ref: 3c8246a31ce776976ee95310efa2c6e64a471993
dir: /sys/src/ape/cmd/diff/context.c/
/* Context-format output routines for GNU DIFF.
Copyright (C) 1988,1989,1991,1992,1993,1994 Free Software Foundation, Inc.
This file is part of GNU DIFF.
GNU DIFF 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 2, or (at your option)
any later version.
GNU DIFF 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 GNU DIFF; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "diff.h"
static struct change *find_hunk PARAMS((struct change *));
static void find_function PARAMS((struct file_data const *, int, char const **, size_t *));
static void mark_ignorable PARAMS((struct change *));
static void pr_context_hunk PARAMS((struct change *));
static void pr_unidiff_hunk PARAMS((struct change *));
static void print_context_label PARAMS ((char const *, struct file_data *, char const *));
static void print_context_number_range PARAMS((struct file_data const *, int, int));
static void print_unidiff_number_range PARAMS((struct file_data const *, int, int));
/* Last place find_function started searching from. */
static int find_function_last_search;
/* The value find_function returned when it started searching there. */
static int find_function_last_match;
/* Print a label for a context diff, with a file name and date or a label. */
static void
print_context_label (mark, inf, label)
char const *mark;
struct file_data *inf;
char const *label;
{
if (label)
fprintf (outfile, "%s %s\n", mark, label);
else
{
char const *ct = ctime (&inf->stat.st_mtime);
if (!ct)
ct = "?\n";
/* See Posix.2 section 4.17.6.1.4 for this format. */
fprintf (outfile, "%s %s\t%s", mark, inf->name, ct);
}
}
/* Print a header for a context diff, with the file names and dates. */
void
print_context_header (inf, unidiff_flag)
struct file_data inf[];
int unidiff_flag;
{
if (unidiff_flag)
{
print_context_label ("---", &inf[0], file_label[0]);
print_context_label ("+++", &inf[1], file_label[1]);
}
else
{
print_context_label ("***", &inf[0], file_label[0]);
print_context_label ("---", &inf[1], file_label[1]);
}
}
/* Print an edit script in context format. */
void
print_context_script (script, unidiff_flag)
struct change *script;
int unidiff_flag;
{
if (ignore_blank_lines_flag || ignore_regexp_list)
mark_ignorable (script);
else
{
struct change *e;
for (e = script; e; e = e->link)
e->ignore = 0;
}
find_function_last_search = - files[0].prefix_lines;
find_function_last_match = find_function_last_search - 1;
if (unidiff_flag)
print_script (script, find_hunk, pr_unidiff_hunk);
else
print_script (script, find_hunk, pr_context_hunk);
}
/* Print a pair of line numbers with a comma, translated for file FILE.
If the second number is not greater, use the first in place of it.
Args A and B are internal line numbers.
We print the translated (real) line numbers. */
static void
print_context_number_range (file, a, b)
struct file_data const *file;
int a, b;
{
int trans_a, trans_b;
translate_range (file, a, b, &trans_a, &trans_b);
/* Note: we can have B < A in the case of a range of no lines.
In this case, we should print the line number before the range,
which is B. */
if (trans_b > trans_a)
fprintf (outfile, "%d,%d", trans_a, trans_b);
else
fprintf (outfile, "%d", trans_b);
}
/* Print a portion of an edit script in context format.
HUNK is the beginning of the portion to be printed.
The end is marked by a `link' that has been nulled out.
