path: root/usr.bin/patch/pch.c

/* $OpenBSD: pch.c,v 1.18 2003/07/21 14:27:35 deraadt Exp $	 */

#ifndef lint
static char rcsid[] = "$OpenBSD: pch.c,v 1.18 2003/07/21 14:27:35 deraadt Exp $";
#endif /* not lint */

#include "EXTERN.h"
#include "common.h"
#include "util.h"
#include "INTERN.h"
#include "pch.h"

extern bool	check_only;
/* Patch (diff listing) abstract type. */

static long	p_filesize;	/* size of the patch file */
static LINENUM	p_first;	/* 1st line number */
static LINENUM	p_newfirst;	/* 1st line number of replacement */
static LINENUM	p_ptrn_lines;	/* # lines in pattern */
static LINENUM	p_repl_lines;	/* # lines in replacement text */
static LINENUM	p_end = -1;	/* last line in hunk */
static LINENUM	p_max;		/* max allowed value of p_end */
static LINENUM	p_context = 3;	/* # of context lines */
static LINENUM	p_input_line = 0;	/* current line # from patch file */
static char	**p_line = Null(char **);	/* the text of the hunk */
static short	*p_len = Null(short *);	/* length of each line */
static char	*p_char = Nullch;/* +, -, and ! */
static int	hunkmax = INITHUNKMAX;	/* size of above arrays to begin with */
static int	p_indent;	/* indent to patch */
static LINENUM	p_base;		/* where to intuit this time */
static LINENUM	p_bline;	/* line # of p_base */
static LINENUM	p_start;	/* where intuit found a patch */
static LINENUM	p_sline;	/* and the line number for it */
static LINENUM	p_hunk_beg;	/* line number of current hunk */
static LINENUM	p_efake = -1;	/* end of faked up lines--don't free */
static LINENUM	p_bfake = -1;	/* beg of faked up lines */

/*
 * Prepare to look for the next patch in the patch file.
 */
void
re_patch(void)
{
	p_first = Nulline;
	p_newfirst = Nulline;
	p_ptrn_lines = Nulline;
	p_repl_lines = Nulline;
	p_end = (LINENUM) - 1;
	p_max = Nulline;
	p_indent = 0;
}

/*
 * Open the patch file at the beginning of time.
 */
void
open_patch_file(char *filename)
{
	if (filename == Nullch || !*filename || strEQ(filename, "-")) {
		pfp = fopen(TMPPATNAME, "w");
		if (pfp == Nullfp)
			pfatal("can't create %s", TMPPATNAME);
		while (fgets(buf, sizeof buf, stdin) != Nullch)
			fputs(buf, pfp);
		fclose(pfp);
		filename = TMPPATNAME;
	}
	pfp = fopen(filename, "r");
	if (pfp == Nullfp)
		pfatal("patch file %s not found", filename);
	fstat(fileno(pfp), &filestat);
	p_filesize = filestat.st_size;
	next_intuit_at(0L, 1L);	/* start at the beginning */
	set_hunkmax();
}

/*
 * Make sure our dynamically realloced tables are malloced to begin with.
 */
void
set_hunkmax(void)
{
#ifndef lint
	if (p_line == Null(char **))
		p_line = (char **) malloc((MEM) hunkmax * sizeof(char *));
	if (p_len == Null(short *))
		p_len = (short *) malloc((MEM) hunkmax * sizeof(short));
#endif
	if (p_char == Nullch)
		p_char = (char *) malloc((MEM) hunkmax * sizeof(char));
}

/*
 * Enlarge the arrays containing the current hunk of patch.
 */
void
grow_hunkmax(void)
{
	hunkmax *= 2;

	/*
	 * Note that on most systems, only the p_line array ever gets fresh memory
	 * since p_len can move into p_line's old space, and p_char can move into
	 * p_len's old space.  Not on PDP-11's however.  But it doesn't matter.
	 */
	assert(p_line != Null(char **) &&p_len != Null(short *) &&p_char != Nullch);
#ifndef lint
	p_line = (char **) realloc((char *) p_line, (MEM) hunkmax * sizeof(char *));
	p_len = (short *) realloc((char *) p_len, (MEM) hunkmax * sizeof(short));
	p_char = (char *) realloc((char *) p_char, (MEM) hunkmax * sizeof(char));
#endif
	if (p_line != Null(char **) &&p_len != Null(short *) &&p_char != Nullch)
		return;
	if (!using_plan_a)
		fatal("out of memory\n");
	out_of_mem = TRUE;	/* whatever is null will be allocated again */
	/* from within plan_a(), of all places */
}

