Chapter 30: Text Formatting and Diagnostics

Co-authored-by: Hsiang-Ying Fu <66062782+fuhsnn@users.noreply.github.com>
Co-authored-by: fuhsnn <66062782+fuhsnn@users.noreply.github.com>
Co-authored-by: Symious <14933944+symious@users.noreply.github.com>
Co-authored-by: Jun Kawasaki <jun784@gmail.com>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 53 insertions, 22 deletions

diff --git a/src/main/smp/sys/io.smp b/src/main/smp/sys/io.smp
index d6263ffe..14993429 100644
--- a/src/main/smp/sys/io.smp
+++ b/src/main/smp/sys/io.smp
@@ -4,43 +4,74 @@
 // Write byte array to stdout
 val p          = { u8[~] str -> write(1,str); };
 val p_noInline = { u8[~] str -> write(1,str); };
+// Write to stderr
+val err = { u8[~] str -> write(libc.STDERR,str); };
 
-// Return fd contents as a u8[].
+
+// Read until EOF, including after short reads.  Return an empty array for an
+// empty stream, or null on error with errno preserved (partial data discarded).
 val read = { i32 fd ->
-    var buf = new u8[8*1024];
-    i64 ptr = buf;
-    int len = 0;
+    val chunk = new u8[8*1024];
+    i64 ptr = chunk;
+    val buf = new aryu8();
     while( true ) {
-        i32 rez = libc.read(fd,ptr,buf#);
-        if( rez > buf# ) libc._exit(libc.errno());
-        len += rez;
-        if( rez < buf# )
-            break;
-        libc._exit(-2); // Need to implement for more than 8K input
+        i64 rez = libc.read(fd,ptr,chunk#);
+        if( rez < 0 ) {
+            if( libc.errno() == libc.EINTR ) continue;
+            return null;
+        }
+        if( rez == 0 ) break;
+        if( buf.len+rez > 4294967295 ) {
+            libc.set_errno(libc.EOVERFLOW);
+            return null;
+        }
+        u32 count = rez;
+        buf._grow(count);
+        ary.copy(buf.buf,buf.len,chunk,0,count);
+        buf.len += count;
     }
-    var out = new u8[len];
-    ary.copy(out,0,buf,0,len);
+    val out = new u8[buf.len];
+    return ary.copy(out,0,buf.buf,0,buf.len);
 };
 
-// Write all of str to fd.
+// Write all bytes, returning the count or -1 with errno set. An error can
+// follow a successfully written prefix; it does not undo that prefix.
 val write = { i32 fd, u8[~] str ->
-  i64 ptr = str;                // Convert array pointer to a i64 for the native call
-  libc.write(fd,ptr,str#);
+    writeOff(fd,str,0,str#);
 };
 
-// Write all of str to fd.
+// Write a slice, capping len at the remaining bytes.  An offset past the end
+// is invalid, including for an empty write.  A valid empty slice returns zero.
+// Invalid arguments return -1;
 val writeOff = { i32 fd, u8[~] str, u32 off, u32 len ->
-  i64 ptr = str;                // Convert array pointer to a i64 for the native call
-  ptr += off;                   // Skip offset
-  // Cap at available length
-  if( len > str# - off ) len = str# - off;
-  // Do the write
-  libc.write(fd,ptr,len);
+    if( off > str# ) return libc.set_errno(libc.EINVAL);
+    if( len > str# - off ) len = str# - off;
+    i64 ptr = str;
+    ptr += off;
+    i64 done = 0;
+    while( done < len ) {
+        i64 rez = libc.write(fd,ptr+done,len-done);
+        if( rez < 0 ) {
+            if( libc.errno() == libc.EINTR ) continue;
+            return -1;
+        }
+        if( rez == 0 ) {
+            libc.set_errno(libc.EIO);
+            return -1;
+        }
+        done += rez;
+    }
+    return done;
 };
 
 // Return stdin as a u8[].
 val stdin = { -> read(0); };
 
+// One byte, without Enter or echo. Restores the previous terminal mode before
+// returning. Files/pipes also work. Returns 0..255, or -1 with libc.errno() set
+// to libc.EOF or an OS error. Ctrl-C is byte 3; escape/UTF-8 sequences are multiple bytes.
+val getch = { -> libc.simple_getch(); };
+
 // Create file for writing.  Return fd, or -1 and errno has the error code
 val create = { u8[~] str ->
     i64 ptr = sys.aryu8.str0(str);