[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Emacs-diffs] master d682f0d: Add command to replace buffer contents
|
From: |
Philipp Stephani |
|
Subject: |
[Emacs-diffs] master d682f0d: Add command to replace buffer contents |
|
Date: |
Sat, 17 Jun 2017 09:46:58 -0400 (EDT) |
branch: master
commit d682f0daa3c0bfdd5ee8ce0e9226353d505e85a9
Author: Philipp Stephani <address@hidden>
Commit: Philipp Stephani <address@hidden>
Add command to replace buffer contents
Add a new command 'replace-buffer-contents' that uses the Myers diff
algorithm to non-destructively replace the accessible portion of the
current buffer. The Myers algorithm is implemented in Gnulib.
* src/editfns.c (Freplace_buffer_contents): New command.
(set_bit, bit_is_set, buffer_chars_equal): New helper functions.
(syms_of_editfns): Define new command.
* test/src/editfns-tests.el (replace-buffer-contents-1)
(replace-buffer-contents-2): New unit tests.
* src/buffer.h (BUF_FETCH_CHAR_AS_MULTIBYTE): New helper macro.
* admin/merge-gnulib (GNULIB_MODULES): Add diffseq.h and minmax.h.
---
admin/merge-gnulib | 4 +-
etc/NEWS | 5 +
lib/diffseq.h | 525 ++++++++++++++++++++++++++++++++++++++++++++++
lib/gnulib.mk.in | 18 +-
lib/minmax.h | 60 ++++++
m4/gnulib-comp.m4 | 6 +
m4/minmax.m4 | 44 ++++
src/buffer.h | 9 +
src/editfns.c | 201 ++++++++++++++++++
test/src/editfns-tests.el | 31 +++
10 files changed, 900 insertions(+), 3 deletions(-)
diff --git a/admin/merge-gnulib b/admin/merge-gnulib
index e5fb0f5..d4bbf17 100755
--- a/admin/merge-gnulib
+++ b/admin/merge-gnulib
@@ -30,12 +30,12 @@ GNULIB_MODULES='
careadlinkat close-stream
count-leading-zeros count-one-bits count-trailing-zeros
crypto/md5 crypto/sha1 crypto/sha256 crypto/sha512
- dtoastr dtotimespec dup2 environ execinfo faccessat
+ diffseq dtoastr dtotimespec dup2 environ execinfo faccessat
fcntl fcntl-h fdatasync fdopendir
filemode filevercmp flexmember fstatat fsync
getloadavg getopt-gnu gettime gettimeofday gitlog-to-changelog
ignore-value intprops largefile lstat
- manywarnings memrchr mkostemp mktime
+ manywarnings memrchr minmax mkostemp mktime
pipe2 pselect pthread_sigmask putenv qcopy-acl readlink readlinkat
sig2str socklen stat-time std-gnu11 stdalign stddef stdio
stpcpy strftime strtoimax symlink sys_stat
diff --git a/etc/NEWS b/etc/NEWS
index 2fb8daa..ab600eb 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -462,6 +462,11 @@ Negative prefix arg flips the direction of selection.
Also,
defun are selected unless they are separated from the defun by a blank
line.
+** New command 'replace-buffer-contents'. This command replaces the
+contents of theaccessible portion of the current buffer with the
+contents of the accessible portion of a different buffer while keeping
+point, mark, markers, and text properties as intact as possible.
+
* Changes in Specialized Modes and Packages in Emacs 26.1
diff --git a/lib/diffseq.h b/lib/diffseq.h
new file mode 100644
index 0000000..d7a3743
--- /dev/null
+++ b/lib/diffseq.h
@@ -0,0 +1,525 @@
+/* Analyze differences between two vectors.
+
+ Copyright (C) 1988-1989, 1992-1995, 2001-2004, 2006-2017 Free Software
+ Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+
+/* The basic idea is to consider two vectors as similar if, when
+ transforming the first vector into the second vector through a
+ sequence of edits (inserts and deletes of one element each),
+ this sequence is short - or equivalently, if the ordered list
+ of elements that are untouched by these edits is long. For a
+ good introduction to the subject, read about the "Levenshtein
+ distance" in Wikipedia.
+
+ The basic algorithm is described in:
+ "An O(ND) Difference Algorithm and its Variations", Eugene W. Myers,
+ Algorithmica Vol. 1, 1986, pp. 251-266,
+ <http://dx.doi.org/10.1007/BF01840446>.
+ See especially section 4.2, which describes the variation used below.
+
+ The basic algorithm was independently discovered as described in:
+ "Algorithms for Approximate String Matching", Esko Ukkonen,
+ Information and Control Vol. 64, 1985, pp. 100-118,
+ <http://dx.doi.org/10.1016/S0019-9958(85)80046-2>.
+
+ Unless the 'find_minimal' flag is set, this code uses the TOO_EXPENSIVE
+ heuristic, by Paul Eggert, to limit the cost to O(N**1.5 log N)
+ at the price of producing suboptimal output for large inputs with
+ many differences. */
+
+/* Before including this file, you need to define:
+ ELEMENT The element type of the vectors being compared.
+ EQUAL A two-argument macro that tests two elements for
+ equality.
+ OFFSET A signed integer type sufficient to hold the
+ difference between two indices. Usually
+ something like ptrdiff_t.