Prints out lines from both files, and precedes each
line with the appropriate flag-character. */
static void
pr_context_hunk (hunk)
struct change *hunk;
{
int first0, last0, first1, last1, show_from, show_to, i;
struct change *next;
char const *prefix;
char const *function;
size_t function_length;
FILE *out;
/* Determine range of line numbers involved in each file. */
analyze_hunk (hunk, &first0, &last0, &first1, &last1, &show_from, &show_to);
if (!show_from && !show_to)
return;
/* Include a context's width before and after. */
i = - files[0].prefix_lines;
first0 = max (first0 - context, i);
first1 = max (first1 - context, i);
last0 = min (last0 + context, files[0].valid_lines - 1);
last1 = min (last1 + context, files[1].valid_lines - 1);
/* If desired, find the preceding function definition line in file 0. */
function = 0;
if (function_regexp_list)
find_function (&files[0], first0, &function, &function_length);
begin_output ();
out = outfile;
/* If we looked for and found a function this is part of,
include its name in the header of the diff section. */
fprintf (out, "***************");
if (function)
{
fprintf (out, " ");
fwrite (function, 1, min (function_length - 1, 40), out);
}
fprintf (out, "\n*** ");
print_context_number_range (&files[0], first0, last0);
fprintf (out, " ****\n");
if (show_from)
{
next = hunk;
for (i = first0; i <= last0; i++)
{
/* Skip past changes that apply (in file 0)
only to lines before line I. */
while (next && next->line0 + next->deleted <= i)
next = next->link;
/* Compute the marking for line I. */
prefix = " ";
if (next && next->line0 <= i)
/* The change NEXT covers this line.
If lines were inserted here in file 1, this is "changed".
Otherwise it is "deleted". */
prefix = (next->inserted > 0 ? "!" : "-");
print_1_line (prefix, &files[0].linbuf[i]);
}
}
fprintf (out, "--- ");
print_context_number_range (&files[1], first1, last1);
fprintf (out, " ----\n");
if (show_to)
{
next = hunk;
for (i = first1; i <= last1; i++)
{
/* Skip past changes that apply (in file 1)
only to lines before line I. */
while (next && next->line1 + next->inserted <= i)
next = next->link;
/* Compute the marking for line I. */
prefix = " ";
if (next && next->line1 <= i)
/* The change NEXT covers this line.
If lines were deleted here in file 0, this is "changed".
Otherwise it is "inserted". */
prefix = (next->deleted > 0 ? "!" : "+");
print_1_line (prefix, &files[1].linbuf[i]);
}
}
}
/* Print a pair of line numbers with a comma, translated for file FILE.
If the second number is smaller, use the first in place of it.
If the numbers are equal, print just one number.
Args A and B are internal line numbers.
We print the translated (real) line numbers. */
static void
print_unidiff_number_range (file, a, b)
struct file_data const *file;
int a, b;
{
int trans_a, trans_b;
translate_range (file, a, b, &trans_a, &trans_b);
/* Note: we can have B < A in the case of a range of no lines.
In this case, we should print the line number before the range,
which is B. */
if (trans_b <= trans_a)
fprintf (outfile, trans_b == trans_a ? "%d" : "%d,0", trans_b);
else
fprintf (outfile, "%d,%d", trans_a, trans_b - trans_a + 1);
}
/* Print a portion of an edit script in unidiff format.
HUNK is the beginning of the portion to be printed.
The end is marked by a `link' that has been nulled out.
