAG_t,
+ FLAG_T,
+ FLAG_U, /* never used, handled by getopt32 */
+ FLAG_w,
+ FLAG_u, /* ignored, this is the default */
+ FLAG_p, /* not implemented */
+ FLAG_B,
+ FLAG_E, /* not implemented */
};
+#define FLAG(x) (1 << FLAG_##x)
+
+/* We cache file position to avoid excessive seeking */
+typedef struct FILE_and_pos_t {
+ FILE *ft_fp;
+ off_t ft_pos;
+} FILE_and_pos_t;
struct globals {
- USE_FEATURE_DIFF_DIR(char **dl;)
- USE_FEATURE_DIFF_DIR(int dl_count;)
- /* This is the default number of lines of context. */
- int context;
- size_t max_context;
- int status;
- char *start;
- const char *label1;
- const char *label2;
- struct line *file[2];
- int *J; /* will be overlaid on class */
- int *class; /* will be overlaid on file[0] */
- int *klist; /* will be overlaid on file[0] after class */
- int *member; /* will be overlaid on file[1] */
- int clen;
- int len[2];
- int pref, suff; /* length of prefix and suffix */
- int slen[2];
- bool anychange;
- long *ixnew; /* will be overlaid on file[1] */
- long *ixold; /* will be overlaid on klist */
- struct cand *clist; /* merely a free storage pot for candidates */
- int clistlen; /* the length of clist */
- 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;
- struct stat stb1, stb2;
+ smallint exit_status;
+ int opt_U_context;
+ const char *other_dir;
+ char *label[2];
+ struct stat stb[2];
};
#define G (*ptr_to_globals)
-#define dl (G.dl )
-#define dl_count (G.dl_count )
-#define context (G.context )
-#define max_context (G.max_context )
-#define status (G.status )
-#define start (G.start )
-#define label1 (G.label1 )
-#define label2 (G.label2 )
-#define file (G.file )
-#define J (G.J )
-#define class (G.class )
-#define klist (G.klist )
-#define member (G.member )
-#define clen (G.clen )
-#define len (G.len )
-#define pref (G.pref )
-#define suff (G.suff )
-#define slen (G.slen )
-#define anychange (G.anychange )
-#define ixnew (G.ixnew )
-#define ixold (G.ixold )
-#define clist (G.clist )
-#define clistlen (G.clistlen )
-#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 exit_status (G.exit_status )
+#define opt_U_context (G.opt_U_context )
+#define label (G.label )
+#define stb (G.stb )
#define INIT_G() do { \
SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
- context = 3; \
- max_context = 64; \
+ opt_U_context = 3; \
} while (0)
+typedef int token_t;
+
+enum {
+ /* Public */
+ TOK_EMPTY = 1 << 9, /* Line fully processed, you can proceed to the next */
+ TOK_EOF = 1 << 10, /* File ended */
+ /* Private (Only to be used by read_token() */
+ TOK_EOL = 1 << 11, /* we saw EOL (sticky) */
+ TOK_SPACE = 1 << 12, /* used -b code, means we are skipping spaces */
+ SHIFT_EOF = (sizeof(token_t)*8 - 8) - 1,
+ CHAR_MASK = 0x1ff, /* 8th bit is used to distinguish EOF from 0xff */
+};
-static void print_only(const char *path, size_t dirlen, const char *entry)
-{
- if (dirlen > 1)
- dirlen--;
- printf("Only in %.*s: %s\n", (int) dirlen, path, entry);
-}
+/* Restores full EOF from one 8th bit: */
+//#define TOK2CHAR(t) (((t) << SHIFT_EOF) >> SHIFT_EOF)
+/* We don't really need the above, we only need to have EOF != any_real_char: */
+#define TOK2CHAR(t) ((t) & CHAR_MASK)
-static void print_status(int val, char *path1, char *path2, char *entry)
+static void seek_ft(FILE_and_pos_t *ft, off_t pos)
{
- 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, strlen(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_MISMATCH1:
- printf("File %s is a %s while file %s is a %s\n",
- _path1, "directory", _path2, "regular file");
- break;
- case D_MISMATCH2:
- 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);
+ if (ft->ft_pos != pos) {
+ ft->ft_pos = pos;
+ fseeko(ft->ft_fp, pos, SEEK_SET);
}
}
-static ALWAYS_INLINE int fiddle_sum(int sum, int t)
-{
- return sum * 127 + t;
-}
-/*
- * Hash function taken from Robert Sedgewick, Algorithms in C, 3d ed., p 578.
+
+/* Reads tokens from given fp, handling -b and -w flags
+ * The user must reset tok every line start
*/
-static int readhash(FILE *fp)
+static int read_token(FILE_and_pos_t *ft, token_t tok)
{
- int i, t, space;
- int sum;
-
- sum = 1;
- space = 0;
- if (!(option_mask32 & (FLAG_b | FLAG_w))) {
- for (i = 0; (t = getc(fp)) != '\n'; i++) {
- if (t == EOF) {
- if (i == 0)
- return 0;
- break;
- }
- sum = fiddle_sum(sum, t);
- }
- } else {
- for (i = 0;;) {
- switch (t = getc(fp)) {
- case '\t':
- case '\r':
- case '\v':
- case '\f':
- case ' ':
- space++;
- continue;
- default:
- if (space && !(option_mask32 & FLAG_w)) {
- i++;
- space = 0;
- }
- sum = fiddle_sum(sum, t);
- i++;
- continue;
- case EOF:
- if (i == 0)
- return 0;
- /* FALLTHROUGH */
- case '\n':
- break;
+ tok |= TOK_EMPTY;
+ while (!(tok & TOK_EOL)) {
+ bool is_space;
+ int t;
+
+ t = fgetc(ft->ft_fp);
+ if (t != EOF)
+ ft->ft_pos++;
+ is_space = (t == EOF || isspace(t));
+
+ /* If t == EOF (-1), set both TOK_EOF and TOK_EOL */
+ tok |= (t & (TOK_EOF + TOK_EOL));
+ /* Only EOL? */
+ if (t == '\n')
+ tok |= TOK_EOL;
+
+ if (option_mask32 & FLAG(i)) /* Handcoded tolower() */
+ t = (t >= 'A' && t <= 'Z') ? t - ('A' - 'a') : t;
+
+ if ((option_mask32 & FLAG(w)) && is_space)
+ continue;
+
+ /* Trim char value to low 9 bits */
+ t &= CHAR_MASK;
+
+ if (option_mask32 & FLAG(b)) {
+ /* Was prev char whitespace? */
+ if (tok & TOK_SPACE) { /* yes */
+ if (is_space) /* this one too, ignore it */
+ continue;
+ tok &= ~TOK_SPACE;
+ } else if (is_space) {
+ /* 1st whitespace char.