/* True if the remainder of the patch file contains a diff of some sort. */

bool
there_is_another_patch(void)
{
	if (p_base != 0L && p_base >= p_filesize) {
		if (verbose)
			say("done\n");
		return FALSE;
	}
	if (verbose)
		say("Hmm...");
	diff_type = intuit_diff_type();
	if (!diff_type) {
		if (p_base != 0L) {
			if (verbose)
				say("  Ignoring the trailing garbage.\ndone\n");
		} else
			say("  I can't seem to find a patch in there anywhere.\n");
		return FALSE;
	}
	if (verbose)
		say("  %sooks like %s to me...\n",
		    (p_base == 0L ? "L" : "The next patch l"),
		    diff_type == UNI_DIFF ? "a unified diff" :
		    diff_type == CONTEXT_DIFF ? "a context diff" :
		diff_type == NEW_CONTEXT_DIFF ? "a new-style context diff" :
		    diff_type == NORMAL_DIFF ? "a normal diff" :
		    "an ed script");
	if (p_indent && verbose)
		say("(Patch is indented %d space%s.)\n", p_indent,
		    p_indent == 1 ? "" : "s");
	skip_to(p_start, p_sline);
	while (filearg[0] == Nullch) {
		if (force || batch) {
			say("No file to patch.  Skipping...\n");
			filearg[0] = savestr(bestguess);
			skip_rest_of_patch = TRUE;
			return TRUE;
		}
		ask("File to patch: ");
		if (*buf != '\n') {
			if (bestguess)
				free(bestguess);
			bestguess = savestr(buf);
			filearg[0] = fetchname(buf, 0, FALSE);
		}
		if (filearg[0] == Nullch) {
			ask("No file found--skip this patch? [n] ");
			if (*buf != 'y')
				continue;
			if (verbose)
				say("Skipping patch...\n");
			filearg[0] = fetchname(bestguess, 0, TRUE);
			skip_rest_of_patch = TRUE;
			return TRUE;
		}
	}
	return TRUE;
}

/* Determine what kind of diff is in the remaining part of the patch file. */

int
intuit_diff_type(void)
{
	long	this_line = 0, previous_line;
	long	first_command_line = -1, fcl_line;
	bool	last_line_was_command = FALSE, this_is_a_command = FALSE;
	bool	stars_last_line = FALSE, stars_this_line = FALSE;
	char	*s, *t;
	char	*indtmp = Nullch;
	char	*oldtmp = Nullch;
	char	*newtmp = Nullch;
	char	*indname = Nullch;
	char	*oldname = Nullch;
	char	*newname = Nullch;
	int	indent, retval;
	bool	no_filearg = (filearg[0] == Nullch);

	ok_to_create_file = FALSE;
	fseek(pfp, p_base, 0);
	p_input_line = p_bline - 1;
	for (;;) {
		previous_line = this_line;
		last_line_was_command = this_is_a_command;
		stars_last_line = stars_this_line;
		this_line = ftell(pfp);
		indent = 0;
		p_input_line++;
		if (fgets(buf, sizeof buf, pfp) == Nullch) {
			if (first_command_line >= 0L) {
				/* nothing but deletes!? */
				p_start = first_command_line;
				p_sline = fcl_line;
				retval = ED_DIFF;
				goto scan_exit;
			} else {
				p_start = this_line;
				p_sline = p_input_line;
				retval = 0;
				goto scan_exit;
			}
		}
		for (s = buf; *s == ' ' || *s == '\t' || *s == 'X'; s++) {
			if (*s == '\t')
				indent += 8 - (indent % 8);
			else
				indent++;
		}
		for (t = s; isdigit(*t) || *t == ','; t++)
			;
		this_is_a_command = (isdigit(*s) &&
		    (*t == 'd' || *t == 'c' || *t == 'a'));
		if (first_command_line < 0L && this_is_a_command) {
			first_command_line = this_line;
			fcl_line = p_input_line;
			p_indent = indent;	/* assume this for now */
		}
		if (!stars_last_line && strnEQ(s, "*** ", 4))
			oldtmp = savestr(s + 4);
		else if (strnEQ(s, "--- ", 4))
			newtmp = savestr(s + 4);
		else if (strnEQ(s, "+++ ", 4))
			oldtmp = savestr(s + 4);	/* pretend it is the old
							 * name */
		else if (strnEQ(s, "Index:", 6))
			indtmp = savestr(s + 6);
		else if (strnEQ(s, "Prereq:", 7)) {
			for (t = s + 7; isspace(*t); t++)
				;
			revision = savestr(t);
			for (t = revision; *t && !isspace(*t); t++)
				;
			*t = '\0';
			if (!*revision) {
				free(revision);
				revision = Nullch;
			}
		}
		if ((!diff_type || diff_type == ED_DIFF) &&
		    first_command_line >= 0L &&
		    strEQ(s, ".\n")) {
			p_indent = indent;
			p_start = first_command_line;
			p_sline = fcl_line;
			retval = ED_DIFF;
			goto scan_exit;
		}
		if ((!diff_type || diff_type == UNI_DIFF) && strnEQ(s, "@@ -", 4)) {
			if (!atol(s + 3))
				ok_to_create_file = TRUE;
			p_indent = indent;
			p_start = this_line;
			p_sline = p_input_line;
			retval = UNI_DIFF;
			goto scan_exit;
		}
		stars_this_line = strnEQ(s, "********", 8);
		if ((!diff_type || diff_type == CONTEXT_DIFF) && stars_last_line &&
		    strnEQ(s, "*** ", 4)) {
			if (!atol(s + 4))
				ok_to_create_file = TRUE;
			/*
			 * if this is a new context diff the character just
			 * before
			 */
			/* the newline is a '*'. */
			while (*s != '\n')
				s++;
			p_indent = indent;
			p_start = previous_line;
			p_sline = p_input_line - 1;
			retval = (*(s - 1) == '*' ? NEW_CONTEXT_DIFF : CONTEXT_DIFF);
			goto scan_exit;
		}
		if ((!diff_type || diff_type == NORMAL_DIFF) &&
		    last_line_was_command &&
		    (strnEQ(s, "< ", 2) || strnEQ(s, "> ", 2))) {
			p_start = previous_line;
			p_sline = p_input_line - 1;
			p_indent = indent;
			retval = NORMAL_DIFF;
			goto scan_exit;
		}
	}
scan_exit:
	if (no_filearg) {
		if (indtmp != Nullch)
			indname = fetchname(indtmp, strippath, ok_to_create_file);
		if (oldtmp != Nullch)
			oldname = fetchname(oldtmp, strippath, ok_to_create_file);
		if (newtmp != Nullch)
			newname = fetchname(newtmp, strippath, ok_to_create_file);
		if (indname)
			filearg[0] = savestr(indname);
		else if (oldname && newname) {
			if (strlen(oldname) < strlen(newname))
				filearg[0] = savestr(oldname);
			else
				filearg[0] = savestr(newname);
		} else if (oldname)
			filearg[0] = savestr(oldname);
		else if (newname)
			filearg[0] = savestr(newname);
	}
	if (bestguess) {
		free(bestguess);
		bestguess = Nullch;
	}
	if (filearg[0] != Nullch)
		bestguess = savestr(filearg[0]);
	else if (indtmp != Nullch)
		bestguess = fetchname(indtmp, strippath, TRUE);
	else {
		if (oldtmp != Nullch)
			oldname = fetchname(oldtmp, strippath, TRUE);
		if (newtmp != Nullch)
			newname = fetchname(newtmp, strippath, TRUE);
		if (oldname && newname) {
			if (strlen(oldname) < strlen(newname))
				bestguess = savestr(oldname);
			else
				bestguess = savestr(newname);
		} else if (oldname)
			bestguess = savestr(oldname);
		else if (newname)
			bestguess = savestr(newname);
	}
	if (indtmp != Nullch)
		free(indtmp);
	if (oldtmp != Nullch)
		free(oldtmp);
	if (newtmp != Nullch)
		free(newtmp);
	if (indname != Nullch)
		free(indname);
	if (oldname != Nullch)
		free(oldname);
	if (newname != Nullch)
		free(newname);
	return retval;
}