+ EXTRA_CONTEXT_FIELDS Declarations of fields for 'struct context'.
+ NOTE_DELETE(ctxt, xoff) Record the removal of the object xvec[xoff].
+ NOTE_INSERT(ctxt, yoff) Record the insertion of the object yvec[yoff].
+ EARLY_ABORT(ctxt) (Optional) A boolean expression that triggers an
+ early abort of the computation.
+ USE_HEURISTIC (Optional) Define if you want to support the
+ heuristic for large vectors.
+ It is also possible to use this file with abstract arrays. In this case,
+ xvec and yvec are not represented in memory. They only exist conceptually.
+ In this case, the list of defines above is amended as follows:
+ ELEMENT Undefined.
+ EQUAL Undefined.
+ XVECREF_YVECREF_EQUAL(ctxt, xoff, yoff)
+ A three-argument macro: References xvec[xoff] and
+ yvec[yoff] and tests these elements for equality.
+ Before including this file, you also need to include:
+ #include <limits.h>
+ #include <stdbool.h>
+ #include "minmax.h"
+ */
+
+/* Maximum value of type OFFSET. */
+#define OFFSET_MAX \
+ ((((OFFSET)1 << (sizeof (OFFSET) * CHAR_BIT - 2)) - 1) * 2 + 1)
+
+/* Default to no early abort. */
+#ifndef EARLY_ABORT
+# define EARLY_ABORT(ctxt) false
+#endif
+
+/* Use this to suppress gcc's "...may be used before initialized" warnings.
+ Beware: The Code argument must not contain commas. */
+#ifndef IF_LINT
+# if defined GCC_LINT || defined lint
+# define IF_LINT(Code) Code
+# else
+# define IF_LINT(Code) /* empty */
+# endif
+#endif
+
+/* As above, but when Code must contain one comma. */
+#ifndef IF_LINT2
+# if defined GCC_LINT || defined lint
+# define IF_LINT2(Code1, Code2) Code1, Code2
+# else
+# define IF_LINT2(Code1, Code2) /* empty */
+# endif
+#endif
+
+/*
+ * Context of comparison operation.
+ */
+struct context
+{
+ #ifdef ELEMENT
+ /* Vectors being compared. */
+ ELEMENT const *xvec;
+ ELEMENT const *yvec;
+ #endif
+
+ /* Extra fields. */
+ EXTRA_CONTEXT_FIELDS
+
+ /* Vector, indexed by diagonal, containing 1 + the X coordinate of the point
+ furthest along the given diagonal in the forward search of the edit
+ matrix. */
+ OFFSET *fdiag;
+
+ /* Vector, indexed by diagonal, containing the X coordinate of the point
+ furthest along the given diagonal in the backward search of the edit
+ matrix. */
+ OFFSET *bdiag;
+
+ #ifdef USE_HEURISTIC
+ /* This corresponds to the diff --speed-large-files flag. With this
+ heuristic, for vectors with a constant small density of changes,
+ the algorithm is linear in the vector size. */
+ bool heuristic;
+ #endif
+
+ /* Edit scripts longer than this are too expensive to compute. */
+ OFFSET too_expensive;
+
+ /* Snakes bigger than this are considered "big". */
+ #define SNAKE_LIMIT 20
+};
+
+struct partition
+{
+ /* Midpoints of this partition. */
+ OFFSET xmid;
+ OFFSET ymid;
+
+ /* True if low half will be analyzed minimally. */
+ bool lo_minimal;
+
+ /* Likewise for high half. */
+ bool hi_minimal;
+};
+
+
+/* Find the midpoint of the shortest edit script for a specified portion
+ of the two vectors.
+
+ Scan from the beginnings of the vectors, and simultaneously from the ends,
+ doing a breadth-first search through the space of edit-sequence.
+ When the two searches meet, we have found the midpoint of the shortest
+ edit sequence.
+
+ If FIND_MINIMAL is true, find the minimal edit script regardless of
+ expense. Otherwise, if the search is too expensive, use heuristics to
+ stop the search and report a suboptimal answer.
+
+ Set PART->(xmid,ymid) to the midpoint (XMID,YMID). The diagonal number
+ XMID - YMID equals the number of inserted elements minus the number
+ of deleted elements (counting only elements before the midpoint).
+
+ Set PART->lo_minimal to true iff the minimal edit script for the
+ left half of the partition is known; similarly for PART->hi_minimal.
+
+ This function assumes that the first elements of the specified portions
+ of the two vectors do not match, and likewise that the last elements do not
+ match. The caller must trim matching elements from the beginning and end
+ of the portions it is going to specify.
+
+ If we return the "wrong" partitions, the worst this can do is cause
+ suboptimal diff output. It cannot cause incorrect diff output. */
+
+static void
+diag (OFFSET xoff, OFFSET xlim, OFFSET yoff, OFFSET ylim, bool find_minimal,
+ struct partition *part, struct context *ctxt)
+{
+ OFFSET *const fd = ctxt->fdiag; /* Give the compiler a chance. */
+ OFFSET *const bd = ctxt->bdiag; /* Additional help for the compiler. */
+#ifdef ELEMENT
+ ELEMENT const *const xv = ctxt->xvec; /* Still more help for the compiler. */
+ ELEMENT const *const yv = ctxt->yvec; /* And more and more . . . */
+ #define XREF_YREF_EQUAL(x,y) EQUAL (xv[x], yv[y])
+#else
+ #define XREF_YREF_EQUAL(x,y) XVECREF_YVECREF_EQUAL (ctxt, x, y)
+#endif
+ const OFFSET dmin = xoff - ylim; /* Minimum valid diagonal. */
+ const OFFSET dmax = xlim - yoff; /* Maximum valid diagonal. */
+ const OFFSET fmid = xoff - yoff; /* Center diagonal of top-down search.
