Introduce libbuf analogous to toybuf but for use by lib/*.c. Change readfile() semantics to be able to read into an existing buffer, or malloc its own if that's NULL.
diff --git a/lib/lib.c b/lib/lib.c
index 86e99ac..38d9cc2 100644
--- a/lib/lib.c
+++ b/lib/lib.c
@@ -96,11 +96,10 @@
if (and != -1 && offset >= lseek(fd, offset, SEEK_END)
&& offset+and == lseek(fd, offset+and, SEEK_SET)) return 0;
else {
- char buf[4096];
while (offset>0) {
- int try = offset>sizeof(buf) ? sizeof(buf) : offset, or;
+ int try = offset>sizeof(libbuf) ? sizeof(libbuf) : offset, or;
- or = readall(fd, buf, try);
+ or = readall(fd, libbuf, try);
if (or < 0) perror_msg("lskip to %lld", (long long)offset);
else offset -= try;
if (or < try) break;
@@ -259,20 +258,28 @@
return base;
}
-// Read contents of file as a single freshly allocated nul-terminated string.
-char *readfile(char *name)
+// Read contents of file as a single nul-terminated string.
+// malloc new one if buf=len=0
+char *readfile(char *name, char *buf, off_t len)
{
- off_t len;
int fd;
- char *buf;
fd = open(name, O_RDONLY);
if (fd == -1) return 0;
- len = fdlength(fd);
- // proc files don't report a length, so try 1 page minimum.
- if (len<4096) len = 4095;
- buf = xmalloc(len+1);
- buf[readall(fd, buf, len)] = 0;
+
+ if (len<1) {
+ len = fdlength(fd);
+ // proc files don't report a length, so try 1 page minimum.
+ if (len<4096) len = 4096;
+ }
+ if (!buf) buf = xmalloc(len+1);
+
+ len = readall(fd, buf, len-1);
+ close(fd);
+ if (len<0) {
+ free(buf);
+ buf = 0;
+ } else buf[len] = 0;
return buf;
}