/*
 * Remember where this patch ends so we know where to start up again.
 */
void
next_intuit_at(long file_pos, long file_line)
{
	p_base = file_pos;
	p_bline = file_line;
}

/*
 * Basically a verbose fseek() to the actual diff listing.
 */
void
skip_to(long file_pos, long file_line)
{
	char	*ret;

	assert(p_base <= file_pos);
	if (verbose && p_base < file_pos) {
		fseek(pfp, p_base, 0);
		say("The text leading up to this was:\n--------------------------\n");
		while (ftell(pfp) < file_pos) {
			ret = fgets(buf, sizeof buf, pfp);
			assert(ret != Nullch);
			say("|%s", buf);
		}
		say("--------------------------\n");
	} else
		fseek(pfp, file_pos, 0);
	p_input_line = file_line - 1;
}

/* Make this a function for better debugging.  */
static void
malformed(void)
{
	fatal("malformed patch at line %ld: %s", p_input_line, buf);
	/* about as informative as "Syntax error" in C */
}

/*
 * True if the line has been discarded (i.e. it is a line saying
 *  "\ No newline at end of file".)
 */
static bool
remove_special_line(void)
{
	int	c;

	c = fgetc(pfp);
	if (c == '\\') {
		do {
			c = fgetc(pfp);
		} while (c != EOF && c != '\n');

		return TRUE;
	}
	if (c != EOF)
		fseek(pfp, -1L, SEEK_CUR);

	return FALSE;
}

/*
 * True if there is more of the current diff listing to process.
 */
bool
another_hunk(void)
{
	long	line_beginning;			/* file pos of the current line */
	LINENUM	repl_beginning;			/* index of --- line */
	LINENUM	fillcnt;			/* #lines of missing ptrn or repl */
	LINENUM	fillsrc;			/* index of first line to copy */
	LINENUM	filldst;			/* index of first missing line */
	bool	ptrn_spaces_eaten;		/* ptrn was slightly misformed */
	bool	repl_could_be_missing;		/* no + or ! lines in this hunk */
	bool	repl_missing;			/* we are now backtracking */
	long	repl_backtrack_position;	/* file pos of first repl line */
	LINENUM	repl_patch_line;		/* input line number for same */
	LINENUM	ptrn_copiable;			/* # of copiable lines in ptrn */
	char	*s, *ret;
	int	context = 0;

	while (p_end >= 0) {
		if (p_end == p_efake)
			p_end = p_bfake;	/* don't free twice */
		else
			free(p_line[p_end]);
		p_end--;
	}
	assert(p_end == -1);
	p_efake = -1;

	p_max = hunkmax;	/* gets reduced when --- found */
	if (diff_type == CONTEXT_DIFF || diff_type == NEW_CONTEXT_DIFF) {
		line_beginning = ftell(pfp);
		repl_beginning = 0;
		fillcnt = 0;
		ptrn_spaces_eaten = FALSE;
		repl_could_be_missing = TRUE;
		repl_missing = FALSE;
		repl_backtrack_position = 0;
		ptrn_copiable = 0;

