ref: 4ce9616cb0aba86a30097ae04eb679f1956d30ec
parent: 22bf74f3ba2d91944c38a542461c3349eb566ef5
author: Sigrid Solveig Haflínudóttir <sigrid@ftrv.se>
date: Sat Jan 4 19:35:49 EST 2025
add io-truncate Fixes: https://todo.sr.ht/~ft/femtolisp/37
--- a/ios.c
+++ b/ios.c
@@ -468,24 +468,23 @@
return fdpos;
}
-size_t
-ios_trunc(ios_t *s, size_t size)
+int
+ios_trunc(ios_t *s, off_t size)
{- if(s->state == bst_closed)
- return 0;
+ if(s->state == bst_closed || s->readonly || size < 0)
+ return -1;
if(s->bm == bm_mem){- if(size == s->size)
- return s->size;
- if(size < s->size){- if(s->bpos > size)
+ if((size_t)size == s->size)
+ return 0;
+ if((size_t)size < s->size){+ if(s->bpos > (size_t)size)
s->bpos = size;
}else if(_buf_realloc(s, size) == nil)
- return s->size;
+ return -1;
s->size = size;
- return size;
+ return 0;
}
- // FIXME
- return 0;
+ return ios_flush(s) == 0 ? ftruncate(s->fd, size) : -1;
}
bool
--- a/ios.h
+++ b/ios.h
@@ -25,12 +25,12 @@
}ios_loc_t;
typedef struct {- uint8_t *buf; // start of buffer
- size_t maxsize; // space allocated to buffer
- size_t size; // length of valid data in buf, >=ndirty
- size_t bpos; // current position in buffer
- size_t ndirty; // # bytes at &buf[0] that need to be written
- off_t fpos; // cached file pos
+ uint8_t *buf; // start of buffer
+ size_t maxsize; // space allocated to buffer
+ size_t size; // length of valid data in buf, >=ndirty
+ size_t bpos; // current position in buffer
+ size_t ndirty; // # bytes at &buf[0] that need to be written
+ off_t fpos; // cached file pos
bufmode_t bm;
int colnowait;
@@ -74,7 +74,7 @@
off_t ios_seek_end(ios_t *s);
off_t ios_skip(ios_t *s, off_t offs); // relative seek
off_t ios_pos(ios_t *s); // get current position
-size_t ios_trunc(ios_t *s, size_t size);
+int ios_trunc(ios_t *s, off_t size);
bool ios_eof(ios_t *s);
int ios_flush(ios_t *s);
void ios_close(ios_t *s);
--- a/iostream.c
+++ b/iostream.c
@@ -180,6 +180,15 @@
return FL_void;
}
+BUILTIN("io-truncate", io_truncate)+{+ argcount(nargs, 2);
+ ios_t *s = toiostream(args[0]);
+ if(ios_trunc(s, tooffset(args[1])) < 0)
+ lerrorf(FL_IOError, "truncation failed");
+ return FL_void;
+}
+
BUILTIN("io-discardbuffer", io_discardbuffer) {argcount(nargs, 1);