py: Add stream reading of n unicode chars; unicode support by default.
With unicode enabled, this patch allows reading a fixed number of characters from text-mode streams; eg file.read(5) will read 5 unicode chars, which can made of more than 5 bytes. For an ASCII stream (ie no chars > 127) it only needs to do 1 read. If there are lots of non-ASCII chars in a stream, then it needs multiple reads of the underlying object. Adds a new test for this case. Enables unicode support by default on unix and stmhal ports.
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02bc882c3d
commit
1694bc733d
88
py/stream.c
88
py/stream.c
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@ -67,6 +67,9 @@ STATIC mp_obj_t stream_read(uint n_args, const mp_obj_t *args) {
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nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "Operation not supported"));
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}
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// What to do if sz < -1? Python docs don't specify this case.
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// CPython does a readall, but here we silently let negatives through,
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// and they will cause a MemoryError.
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mp_int_t sz;
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if (n_args == 1 || ((sz = mp_obj_get_int(args[1])) == -1)) {
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return stream_readall(args[0]);
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@ -74,7 +77,90 @@ STATIC mp_obj_t stream_read(uint n_args, const mp_obj_t *args) {
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#if MICROPY_PY_BUILTINS_STR_UNICODE
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if (!o->type->stream_p->is_bytes) {
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mp_not_implemented("Reading from unicode text streams by character count");
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// We need to read sz number of unicode characters. Because we don't have any
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// buffering, and because the stream API can only read bytes, we must read here
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// in units of bytes and must never over read. If we want sz chars, then reading
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// sz bytes will never over-read, so we follow this approach, in a loop to keep
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// reading until we have exactly enough chars. This will be 1 read for text
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// with ASCII-only chars, and about 2 reads for text with a couple of non-ASCII
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// chars. For text with lots of non-ASCII chars, it'll be pretty inefficient
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// in time and memory.
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vstr_t vstr;
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vstr_init(&vstr, sz);
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mp_uint_t more_bytes = sz;
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mp_uint_t last_buf_offset = 0;
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while (more_bytes > 0) {
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char *p = vstr_add_len(&vstr, more_bytes);
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if (p == NULL) {
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nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_MemoryError, "out of memory"));
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}
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int error;
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mp_int_t out_sz = o->type->stream_p->read(o, p, more_bytes, &error);
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if (out_sz == -1) {
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vstr_cut_tail_bytes(&vstr, more_bytes);
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if (is_nonblocking_error(error)) {
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// With non-blocking streams, we read as much as we can.
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// If we read nothing, return None, just like read().
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// Otherwise, return data read so far.
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// TODO what if we have read only half a non-ASCII char?
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if (vstr.len == 0) {
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vstr_clear(&vstr);
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return mp_const_none;
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}
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break;
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}
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nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "[Errno %d]", error));
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}
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if (out_sz == 0) {
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// Finish reading.
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// TODO what if we have read only half a non-ASCII char?
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vstr_cut_tail_bytes(&vstr, more_bytes);
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break;
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}
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// count chars from bytes just read
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for (mp_uint_t off = last_buf_offset;;) {
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byte b = vstr.buf[off];
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int n;
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if (!UTF8_IS_NONASCII(b)) {
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// 1-byte ASCII char
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n = 1;
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} else if ((b & 0xe0) == 0xc0) {
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// 2-byte char
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n = 2;
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} else if ((b & 0xf0) == 0xe0) {
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// 3-byte char
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n = 3;
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} else if ((b & 0xf8) == 0xf0) {
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// 4-byte char
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n = 4;
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} else {
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// TODO
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n = 5;
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}
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if (off + n <= vstr.len) {
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// got a whole char in n bytes
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off += n;
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sz -= 1;
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last_buf_offset = off;
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if (off >= vstr.len) {
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more_bytes = sz;
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break;
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}
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} else {
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// didn't get a whole char, so work out how many extra bytes are needed for
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// this partial char, plus bytes for additional chars that we want
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more_bytes = (off + n - vstr.len) + (sz - 1);
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break;
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}
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}
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}
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mp_obj_t ret = mp_obj_new_str_of_type(&mp_type_str, (byte*)vstr.buf, vstr.len);
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vstr_clear(&vstr);
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return ret;
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}
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#endif
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@ -44,7 +44,7 @@
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*/
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#define MICROPY_ENABLE_LFN (1)
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#define MICROPY_LFN_CODE_PAGE (437) /* 1=SFN/ANSI 437=LFN/U.S.(OEM) */
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#define MICROPY_PY_BUILTINS_STR_UNICODE (0)
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#define MICROPY_PY_BUILTINS_STR_UNICODE (1)
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#define MICROPY_PY_BUILTINS_FROZENSET (1)
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#define MICROPY_PY_SYS_EXIT (1)
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#define MICROPY_PY_SYS_STDFILES (1)
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@ -134,7 +134,7 @@ def main():
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if args.test_dirs is None:
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if pyb is None:
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# run PC tests
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test_dirs = ('basics', 'micropython', 'float', 'import', 'io', 'misc')
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test_dirs = ('basics', 'micropython', 'float', 'import', 'io', 'misc', 'unicode')
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else:
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# run pyboard tests
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test_dirs = ('basics', 'micropython', 'float', 'pyb', 'pybnative', 'inlineasm')
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@ -0,0 +1 @@
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aαbβcγdδ
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@ -0,0 +1,12 @@
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# test reading a given number of characters
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def do(mode):
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f = open('unicode/data/utf-8_2.txt', mode)
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print(f.read(1))
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print(f.read(1))
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print(f.read(2))
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print(f.read(4))
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f.close()
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do('rb')
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do('rt')
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@ -43,7 +43,7 @@
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#define MICROPY_LONGINT_IMPL (MICROPY_LONGINT_IMPL_MPZ)
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#define MICROPY_STREAMS_NON_BLOCK (1)
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#define MICROPY_OPT_COMPUTED_GOTO (1)
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#define MICROPY_PY_BUILTINS_STR_UNICODE (0)
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#define MICROPY_PY_BUILTINS_STR_UNICODE (1)
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#define MICROPY_PY_BUILTINS_FROZENSET (1)
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#define MICROPY_PY_SYS_EXIT (1)
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#define MICROPY_PY_SYS_PLATFORM "linux"
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