+ * Set TOK_SPACE and replace char by ' ' */
+ t = TOK_SPACE + ' ';
}
- break;
}
+ /* Clear EMPTY */
+ tok &= ~(TOK_EMPTY + CHAR_MASK);
+ /* Assign char value (low 9 bits) and maybe set TOK_SPACE */
+ tok |= t;
+ 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);
+#if 0
+ bb_error_msg("fp:%p tok:%x '%c'%s%s%s%s", fp, tok, tok & 0xff
+ , tok & TOK_EOF ? " EOF" : ""
+ , tok & TOK_EOL ? " EOL" : ""
+ , tok & TOK_EMPTY ? " EMPTY" : ""
+ , tok & TOK_SPACE ? " SPACE" : ""
+ );
+#endif
+ return tok;
}
+struct cand {
+ int x;
+ int y;
+ int pred;
+};
-/*
- * Check to see if the given files differ.
- * Returns 0 if they are the same, 1 if different, and -1 on error.
- */
-static int files_differ(FILE *f1, FILE *f2, int flags)
+static int search(const int *c, int k, int y, const struct cand *list)
{
- size_t i, j;
+ int i, j;
- if ((flags & (D_EMPTY1 | D_EMPTY2)) || stb1.st_size != stb2.st_size
- || (stb1.st_mode & S_IFMT) != (stb2.st_mode & S_IFMT)
- ) {
- 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));
- if (memcmp(g_read_buf,
- g_read_buf + COMMON_BUFSIZE/2, i) != 0)
- return 1;
+ if (list[c[k]].y < y) /* quick look for typical case */
+ return k + 1;
+
+ for (i = 0, j = k + 1;;) {
+ const int l = (i + j) >> 1;
+ if (l > i) {
+ const int t = list[c[l]].y;
+ if (t > y)
+ j = l;
+ else if (t < y)
+ i = l;
+ else
+ return l;
+ } else
+ return l + 1;
}
}
-
-static void prepare(int i, FILE *fp /*, off_t filesize*/)
+static unsigned isqrt(unsigned n)
{
- 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))) {
- if (j == sz) {
- sz = sz * 3 / 2;
- p = xrealloc(p, (sz + 3) * sizeof(p[0]));
- }
- p[++j].value = h;
+ unsigned x = 1;
+ while (1) {
+ const unsigned y = x;
+ x = ((n / x) + x) >> 1;
+ if (x <= (y + 1) && x >= (y - 1))
+ return x;
}
- len[i] = j;
- file[i] = p;
}
-
-static void prune(void)
+static void stone(const int *a, int n, const int *b, int *J, int pref)
{
- int i, j;
+ const unsigned isq = isqrt(n);
+ const unsigned bound =
+ (option_mask32 & FLAG(d)) ? UINT_MAX : MAX(256, isq);
+ int clen = 1;
+ int clistlen = 100;
+ int k = 0;
+ struct cand *clist = xzalloc(clistlen * sizeof(clist[0]));
+ struct cand cand;
+ struct cand *q;
+ int *klist = xzalloc((n + 2) * sizeof(klist[0]));
+ /*clist[0] = (struct cand){0}; - xzalloc did it */
+ /*klist[0] = 0; */
- for (pref = 0; pref < len[0] && pref < len[1] &&
- file[0][pref + 1].value == file[1][pref + 1].value; pref++)
- continue;
- for (suff = 0; suff < len[0] - pref && suff < len[1] - pref &&
- file[0][len[0] - suff].value == file[1][len[1] - suff].value;
- suff++)
- continue;
- for (j = 0; j < 2; j++) {
- sfile[j] = file[j] + pref;
- slen[j] = len[j] - pref - suff;
- for (i = 0; i <= slen[j]; i++)
- sfile[j][i].serial = i;
+ for (cand.x = 1; cand.x <= n; cand.x++) {
+ int j = a[cand.x], oldl = 0;
+ unsigned numtries = 0;
+ if (j == 0)
+ continue;
+ cand.y = -b[j];
+ cand.pred = klist[0];
+ do {
+ int l, tc;
+ if (cand.y <= clist[cand.pred].y)
+ continue;
+ l = search(klist, k, cand.y, clist);
+ if (l != oldl + 1)
+ cand.pred = klist[l - 1];
+ if (l <= k && clist[klist[l]].y <= cand.y)
+ continue;
+ if (clen == clistlen) {
+ clistlen = clistlen * 11 / 10;
+ clist = xrealloc(clist, clistlen * sizeof(clist[0]));
+ }
+ clist[clen] = cand;
+ tc = klist[l];
+ klist[l] = clen++;
+ if (l <= k) {
+ cand.pred = tc;
+ oldl = l;
+ numtries++;
+ } else {
+ k++;
+ break;
+ }
+ } while ((cand.y = b[++j]) > 0 && numtries < bound);
}
+ /* Unravel */
+ for (q = clist + klist[k]; q->y; q = clist + q->pred)
+ J[q->x + pref] = q->y + pref;
+ free(klist);
+ free(clist);
}
+struct line {
+ /* 'serial' is not used in the begining, so we reuse it
+ * to store line offsets, thus reducing memory pressure
+ */
+ union {
+ unsigned serial;
+ off_t offset;
+ };
+ unsigned value;
+};
static void equiv(struct line *a, int n, struct line *b, int m, int *c)
{
- int i, j;
+ int i = 1, j = 1;
- i = j = 1;
while (i <= n && j <= m) {
if (a[i].value < b[j].value)
a[i++].value = 0;
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)
+static void unsort(const struct line *f, int l, int *b)
{
- 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 <= len[0]; i++)
- J[i] = i <= pref ? i : i > len[0] - suff ? i + len[1] - len[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));
+ int *a = xmalloc((l + 1) * sizeof(a[0]));
for (i = 1; i <= l; i++)
a[f[i].serial] = f[i].value;
for (i = 1; i <= l; i++)
free(a);
}
-
-static int skipline(FILE * f)
+static int line_compar(const void *a, const void *b)
{
- int i, c;
-
- for (i = 1; (c = getc(f)) != '\n' && c != EOF; i++)
- continue;
- return i;
+#define l0 ((const struct line*)a)
+#define l1 ((const struct line*)b)