Prints out lines from both files, and precedes each
line with the appropriate flag-character. */
static void
pr_unidiff_hunk (hunk)
struct change *hunk;
{
int first0, last0, first1, last1, show_from, show_to, i, j, k;
struct change *next;
char const *function;
size_t function_length;
FILE *out;
/* Determine range of line numbers involved in each file. */
analyze_hunk (hunk, &first0, &last0, &first1, &last1, &show_from, &show_to);
if (!show_from && !show_to)
return;
/* Include a context's width before and after. */
i = - files[0].prefix_lines;
first0 = max (first0 - context, i);
first1 = max (first1 - context, i);
last0 = min (last0 + context, files[0].valid_lines - 1);
last1 = min (last1 + context, files[1].valid_lines - 1);
/* If desired, find the preceding function definition line in file 0. */
function = 0;
if (function_regexp_list)
find_function (&files[0], first0, &function, &function_length);
begin_output ();
out = outfile;
fprintf (out, "@@ -");
print_unidiff_number_range (&files[0], first0, last0);
fprintf (out, " +");
print_unidiff_number_range (&files[1], first1, last1);
fprintf (out, " @@");
/* If we looked for and found a function this is part of,
include its name in the header of the diff section. */
if (function)
{
putc (' ', out);
fwrite (function, 1, min (function_length - 1, 40), out);
}
putc ('\n', out);
next = hunk;
i = first0;
j = first1;
while (i <= last0 || j <= last1)
{
/* If the line isn't a difference, output the context from file 0. */
if (!next || i < next->line0)
{
putc (tab_align_flag ? '\t' : ' ', out);
print_1_line (0, &files[0].linbuf[i++]);
j++;
}
else
{
/* For each difference, first output the deleted part. */
k = next->deleted;
while (k--)
{
putc ('-', out);
if (tab_align_flag)
putc ('\t', out);
print_1_line (0, &files[0].linbuf[i++]);
}
/* Then output the inserted part. */
k = next->inserted;
while (k--)
{
putc ('+', out);
if (tab_align_flag)
putc ('\t', out);
print_1_line (0, &files[1].linbuf[j++]);
}
/* We're done with this hunk, so on to the next! */
next = next->link;
}
}
}
/* Scan a (forward-ordered) edit script for the first place that more than
2*CONTEXT unchanged lines appear, and return a pointer
to the `struct change' for the last change before those lines. */
static struct change *
find_hunk (start)
struct change *start;
{
struct change *prev;
int top0, top1;
int thresh;
do
{
/* Compute number of first line in each file beyond this changed. */
top0 = start->line0 + start->deleted;
top1 = start->line1 + start->inserted;
prev = start;
start = start->link;
/* Threshold distance is 2*CONTEXT between two non-ignorable changes,
but only CONTEXT if one is ignorable. */
thresh = ((prev->ignore || (start && start->ignore))
? context
: 2 * context + 1);
/* It is not supposed to matter which file we check in the end-test.
If it would matter, crash. */
if (start && start->line0 - top0 != start->line1 - top1)
abort ();
} while (start
/* Keep going if less than THRESH lines
elapse before the affected line. */
&& start->line0 < top0 + thresh);
return prev;
}
/* Set the `ignore' flag properly in each change in SCRIPT.
It should be 1 if all the lines inserted or deleted in that change
are ignorable lines. */
static void
mark_ignorable (script)
struct change *script;
{
while (script)
{
struct change *next = script->link;
int first0, last0, first1, last1, deletes, inserts;
/* Turn this change into a hunk: detach it from the others. */
script->link = 0;
/* Determine whether this change is ignorable. */
analyze_hunk (script, &first0, &last0, &first1, &last1, &deletes, &inserts);
/* Reconnect the chain as before. */
script->link = next;
/* If the change is ignorable, mark it. */
script->ignore = (!deletes && !inserts);
/* Advance to the following change. */
script = next;
}
}
/* Find the last function-header line in FILE prior to line number LINENUM.
This is a line containing a match for the regexp in `function_regexp'.
Store the address of the line text into LINEP and the length of the
line into LENP.
Do not store anything if no function-header is found. */
static void
find_function (file, linenum, linep, lenp)
struct file_data const *file;
int linenum;
char const **linep;
size_t *lenp;
{
int i = linenum;
int last = find_function_last_search;
find_function_last_search = i;
while (--i >= last)
{
/* See if this line is what we want. */
struct regexp_list *r;
char const *line = file->linbuf[i];
size_t len = file->linbuf[i + 1] - line;
for (r = function_regexp_list; r; r = r->next)
if (0 <= re_search (&r->buf, line, len, 0, len, 0))
{
*linep = line;
*lenp = len;
find_function_last_match = i;
return;
}
}
/* If we search back to where we started searching the previous time,
find the line we found last time. */
if (find_function_last_match >= - file->prefix_lines)
{
i = find_function_last_match;
*linep = file->linbuf[i];
*lenp = file->linbuf[i + 1] - *linep;
return;
}
return;
}