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Optimizing comm(1) with the second sent in patch.

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This commit is contained in:
Christoph Lohmann 2013-06-19 21:09:50 +02:00
parent e28c17c7cc
commit 7f88cf7021
2 changed files with 67 additions and 92 deletions
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158
comm.c
View File

@ -3,12 +3,16 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include "util.h"
enum { Suppress1 = 1, Suppress2 = 2, Suppress3 = 4 };
#define CLAMP(x, l, h) MIN(h, MAX(l, x))
static void comm(FILE *fp1, const char *s1, FILE *fp2,
const char *s2, int sflags);
static void printline(int, char *);
static char *nextline(char *, int, FILE *, char *);
static void finish(int, FILE *, char *);
static int show = 0x07;
static void
usage(void)
@ -19,114 +23,84 @@ usage(void)
int
main(int argc, char *argv[])
{
int sflags = 0;
FILE *fp1, *fp2;
int i, dif = 0;
FILE *fp[2];
char lines[2][LINE_MAX+1];
ARGBEGIN {
case '1':
sflags |= Suppress1;
break;
case '2':
sflags |= Suppress2;
break;
case '3':
sflags |= Suppress3;
show &= 0x07 ^ (1 << (ARGC() - '1'));
break;
default:
usage();
} ARGEND;
if (argc < 2)
if(argc != 2)
usage();
if (!(fp1 = fopen(argv[0], "r")))
eprintf("fopen %s:", argv[0]);
if (!(fp2 = fopen(argv[1], "r")))
eprintf("fopen %s:", argv[1]);
for(i = 0; i < LEN(fp); i++) {
if(!(fp[i] = fopen(argv[i], "r")))
eprintf("comm: '%s':", argv[i]);
}
comm(fp1, argv[0], fp2, argv[1], sflags);
for(;;) {
if(dif <= 0) {
if(!nextline(lines[0], sizeof(lines[0]),
fp[0], argv[0])) {
finish(1, fp[1], argv[1]);
}
}
if(dif >= 0) {
if(!nextline(lines[1], sizeof(lines[1]),
fp[1], argv[1])) {
finish(0, fp[0], argv[0]);
}
}
dif = strcmp(lines[0], lines[1]);
dif = CLAMP(dif, -1, 1);
printline((2-dif) % 3, lines[MAX(0, dif)]);
}
return 0;
}
static void
print_col1(const char *s, int sflags)
void
printline(int pos, char *line)
{
if (sflags & Suppress1)
int i;
if(!(show & (0x1 << pos)))
return;
printf("%s", s);
}
static void
print_col2(const char *s, int sflags)
{
const char *tabs = "\t";
if (sflags & Suppress1)
tabs = "";
if (sflags & Suppress2)
return;
printf("%s%s", tabs, s);
}
static void
print_col3(const char *s, int sflags)
{
const char *tabs = "\t\t";
if (sflags & Suppress1)
tabs = "\t";
if (sflags & Suppress2)
tabs = "";
if (sflags & Suppress3)
return;
printf("%s%s", tabs, s);
}
static void
comm(FILE *fp1, const char *s1, FILE *fp2, const char *s2, int sflags)
{
char buf1[BUFSIZ], buf2[BUFSIZ];
bool eof1 = false, eof2 = false;
bool r1 = true, r2 = true;
int ret;
for (;;) {
if (r1)
if (!fgets(buf1, sizeof buf1, fp1))
eof1 = true;
if (r2)
if (!fgets(buf2, sizeof buf2, fp2))
eof2 = true;
/* If we reached EOF on fp1 then just dump fp2 */
if (eof1) {
do {
print_col2(buf2, sflags);
} while (fgets(buf2, sizeof buf2, fp2));
return;
}
/* If we reached EOF on fp2 then just dump fp1 */
if (eof2) {
do {
print_col1(buf1, sflags);
} while (fgets(buf1, sizeof buf1, fp1));
return;
}
ret = strcmp(buf1, buf2);
if (!ret) {
r1 = r2 = true;
print_col3(buf1, sflags);
continue;
} else if (ret < 0) {
r1 = true;
r2 = false;
print_col1(buf1, sflags);
continue;
} else {
r1 = false;
r2 = true;
print_col2(buf2, sflags);
continue;
}
for(i = 0; i < pos; i++) {
if(show & (0x1 << i))
putchar('\t');
}
printf("%s", line);
}
char *
nextline(char *buf, int n, FILE *f, char *name)
{
buf = fgets(buf, n, f);
if(!buf && !feof(f))
eprintf("comm: '%s':", name);
if(buf && !strchr(buf, '\n'))
eprintf("comm: '%s': line too long.\n", name);
return buf;
}
void
finish(int pos, FILE *f, char *name)
{
char buf[LINE_MAX+1];
while(nextline(buf, sizeof(buf), f, name))
printline(pos, buf);
exit(1);
}

1
util.h
View File

@ -20,3 +20,4 @@ long estrtol(const char *, int);
void fnck(const char *, const char *, int (*)(const char *, const char *));
void putword(const char *);
void recurse(const char *, void (*)(const char *));