+ int r = l0->value - l1->value;
+ if (r)
+ return r;
+ return l0->serial - l1->serial;
+#undef l0
+#undef l1
}
-
-/*
- * 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 void check(FILE * f1, FILE * f2)
+static void fetch(FILE_and_pos_t *ft, const off_t *ix, int a, int b, int ch)
{
- 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 <= len[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) || (option_mask32 & FLAG_w)
- || (option_mask32 & 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) || (option_mask32 & 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++;
- } while (isspace(c = getc(f1)));
- do {
- if (d == '\n')
- break;
- ctnew++;
- } while (isspace(d = getc(f2)));
- } 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);
- if (d != '\n' && c != EOF)
- ctnew += skipline(f2);
- break;
- }
- if (c == '\n' || c == EOF)
- break;
- }
- }
- ixold[i] = ctold;
- ixnew[j] = ctnew;
- j++;
- }
- for (; j <= len[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;
+ int i, j, col;
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);
+ seek_ft(ft, ix[i - 1]);
+ putchar(ch);
+ if (option_mask32 & FLAG(T))
+ putchar('\t');
+ for (j = 0, col = 0; j < ix[i] - ix[i - 1]; j++) {
+ int c = fgetc(ft->ft_fp);
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 {
+ ft->ft_pos++;
+ if (c == '\t' && (option_mask32 & FLAG(t)))
+ do putchar(' '); while (++col & 7);
+ else {
putchar(c);
col++;
}
}
}
-
-static int asciifile(FILE * f)
+/* Creates the match vector J, where J[i] is the index
+ * of the line in the new file corresponding to the line i
+ * in the old file. Lines start at 1 instead of 0, that value
+ * being used instead to denote no corresponding line.
+ * This vector is dynamically allocated and must be freed by the caller.
+ *
+ * * fp is an input parameter, where fp[0] and fp[1] are the open
+ * old file and new file respectively.
+ * * nlen is an output variable, where nlen[0] and nlen[1]
+ * gets the number of lines in the old and new file respectively.
+ * * ix is an output variable, where ix[0] and ix[1] gets
+ * assigned dynamically allocated vectors of the offsets of the lines
+ * of the old and new file respectively. These must be freed by the caller.
+ */
+static NOINLINE int *create_J(FILE_and_pos_t ft[2], int nlen[2], off_t *ix[2])
{
-#if ENABLE_FEATURE_DIFF_BINARY
- int i, cnt;
-#endif
-
- if ((option_mask32 & FLAG_a) || f == NULL)
- return 1;
-
-#if ENABLE_FEATURE_DIFF_BINARY
- 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;
+ int *J, slen[2], *class, *member;
+ struct line *nfile[2], *sfile[2];
+ int pref = 0, suff = 0, i, j, delta;
+
+ /* Lines of both files are hashed, and in the process
+ * their offsets are stored in the array ix[fileno]
+ * where fileno == 0 points to the old file, and
+ * fileno == 1 points to the new one.
+ */
+ for (i = 0; i < 2; i++) {
+ unsigned hash;
+ token_t tok;
+ size_t sz = 100;
+ nfile[i] = xmalloc((sz + 3) * sizeof(nfile[i][0]));
+ /* ft gets here without the correct position, cant use seek_ft */
+ ft[i].ft_pos = 0;
+ fseeko(ft[i].ft_fp, 0, SEEK_SET);
+
+ nlen[i] = 0;
+ /* We could zalloc nfile, but then zalloc starts showing in gprof at ~1% */
+ nfile[i][0].offset = 0;
+ goto start; /* saves code */
+ while (1) {
+ tok = read_token(&ft[i], tok);
+ if (!(tok & TOK_EMPTY)) {
+ /* Hash algorithm taken from Robert Sedgewick, Algorithms in C, 3d ed., p 578. */
+ /*hash = hash * 128 - hash + TOK2CHAR(tok);
+ * gcc insists on optimizing above to "hash * 127 + ...", thus... */
+ unsigned o = hash - TOK2CHAR(tok);
+ hash = hash * 128 - o; /* we want SPEED here */
+ continue;
+ }
+ if (nlen[i]++ == sz) {
+ sz = sz * 3 / 2;
+ nfile[i] = xrealloc(nfile[i], (sz + 3) * sizeof(nfile[i][0]));
+ }
+ /* line_compar needs hashes fit into positive int */
+ nfile[i][nlen[i]].value = hash & INT_MAX;
+ /* like ftello(ft[i].ft_fp) but faster (avoids lseek syscall) */
+ nfile[i][nlen[i]].offset = ft[i].ft_pos;
+ if (tok & TOK_EOF) {
+ /* EOF counts as a token, so we have to adjust it here */
+ nfile[i][nlen[i]].offset++;
+ break;
+ }
+start:
+ hash = tok = 0;
}
+ /* Exclude lone EOF line from the end of the file, to make fetch()'s job easier */
+ if (nfile[i][nlen[i]].offset - nfile[i][nlen[i] - 1].offset == 1)
+ nlen[i]--;
+ /* Now we copy the line offsets into ix */
+ ix[i] = xmalloc((nlen[i] + 2) * sizeof(ix[i][0]));
+ for (j = 0; j < nlen[i] + 1; j++)
+ ix[i][j] = nfile[i][j].offset;
}
-#endif
- return 1;
-}
-
-/* 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 - context);
- upb = MIN(len[0], context_vec_ptr->b + context);
- lowc = MAX(1, cvp->c - context);
- upd = MIN(len[1], context_vec_ptr->d + 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.