		ret = pgets(buf, sizeof buf, pfp);
		p_input_line++;
		if (ret == Nullch || strnNE(buf, "********", 8)) {
			next_intuit_at(line_beginning, p_input_line);
			return FALSE;
		}
		p_context = 100;
		p_hunk_beg = p_input_line + 1;
		while (p_end < p_max) {
			line_beginning = ftell(pfp);
			ret = pgets(buf, sizeof buf, pfp);
			p_input_line++;
			if (ret == Nullch) {
				if (p_max - p_end < 4) {
					/* assume blank lines got chopped */
					strlcpy(buf, "  \n", sizeof buf);
				} else {
					if (repl_beginning && repl_could_be_missing) {
						repl_missing = TRUE;
						goto hunk_done;
					}
					fatal("unexpected end of file in patch\n");
				}
			}
			p_end++;
			assert(p_end < hunkmax);
			p_char[p_end] = *buf;
			p_line[p_end] = Nullch;
			switch (*buf) {
			case '*':
				if (strnEQ(buf, "********", 8)) {
					if (repl_beginning && repl_could_be_missing) {
						repl_missing = TRUE;
						goto hunk_done;
					} else
						fatal("unexpected end of hunk "
						    "at line %ld\n",
						    p_input_line);
				}
				if (p_end != 0) {
					if (repl_beginning && repl_could_be_missing) {
						repl_missing = TRUE;
						goto hunk_done;
					}
					fatal("unexpected *** at line %ld: %s",
					    p_input_line, buf);
				}
				context = 0;
				p_line[p_end] = savestr(buf);
				if (out_of_mem) {
					p_end--;
					return FALSE;
				}
				for (s = buf; *s && !isdigit(*s); s++)
					;
				if (!*s)
					malformed();
				if (strnEQ(s, "0,0", 3))
					memmove(s, s + 2, strlen(s + 2) + 1);
				p_first = (LINENUM) atol(s);
				while (isdigit(*s))
					s++;
				if (*s == ',') {
					for (; *s && !isdigit(*s); s++)
						;
					if (!*s)
						malformed();
					p_ptrn_lines = ((LINENUM) atol(s)) - p_first + 1;
				} else if (p_first)
					p_ptrn_lines = 1;
				else {
					p_ptrn_lines = 0;
					p_first = 1;
				}
				p_max = p_ptrn_lines + 6;	/* we need this much at
								 * least */
				while (p_max >= hunkmax)
					grow_hunkmax();
				p_max = hunkmax;
				break;
			case '-':
				if (buf[1] == '-') {
					if (repl_beginning ||
					    (p_end != p_ptrn_lines + 1 +
					    (p_char[p_end - 1] == '\n'))) {
						if (p_end == 1) {
							/*
							 * `old' lines were omitted;
							 * set up to fill them in
							 * from 'new' context lines.
							 */
							p_end = p_ptrn_lines + 1;
							fillsrc = p_end + 1;
							filldst = 1;
							fillcnt = p_ptrn_lines;
						} else {
							if (repl_beginning) {
								if (repl_could_be_missing) {
									repl_missing = TRUE;
									goto hunk_done;
								}
								fatal("duplicate \"---\" at line %ld--check line numbers at line %ld\n",
								    p_input_line, p_hunk_beg + repl_beginning);
							} else {
								fatal("%s \"---\" at line %ld--check line numbers at line %ld\n",
								    (p_end <= p_ptrn_lines
								    ? "Premature"
								    : "Overdue"),
								    p_input_line, p_hunk_beg);
							}
						}
					}
					repl_beginning = p_end;
					repl_backtrack_position = ftell(pfp);
					repl_patch_line = p_input_line;
					p_line[p_end] = savestr(buf);
					if (out_of_mem) {
						p_end--;
						return FALSE;
					}
					p_char[p_end] = '=';
					for (s = buf; *s && !isdigit(*s); s++)
						;
					if (!*s)
						malformed();
					p_newfirst = (LINENUM) atol(s);
					while (isdigit(*s))
						s++;
					if (*s == ',') {
						for (; *s && !isdigit(*s); s++)
							;
						if (!*s)
							malformed();
						p_repl_lines = ((LINENUM) atol(s)) -
						    p_newfirst + 1;
					} else if (p_newfirst)
						p_repl_lines = 1;
					else {
						p_repl_lines = 0;
						p_newfirst = 1;
					}
					p_max = p_repl_lines + p_end;
					if (p_max > MAXHUNKSIZE)
						fatal("hunk too large (%ld lines) at line %ld: %s",
						    p_max, p_input_line, buf);
					while (p_max >= hunkmax)
						grow_hunkmax();
					if (p_repl_lines != ptrn_copiable &&
					    (p_context != 0 || p_repl_lines != 1))
						repl_could_be_missing = FALSE;
					break;
				}
				goto change_line;
			case '+':
			case '!':
				repl_could_be_missing = FALSE;
		change_line:
				if (buf[1] == '\n' && canonicalize)
					strlcpy(buf + 1, " \n", sizeof buf - 1);
				if (!isspace(buf[1]) && buf[1] != '>' &&
				    buf[1] != '<' &&
				    repl_beginning && repl_could_be_missing) {
					repl_missing = TRUE;
					goto hunk_done;
				}
				if (context >= 0) {
					if (context < p_context)
						p_context = context;
					context = -1000;
				}
				p_line[p_end] = savestr(buf + 2);
				if (out_of_mem) {
					p_end--;
					return FALSE;
				}
				if (p_end == p_ptrn_lines) {
					if (remove_special_line()) {
						int	len;

