add circuitpython code

1 files changed, 285 insertions, 0 deletions

diff --git a/circuitpython/py/modstruct.c b/circuitpython/py/modstruct.c
new file mode 100644
index 0000000..c0b0fb7
--- /dev/null
+++ b/circuitpython/py/modstruct.c
@@ -0,0 +1,285 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * SPDX-FileCopyrightText: Copyright (c) 2013, 2014 Damien P. George
+ * Copyright (c) 2014 Paul Sokolovsky
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <assert.h>
+#include <string.h>
+
+#include "py/runtime.h"
+#include "py/builtin.h"
+#include "py/objtuple.h"
+#include "py/binary.h"
+#include "py/parsenum.h"
+#include "supervisor/shared/translate.h"
+
+#if MICROPY_PY_STRUCT
+
+/*
+    This module implements most of character typecodes from CPython, with
+    some extensions:
+
+    O - (Pointer to) an arbitrary Python object. This is useful for callback
+        data, etc. Note that you must keep reference to passed object in
+        your Python application, otherwise it may be garbage-collected,
+        and then when you get back this value from callback it may be
+        invalid (and lead to crash).
+    S - Pointer to a string (returned as a Python string). Note the
+        difference from "Ns", - the latter says "in this place of structure
+        is character data of up to N bytes length", while "S" means
+        "in this place of a structure is a pointer to zero-terminated
+        character data".
+ */
+
+STATIC char get_fmt_type(const char **fmt) {
+    char t = **fmt;
+    switch (t) {
+        case '!':
+            t = '>';
+            break;
+        case '@':
+        case '=':
+        case '<':
+        case '>':
+            break;
+        default:
+            return '@';
+    }
+    // Skip type char
+    (*fmt)++;
+    return t;
+}
+
+STATIC mp_uint_t get_fmt_num(const char **p) {
+    const char *num = *p;
+    uint len = 1;
+    while (unichar_isdigit(*++num)) {
+        len++;
+    }
+    mp_uint_t val = (mp_uint_t)MP_OBJ_SMALL_INT_VALUE(mp_parse_num_integer(*p, len, 10, NULL));
+    *p = num;
+    return val;
+}
+
+STATIC size_t calc_size_items(const char *fmt, size_t *total_sz) {
+    char fmt_type = get_fmt_type(&fmt);
+    size_t total_cnt = 0;
+    size_t size;
+    for (size = 0; *fmt; fmt++) {
+        mp_uint_t cnt = 1;
+        if (unichar_isdigit(*fmt)) {
+            cnt = get_fmt_num(&fmt);
+        }
+
+        if (*fmt == 's') {
+            total_cnt += 1;
+            size += cnt;
+        } else {
+            // Pad bytes are skipped and don't get included in the item count.
+            if (*fmt != 'x') {
+                total_cnt += cnt;
+            }
+            size_t align;
+            size_t sz = mp_binary_get_size(fmt_type, *fmt, &align);
+            while (cnt--) {
+                // Apply alignment
+                size = (size + align - 1) & ~(align - 1);
+                size += sz;
+            }
+        }
+    }
+    *total_sz = size;
+    return total_cnt;
+}
+
+STATIC mp_obj_t struct_calcsize(mp_obj_t fmt_in) {
+    const char *fmt = mp_obj_str_get_str(fmt_in);
+    size_t size;
+    calc_size_items(fmt, &size);
+    return MP_OBJ_NEW_SMALL_INT(size);
+}
+MP_DEFINE_CONST_FUN_OBJ_1(struct_calcsize_obj, struct_calcsize);
+
+STATIC mp_obj_t struct_unpack_from(size_t n_args, const mp_obj_t *args) {
+    // unpack requires that the buffer be exactly the right size.
+    // unpack_from requires that the buffer be "big enough".
+    // Since we implement unpack and unpack_from using the same function
+    // we relax the "exact" requirement, and only implement "big enough".
+    const char *fmt = mp_obj_str_get_str(args[0]);
+    size_t total_sz;
+    size_t num_items = calc_size_items(fmt, &total_sz);
+    char fmt_type = get_fmt_type(&fmt);
+    mp_obj_tuple_t *res = MP_OBJ_TO_PTR(mp_obj_new_tuple(num_items, NULL));
+    mp_buffer_info_t bufinfo;
+    mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_READ);
+    byte *p = bufinfo.buf;
+    byte *end_p = &p[bufinfo.len];
+    mp_int_t offset = 0;
+
+    if (n_args > 2) {
+        // offset arg provided
+        offset = mp_obj_get_int(args[2]);
+        if (offset < 0) {
+            // negative offsets are relative to the end of the buffer
+            offset = bufinfo.len + offset;
+            if (offset < 0) {
+                mp_raise_ValueError(MP_ERROR_TEXT("buffer too small"));
+            }
+        }
+        p += offset;
+    }
+    byte *p_base = p;
+
+    // Check that the input buffer is big enough to unpack all the values
+    if (p + total_sz > end_p) {
+        mp_raise_ValueError(MP_ERROR_TEXT("buffer too small"));
+    }
+
+    for (size_t i = 0; i < num_items;) {
+        mp_uint_t cnt = 1;
+        if (unichar_isdigit(*fmt)) {
+            cnt = get_fmt_num(&fmt);
+        }
+        mp_obj_t item;
+        if (*fmt == 's') {
+            item = mp_obj_new_bytes(p, cnt);
+            p += cnt;
+            res->items[i++] = item;
+        } else {
+            while (cnt--) {
+                item = mp_binary_get_val(fmt_type, *fmt, p_base, &p);
+                // Pad bytes ('x') are just skipped.