+ /* length of prefix and suffix is calculated */
+ for (; pref < nlen[0] && pref < nlen[1] &&
+ nfile[0][pref + 1].value == nfile[1][pref + 1].value;
+ pref++);
+ for (; suff < nlen[0] - pref && suff < nlen[1] - pref &&
+ nfile[0][nlen[0] - suff].value == nfile[1][nlen[1] - suff].value;
+ suff++);
+ /* Arrays are pruned by the suffix and prefix length,
+ * the result being sorted and stored in sfile[fileno],
+ * and their sizes are stored in slen[fileno]
+ */
+ 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;
+ qsort(sfile[j] + 1, slen[j], sizeof(*sfile[j]), line_compar);
+ }
+ /* nfile arrays are reused to reduce memory pressure
+ * The #if zeroed out section performs the same task as the
+ * one in the #else section.
+ * Peak memory usage is higher, but one array copy is avoided
+ * by not using unsort()
*/
- 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(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;
- }
+ member = xmalloc((slen[1] + 2) * sizeof(member[0]));
+ equiv(sfile[0], slen[0], sfile[1], slen[1], member);
+ free(nfile[1]);
+
+ class = xmalloc((slen[0] + 1) * sizeof(class[0]));
+ for (i = 1; i <= slen[0]; i++) /* Unsorting */
+ class[sfile[0][i].serial] = sfile[0][i].value;
+ free(nfile[0]);
#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, ' ');
+ member = (int *)nfile[1];
+ equiv(sfile[0], slen[0], sfile[1], slen[1], member);
+ member = xrealloc(member, (slen[1] + 2) * sizeof(member[0]));
- context_vec_ptr = context_vec_start - 1;
-}
+ class = (int *)nfile[0];
+ unsort(sfile[0], slen[0], (int *)nfile[0]);
+ class = xrealloc(class, (slen[0] + 2) * sizeof(class[0]));
+#endif
+ J = xmalloc((nlen[0] + 2) * sizeof(J[0]));
+ /* The elements of J which fall inside the prefix and suffix regions
+ * are marked as unchanged, while the ones which fall outside
+ * are initialized with 0 (no matches), so that function stone can
+ * then assign them their right values
+ */
+ for (i = 0, delta = nlen[1] - nlen[0]; i <= nlen[0]; i++)
+ J[i] = i <= pref ? i :
+ i > (nlen[0] - suff) ? (i + delta) : 0;
+ /* Here the magic is performed */
+ stone(class, slen[0], member, J, pref);
+ J[nlen[0] + 1] = nlen[1] + 1;
+ free(class);
+ free(member);
-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));
-}
+ /* Both files are rescanned, in an effort to find any lines
+ * which, due to limitations intrinsic to any hashing algorithm,
+ * are different but ended up confounded as the same
+ */
+ for (i = 1; i <= nlen[0]; i++) {
+ if (!J[i])
+ continue;
+ seek_ft(&ft[0], ix[0][i - 1]);
+ seek_ft(&ft[1], ix[1][J[i] - 1]);
-/*
- * 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;
- }
+ for (j = J[i]; i <= nlen[0] && J[i] == j; i++, j++) {
+ token_t tok0 = 0, tok1 = 0;
+ do {
+ tok0 = read_token(&ft[0], tok0);
+ tok1 = read_token(&ft[1], tok1);
- /*
- * 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 * context) + 1 &&
- c > context_vec_ptr->d + (2 * context) + 1) {
- /*
- * If this change is more than 'context' lines from the
- * previous change, dump the record and reset it.
- */
- dump_unified_vec(f1, f2);
+ if (((tok0 ^ tok1) & TOK_EMPTY) != 0 /* one is empty (not both) */
+ || (!(tok0 & TOK_EMPTY) && TOK2CHAR(tok0) != TOK2CHAR(tok1))
+ ) {
+ J[i] = 0; /* Break the correspondence */
+ }
+ } while (!(tok0 & tok1 & TOK_EMPTY));
+ }
}
- 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 = len[0];
- J[0] = 0;
- J[m + 1] = len[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(file1, f1, file2, f2, i0, i1, j00, j01);
- }
- if (m == 0) {
- change(file1, f1, file2, f2, 1, 0, 1, len[1]);
- }
- if (anychange != 0 && !(option_mask32 & FLAG_q)) {
- dump_unified_vec(f1, f2);
- }
+ return J;
}
-/*
- * 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 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.