						len = strlen(p_line[p_end]) - 1;
						(p_line[p_end])[len] = 0;
					}
				}
				break;
			case '\t':
			case '\n':	/* assume the 2 spaces got eaten */
				if (repl_beginning && repl_could_be_missing &&
				    (!ptrn_spaces_eaten ||
				    diff_type == NEW_CONTEXT_DIFF)) {
					repl_missing = TRUE;
					goto hunk_done;
				}
				p_line[p_end] = savestr(buf);
				if (out_of_mem) {
					p_end--;
					return FALSE;
				}
				if (p_end != p_ptrn_lines + 1) {
					ptrn_spaces_eaten |= (repl_beginning != 0);
					context++;
					if (!repl_beginning)
						ptrn_copiable++;
					p_char[p_end] = ' ';
				}
				break;
			case ' ':
				if (!isspace(buf[1]) &&
				  repl_beginning && repl_could_be_missing) {
					repl_missing = TRUE;
					goto hunk_done;
				}
				context++;
				if (!repl_beginning)
					ptrn_copiable++;
				p_line[p_end] = savestr(buf + 2);
				if (out_of_mem) {
					p_end--;
					return FALSE;
				}
				break;
			default:
				if (repl_beginning && repl_could_be_missing) {
					repl_missing = TRUE;
					goto hunk_done;
				}
				malformed();
			}
			/* set up p_len for strncmp() so we don't have to */
			/* assume null termination */
			if (p_line[p_end])
				p_len[p_end] = strlen(p_line[p_end]);
			else
				p_len[p_end] = 0;
		}

hunk_done:
		if (p_end >= 0 && !repl_beginning)
			fatal("no --- found in patch at line %ld\n", pch_hunk_beg());

		if (repl_missing) {

			/* reset state back to just after --- */
			p_input_line = repl_patch_line;
			for (p_end--; p_end > repl_beginning; p_end--)
				free(p_line[p_end]);
			fseek(pfp, repl_backtrack_position, 0);

			/* redundant 'new' context lines were omitted - set */
			/* up to fill them in from the old file context */
			if (!p_context && p_repl_lines == 1) {
				p_repl_lines = 0;
				p_max--;
			}
			fillsrc = 1;
			filldst = repl_beginning + 1;
			fillcnt = p_repl_lines;
			p_end = p_max;
		} else if (!p_context && fillcnt == 1) {
			/* the first hunk was a null hunk with no context */
			/* and we were expecting one line -- fix it up. */
			while (filldst < p_end) {
				p_line[filldst] = p_line[filldst + 1];
				p_char[filldst] = p_char[filldst + 1];
				p_len[filldst] = p_len[filldst + 1];
				filldst++;
			}
#if 0
			repl_beginning--;	/* this doesn't need to be
						 * fixed */
#endif
			p_end--;
			p_first++;	/* do append rather than insert */
			fillcnt = 0;
			p_ptrn_lines = 0;
		}
		if (diff_type == CONTEXT_DIFF &&
		    (fillcnt || (p_first > 1 && ptrn_copiable > 2 * p_context))) {
			if (verbose)
				say("%s\n%s\n%s\n",
				    "(Fascinating--this is really a new-style context diff but without",
				    "the telltale extra asterisks on the *** line that usually indicate",
				    "the new style...)");
			diff_type = NEW_CONTEXT_DIFF;
		}
		/* if there were omitted context lines, fill them in now */
		if (fillcnt) {
			p_bfake = filldst;	/* remember where not to
						 * free() */
			p_efake = filldst + fillcnt - 1;
			while (fillcnt-- > 0) {
				while (fillsrc <= p_end && p_char[fillsrc] != ' ')
					fillsrc++;
				if (fillsrc > p_end)
					fatal("replacement text or line numbers mangled in hunk at line %ld\n",
					    p_hunk_beg);
				p_line[filldst] = p_line[fillsrc];
				p_char[filldst] = p_char[fillsrc];
				p_len[filldst] = p_len[fillsrc];
				fillsrc++;
				filldst++;
			}
			while (fillsrc <= p_end && fillsrc != repl_beginning &&
			    p_char[fillsrc] != ' ')
				fillsrc++;
#ifdef DEBUGGING
			if (debug & 64)
				printf("fillsrc %ld, filldst %ld, rb %ld, e+1 %ld\n",
				fillsrc, filldst, repl_beginning, p_end + 1);
#endif
			assert(fillsrc == p_end + 1 || fillsrc == repl_beginning);
			assert(filldst == p_end + 1 || filldst == repl_beginning);
		}
		if (p_line[p_end] != NULL) {
			if (remove_special_line()) {
				p_len[p_end] -= 1;
				(p_line[p_end])[p_len[p_end]] = 0;
			}
		}
	} else if (diff_type == UNI_DIFF) {
		long	line_beginning = ftell(pfp); /* file pos of the current line */
		LINENUM	fillsrc;	/* index of old lines */
		LINENUM	filldst;	/* index of new lines */
		char	ch;

