Rockbox open source high quality audio player as a Music Player Daemon
mpris
rockbox
mpd
libadwaita
audio
rust
zig
deno
Add a 32 byte read buffer to read_line.
Do as with fdprintf and avoid filesystem calls for every single
byte. If it overreads, just put the excess back with lseek, which
does no I/O itself.
Change-Id: Ifd5d21b5dca7183346e44d365d3f7d45e8cc6438
+32
-10
+32
-10
apps/misc.c
+32
-10
apps/misc.c
···
1029
1029
*/
1030
1030
int read_line(int fd, char* buffer, int buffer_size)
1031
1031
{
1032
+
if (!buffer || buffer_size-- <= 0)
1033
+
{
1034
+
errno = EINVAL;
1035
+
return -1;
1036
+
}
1037
+
1038
+
unsigned char rdbuf[32];
1039
+
off_t rdbufend = 0;
1040
+
int rdbufidx = 0;
1032
1041
int count = 0;
1033
1042
int num_read = 0;
1034
-
1035
-
errno = 0;
1036
1043
1037
1044
while (count < buffer_size)
1038
1045
{
1039
-
unsigned char c;
1046
+
if (rdbufidx >= rdbufend)
1047
+
{
1048
+
rdbufidx = 0;
1049
+
rdbufend = read(fd, rdbuf, sizeof (rdbuf));
1040
1050
1041
-
if (1 != read(fd, &c, 1))
1042
-
break;
1051
+
if (rdbufend <= 0)
1052
+
break;
1043
1053
1044
-
num_read++;
1054
+
num_read += rdbufend;
1055
+
}
1045
1056
1046
-
if ( c == '\n' )
1057
+
int c = rdbuf[rdbufidx++];
1058
+
1059
+
if (c == '\n')
1047
1060
break;
1048
1061
1049
-
if ( c == '\r' )
1062
+
if (c == '\r')
1050
1063
continue;
1051
1064
1052
1065
buffer[count++] = c;
1053
1066
}
1054
1067
1055
-
buffer[MIN(count, buffer_size - 1)] = 0;
1068
+
rdbufidx -= rdbufend;
1069
+
1070
+
if (rdbufidx < 0)
1071
+
{
1072
+
/* "put back" what wasn't read from the buffer */
1073
+
num_read += rdbufidx;
1074
+
rdbufend = lseek(fd, rdbufidx, SEEK_CUR);
1075
+
}
1076
+
1077
+
buffer[count] = '\0';
1056
1078
1057
-
return errno ? -1 : num_read;
1079
+
return rdbufend >= 0 ? num_read : -1;
1058
1080
}
1059
1081
1060
1082