*/
+ const OFFSET bmid = xlim - ylim; /* Center diagonal of bottom-up
search. */
+ OFFSET fmin = fmid;
+ OFFSET fmax = fmid; /* Limits of top-down search. */
+ OFFSET bmin = bmid;
+ OFFSET bmax = bmid; /* Limits of bottom-up search. */
+ OFFSET c; /* Cost. */
+ bool odd = (fmid - bmid) & 1; /* True if southeast corner is on an odd
+ diagonal with respect to the northwest. */
+
+ fd[fmid] = xoff;
+ bd[bmid] = xlim;
+
+ for (c = 1;; ++c)
+ {
+ OFFSET d; /* Active diagonal. */
+ bool big_snake = false;
+
+ /* Extend the top-down search by an edit step in each diagonal. */
+ if (fmin > dmin)
+ fd[--fmin - 1] = -1;
+ else
+ ++fmin;
+ if (fmax < dmax)
+ fd[++fmax + 1] = -1;
+ else
+ --fmax;
+ for (d = fmax; d >= fmin; d -= 2)
+ {
+ OFFSET x;
+ OFFSET y;
+ OFFSET tlo = fd[d - 1];
+ OFFSET thi = fd[d + 1];
+ OFFSET x0 = tlo < thi ? thi : tlo + 1;
+
+ for (x = x0, y = x0 - d;
+ x < xlim && y < ylim && XREF_YREF_EQUAL (x, y);
+ x++, y++)
+ continue;
+ if (x - x0 > SNAKE_LIMIT)
+ big_snake = true;
+ fd[d] = x;
+ if (odd && bmin <= d && d <= bmax && bd[d] <= x)
+ {
+ part->xmid = x;
+ part->ymid = y;
+ part->lo_minimal = part->hi_minimal = true;
+ return;
+ }
+ }
+
+ /* Similarly extend the bottom-up search. */
+ if (bmin > dmin)
+ bd[--bmin - 1] = OFFSET_MAX;
+ else
+ ++bmin;
+ if (bmax < dmax)
+ bd[++bmax + 1] = OFFSET_MAX;
+ else
+ --bmax;
+ for (d = bmax; d >= bmin; d -= 2)
+ {
+ OFFSET x;
+ OFFSET y;
+ OFFSET tlo = bd[d - 1];
+ OFFSET thi = bd[d + 1];
+ OFFSET x0 = tlo < thi ? tlo : thi - 1;
+
+ for (x = x0, y = x0 - d;
+ xoff < x && yoff < y && XREF_YREF_EQUAL (x - 1, y - 1);
+ x--, y--)
+ continue;
+ if (x0 - x > SNAKE_LIMIT)
+ big_snake = true;
+ bd[d] = x;
+ if (!odd && fmin <= d && d <= fmax && x <= fd[d])
+ {
+ part->xmid = x;
+ part->ymid = y;
+ part->lo_minimal = part->hi_minimal = true;
+ return;
+ }
+ }
+
+ if (find_minimal)
+ continue;
+
+#ifdef USE_HEURISTIC
+ /* Heuristic: check occasionally for a diagonal that has made lots
+ of progress compared with the edit distance. If we have any
+ such, find the one that has made the most progress and return it
+ as if it had succeeded.