- */
-static unsigned diffreg(char *ofile1, char *ofile2, int flags)
+static bool diff(FILE* fp[2], char *file[2])
{
- char *file1 = ofile1;
- char *file2 = ofile2;
- FILE *f1 = stdin, *f2 = stdin;
- unsigned rval;
- int i;
+ int nlen[2];
+ off_t *ix[2];
+ FILE_and_pos_t ft[2];
+ typedef struct { int a, b; } vec_t[2];
+ vec_t *vec = NULL;
+ int i = 1, j, k, idx = -1;
+ bool anychange = false;
+ int *J;
+
+ ft[0].ft_fp = fp[0];
+ ft[1].ft_fp = fp[1];
+ /* note that ft[i].ft_pos is unintitalized, create_J()
+ * must not assume otherwise */
+ J = create_J(ft, nlen, ix);
- anychange = 0;
- context_vec_ptr = context_vec_start - 1;
-
- if (S_ISDIR(stb1.st_mode) != S_ISDIR(stb2.st_mode))
- return (S_ISDIR(stb1.st_mode) ? D_MISMATCH1 : D_MISMATCH2);
-
- rval = D_SAME;
-
- if (LONE_DASH(file1) && LONE_DASH(file2))
- goto closem;
-
- if (flags & D_EMPTY1)
- f1 = xfopen(bb_dev_null, "r");
- else if (NOT_LONE_DASH(file1))
- f1 = xfopen(file1, "r");
- if (flags & D_EMPTY2)
- f2 = xfopen(bb_dev_null, "r");
- else if (NOT_LONE_DASH(file2))
- f2 = xfopen(file2, "r");
-
-/* We can't diff non-seekable stream - we use rewind(), fseek().
- * This can be fixed (volunteers?).
- * Meanwhile we should check it here by stat'ing input fds,
- * but I am lazy and check that in main() instead.
- * Check in main won't catch "diffing fifos buried in subdirectories"
- * failure scenario - not very likely in real life... */
-
- i = files_differ(f1, f2, flags);
- if (i == 0)
- goto closem;
- else if (i != 1) { /* 1 == ok */
- /* error */
- status |= 2;
- goto closem;
- }
+ do {
+ bool nonempty = false;
- if (!asciifile(f1) || !asciifile(f2)) {
- rval = D_BINARY;
- status |= 1;
- goto closem;
- }
+ while (1) {
+ vec_t v;
- prepare(0, f1 /*, stb1.st_size*/);
- prepare(1, f2 /*, stb2.st_size*/);
- prune();
- sort(sfile[0], slen[0]);
- sort(sfile[1], slen[1]);
+ for (v[0].a = i; v[0].a <= nlen[0] && J[v[0].a] == J[v[0].a - 1] + 1; v[0].a++)
+ continue;
+ v[1].a = J[v[0].a - 1] + 1;
- member = (int *) file[1];
- equiv(sfile[0], slen[0], sfile[1], slen[1], member);
- member = xrealloc(member, (slen[1] + 2) * sizeof(int));
+ for (v[0].b = v[0].a - 1; v[0].b < nlen[0] && !J[v[0].b + 1]; v[0].b++)
+ continue;
+ v[1].b = J[v[0].b + 1] - 1;
+ /*
+ * 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.
+ */
+ if (v[0].a <= v[0].b || v[1].a <= v[1].b) {
+ /*
+ * If this change is more than 'context' lines from the
+ * previous change, dump the record and reset it.
+ */
+ int ct = (2 * opt_U_context) + 1;
+ if (idx >= 0
+ && v[0].a > vec[idx][0].b + ct
+ && v[1].a > vec[idx][1].b + ct
+ ) {
+ break;
+ }
- class = (int *) file[0];
- unsort(sfile[0], slen[0], class);
- class = xrealloc(class, (slen[0] + 2) * sizeof(int));
+ for (j = 0; j < 2; j++)
+ for (k = v[j].a; k < v[j].b; k++)
+ nonempty |= (ix[j][k+1] - ix[j][k] != 1);
- 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);
+ vec = xrealloc_vector(vec, 6, ++idx);
+ memcpy(vec[idx], v, sizeof(v));
+ }
- J = xrealloc(J, (len[0] + 2) * sizeof(int));
- unravel(klist[i]);
- free(clist);
- free(klist);
+ i = v[0].b + 1;
+ if (i > nlen[0])
+ break;
+ J[v[0].b] = v[1].b;
+ }
+ if (idx < 0 || ((option_mask32 & FLAG(B)) && !nonempty))
+ goto cont;
+ if (!(option_mask32 & FLAG(q))) {
+ int lowa;
+ vec_t span, *cvp = vec;
+
+ if (!anychange) {
+ /* Print the context/unidiff header first time through */
+ printf("--- %s\n", label[0] ? label[0] : file[0]);
+ printf("+++ %s\n", label[1] ? label[1] : file[1]);
+ }
- ixold = xrealloc(ixold, (len[0] + 2) * sizeof(long));
- ixnew = xrealloc(ixnew, (len[1] + 2) * sizeof(long));
- check(f1, f2);
- output(file1, f1, file2, f2);
+ printf("@@");
+ for (j = 0; j < 2; j++) {
+ int a = span[j].a = MAX(1, (*cvp)[j].a - opt_U_context);
+ int b = span[j].b = MIN(nlen[j], vec[idx][j].b + opt_U_context);
- closem:
- if (anychange) {
- status |= 1;
- if (rval == D_SAME)
- rval = D_DIFFER;
- }
- fclose_if_not_stdin(f1);
- fclose_if_not_stdin(f2);
- if (file1 != ofile1)
- free(file1);
- if (file2 != ofile2)
- free(file2);
- return rval;
+ printf(" %c%d", j ? '+' : '-', MIN(a, b));
+ if (a == b)
+ continue;
+ printf(",%d", (a < b) ? b - a + 1 : 0);
+ }
+ printf(" @@\n");
+ /*
+ * Output changes in "unified" diff format--the old and new lines
+ * are printed together.
