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concat: Use plain read/write instead of buffered stdio

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If we are just copying data from one file to another, we don't need to
fill a complete buffer, just read a chunk at a time, and write it to the
output.
This commit is contained in:
Michael Forney
2017-07-03 14:58:49 -07:00
committed by Anselm R Garbe
parent 9a3b12525b
commit 3276fbea1c
8 changed files with 202 additions and 171 deletions
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24
libutil/concat.c
View File

@@ -1,19 +1,23 @@
/* See LICENSE file for copyright and license details. */
#include <stdio.h>
#include <unistd.h>
#include "../text.h"
#include "../util.h"
void
concat(FILE *fp1, const char *s1, FILE *fp2, const char *s2)
int
concat(int f1, const char *s1, int f2, const char *s2)
{
char buf[BUFSIZ];
size_t n;
ssize_t n;
while ((n = fread(buf, 1, sizeof(buf), fp1))) {
fwrite(buf, 1, n, fp2);
if (feof(fp1) || ferror(fp1) || ferror(fp2))
break;
while ((n = read(f1, buf, sizeof(buf))) > 0) {
if (writeall(f2, buf, n) < 0) {
weprintf("write %s:", s2);
return -2;
}
}
if (n < 0) {
weprintf("read %s:", s1);
return -1;
}
return 0;
}

55
libutil/cp.c
View File

@@ -12,7 +12,6 @@
#include <utime.h>
#include "../fs.h"
#include "../text.h"
#include "../util.h"
int cp_aflag = 0;
@@ -27,7 +26,7 @@ int
cp(const char *s1, const char *s2, int depth)
{
DIR *dp;
FILE *f1, *f2;
int f1, f2;
struct dirent *d;
struct stat st;
struct timespec times[2];
@@ -113,46 +112,38 @@ cp(const char *s1, const char *s2, int depth)
return 0;
}
} else {
if (!(f1 = fopen(s1, "r"))) {
weprintf("fopen %s:", s1);
if ((f1 = open(s1, O_RDONLY)) < 0) {
weprintf("open %s:", s1);
cp_status = 1;
return 0;
}
if (!(f2 = fopen(s2, "w"))) {
if (cp_fflag) {
if (unlink(s2) < 0 && errno != ENOENT) {
weprintf("unlink %s:", s2);
cp_status = 1;
fclose(f1);
return 0;
} else if (!(f2 = fopen(s2, "w"))) {
weprintf("fopen %s:", s2);
cp_status = 1;
fclose(f1);
return 0;
}
} else {
weprintf("fopen %s:", s2);
if ((f2 = creat(s2, st.st_mode)) < 0 && cp_fflag) {
if (unlink(s2) < 0 && errno != ENOENT) {
weprintf("unlink %s:", s2);
cp_status = 1;
fclose(f1);
close(f1);
return 0;
}
f2 = creat(s2, st.st_mode);
}
if (f2 < 0) {
weprintf("creat %s:", s2);
cp_status = 1;
close(f1);
return 0;
}
if (concat(f1, s1, f2, s2) < 0) {
cp_status = 1;
close(f1);
close(f2);
return 0;
}
concat(f1, s1, f2, s2);
/* preserve permissions by default */
fchmod(fileno(f2), st.st_mode);
fchmod(f2, st.st_mode);
if (fclose(f2) == EOF) {
weprintf("fclose %s:", s2);
cp_status = 1;
return 0;
}
if (fclose(f1) == EOF) {
weprintf("fclose %s:", s1);
cp_status = 1;
return 0;
}
close(f1);
close(f2);
}
if (cp_aflag || cp_pflag) {