+
+ With this heuristic, for vectors with a constant small density
+ of changes, the algorithm is linear in the vector size. */
+
+ if (200 < c && big_snake && ctxt->heuristic)
+ {
+ {
+ OFFSET best = 0;
+
+ for (d = fmax; d >= fmin; d -= 2)
+ {
+ OFFSET dd = d - fmid;
+ OFFSET x = fd[d];
+ OFFSET y = x - d;
+ OFFSET v = (x - xoff) * 2 - dd;
+
+ if (v > 12 * (c + (dd < 0 ? -dd : dd)))
+ {
+ if (v > best
+ && xoff + SNAKE_LIMIT <= x && x < xlim
+ && yoff + SNAKE_LIMIT <= y && y < ylim)
+ {
+ /* We have a good enough best diagonal; now insist
+ that it end with a significant snake. */
+ int k;
+
+ for (k = 1; XREF_YREF_EQUAL (x - k, y - k); k++)
+ if (k == SNAKE_LIMIT)
+ {
+ best = v;
+ part->xmid = x;
+ part->ymid = y;
+ break;
+ }
+ }
+ }
+ }
+ if (best > 0)
+ {
+ part->lo_minimal = true;
+ part->hi_minimal = false;
+ return;
+ }
+ }
+
+ {
+ OFFSET best = 0;
+
+ for (d = bmax; d >= bmin; d -= 2)
+ {
+ OFFSET dd = d - bmid;
+ OFFSET x = bd[d];
+ OFFSET y = x - d;
+ OFFSET v = (xlim - x) * 2 + dd;
+
+ if (v > 12 * (c + (dd < 0 ? -dd : dd)))
+ {
+ if (v > best
+ && xoff < x && x <= xlim - SNAKE_LIMIT
+ && yoff < y && y <= ylim - SNAKE_LIMIT)
+ {
+ /* We have a good enough best diagonal; now insist
+ that it end with a significant snake. */
+ int k;
+
+ for (k = 0; XREF_YREF_EQUAL (x + k, y + k); k++)
+ if (k == SNAKE_LIMIT - 1)
+ {
+ best = v;
+ part->xmid = x;
+ part->ymid = y;
+ break;
+ }
+ }
+ }
+ }
+ if (best > 0)
+ {
+ part->lo_minimal = false;
+ part->hi_minimal = true;
+ return;
+ }
+ }
+ }
+#endif /* USE_HEURISTIC */
+
+ /* Heuristic: if we've gone well beyond the call of duty, give up
+ and report halfway between our best results so far. */
+ if (c >= ctxt->too_expensive)
+ {
+ OFFSET fxybest;
+ OFFSET fxbest IF_LINT (= 0);
+ OFFSET bxybest;
+ OFFSET bxbest IF_LINT (= 0);
+
+ /* Find forward diagonal that maximizes X + Y. */
+ fxybest = -1;
+ for (d = fmax; d >= fmin; d -= 2)
+ {
+ OFFSET x = MIN (fd[d], xlim);
+ OFFSET y = x - d;
+ if (ylim < y)
+ {
+ x = ylim + d;
+ y = ylim;
+ }
+ if (fxybest < x + y)
+ {
+ fxybest = x + y;
+ fxbest = x;
+ }
+ }
+
+ /* Find backward diagonal that minimizes X + Y. */
+ bxybest = OFFSET_MAX;
+ for (d = bmax; d >= bmin; d -= 2)
+ {
+ OFFSET x = MAX (xoff, bd[d]);
+ OFFSET y = x - d;
+ if (y < yoff)
+ {
+ x = yoff + d;
+ y = yoff;
+ }
+ if (x + y < bxybest)
+ {
+ bxybest = x + y;
+ bxbest = x;
+ }
+ }
+
+ /* Use the better of the two diagonals. */
+ if ((xlim + ylim) - bxybest < fxybest - (xoff + yoff))
+ {
+ part->xmid = fxbest;
+ part->ymid = fxybest - fxbest;
+ part->lo_minimal = true;
+ part->hi_minimal = false;
+ }
+ else
+ {
+ part->xmid = bxbest;
+ part->ymid = bxybest - bxbest;
+ part->lo_minimal = false;
+ part->hi_minimal = true;
+ }
+ return;
+ }
+ }
+ #undef XREF_YREF_EQUAL
+}
+
+
+/* Compare in detail contiguous subsequences of the two vectors
+ which are known, as a whole, to match each other.
+
+ The subsequence of vector 0 is [XOFF, XLIM) and likewise for vector 1.
+
+ Note that XLIM, YLIM are exclusive bounds. All indices into the vectors
+ are origin-0.
+
+ If FIND_MINIMAL, find a minimal difference no matter how
+ expensive it is.
+
+ The results are recorded by invoking NOTE_DELETE and NOTE_INSERT.
+
+ Return false if terminated normally, or true if terminated through early
+ abort. */
+
+static bool
+compareseq (OFFSET xoff, OFFSET xlim, OFFSET yoff, OFFSET ylim,
+ bool find_minimal, struct context *ctxt)
+{
+#ifdef ELEMENT
+ ELEMENT const *xv = ctxt->xvec; /* Help the compiler. */
+ ELEMENT const *yv = ctxt->yvec;
+ #define XREF_YREF_EQUAL(x,y) EQUAL (xv[x], yv[y])
+#else
+ #define XREF_YREF_EQUAL(x,y) XVECREF_YVECREF_EQUAL (ctxt, x, y)
+#endif
+
+ /* Slide down the bottom initial diagonal. */
+ while (xoff < xlim && yoff < ylim && XREF_YREF_EQUAL (xoff, yoff))
+ {
+ xoff++;
+ yoff++;
+ }
+
+ /* Slide up the top initial diagonal. */
+ while (xoff < xlim && yoff < ylim && XREF_YREF_EQUAL (xlim - 1, ylim - 1))
+ {
+ xlim--;
+ ylim--;
+ }
+
+ /* Handle simple cases. */
+ if (xoff == xlim)
+ while (yoff < ylim)
+ {
+ NOTE_INSERT (ctxt, yoff);
+ if (EARLY_ABORT (ctxt))
+ return true;
+ yoff++;
+ }
+ else if (yoff == ylim)
+ while (xoff < xlim)
+ {
+ NOTE_DELETE (ctxt, xoff);
+ if (EARLY_ABORT (ctxt))
+ return true;
+ xoff++;
+ }
+ else
+ {
+ struct partition part IF_LINT2 (= { .xmid = 0, .ymid = 0 });
+
+ /* Find a point of correspondence in the middle of the vectors. */
+ diag (xoff, xlim, yoff, ylim, find_minimal, &part, ctxt);
+
+ /* Use the partitions to split this problem into subproblems. */
+ if (compareseq (xoff, part.xmid, yoff, part.ymid, part.lo_minimal, ctxt))
+ return true;
+ if (compareseq (part.xmid, xlim, part.ymid, ylim, part.hi_minimal, ctxt))
+ return true;
+ }
+
+ return false;