+ */
+ for (lowa = span[0].a; ; lowa = (*cvp++)[0].b + 1) {
+ bool end = cvp > &vec[idx];
+ fetch(&ft[0], ix[0], lowa, end ? span[0].b : (*cvp)[0].a - 1, ' ');
+ if (end)
+ break;
+ for (j = 0; j < 2; j++)
+ fetch(&ft[j], ix[j], (*cvp)[j].a, (*cvp)[j].b, j ? '+' : '-');
+ }
+ }
+ anychange = true;
+ cont:
+ idx = -1;
+ } while (i <= nlen[0]);
+
+ free(vec);
+ free(ix[0]);
+ free(ix[1]);
+ free(J);
+ return anychange;
}
-
-#if ENABLE_FEATURE_DIFF_DIR
-static void do_diff(char *dir1, char *path1, char *dir2, char *path2)
+static int diffreg(char *file[2])
{
- int flags = 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);
+ FILE *fp[2];
+ bool binary = false, differ = false;
+ int status = STATUS_SAME, i;
+
+ fp[0] = stdin;
+ fp[1] = stdin;
+ for (i = 0; i < 2; i++) {
+ int fd = open_or_warn_stdin(file[i]);
+ if (fd == -1)
+ goto out;
+ /* Our diff implementation is using seek.
+ * When we meet non-seekable file, we must make a temp copy.
+ */
+ if (lseek(fd, 0, SEEK_SET) == -1 && errno == ESPIPE) {
+ char name[] = "/tmp/difXXXXXX";
+ int fd_tmp = xmkstemp(name);
+
+ unlink(name);
+ if (bb_copyfd_eof(fd, fd_tmp) < 0)
+ xfunc_die();
+ if (fd != STDIN_FILENO)
+ close(fd);
+ fd = fd_tmp;
+ xlseek(fd, 0, SEEK_SET);
}
+ fp[i] = fdopen(fd, "r");
}
- 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);
+
+ while (1) {
+ const size_t sz = COMMON_BUFSIZE / 2;
+ char *const buf0 = bb_common_bufsiz1;
+ char *const buf1 = buf0 + sz;
+ int j, k;
+ i = fread(buf0, 1, sz, fp[0]);
+ j = fread(buf1, 1, sz, fp[1]);
+ if (i != j) {
+ differ = true;
+ i = MIN(i, j);
+ }
+ if (i == 0)
+ break;
+ for (k = 0; k < i; k++) {
+ if (!buf0[k] || !buf1[k])
+ binary = true;
+ if (buf0[k] != buf1[k])
+ differ = true;
}
}
-
- 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 (differ) {
+ if (binary && !(option_mask32 & FLAG(a)))
+ status = STATUS_BINARY;
+ else if (diff(fp, file))
+ status = STATUS_DIFFER;
}
+ if (status != STATUS_SAME)
+ exit_status |= 1;
+out:
+ fclose_if_not_stdin(fp[0]);
+ fclose_if_not_stdin(fp[1]);
- 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
- val = diffreg(fullpath1, fullpath2, flags);
-
- print_status(val, fullpath1, fullpath2, NULL);
- ret:
- free(fullpath1);
- free(fullpath2);
+ return status;
}
-#endif
+static void print_status(int status, char *path[2])
+{
+ switch (status) {
+ case STATUS_BINARY:
+ case STATUS_DIFFER:
+ if ((option_mask32 & FLAG(q)) || status == STATUS_BINARY)
+ printf("Files %s and %s differ\n", path[0], path[1]);
+ break;
+ case STATUS_SAME:
+ if (option_mask32 & FLAG(s))
+ printf("Files %s and %s are identical\n", path[0], path[1]);
+ break;
+ }
+}
#if ENABLE_FEATURE_DIFF_DIR
+struct dlist {
+ size_t len;
+ int s, e;
+ char **dl;
+};
+
/* This function adds a filename to dl, the directory listing. */
-static int add_to_dirlist(const char *filename,
- struct stat ATTRIBUTE_UNUSED * sb, void *userdata,
- int depth ATTRIBUTE_UNUSED)
+static int FAST_FUNC add_to_dirlist(const char *filename,
+ struct stat *sb UNUSED_PARAM,
+ void *userdata, int depth UNUSED_PARAM)
{
- /* +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++;
+ struct dlist *const l = userdata;
+ const char *file = filename + l->len;
+ while (*file == '/')
+ file++;
+ l->dl = xrealloc_vector(l->dl, 6, l->e);
+ l->dl[l->e] = xstrdup(file);
+ l->e++;
return TRUE;
}
-
-/* This returns a sorted directory listing. */
-static char **get_dir(char *path)
+/* If recursion is not set, this function adds the directory
+ * to the list and prevents recursive_action from recursing into it.
+ */
+static int FAST_FUNC skip_dir(const char *filename,
+ struct stat *sb, void *userdata,
+ int depth)
{
- dl_count = 0;
- dl = xzalloc(sizeof(dl[0]));
-
- /* If -r has been set, then the recursive_action function will be
- * used. Unfortunately, this outputs the root directory along with
- * the recursed paths, so use void *userdata to specify the string
- * length of the root directory - '(void*)(strlen(path)+)'.
- * add_to_dirlist then removes root dir prefix. */
-
- if (option_mask32 & FLAG_r) {
- recursive_action(path, ACTION_RECURSE|ACTION_FOLLOWLINKS,
- add_to_dirlist, NULL,
- (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);
+ if (!(option_mask32 & FLAG(r)) && depth) {
+ add_to_dirlist(filename, sb, userdata, depth);
+ return SKIP;
+ }
+ if (!(option_mask32 & FLAG(N))) {
+ /* -r without -N: no need to recurse into dirs
+ * which do not exist on the "other side".
