code: plan9front

Info  •  Files  •  Log

read: add -r to read runes instead of bytes (thanks umbraticus)

--- a/sys/man/1/cat

+++ b/sys/man/1/cat

@@ -10,12 +10,15 @@

 .B read

 [

 .B -m

-] [

+|

 .B -n

 .I nlines

-] [

+|

 .B -c

 .I nbytes

+|

+.B -r

+.I nrunes

 ] [

 .I file ...

 ]

@@ -59,20 +62,14 @@

 causes it to read no more than

 .I nlines

 lines.

-.PP

-With the

+The

 .B -c

-flag,

-.I read

-copies exactly

-.I nbytes

-of characters instead of lines. It is mutually exclusive with

-.B -n

 and

-.B -m

-flag.

+.B -r

+flags specify a number of bytes or runes to read instead of lines.

 .PP

-.I Read

+When reading lines,

+.I read

 always executes a single

 .B write

 for each line of input, which can be helpful when

--- a/sys/src/cmd/read.c

+++ b/sys/src/cmd/read.c

@@ -2,8 +2,7 @@

 #include <libc.h>

 int	multi;

-int	nlines;

-vlong	nchars;

+vlong	count;

 char	*status = nil;

 int

@@ -50,7 +49,7 @@

 	do{

 		if(line(fd, file) == 0)

 			break;

-	}while(multi || --nlines>0);

+	}while(multi || --count > 0);

 }

 void

@@ -60,10 +59,10 @@

 	vlong m;

 	int n;

-	for(m = 0; m < nchars; m += n){

+	for(m = 0; m < count; m += n){

 		n = sizeof(buf);

-		if(n > (nchars - m))

-			n = nchars - m;

+		if(n > (count - m))

+			n = count - m;

 		if((n = read(fd, buf, n)) < 0){

 			fprint(2, "read: error reading %s: %r\n", file);

 			exits("read error");

@@ -78,9 +77,45 @@

 }

 void

+runes(int fd, char *file)

+{

+	char buf[8*1024], *s, *e;

+	Rune r;

+

+	while(count > 0){

+		e = buf + read(fd, buf, count + UTFmax < sizeof buf ? count : sizeof buf - UTFmax);

+		if(e < buf){

+			fprint(2, "read: error reading %s: %r\n", file);

+			exits("read error");

+		}

+		if(e == buf)

+			break;

+		for(s = buf; s < e && fullrune(s, e - s); s += chartorune(&r, s))

+			count--;

+		if(s < e){

+			while(!fullrune(s, e - s))

+				switch(read(fd, e, 1)){

+				case -1:

+					fprint(2, "read: error reading %s: %r\n", file);

+					exits("read error");

+				case 0:

+					fprint(2, "warning: partial rune at end of %s: %r\n", file);

+					write(1, buf, e - buf);

+					return;

+				case 1:

+					e++;

+					break;

+				}

+			count--;

+		}

+		write(1, buf, e - buf);

+	}

+}

+

+void

 usage(void)

 {

-	fprint(2, "usage: read [-m] [-n nlines] [-c nbytes] [files...]\n");

+	fprint(2, "usage: read [ -m | -n nlines | -c nbytes | -r nrunes ] [ file ... ]\n");

 	exits("usage");

 }

@@ -93,11 +128,15 @@

 	proc = lines;

 	ARGBEGIN{

 	case 'c':

-		nchars = atoll(EARGF(usage()));

+		count = atoll(EARGF(usage()));

 		proc = chars;

 		break;

+	case 'r':

+		count = atoll(EARGF(usage()));

+		proc = runes;

+		break;

 	case 'n':

-		nlines = atoi(EARGF(usage()));

+		count = atoi(EARGF(usage()));

 		break;

 	case 'm':

 		multi = 1;