+                if (*fmt != 'x') {
+                    res->items[i++] = item;
+                }
+            }
+        }
+        fmt++;
+    }
+    return MP_OBJ_FROM_PTR(res);
+}
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(struct_unpack_from_obj, 2, 3, struct_unpack_from);
+
+// This function assumes there is enough room in p to store all the values
+STATIC void struct_pack_into_internal(mp_obj_t fmt_in, byte *p, size_t n_args, const mp_obj_t *args) {
+    size_t size;
+    size_t count = calc_size_items(mp_obj_str_get_str(fmt_in), &size);
+    if (count != n_args) {
+        #if MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE
+        mp_raise_ValueError(NULL);
+        #else
+        mp_raise_ValueError_varg(MP_ERROR_TEXT("pack expected %d items for packing (got %d)"), count, n_args);
+        #endif
+    }
+    const char *fmt = mp_obj_str_get_str(fmt_in);
+    char fmt_type = get_fmt_type(&fmt);
+
+    byte *p_base = p;
+    size_t i;
+    for (i = 0; i < n_args;) {
+        mp_uint_t cnt = 1;
+        if (unichar_isdigit(*fmt)) {
+            cnt = get_fmt_num(&fmt);
+        }
+
+        if (*fmt == 's') {
+            mp_buffer_info_t bufinfo;
+            mp_get_buffer_raise(args[i++], &bufinfo, MP_BUFFER_READ);
+            mp_uint_t to_copy = cnt;
+            if (bufinfo.len < to_copy) {
+                to_copy = bufinfo.len;
+            }
+            memcpy(p, bufinfo.buf, to_copy);
+            memset(p + to_copy, 0, cnt - to_copy);
+            p += cnt;
+        } else {
+            while (cnt--) {
+                // Pad bytes don't have a corresponding argument.
+                if (*fmt == 'x') {
+                    mp_binary_set_val(fmt_type, *fmt, MP_OBJ_NEW_SMALL_INT(0), p_base, &p);
+                } else {
+                    mp_binary_set_val(fmt_type, *fmt, args[i], p_base, &p);
+                    i++;
+                }
+            }
+        }
+        fmt++;
+    }
+}
+
+STATIC mp_obj_t struct_pack(size_t n_args, const mp_obj_t *args) {
+    mp_int_t size = MP_OBJ_SMALL_INT_VALUE(struct_calcsize(args[0]));
+    vstr_t vstr;
+    vstr_init_len(&vstr, size);
+    byte *p = (byte *)vstr.buf;
+    memset(p, 0, size);
+    struct_pack_into_internal(args[0], p, n_args - 1, &args[1]);
+    return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
+}
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(struct_pack_obj, 1, MP_OBJ_FUN_ARGS_MAX, struct_pack);
+
+STATIC mp_obj_t struct_pack_into(size_t n_args, const mp_obj_t *args) {
+    mp_buffer_info_t bufinfo;
+    mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_WRITE);
+    mp_int_t offset = mp_obj_get_int(args[2]);
+    if (offset < 0) {
+        // negative offsets are relative to the end of the buffer
+        offset = (mp_int_t)bufinfo.len + offset;
+        if (offset < 0) {
+            mp_raise_ValueError(MP_ERROR_TEXT("buffer too small"));
+        }
+    }
+    byte *p = (byte *)bufinfo.buf;
+    byte *end_p = &p[bufinfo.len];
+    p += offset;
+
+    // Check that the output buffer is big enough to hold all the values
+    mp_int_t sz = MP_OBJ_SMALL_INT_VALUE(struct_calcsize(args[0]));
+    if (p + sz > end_p) {
+        mp_raise_ValueError(MP_ERROR_TEXT("buffer too small"));
+    }
+
+    struct_pack_into_internal(args[0], p, n_args - 3, &args[3]);
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(struct_pack_into_obj, 3, MP_OBJ_FUN_ARGS_MAX, struct_pack_into);
+
+STATIC const mp_rom_map_elem_t mp_module_struct_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_ustruct) },
+    { MP_ROM_QSTR(MP_QSTR_calcsize), MP_ROM_PTR(&struct_calcsize_obj) },
+    { MP_ROM_QSTR(MP_QSTR_pack), MP_ROM_PTR(&struct_pack_obj) },
+    { MP_ROM_QSTR(MP_QSTR_pack_into), MP_ROM_PTR(&struct_pack_into_obj) },
+    { MP_ROM_QSTR(MP_QSTR_unpack), MP_ROM_PTR(&struct_unpack_from_obj) },
+    { MP_ROM_QSTR(MP_QSTR_unpack_from), MP_ROM_PTR(&struct_unpack_from_obj) },
+};
+
+STATIC MP_DEFINE_CONST_DICT(mp_module_struct_globals, mp_module_struct_globals_table);
+
+const mp_obj_module_t mp_module_ustruct = {
+    .base = { &mp_type_module },
+    .globals = (mp_obj_dict_t *)&mp_module_struct_globals,
+};
+
+#endif