+ #undef XREF_YREF_EQUAL
+}
+
+#undef ELEMENT
+#undef EQUAL
+#undef OFFSET
+#undef EXTRA_CONTEXT_FIELDS
+#undef NOTE_DELETE
+#undef NOTE_INSERT
+#undef EARLY_ABORT
+#undef USE_HEURISTIC
+#undef XVECREF_YVECREF_EQUAL
+#undef OFFSET_MAX
diff --git a/lib/gnulib.mk.in b/lib/gnulib.mk.in
index 73d3043..509089e 100644
--- a/lib/gnulib.mk.in
+++ b/lib/gnulib.mk.in
@@ -21,7 +21,7 @@
# the same distribution terms as the rest of that program.
#
# Generated by gnulib-tool.
-# Reproduce by: gnulib-tool --import --lib=libgnu --source-base=lib
--m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux
--avoid=close --avoid=dup --avoid=fchdir --avoid=fstat --avoid=malloc-posix
--avoid=msvc-inval --avoid=msvc-nothrow --avoid=open --avoid=openat-die
--avoid=opendir --avoid=raise --avoid=save-cwd --avoid=select --avoid=setenv
--avoid=sigprocmask --avoid=stat --avoid=stdarg --avoid=stdbool
--avoid=threadlib --avoid=tzset --avoid=unsetenv --avoid=utime --avo [...]
+# Reproduce by: gnulib-tool --import --lib=libgnu --source-base=lib
--m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux
--avoid=close --avoid=dup --avoid=fchdir --avoid=fstat --avoid=malloc-posix
--avoid=msvc-inval --avoid=msvc-nothrow --avoid=open --avoid=openat-die
--avoid=opendir --avoid=raise --avoid=save-cwd --avoid=select --avoid=setenv
--avoid=sigprocmask --avoid=stat --avoid=stdarg --avoid=stdbool
--avoid=threadlib --avoid=tzset --avoid=unsetenv --avoid=utime --avo [...]
MOSTLYCLEANFILES += core *.stackdump
@@ -1167,6 +1167,14 @@ EXTRA_DIST += gl_openssl.h sha512.h
endif
## end gnulib module crypto/sha512
+## begin gnulib module diffseq
+ifeq (,$(OMIT_GNULIB_MODULE_diffseq))
+
+libgnu_a_SOURCES += diffseq.h
+
+endif
+## end gnulib module diffseq
+
## begin gnulib module dirent
ifeq (,$(OMIT_GNULIB_MODULE_dirent))
@@ -1747,6 +1755,14 @@ EXTRA_libgnu_a_SOURCES += memrchr.c
endif
## end gnulib module memrchr
+## begin gnulib module minmax
+ifeq (,$(OMIT_GNULIB_MODULE_minmax))
+
+libgnu_a_SOURCES += minmax.h
+
+endif
+## end gnulib module minmax
+
## begin gnulib module mkostemp
ifeq (,$(OMIT_GNULIB_MODULE_mkostemp))
diff --git a/lib/minmax.h b/lib/minmax.h
new file mode 100644
index 0000000..6b602a9
--- /dev/null
+++ b/lib/minmax.h
@@ -0,0 +1,60 @@
+/* MIN, MAX macros.
+ Copyright (C) 1995, 1998, 2001, 2003, 2005, 2009-2017 Free Software
+ Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, see <http://www.gnu.org/licenses/>. */
+
+#ifndef _MINMAX_H
+#define _MINMAX_H
+
+/* Note: MIN, MAX are also defined in <sys/param.h> on some systems
+ (glibc, IRIX, HP-UX, OSF/1). Therefore you might get warnings about
+ MIN, MAX macro redefinitions on some systems; the workaround is to
+ #include this file as the last one among the #include list. */
+
+/* Before we define the following symbols we get the <limits.h> file
+ since otherwise we get redefinitions on some systems if <limits.h> is
+ included after this file. Likewise for <sys/param.h>.
+ If more than one of these system headers define MIN and MAX, pick just
+ one of the headers (because the definitions most likely are the same). */
+#if HAVE_MINMAX_IN_LIMITS_H
+# include <limits.h>
+#elif HAVE_MINMAX_IN_SYS_PARAM_H
+# include <sys/param.h>
+#endif
+
+/* Note: MIN and MAX should be used with two arguments of the
+ same type. They might not return the minimum and maximum of their two
+ arguments, if the arguments have different types or have unusual
+ floating-point values. For example, on a typical host with 32-bit 'int',
+ 64-bit 'long long', and 64-bit IEEE 754 'double' types:
+
+ MAX (-1, 2147483648) returns 4294967295.
+ MAX (9007199254740992.0, 9007199254740993) returns 9007199254740992.0.
+ MAX (NaN, 0.0) returns 0.0.
+ MAX (+0.0, -0.0) returns -0.0.