		ret = pgets(buf, sizeof buf, pfp);
		p_input_line++;
		if (ret == Nullch || strnNE(buf, "@@ -", 4)) {
			next_intuit_at(line_beginning, p_input_line);
			return FALSE;
		}
		s = buf + 4;
		if (!*s)
			malformed();
		p_first = (LINENUM) atol(s);
		while (isdigit(*s))
			s++;
		if (*s == ',') {
			p_ptrn_lines = (LINENUM) atol(++s);
			while (isdigit(*s))
				s++;
		} else
			p_ptrn_lines = 1;
		if (*s == ' ')
			s++;
		if (*s != '+' || !*++s)
			malformed();
		p_newfirst = (LINENUM) atol(s);
		while (isdigit(*s))
			s++;
		if (*s == ',') {
			p_repl_lines = (LINENUM) atol(++s);
			while (isdigit(*s))
				s++;
		} else
			p_repl_lines = 1;
		if (*s == ' ')
			s++;
		if (*s != '@')
			malformed();
		if (!p_ptrn_lines)
			p_first++;	/* do append rather than insert */
		p_max = p_ptrn_lines + p_repl_lines + 1;
		while (p_max >= hunkmax)
			grow_hunkmax();
		fillsrc = 1;
		filldst = fillsrc + p_ptrn_lines;
		p_end = filldst + p_repl_lines;
		snprintf(buf, sizeof buf, "*** %ld,%ld ****\n", p_first,
			 p_first + p_ptrn_lines - 1);
		p_line[0] = savestr(buf);
		if (out_of_mem) {
			p_end = -1;
			return FALSE;
		}
		p_char[0] = '*';
		snprintf(buf, sizeof buf, "--- %ld,%ld ----\n", p_newfirst,
			 p_newfirst + p_repl_lines - 1);
		p_line[filldst] = savestr(buf);
		if (out_of_mem) {
			p_end = 0;
			return FALSE;
		}
		p_char[filldst++] = '=';
		p_context = 100;
		context = 0;
		p_hunk_beg = p_input_line + 1;
		while (fillsrc <= p_ptrn_lines || filldst <= p_end) {
			line_beginning = ftell(pfp);
			ret = pgets(buf, sizeof buf, pfp);
			p_input_line++;
			if (ret == Nullch) {
				if (p_max - filldst < 3) {
					/* assume blank lines got chopped */
					strlcpy(buf, " \n", sizeof buf);
				} else {
					fatal("unexpected end of file in patch\n");
				}
			}
			if (*buf == '\t' || *buf == '\n') {
				ch = ' ';	/* assume the space got eaten */
				s = savestr(buf);
			} else {
				ch = *buf;
				s = savestr(buf + 1);
			}
			if (out_of_mem) {
				while (--filldst > p_ptrn_lines)
					free(p_line[filldst]);
				p_end = fillsrc - 1;
				return FALSE;
			}
			switch (ch) {
			case '-':
				if (fillsrc > p_ptrn_lines) {
					free(s);
					p_end = filldst - 1;
					malformed();
				}
				p_char[fillsrc] = ch;
				p_line[fillsrc] = s;
				p_len[fillsrc++] = strlen(s);
				if (fillsrc > p_ptrn_lines) {
					if (remove_special_line()) {
						p_len[fillsrc - 1] -= 1;
						s[p_len[fillsrc - 1]] = 0;
					}
				}
				break;
			case '=':
				ch = ' ';
				/* FALL THROUGH */
			case ' ':
				if (fillsrc > p_ptrn_lines) {
					free(s);
					while (--filldst > p_ptrn_lines)
						free(p_line[filldst]);
					p_end = fillsrc - 1;
					malformed();
				}
				context++;
				p_char[fillsrc] = ch;
				p_line[fillsrc] = s;
				p_len[fillsrc++] = strlen(s);
				s = savestr(s);
				if (out_of_mem) {
					while (--filldst > p_ptrn_lines)
						free(p_line[filldst]);
					p_end = fillsrc - 1;
					return FALSE;
				}
				/* FALL THROUGH */
			case '+':
				if (filldst > p_end) {
					free(s);
					while (--filldst > p_ptrn_lines)
						free(p_line[filldst]);
					p_end = fillsrc - 1;
					malformed();
				}
				p_char[filldst] = ch;
				p_line[filldst] = s;
				p_len[filldst++] = strlen(s);
				if (fillsrc > p_ptrn_lines) {
					if (remove_special_line()) {
						p_len[filldst - 1] -= 1;
						s[p_len[filldst - 1]] = 0;
					}
				}
				break;
			default:
				p_end = filldst;
				malformed();
			}
			if (ch != ' ' && context > 0) {
				if (context < p_context)
					p_context = context;
				context = -1000;
			}
		}		/* while */
	} else {		/* normal diff--fake it up */
		char	hunk_type;
		int	i;
		LINENUM	min, max;
		long	line_beginning = ftell(pfp);

