From 0cd9ab77550eada4def492a3a25286ead71a3b24 Mon Sep 17 00:00:00 2001 From: Paul Sokolovsky Date: Sun, 20 Aug 2017 21:32:17 +0300 Subject: [PATCH] py/objstringio: Fix regression with handling SEEK_SET. For SEEK_SET, offset should be treated as unsigned, to allow full-width stream sizes (e.g. 32-bit instead of 31-bit). This is now fully documented in stream.h. Also, seek symbolic constants are added. --- py/objstringio.c | 8 +++++--- py/stream.h | 8 ++++++++ 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/py/objstringio.c b/py/objstringio.c index cb8003bcdd..61da0203e1 100644 --- a/py/objstringio.c +++ b/py/objstringio.c @@ -118,15 +118,17 @@ STATIC mp_uint_t stringio_ioctl(mp_obj_t o_in, mp_uint_t request, uintptr_t arg, struct mp_stream_seek_t *s = (struct mp_stream_seek_t*)arg; mp_uint_t ref = 0; switch (s->whence) { - case 1: // SEEK_CUR + case MP_SEEK_CUR: ref = o->pos; break; - case 2: // SEEK_END + case MP_SEEK_END: ref = o->vstr->len; break; } mp_uint_t new_pos = ref + s->offset; - if (s->offset < 0) { + + // For MP_SEEK_SET, offset is unsigned + if (s->whence != MP_SEEK_SET && s->offset < 0) { if (new_pos > ref) { // Negative offset from SEEK_CUR or SEEK_END went past 0. // CPython sets position to 0, POSIX returns an EINVAL error diff --git a/py/stream.h b/py/stream.h index 401ae313cd..fbe3d7d859 100644 --- a/py/stream.h +++ b/py/stream.h @@ -50,10 +50,18 @@ // Argument structure for MP_STREAM_SEEK struct mp_stream_seek_t { + // If whence == MP_SEEK_SET, offset should be treated as unsigned. + // This allows dealing with full-width stream sizes (16, 32, 64, + // etc. bits). For other seek types, should be treated as signed. mp_off_t offset; int whence; }; +// seek ioctl "whence" values +#define MP_SEEK_SET (0) +#define MP_SEEK_CUR (1) +#define MP_SEEK_END (2) + MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_read_obj); MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_read1_obj); MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_readinto_obj);