+
+ and in each case the answer is in some sense bogus. */
+
+/* MAX(a,b) returns the maximum of A and B. */
+#ifndef MAX
+# define MAX(a,b) ((a) > (b) ? (a) : (b))
+#endif
+
+/* MIN(a,b) returns the minimum of A and B. */
+#ifndef MIN
+# define MIN(a,b) ((a) < (b) ? (a) : (b))
+#endif
+
+#endif /* _MINMAX_H */
diff --git a/m4/gnulib-comp.m4 b/m4/gnulib-comp.m4
index 8f53a99..1ac58e8 100644
--- a/m4/gnulib-comp.m4
+++ b/m4/gnulib-comp.m4
@@ -61,6 +61,7 @@ AC_DEFUN([gl_EARLY],
# Code from module crypto/sha1:
# Code from module crypto/sha256:
# Code from module crypto/sha512:
+ # Code from module diffseq:
# Code from module dirent:
# Code from module dirfd:
# Code from module dosname:
@@ -105,6 +106,7 @@ AC_DEFUN([gl_EARLY],
# Code from module lstat:
# Code from module manywarnings:
# Code from module memrchr:
+ # Code from module minmax:
# Code from module mkostemp:
# Code from module mktime:
# Code from module mktime-internal:
@@ -289,6 +291,7 @@ AC_DEFUN([gl_INIT],
gl_PREREQ_MEMRCHR
fi
gl_STRING_MODULE_INDICATOR([memrchr])
+ gl_MINMAX
gl_FUNC_MKOSTEMP
if test $HAVE_MKOSTEMP = 0; then
AC_LIBOBJ([mkostemp])
@@ -821,6 +824,7 @@ AC_DEFUN([gl_FILE_LIST], [
lib/count-one-bits.h
lib/count-trailing-zeros.c
lib/count-trailing-zeros.h
+ lib/diffseq.h
lib/dirent.in.h
lib/dirfd.c
lib/dosname.h
@@ -875,6 +879,7 @@ AC_DEFUN([gl_FILE_LIST], [
lib/md5.c
lib/md5.h
lib/memrchr.c
+ lib/minmax.h
lib/mkostemp.c
lib/mktime-internal.h
lib/mktime.c
@@ -991,6 +996,7 @@ AC_DEFUN([gl_FILE_LIST], [
m4/manywarnings.m4
m4/md5.m4
m4/memrchr.m4
+ m4/minmax.m4
m4/mkostemp.m4
m4/mktime.m4
m4/multiarch.m4
diff --git a/m4/minmax.m4 b/m4/minmax.m4
new file mode 100644
index 0000000..6845fce
--- /dev/null
+++ b/m4/minmax.m4
@@ -0,0 +1,44 @@
+# minmax.m4 serial 4
+dnl Copyright (C) 2005, 2009-2017 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_PREREQ([2.53])
+
+AC_DEFUN([gl_MINMAX],
+[
+ AC_REQUIRE([gl_PREREQ_MINMAX])
+])
+
+# Prerequisites of lib/minmax.h.
+AC_DEFUN([gl_PREREQ_MINMAX],
+[
+ gl_MINMAX_IN_HEADER([limits.h])
+ gl_MINMAX_IN_HEADER([sys/param.h])
+])
+
+dnl gl_MINMAX_IN_HEADER(HEADER)
+dnl The parameter has to be a literal header name; it cannot be macro,
+dnl nor a shell variable. (Because autoheader collects only AC_DEFINE
+dnl invocations with a literal macro name.)
+AC_DEFUN([gl_MINMAX_IN_HEADER],
+[
+ m4_pushdef([header], AS_TR_SH([$1]))
+ m4_pushdef([HEADER], AS_TR_CPP([$1]))
+ AC_CACHE_CHECK([whether <$1> defines MIN and MAX],
+ [gl_cv_minmax_in_]header,
+ [AC_COMPILE_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <$1>
+ int x = MIN (42, 17);]],
+ [[]])],
+ [gl_cv_minmax_in_]header[=yes],
+ [gl_cv_minmax_in_]header[=no])])
+ if test $gl_cv_minmax_in_[]header = yes; then
+ AC_DEFINE([HAVE_MINMAX_IN_]HEADER, 1,
+ [Define to 1 if <$1> defines the MIN and MAX macros.])