		p_context = 0;
		ret = pgets(buf, sizeof buf, pfp);
		p_input_line++;
		if (ret == Nullch || !isdigit(*buf)) {
			next_intuit_at(line_beginning, p_input_line);
			return FALSE;
		}
		p_first = (LINENUM) atol(buf);
		for (s = buf; isdigit(*s); s++)
			;
		if (*s == ',') {
			p_ptrn_lines = (LINENUM) atol(++s) - p_first + 1;
			while (isdigit(*s))
				s++;
		} else
			p_ptrn_lines = (*s != 'a');
		hunk_type = *s;
		if (hunk_type == 'a')
			p_first++;	/* do append rather than insert */
		min = (LINENUM) atol(++s);
		for (; isdigit(*s); s++)
			;
		if (*s == ',')
			max = (LINENUM) atol(++s);
		else
			max = min;
		if (hunk_type == 'd')
			min++;
		p_end = p_ptrn_lines + 1 + max - min + 1;
		if (p_end > MAXHUNKSIZE)
			fatal("hunk too large (%ld lines) at line %ld: %s",
			    p_end, p_input_line, buf);
		while (p_end >= hunkmax)
			grow_hunkmax();
		p_newfirst = min;
		p_repl_lines = max - min + 1;
		snprintf(buf, sizeof buf, "*** %ld,%ld\n", p_first,
			 p_first + p_ptrn_lines - 1);
		p_line[0] = savestr(buf);
		if (out_of_mem) {
			p_end = -1;
			return FALSE;
		}
		p_char[0] = '*';
		for (i = 1; i <= p_ptrn_lines; i++) {
			ret = pgets(buf, sizeof buf, pfp);
			p_input_line++;
			if (ret == Nullch)
				fatal("unexpected end of file in patch at line %ld\n",
				    p_input_line);
			if (*buf != '<')
				fatal("< expected at line %ld of patch\n",
				    p_input_line);
			p_line[i] = savestr(buf + 2);
			if (out_of_mem) {
				p_end = i - 1;
				return FALSE;
			}
			p_len[i] = strlen(p_line[i]);
			p_char[i] = '-';
		}

		if (remove_special_line()) {
			p_len[i - 1] -= 1;
			(p_line[i - 1])[p_len[i - 1]] = 0;
		}
		if (hunk_type == 'c') {
			ret = pgets(buf, sizeof buf, pfp);
			p_input_line++;
			if (ret == Nullch)
				fatal("unexpected end of file in patch at line %ld\n",
				    p_input_line);
			if (*buf != '-')
				fatal("--- expected at line %ld of patch\n",
				    p_input_line);
		}
		snprintf(buf, sizeof(buf), "--- %ld,%ld\n", min, max);
		p_line[i] = savestr(buf);
		if (out_of_mem) {
			p_end = i - 1;
			return FALSE;
		}
		p_char[i] = '=';
		for (i++; i <= p_end; i++) {
			ret = pgets(buf, sizeof buf, pfp);
			p_input_line++;
			if (ret == Nullch)
				fatal("unexpected end of file in patch at line %ld\n",
				    p_input_line);
			if (*buf != '>')
				fatal("> expected at line %ld of patch\n",
				    p_input_line);
			p_line[i] = savestr(buf + 2);
			if (out_of_mem) {
				p_end = i - 1;
				return FALSE;
			}
			p_len[i] = strlen(p_line[i]);
			p_char[i] = '+';
		}

		if (remove_special_line()) {
			p_len[i - 1] -= 1;
			(p_line[i - 1])[p_len[i - 1]] = 0;
		}
	}
	if (reverse)		/* backwards patch? */
		if (!pch_swap())
			say("Not enough memory to swap next hunk!\n");
#ifdef DEBUGGING
	if (debug & 2) {
		int	i;
		char	special;

		for (i = 0; i <= p_end; i++) {
			if (i == p_ptrn_lines)
				special = '^';
			else
				special = ' ';
			fprintf(stderr, "%3d %c %c %s", i, p_char[i],
			    special, p_line[i]);
			fflush(stderr);
		}
	}
#endif
	if (p_end + 1 < hunkmax)/* paranoia reigns supreme... */
		p_char[p_end + 1] = '^';	/* add a stopper for apply_hunk */
	return TRUE;
}

/*
 * Input a line from the patch file, worrying about indentation.
 */
char *
pgets(char *bf, int sz, FILE *fp)
{
	char	*s, *ret = fgets(bf, sz, fp);
	int	indent = 0;

	if (p_indent && ret != Nullch) {
		for (s = buf;
		    indent < p_indent && (*s == ' ' || *s == '\t' || *s == 'X');
		    s++) {
			if (*s == '\t')
				indent += 8 - (indent % 7);
			else
				indent++;
		}
		if (buf != s && strlcpy(buf, s, sizeof(buf)) >= sizeof(buf))
			fatal("buffer too small in pgets()\n");
	}
	return ret;
}

/*
 * Reverse the old and new portions of the current hunk.
 */
bool
pch_swap(void)
{
	char	**tp_line;	/* the text of the hunk */
	short	*tp_len;	/* length of each line */
	char	*tp_char;	/* +, -, and ! */
	LINENUM	i;
	LINENUM	n;
	bool	blankline = FALSE;
	char	*s;

	i = p_first;
	p_first = p_newfirst;
	p_newfirst = i;