+ * Testcase: diff -r /tmp /
+ * (it would recurse deep into /proc without this code) */
+ struct dlist *const l = userdata;
+ filename += l->len;
+ if (filename[0]) {
+ struct stat osb;
+ char *othername = concat_path_file(G.other_dir, filename);
+ int r = stat(othername, &osb);
+ free(othername);
+ if (r != 0 || !S_ISDIR(osb.st_mode)) {
+ /* other dir doesn't have similarly named
+ * directory, don't recurse; return 1 upon
+ * exit, just like diffutils' diff */
+ exit_status |= 1;
+ return SKIP;
+ }
}
- closedir(dp);
}
-
- /* Sort dl alphabetically. */
- qsort_string_vector(dl, dl_count);
-
- dl[dl_count] = NULL;
- return dl;
+ return TRUE;
}
-
-static void diffdir(char *p1, char *p2)
+static void diffdir(char *p[2], const char *s_start)
{
- 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_dir(p1);
- dirlist2 = get_dir(p2);
-
- /* If -S was set, find the starting point. */
- if (start) {
- while (*dirlist1 != NULL && strcmp(*dirlist1, start) < 0)
- dirlist1++;
- while (*dirlist2 != NULL && strcmp(*dirlist2, start) < 0)
- dirlist2++;
- if ((*dirlist1 == NULL) || (*dirlist2 == NULL))
- bb_error_msg(bb_msg_invalid_arg, "NULL", "-S");
- }
+ struct dlist list[2];
+ int i;
+ memset(&list, 0, sizeof(list));
+ for (i = 0; i < 2; i++) {
+ /*list[i].s = list[i].e = 0; - memset did it */
+ /*list[i].dl = NULL; */
+
+ G.other_dir = p[1 - i];
+ /* We need to trim root directory prefix.
+ * Using list.len to specify its length,
+ * add_to_dirlist will remove it. */
+ list[i].len = strlen(p[i]);
+ recursive_action(p[i], ACTION_RECURSE | ACTION_FOLLOWLINKS,
+ add_to_dirlist, skip_dir, &list[i], 0);
+ /* Sort dl alphabetically.
+ * GNU diff does this ignoring any number of trailing dots.
+ * We don't, so for us dotted files almost always are
+ * first on the list.
+ */
+ qsort_string_vector(list[i].dl, list[i].e);
+ /* If -S was set, find the starting point. */
+ if (!s_start)
+ continue;
+ while (list[i].s < list[i].e && strcmp(list[i].dl[list[i].s], s_start) < 0)
+ list[i].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, strlen(p1) + 1, dp1);
- dirlist1++;
+ while (1) {
+ char *dp[2];
+ int pos;
+ int k;
+
+ dp[0] = list[0].s < list[0].e ? list[0].dl[list[0].s] : NULL;
+ dp[1] = list[1].s < list[1].e ? list[1].dl[list[1].s] : NULL;
+ if (!dp[0] && !dp[1])
+ break;
+ pos = !dp[0] ? 1 : (!dp[1] ? -1 : strcmp(dp[0], dp[1]));
+ k = pos > 0;
+ if (pos && !(option_mask32 & FLAG(N))) {
+ printf("Only in %s: %s\n", p[k], dp[k]);
+ exit_status |= 1;
} else {
- if (option_mask32 & FLAG_N)
- do_diff(p1, NULL, p2, dp2);
- else
- print_only(p2, strlen(p2) + 1, dp2);
- dirlist2++;
+ char *fullpath[2], *path[2]; /* if -N */
+
+ for (i = 0; i < 2; i++) {
+ if (pos == 0 || i == k) {
+ path[i] = fullpath[i] = concat_path_file(p[i], dp[i]);
+ stat(fullpath[i], &stb[i]);
+ } else {
+ fullpath[i] = concat_path_file(p[i], dp[1 - i]);
+ path[i] = (char *)bb_dev_null;
+ }
+ }
+ if (pos)
+ stat(fullpath[k], &stb[1 - k]);
+
+ if (S_ISDIR(stb[0].st_mode) && S_ISDIR(stb[1].st_mode))
+ printf("Common subdirectories: %s and %s\n", fullpath[0], fullpath[1]);
+ else if (!S_ISREG(stb[0].st_mode) && !S_ISDIR(stb[0].st_mode))
+ printf("File %s is not a regular file or directory and was skipped\n", fullpath[0]);
+ else if (!S_ISREG(stb[1].st_mode) && !S_ISDIR(stb[1].st_mode))
+ printf("File %s is not a regular file or directory and was skipped\n", fullpath[1]);
+ else if (S_ISDIR(stb[0].st_mode) != S_ISDIR(stb[1].st_mode)) {
+ if (S_ISDIR(stb[0].st_mode))
+ printf("File %s is a %s while file %s is a %s\n", fullpath[0], "directory", fullpath[1], "regular file");
+ else
+ printf("File %s is a %s while file %s is a %s\n", fullpath[0], "regular file", fullpath[1], "directory");
+ } else
+ print_status(diffreg(path), fullpath);
+
+ free(fullpath[0]);
+ free(fullpath[1]);
+ }
+ free(dp[k]);
+ list[k].s++;
+ if (pos == 0) {
+ free(dp[1 - k]);
+ list[1 - k].s++;
}
}
+ if (ENABLE_FEATURE_CLEAN_UP) {
+ free(list[0].dl);
+ free(list[1].dl);
+ }
}
#endif
+#if ENABLE_FEATURE_DIFF_LONG_OPTIONS
+static const char diff_longopts[] ALIGN1 =
+ "ignore-case\0" No_argument "i"
+ "ignore-tab-expansion\0" No_argument "E"
+ "ignore-space-change\0" No_argument "b"
+ "ignore-all-space\0" No_argument "w"
+ "ignore-blank-lines\0" No_argument "B"
+ "text\0" No_argument "a"
+ "unified\0" Required_argument "U"
+ "label\0" Required_argument "L"
+ "show-c-function\0" No_argument "p"
+ "brief\0" No_argument "q"
+ "expand-tabs\0" No_argument "t"
+ "initial-tab\0" No_argument "T"
+ "recursive\0" No_argument "r"