+ fi
+ m4_popdef([HEADER])
+ m4_popdef([header])
+])
diff --git a/src/buffer.h b/src/buffer.h
index a2bdc4e..be270fe 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -412,6 +412,15 @@ extern void enlarge_buffer_text (struct buffer *,
ptrdiff_t);
? BUF_FETCH_MULTIBYTE_CHAR ((buf), (pos)) \
: BUF_FETCH_BYTE ((buf), (pos)))
+/* Return character at byte position POS in buffer BUF. If BUF is
+ unibyte and the character is not ASCII, make the returning
+ character multibyte. */
+
+#define BUF_FETCH_CHAR_AS_MULTIBYTE(buf, pos) \
+ (! NILP (BVAR ((buf), enable_multibyte_characters)) \
+ ? BUF_FETCH_MULTIBYTE_CHAR ((buf), (pos)) \
+ : UNIBYTE_TO_CHAR (BUF_FETCH_BYTE ((buf), (pos))))
+
/* Return the byte at byte position N in buffer BUF. */
#define BUF_FETCH_BYTE(buf, n) \
diff --git a/src/editfns.c b/src/editfns.c
index 43b17f9..76b4aaf 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -3105,6 +3105,206 @@ determines whether case is significant or ignored. */)
/* Same length too => they are equal. */
return make_number (0);
}
+
+
+/* Set up necessary definitions for diffseq.h; see comments in
+ diffseq.h for explanation. */
+
+#undef ELEMENT
+#undef EQUAL
+
+#define XVECREF_YVECREF_EQUAL(ctx, xoff, yoff) \
+ buffer_chars_equal ((ctx), (xoff), (yoff))
+
+#define OFFSET ptrdiff_t
+
+#define EXTRA_CONTEXT_FIELDS \
+ /* Buffers to compare. */ \
+ struct buffer *buffer_a; \
+ struct buffer *buffer_b; \
+ /* Bit vectors recording for each character whether it was deleted
+ or inserted. */ \
+ unsigned char *deletions; \
+ unsigned char *insertions;
+
+#define NOTE_DELETE(ctx, xoff) set_bit ((ctx)->deletions, (xoff))
+#define NOTE_INSERT(ctx, yoff) set_bit ((ctx)->insertions, (yoff))
+
+struct context;
+static void set_bit (unsigned char *, OFFSET);
+static bool bit_is_set (const unsigned char *, OFFSET);
+static bool buffer_chars_equal (struct context *, OFFSET, OFFSET);
+
+#include "minmax.h"
+#include "diffseq.h"
+
+DEFUN ("replace-buffer-contents", Freplace_buffer_contents,
+ Sreplace_buffer_contents, 1, 1, "bSource buffer: ",
+ doc: /* Replace accessible portion of the current buffer with
accessible portion of SOURCE.
+As far as possible the replacement is non-destructive, i.e. existing
+buffer contents, markers, properties, and overlays in the current
+buffer stay intact. */)
+ (Lisp_Object source)
+{
+ struct buffer *a = current_buffer;
+ Lisp_Object source_buffer = Fget_buffer (source);
+ if (NILP (source_buffer))
+ nsberror (source);
+ struct buffer *b = XBUFFER (source_buffer);
+ if (! BUFFER_LIVE_P (b))
+ error ("Selecting deleted buffer");
+ if (a == b)
+ error ("Cannot replace a buffer with itself");
+
+ ptrdiff_t min_a = BEGV;
+ ptrdiff_t min_b = BUF_BEGV (b);
+ ptrdiff_t size_a = ZV - min_a;
+ ptrdiff_t size_b = BUF_ZV (b) - min_b;
+ eassume (size_a >= 0);
+ eassume (size_b >= 0);
+ bool a_empty = size_a == 0;
+ bool b_empty = size_b == 0;
+
+ /* Handle trivial cases where at least one accessible portion is
+ empty. */
+
+ if (a_empty && b_empty)
+ return Qnil;
+
+ if (a_empty)
+ return Finsert_buffer_substring (source, Qnil, Qnil);
+
+ if (b_empty)
+ {
+ del_range_both (BEGV, BEGV_BYTE, ZV, ZV_BYTE, true);
+ return Qnil;
+ }
+
+ /* FIXME: It is not documented how to initialize the contents of the
+ context structure. This code cargo-cults from the existing
+ caller in src/analyze.c of GNU Diffutils, which appears to
+ work. */
+
+ ptrdiff_t diags = size_a + size_b + 3;
+ ptrdiff_t *buffer;
+ USE_SAFE_ALLOCA;
+ SAFE_NALLOCA (buffer, 2, diags);
+ /* Micro-optimization: Casting to size_t generates much better
+ code. */
+ ptrdiff_t del_bytes = (size_t) size_a / CHAR_BIT + 1;
+ ptrdiff_t ins_bytes = (size_t) size_b / CHAR_BIT + 1;
+ struct context ctx = {
+ .buffer_a = a,
+ .buffer_b = b,
+ .deletions = SAFE_ALLOCA (del_bytes),
+ .insertions = SAFE_ALLOCA (ins_bytes),
+ .fdiag = buffer + size_b + 1,
+ .bdiag = buffer + diags + size_b + 1,
+ /* FIXME: Find a good number for .too_expensive. */
+ .too_expensive = 1000000,
+ };
+ memclear (ctx.deletions, del_bytes);
+ memclear (ctx.insertions, ins_bytes);
+ /* compareseq requires indices to be zero-based. We add BEGV back
+ later. */
+ bool early_abort = compareseq (0, size_a, 0, size_b, false, &ctx);
+ /* Since we didn’t define EARLY_ABORT, we should never abort
+ early. */
+ eassert (! early_abort);
