circuitpython/py/sequence.c

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#include <assert.h>
#include <stdbool.h>
#include <string.h>
#include "nlr.h"
#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "obj.h"
#include "runtime0.h"
#include "runtime.h"
// Helpers for sequence types
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#define SWAP(type, var1, var2) { type t = var2; var2 = var1; var1 = t; }
// Implements backend of sequence * integer operation. Assumes elements are
// memory-adjacent in sequence.
void mp_seq_multiply(const void *items, uint item_sz, uint len, uint times, void *dest) {
for (int i = 0; i < times; i++) {
uint copy_sz = item_sz * len;
memcpy(dest, items, copy_sz);
dest = (char*)dest + copy_sz;
}
}
bool m_seq_get_fast_slice_indexes(machine_uint_t len, mp_obj_t slice, machine_uint_t *begin, machine_uint_t *end) {
machine_int_t start, stop, step;
mp_obj_slice_get(slice, &start, &stop, &step);
if (step != 1) {
return false;
}
// Unlike subscription, out-of-bounds slice indexes are never error
if (start < 0) {
start = len + start;
if (start < 0) {
start = 0;
}
} else if (start > len) {
start = len;
}
if (stop <= 0) {
stop = len + stop;
// CPython returns empty sequence in such case
if (stop < 0) {
stop = start;
}
} else if (stop > len) {
stop = len;
}
*begin = start;
*end = stop;
return true;
}
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// Special-case comparison function for sequences of bytes
// Don't pass MP_BINARY_OP_NOT_EQUAL here
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bool mp_seq_cmp_bytes(int op, const byte *data1, uint len1, const byte *data2, uint len2) {
// Let's deal only with > & >=
if (op == MP_BINARY_OP_LESS || op == MP_BINARY_OP_LESS_EQUAL) {
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SWAP(const byte*, data1, data2);
SWAP(uint, len1, len2);
if (op == MP_BINARY_OP_LESS) {
op = MP_BINARY_OP_MORE;
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} else {
op = MP_BINARY_OP_MORE_EQUAL;
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}
}
uint min_len = len1 < len2 ? len1 : len2;
int res = memcmp(data1, data2, min_len);
if (res < 0) {
return false;
}
if (res > 0) {
return true;
}
// If we had tie in the last element...
// ... and we have lists of different lengths...
if (len1 != len2) {
if (len1 < len2) {
// ... then longer list length wins (we deal only with >)
return false;
}
} else if (op == MP_BINARY_OP_MORE) {
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// Otherwise, if we have strict relation, equality means failure
return false;
}
return true;
}
// Special-case comparison function for sequences of mp_obj_t
// Don't pass MP_BINARY_OP_NOT_EQUAL here
bool mp_seq_cmp_objs(int op, const mp_obj_t *items1, uint len1, const mp_obj_t *items2, uint len2) {
if (op == MP_BINARY_OP_EQUAL && len1 != len2) {
return false;
}
// Let's deal only with > & >=
if (op == MP_BINARY_OP_LESS || op == MP_BINARY_OP_LESS_EQUAL) {
SWAP(const mp_obj_t *, items1, items2);
SWAP(uint, len1, len2);
if (op == MP_BINARY_OP_LESS) {
op = MP_BINARY_OP_MORE;
} else {
op = MP_BINARY_OP_MORE_EQUAL;
}
}
int len = len1 < len2 ? len1 : len2;
bool eq_status = true; // empty lists are equal
for (int i = 0; i < len; i++) {
eq_status = mp_obj_equal(items1[i], items2[i]);
// If current elements equal, can't decide anything - go on
if (eq_status) {
continue;
}
// Othewise, if they are not equal, we can have final decision based on them
if (op == MP_BINARY_OP_EQUAL) {
// In particular, if we are checking for equality, here're the answer
return false;
}
// Otherwise, application of relation op gives the answer
return (mp_binary_op(op, items1[i], items2[i]) == mp_const_true);
}
assert(eq_status);
// If we had tie in the last element...
if (eq_status) {
// ... and we have lists of different lengths...
if (len1 != len2) {
if (len1 < len2) {
// ... then longer list length wins (we deal only with >)
return false;
}
} else if (op == MP_BINARY_OP_MORE) {
// Otherwise, if we have strict relation, equality means failure
return false;
}
}
return true;
}
// Special-case of index() which searches for mp_obj_t
mp_obj_t mp_seq_index_obj(const mp_obj_t *items, uint len, uint n_args, const mp_obj_t *args) {
mp_obj_type_t *type = mp_obj_get_type(args[0]);
mp_obj_t *value = args[1];
uint start = 0;
uint stop = len;
if (n_args >= 3) {
start = mp_get_index(type, len, args[2], true);
if (n_args >= 4) {
stop = mp_get_index(type, len, args[3], true);
}
}
for (machine_uint_t i = start; i < stop; i++) {
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if (mp_obj_equal(items[i], value)) {
// Common sense says this cannot overflow small int
return MP_OBJ_NEW_SMALL_INT(i);
}
}
nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, "object not in sequence"));
}
mp_obj_t mp_seq_count_obj(const mp_obj_t *items, uint len, mp_obj_t value) {
machine_uint_t count = 0;
for (uint i = 0; i < len; i++) {
if (mp_obj_equal(items[i], value)) {
count++;
}
}
// Common sense says this cannot overflow small int
return MP_OBJ_NEW_SMALL_INT(count);
}