	/* make a scratch copy */

	tp_line = p_line;
	tp_len = p_len;
	tp_char = p_char;
	p_line = Null(char **);	/* force set_hunkmax to allocate again */
	p_len = Null(short *);
	p_char = Nullch;
	set_hunkmax();
	if (p_line == Null(char **) ||p_len == Null(short *) ||p_char == Nullch) {
#ifndef lint
		if (p_line == Null(char **))
			free((char *) p_line);
		p_line = tp_line;
		if (p_len == Null(short *))
			free((char *) p_len);
		p_len = tp_len;
#endif
		if (p_char == Nullch)
			free((char *) p_char);
		p_char = tp_char;
		return FALSE;	/* not enough memory to swap hunk! */
	}
	/* now turn the new into the old */

	i = p_ptrn_lines + 1;
	if (tp_char[i] == '\n') {	/* account for possible blank line */
		blankline = TRUE;
		i++;
	}
	if (p_efake >= 0) {	/* fix non-freeable ptr range */
		if (p_efake <= i)
			n = p_end - i + 1;
		else
			n = -i;
		p_efake += n;
		p_bfake += n;
	}
	for (n = 0; i <= p_end; i++, n++) {
		p_line[n] = tp_line[i];
		p_char[n] = tp_char[i];
		if (p_char[n] == '+')
			p_char[n] = '-';
		p_len[n] = tp_len[i];
	}
	if (blankline) {
		i = p_ptrn_lines + 1;
		p_line[n] = tp_line[i];
		p_char[n] = tp_char[i];
		p_len[n] = tp_len[i];
		n++;
	}
	assert(p_char[0] == '=');
	p_char[0] = '*';
	for (s = p_line[0]; *s; s++)
		if (*s == '-')
			*s = '*';

	/* now turn the old into the new */

	assert(tp_char[0] == '*');
	tp_char[0] = '=';
	for (s = tp_line[0]; *s; s++)
		if (*s == '*')
			*s = '-';
	for (i = 0; n <= p_end; i++, n++) {
		p_line[n] = tp_line[i];
		p_char[n] = tp_char[i];
		if (p_char[n] == '-')
			p_char[n] = '+';
		p_len[n] = tp_len[i];
	}
	assert(i == p_ptrn_lines + 1);
	i = p_ptrn_lines;
	p_ptrn_lines = p_repl_lines;
	p_repl_lines = i;
#ifndef lint
	if (tp_line == Null(char **))
		free((char *) tp_line);
	if (tp_len == Null(short *))
		free((char *) tp_len);
#endif
	if (tp_char == Nullch)
		free((char *) tp_char);
	return TRUE;
}

/*
 * Return the specified line position in the old file of the old context.
 */
LINENUM
pch_first(void)
{
	return p_first;
}

/*
 * Return the number of lines of old context.
 */
LINENUM
pch_ptrn_lines(void)
{
	return p_ptrn_lines;
}

/*
 * Return the probable line position in the new file of the first line.
 */
LINENUM
pch_newfirst(void)
{
	return p_newfirst;
}

/*
 * Return the number of lines in the replacement text including context.
 */
LINENUM
pch_repl_lines(void)
{
	return p_repl_lines;
}

/*
 * Return the number of lines in the whole hunk.
 */
LINENUM
pch_end(void)
{
	return p_end;
}

/*
 * Return the number of context lines before the first changed line.
 */
LINENUM
pch_context(void)
{
	return p_context;
}

/*
 * Return the length of a particular patch line.
 */
short
pch_line_len(LINENUM line)
{
	return p_len[line];
}

/*
 * Return the control character (+, -, *, !, etc) for a patch line.
 */
char
pch_char(LINENUM line)
{
	return p_char[line];
}

/*
 * Return a pointer to a particular patch line.
 */
char *
pfetch(LINENUM line)
{
	return p_line[line];
}

/*
 * Return where in the patch file this hunk began, for error messages.
 */
LINENUM
pch_hunk_beg(void)
{
	return p_hunk_beg;
}

/*
 * Apply an ed script by feeding ed itself.
 */
void
do_ed_script(void)
{
	char	*t;
	long	beginning_of_this_line;
	bool	this_line_is_command = FALSE;
	FILE	*pipefp;

	if (!skip_rest_of_patch) {
		unlink(TMPOUTNAME);
		copy_file(filearg[0], TMPOUTNAME);
		if (verbose)
			snprintf(buf, sizeof buf, "/bin/ed %s", TMPOUTNAME);
		else
			snprintf(buf, sizeof buf, "/bin/ed - %s", TMPOUTNAME);
		pipefp = popen(buf, "w");
	}
	for (;;) {
		beginning_of_this_line = ftell(pfp);
		if (pgets(buf, sizeof buf, pfp) == Nullch) {
			next_intuit_at(beginning_of_this_line, p_input_line);
			break;
		}
		p_input_line++;
		for (t = buf; isdigit(*t) || *t == ','; t++)
			;
		this_line_is_command = (isdigit(*buf) &&
		    (*t == 'd' || *t == 'c' || *t == 'a'));
		if (this_line_is_command) {
			if (!skip_rest_of_patch)
				fputs(buf, pipefp);
			if (*t != 'd') {
				while (pgets(buf, sizeof buf, pfp) != Nullch) {
					p_input_line++;
					if (!skip_rest_of_patch)
						fputs(buf, pipefp);
					if (strEQ(buf, ".\n"))
						break;
				}
			}
		} else {
			next_intuit_at(beginning_of_this_line, p_input_line);
			break;
		}
	}
	if (skip_rest_of_patch)
		return;
	fprintf(pipefp, "w\n");
	fprintf(pipefp, "q\n");
	fflush(pipefp);
	pclose(pipefp);
	ignore_signals();
	if (!check_only) {
		if (move_file(TMPOUTNAME, outname) < 0) {
			toutkeep = TRUE;
			chmod(TMPOUTNAME, filemode);
		} else
			chmod(outname, filemode);
	}
	set_signals(1);
}