+ "new-file\0" No_argument "N"
+ "report-identical-files\0" No_argument "s"
+ "starting-file\0" Required_argument "S"
+ "minimal\0" No_argument "d"
+ ;
+#endif
int diff_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int diff_main(int argc ATTRIBUTE_UNUSED, char **argv)
+int diff_main(int argc UNUSED_PARAM, char **argv)
{
- bool gotstdin = 0;
- char *U_opt;
- char *f1, *f2;
+ int gotstdin = 0, i;
+ char *file[2], *s_start = NULL;
llist_t *L_arg = NULL;
INIT_G();
- /* exactly 2 params; collect multiple -L <label> */
- opt_complementary = "=2:L::";
- getopt32(argv, "abdiL:NqrsS:tTU:wu"
- "p" /* ignored (for compatibility) */,
- &L_arg, &start, &U_opt);
- /*argc -= optind;*/
+ /* exactly 2 params; collect multiple -L <label>; -U N */
+ opt_complementary = "=2:L::U+";
+#if ENABLE_FEATURE_DIFF_LONG_OPTIONS
+ applet_long_options = diff_longopts;
+#endif
+ getopt32(argv, "abdiL:NqrsS:tTU:wupBE",
+ &L_arg, &s_start, &opt_U_context);
argv += optind;
- while (L_arg) {
- if (label1 && label2)
- bb_show_usage();
- if (!label1)
- label1 = L_arg->data;
- else { /* then label2 is NULL */
- label2 = label1;
- label1 = L_arg->data;
- }
- /* we leak L_arg here... */
- L_arg = L_arg->link;
+ while (L_arg)
+ label[!!label[0]] = llist_pop(&L_arg);
+ xfunc_error_retval = 2;
+ for (i = 0; i < 2; i++) {
+ file[i] = argv[i];
+ /* Compat: "diff file name_which_doesnt_exist" exits with 2 */
+ if (LONE_DASH(file[i])) {
+ fstat(STDIN_FILENO, &stb[i]);
+ gotstdin++;
+ } else
+ xstat(file[i], &stb[i]);
}
- if (option_mask32 & FLAG_U)
- context = xatoi_u(U_opt);
-
- /*
- * Do sanity checks, fill in stb1 and stb2 and call the appropriate
- * driver routine. Both drivers use the contents of stb1 and stb2.
+ xfunc_error_retval = 1;
+ if (gotstdin && (S_ISDIR(stb[0].st_mode) || S_ISDIR(stb[1].st_mode)))
+ bb_error_msg_and_die("can't compare stdin to a directory");
+
+ /* Compare metadata to check if the files are the same physical file.
+ *
+ * Comment from diffutils source says:
+ * POSIX says that two files are identical if st_ino and st_dev are
+ * the same, but many file systems incorrectly assign the same (device,
+ * inode) pair to two distinct files, including:
+ * GNU/Linux NFS servers that export all local file systems as a
+ * single NFS file system, if a local device number (st_dev) exceeds
+ * 255, or if a local inode number (st_ino) exceeds 16777215.
*/
+ if (ENABLE_DESKTOP
+ && stb[0].st_ino == stb[1].st_ino
+ && stb[0].st_dev == stb[1].st_dev
+ && stb[0].st_size == stb[1].st_size
+ && stb[0].st_mtime == stb[1].st_mtime
+ && stb[0].st_ctime == stb[1].st_ctime
+ && stb[0].st_mode == stb[1].st_mode
+ && stb[0].st_nlink == stb[1].st_nlink
+ && stb[0].st_uid == stb[1].st_uid
+ && stb[0].st_gid == stb[1].st_gid
+ ) {
+ /* files are physically the same; no need to compare them */
+ return STATUS_SAME;
+ }
- f1 = argv[0];
- f2 = argv[1];
- if (LONE_DASH(f1)) {
- fstat(STDIN_FILENO, &stb1);
- gotstdin = 1;
- } else
- xstat(f1, &stb1);
- if (LONE_DASH(f2)) {
- fstat(STDIN_FILENO, &stb2);
- gotstdin = 1;
- } else
- xstat(f2, &stb2);
- if (gotstdin && (S_ISDIR(stb1.st_mode) || S_ISDIR(stb2.st_mode)))
- bb_error_msg_and_die("can't compare - to a directory");
- if (S_ISDIR(stb1.st_mode) && S_ISDIR(stb2.st_mode)) {
+ if (S_ISDIR(stb[0].st_mode) && S_ISDIR(stb[1].st_mode)) {
#if ENABLE_FEATURE_DIFF_DIR
- diffdir(f1, f2);
+ diffdir(file, s_start);
#else
- bb_error_msg_and_die("directory comparison not supported");
+ bb_error_msg_and_die("no support for directory comparison");
#endif
} else {
- if (S_ISDIR(stb1.st_mode)) {
- f1 = concat_path_file(f1, f2);
- xstat(f1, &stb1);
- }
- if (S_ISDIR(stb2.st_mode)) {
- f2 = concat_path_file(f2, f1);
- xstat(f2, &stb2);
+ bool dirfile = S_ISDIR(stb[0].st_mode) || S_ISDIR(stb[1].st_mode);
+ bool dir = S_ISDIR(stb[1].st_mode);
+ if (dirfile) {
+ const char *slash = strrchr(file[!dir], '/');
+ file[dir] = concat_path_file(file[dir], slash ? slash + 1 : file[!dir]);
+ xstat(file[dir], &stb[dir]);
}
-/* XXX: FIXME: */
-/* We can't diff e.g. stdin supplied by a pipe - we use rewind(), fseek().
- * This can be fixed (volunteers?) */
- if (!S_ISREG(stb1.st_mode) || !S_ISREG(stb2.st_mode))
- bb_error_msg_and_die("can't diff non-seekable stream");
- print_status(diffreg(f1, f2, 0), f1, f2, NULL);
+ /* diffreg can get non-regular files here */
+ print_status(gotstdin > 1 ? STATUS_SAME : diffreg(file), file);
+
+ if (dirfile)
+ free(file[dir]);
}
- return status;
+
+ return exit_status;
}
projects / oweals / busybox.git / blobdiff