+ SAFE_FREE ();
+
+ Fundo_boundary ();
+ ptrdiff_t count = SPECPDL_INDEX ();
+ record_unwind_protect (save_excursion_restore, save_excursion_save ());
+
+ SET_PT_BOTH (BEGV, BEGV_BYTE);
+ ptrdiff_t i = size_a;
+ ptrdiff_t j = size_b;
+ /* Walk backwards through the lists of changes. This was also
+ cargo-culted from src/analyze.c in GNU Diffutils. Because we
+ walk backwards, we don’t have to keep the positions in sync. */
+ while (i >= 0 || j >= 0)
+ {
+ /* Check whether there is a change (insertion or deletion)
+ before the current position. */
+ if ((i > 0 && bit_is_set (ctx.deletions, i - 1)) ||
+ (j > 0 && bit_is_set (ctx.insertions, j - 1)))
+ {
+ ptrdiff_t end_a = min_a + i;
+ ptrdiff_t end_b = min_b + j;
+ /* Find the beginning of the current change run. */
+ while (i > 0 && bit_is_set (ctx.deletions, i - 1))
+ --i;
+ while (j > 0 && bit_is_set (ctx.insertions, j - 1))
+ --j;
+ ptrdiff_t beg_a = min_a + i;
+ ptrdiff_t beg_b = min_b + j;
+ eassert (beg_a >= BEGV);
+ eassert (beg_b >= BUF_BEGV (b));
+ eassert (beg_a <= end_a);
+ eassert (beg_b <= end_b);
+ eassert (end_a <= ZV);
+ eassert (end_b <= BUF_ZV (b));
+ eassert (beg_a < end_a || beg_b < end_b);
+ if (beg_a < end_a)
+ del_range (beg_a, end_a);
+ if (beg_b < end_b)
+ {
+ SET_PT (beg_a);
+ Finsert_buffer_substring (source, make_natnum (beg_b),
+ make_natnum (end_b));
+ }
+ }
+ --i;
+ --j;
+ }
+
+ return unbind_to (count, Qnil);
+}
+
+static void
+set_bit (unsigned char *a, ptrdiff_t i)
+{
+ eassert (i >= 0);
+ /* Micro-optimization: Casting to size_t generates much better
+ code. */
+ size_t j = i;
+ a[j / CHAR_BIT] |= (1 << (j % CHAR_BIT));
+}
+
+static bool
+bit_is_set (const unsigned char *a, ptrdiff_t i)
+{
+ eassert (i >= 0);
+ /* Micro-optimization: Casting to size_t generates much better
+ code. */
+ size_t j = i;
+ return a[j / CHAR_BIT] & (1 << (j % CHAR_BIT));
+}
+
+/* Return true if the characters at position POS_A of buffer
+ CTX->buffer_a and at position POS_B of buffer CTX->buffer_b are
+ equal. POS_A and POS_B are zero-based. Text properties are
+ ignored. */
+
+static bool
+buffer_chars_equal (struct context *ctx,
+ ptrdiff_t pos_a, ptrdiff_t pos_b)
+{
+ eassert (pos_a >= 0);
+ pos_a += BUF_BEGV (ctx->buffer_a);
+ eassert (pos_a >= BUF_BEGV (ctx->buffer_a));
+ eassert (pos_a < BUF_ZV (ctx->buffer_a));
+
+ eassert (pos_b >= 0);
+ pos_b += BUF_BEGV (ctx->buffer_b);
+ eassert (pos_b >= BUF_BEGV (ctx->buffer_b));
+ eassert (pos_b < BUF_ZV (ctx->buffer_b));
+
+ return BUF_FETCH_CHAR_AS_MULTIBYTE (ctx->buffer_a, pos_a)
+ == BUF_FETCH_CHAR_AS_MULTIBYTE (ctx->buffer_b, pos_b);
+}
+
static void
subst_char_in_region_unwind (Lisp_Object arg)
@@ -5315,6 +5515,7 @@ functions if all the text being accessed has this
property. */);
defsubr (&Sinsert_buffer_substring);
defsubr (&Scompare_buffer_substrings);
+ defsubr (&Sreplace_buffer_contents);
defsubr (&Ssubst_char_in_region);
defsubr (&Stranslate_region_internal);
defsubr (&Sdelete_region);
diff --git a/test/src/editfns-tests.el b/test/src/editfns-tests.el
index 3073e37..a3ea8ab 100644
--- a/test/src/editfns-tests.el
+++ b/test/src/editfns-tests.el
@@ -208,4 +208,35 @@
'(error "Invalid format operation %$")))
(should (equal (format "%1$c %1$s" ?±) "± 177")))
+(ert-deftest replace-buffer-contents-1 ()
+ (with-temp-buffer
+ (insert #("source" 2 4 (prop 7)))
+ (let ((source (current-buffer)))
+ (with-temp-buffer
+ (insert "before dest after")
+ (let ((marker (set-marker (make-marker) 14)))
+ (save-restriction
+ (narrow-to-region 8 12)
+ (replace-buffer-contents source))
+ (should (equal (marker-buffer marker) (current-buffer)))
+ (should (equal (marker-position marker) 16)))
+ (should (equal-including-properties
+ (buffer-string)
+ #("before source after" 9 11 (prop 7))))
+ (should (equal (point) 9))))
+ (should (equal-including-properties
+ (buffer-string)
+ #("source" 2 4 (prop 7))))))
+
+(ert-deftest replace-buffer-contents-2 ()
+ (with-temp-buffer
+ (insert "foo bar baz qux")
+ (let ((source (current-buffer)))
+ (with-temp-buffer
+ (insert "foo BAR baz qux")
+ (replace-buffer-contents source)
+ (should (equal-including-properties
+ (buffer-string)
+ "foo bar baz qux"))))))
+
;;; editfns-tests.el ends here
| [Prev in Thread] |
Current Thread |
[Next in Thread] |
- [Emacs-diffs] master d682f0d: Add command to replace buffer contents,
Philipp Stephani <=