/* whatsnew - mark changes in a patched file	Author: Andy Tanenbaum *//* MINIX programs are constantly being updated.  When a cdiff patch comes in, * it would be nice to be able to apply the patch, and then list the new file, * which the changed lines marked somehow.  This program allows that.  Suppose * prog.c is the newly patched file and prog.cdif is the cdiff listing that was * used to produce it.  Then the command * * 	whatsnew prog.c prog.cdif * * will copy prog.c to standard output, marking all added or changed lines * with + or ! at the end, respectively.  Output lines are forced to a standard * length to make the + and ! symbols easy to find.  The default length is 80, * but it can be changed using a flag.  For example, * *	whatsnew -75 prog.c prog.cdif * * which pads or truncates the output lines to 75 characters before appending * ! or +.  Tabs are converted to spaces in the process. */#include <string.h>#include <stdlib.h>#include <stdio.h>#define MAX_WIDTH       256	/* max line length */#define HEAP_LINES    10000	/* max length of the diff listing */#define HEAP_BYTES    30000	/* total space for saved lines */#define HASH_SIZE        10	/* how much of a line is the hash key */#define TAB_WIDTH         8	/* how far apart are the tab stops */#define DEF_WIDTH        80	/* default width */int cdif_found = 0;		/* set to 1 if cdif entry found */char *indices[HEAP_LINES];	/* pointers into the heap */char heap[HEAP_BYTES];		/* the + and ! lines are saved here. */int lines_used;			/* number of index slots used */char *hp = heap;		/* pointer to end of the heap */int width = DEF_WIDTH;		/* how wide to print the listing */_PROTOTYPE(int main, (int argc, char **argv));_PROTOTYPE(void eat_cdif, (FILE *cdif, char *name));_PROTOTYPE(void read_and_print, (FILE *newf));_PROTOTYPE(int present, (char *line, char *name));_PROTOTYPE(void enter_line, (char *line));_PROTOTYPE(int hash, (char *p));_PROTOTYPE(void print_line, (char *line, int c));_PROTOTYPE(void usage, (void));int main(argc, argv)int argc;char *argv[];{  int k;  char *p;  FILE *newf, *cdif;  /* Process the command line. */  if (argc < 2) usage();  k = 1;  p = argv[1];  if (*p == '-') {	width = atoi(p + 1);	if (width < 0 || width > MAX_WIDTH) {		fprintf(stderr, "%s: max line size is %d\n",argv[0],MAX_WIDTH);		exit(1);	}	k++;	if (argc != 4) usage();  } else {	if (argc != 3) usage();  }  newf = fopen(argv[k], "r");  if (newf == NULL) {	fprintf(stderr, "%s: cannot open %s\n", argv[0], argv[k]);	exit(1);  }  cdif = fopen(argv[k + 1], "r");  if (cdif == NULL) {	fprintf(stderr, "%s: cannot open %s\n", argv[0], argv[k + 1]);	exit(1);  }  /* Read the cdif file and hash all the relevant lines. */  eat_cdif(cdif, argv[k]);  /* Read and print the new file. */  read_and_print(newf);  return(0);}void eat_cdif(cdif, name)FILE *cdif;char *name;{  char line[MAX_WIDTH];  /* First find the start of the relevant cdif stuff. */  while (fgets(line, MAX_WIDTH, cdif) != NULL) {	if (strncmp(line, "*** ", (size_t)4) != 0) continue;	if (present(line, name) && present(line, ":")) {		cdif_found = 1;		break;	}  }  if (cdif_found == 0) {	fprintf(stderr, "no cdif found for %s\n", name);	exit(2);  }  /* We found it. Save all the ! and + lines in the hash table. */  while (fgets(line, MAX_WIDTH, cdif) != NULL) {	if (strncmp(line, "*** ", (size_t)4) == 0 && present(line, ":")) break;	if (line[0] != '+' && line[0] != '!') continue;	if (line[1] != ' ') continue;	enter_line(line);  }}void read_and_print(newf)FILE *newf;{  int h, hit;  char line[MAX_WIDTH], c;  /* Examine each line in the patched file. */  while (fgets(line, MAX_WIDTH, newf) != NULL) {	/* Hash the line and see if it is in the table. */	hit = -1;	h = hash(line);	while (indices[h] != 0) {		if (strcmp(line, indices[h] + 2) == 0) {			hit = h;			break;		}		h = (h + 1) % HEAP_LINES;	}	c = (hit >= 0 ? *(indices[h]) : ' ');	print_line(line, c);  }}int present(line, name)char *line, *name;{/* Scan line to see if the string name is present in it anywhere.  If so, * return 1, else return 0. */  register int n;  register char *p;  p = line;  n = strlen(name);  while (*p != 0) {	if (strncmp(p, name, (size_t)n) == 0) return(1);	p++;  }  return(0);}void enter_line(line)char *line;{/* Enter a line in the hash table.  Note that the first two characters * do not count, as they have been added by cdiff. */  int n, h;  /* Certain lines should not be entered as they occur often. */  n = strlen(line) - 2;  if (n == 1) return;		/* don't enter null lines */  if (strncmp(line, "+ /*==", (size_t)6) == 0) return;  if (strncmp(line, "+  *==", (size_t)6) == 0) return;  if (strncmp(line, "+   {", (size_t)5) == 0) return;  if (strncmp(line, "+   }", (size_t)5) == 0) return;  if (strncmp(line, "+ {", (size_t)3) == 0) return;  if (strncmp(line, "+ }", (size_t)3) == 0) return;  if (strncmp(line, "+ \t{", (size_t)4) == 0) return;  if (strncmp(line, "+ \t}", (size_t)4) == 0) return;  if (strncmp(line, "+ else", (size_t)6) == 0) return;  if (strncmp(line, "+ #end", (size_t)6) == 0) return;  if (lines_used == HEAP_LINES) {	fprintf(stderr, "cdif listing has too many lines\n");	exit(1);  }  if (hp + n >= &heap[HEAP_BYTES]) {	fprintf(stderr, "cdif listing has too many bytes\n");	exit(1);  }  /* Make the heap entry. */  h = hash(line + 2);  while (indices[h] != 0) h = (h + 1) % HEAP_LINES;  indices[h] = hp;		/* indices table points to the lines */  strcpy(hp, line);		/* first two chars also copied */  lines_used++;			/* count # table slots used */  hp += n + 3;			/* 0 byte counts also */}int hash(p)char *p;{/* Compute and return the hash code of p. */  int i, n;  unsigned h;  n = strlen(p);  if (n > HASH_SIZE) n = HASH_SIZE;  h = 0;  for (i = 0; i < n; i++) {	h += 23 * i * (int) *p;	p++;  }  h = h % HEAP_LINES;  return((int) h);}void print_line(line, c)char *line, c;{/* Print the line. */  int col, spaces;  char out_buf[3 * MAX_WIDTH], *p, *q;  p = line;  q = out_buf;  col = 0;  while (*p != '\n') {	/* This loop executed once for each character in the line. */	if (*p != '\t') {		/* Not a tab. */		*q++ = *p++;		col++;	} else {		/* Tab. */		spaces = TAB_WIDTH - (col % TAB_WIDTH);		col += spaces;		while (spaces--) *q++ = ' ';		p++;	}  }  while (q < &out_buf[width]) *q++ = ' ';  q = &out_buf[width];  *q++ = ' ';  *q++ = c;  *q++ = '\n';  *q = 0;  fputs(out_buf, stdout);}void usage(){  fprintf(stderr, "Usage: whatsnew [-<width>] file file.cdif\n");  exit(1);}