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micropython/py/qstr.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 Damien P. George
*
* 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 <stdio.h>
#include "py/mpstate.h"
#include "py/qstr.h"
#include "py/gc.h"
// NOTE: we are using linear arrays to store and search for qstr's (unique strings, interned strings)
// ultimately we will replace this with a static hash table of some kind
// also probably need to include the length in the string data, to allow null bytes in the string
#if MICROPY_DEBUG_VERBOSE // print debugging info
#define DEBUG_printf DEBUG_printf
#else // don't print debugging info
#define DEBUG_printf(...) (void)0
#endif
// A qstr is an index into the qstr pool.
// The data for a qstr contains (hash, length, data):
// - hash (configurable number of bytes)
// - length (configurable number of bytes)
// - data ("length" number of bytes)
// - \0 terminated (so they can be printed using printf)
#if MICROPY_QSTR_BYTES_IN_HASH == 1
#define Q_HASH_MASK (0xff)
#define Q_GET_HASH(q) ((mp_uint_t)(q)[0])
#define Q_SET_HASH(q, hash) do { (q)[0] = (hash); } while (0)
#elif MICROPY_QSTR_BYTES_IN_HASH == 2
#define Q_HASH_MASK (0xffff)
#define Q_GET_HASH(q) ((mp_uint_t)(q)[0] | ((mp_uint_t)(q)[1] << 8))
#define Q_SET_HASH(q, hash) do { (q)[0] = (hash); (q)[1] = (hash) >> 8; } while (0)
#else
#error unimplemented qstr hash decoding
#endif
#define Q_GET_ALLOC(q) (MICROPY_QSTR_BYTES_IN_HASH + MICROPY_QSTR_BYTES_IN_LEN + Q_GET_LENGTH(q) + 1)
#define Q_GET_DATA(q) ((q) + MICROPY_QSTR_BYTES_IN_HASH + MICROPY_QSTR_BYTES_IN_LEN)
#if MICROPY_QSTR_BYTES_IN_LEN == 1
#define Q_GET_LENGTH(q) ((q)[MICROPY_QSTR_BYTES_IN_HASH])
#define Q_SET_LENGTH(q, len) do { (q)[MICROPY_QSTR_BYTES_IN_HASH] = (len); } while (0)
#elif MICROPY_QSTR_BYTES_IN_LEN == 2
#define Q_GET_LENGTH(q) ((q)[MICROPY_QSTR_BYTES_IN_HASH] | ((q)[MICROPY_QSTR_BYTES_IN_HASH + 1] << 8))
#define Q_SET_LENGTH(q, len) do { (q)[MICROPY_QSTR_BYTES_IN_HASH] = (len); (q)[MICROPY_QSTR_BYTES_IN_HASH + 1] = (len) >> 8; } while (0)
#else
#error unimplemented qstr length decoding
#endif
#if MICROPY_PY_THREAD && !MICROPY_PY_THREAD_GIL
#define QSTR_ENTER() mp_thread_mutex_lock(&MP_STATE_VM(qstr_mutex), 1)
#define QSTR_EXIT() mp_thread_mutex_unlock(&MP_STATE_VM(qstr_mutex))
#else
#define QSTR_ENTER()
#define QSTR_EXIT()
#endif
// Initial number of entries for qstr pool, set so that the first dynamically
// allocated pool is twice this size. The value here must be <= MP_QSTRnumber_of.
#define MICROPY_ALLOC_QSTR_ENTRIES_INIT (10)
// this must match the equivalent function in makeqstrdata.py
mp_uint_t qstr_compute_hash(const byte *data, size_t len) {
// djb2 algorithm; see http://www.cse.yorku.ca/~oz/hash.html
mp_uint_t hash = 5381;
for (const byte *top = data + len; data < top; data++) {
hash = ((hash << 5) + hash) ^ (*data); // hash * 33 ^ data
}
hash &= Q_HASH_MASK;
// Make sure that valid hash is never zero, zero means "hash not computed"
if (hash == 0) {
hash++;
}
return hash;
}
const qstr_pool_t mp_qstr_const_pool = {
NULL, // no previous pool
0, // no previous pool
MICROPY_ALLOC_QSTR_ENTRIES_INIT,
MP_QSTRnumber_of, // corresponds to number of strings in array just below
{
#ifndef NO_QSTR
#define QDEF(id, str) str,
#include "genhdr/qstrdefs.generated.h"
#undef QDEF
#endif
},
};
#ifdef MICROPY_QSTR_EXTRA_POOL
extern const qstr_pool_t MICROPY_QSTR_EXTRA_POOL;
#define CONST_POOL MICROPY_QSTR_EXTRA_POOL
#else
#define CONST_POOL mp_qstr_const_pool
#endif
void qstr_init(void) {
MP_STATE_VM(last_pool) = (qstr_pool_t*)&CONST_POOL; // we won't modify the const_pool since it has no allocated room left
MP_STATE_VM(qstr_last_chunk) = NULL;
#if MICROPY_PY_THREAD
mp_thread_mutex_init(&MP_STATE_VM(qstr_mutex));
#endif
}
STATIC const byte *find_qstr(qstr q) {
// search pool for this qstr
// total_prev_len==0 in the final pool, so the loop will always terminate
qstr_pool_t *pool = MP_STATE_VM(last_pool);
while (q < pool->total_prev_len) {
pool = pool->prev;
}
return pool->qstrs[q - pool->total_prev_len];
}
// qstr_mutex must be taken while in this function
STATIC qstr qstr_add(const byte *q_ptr) {
DEBUG_printf("QSTR: add hash=%d len=%d data=%.*s\n", Q_GET_HASH(q_ptr), Q_GET_LENGTH(q_ptr), Q_GET_LENGTH(q_ptr), Q_GET_DATA(q_ptr));
// make sure we have room in the pool for a new qstr
if (MP_STATE_VM(last_pool)->len >= MP_STATE_VM(last_pool)->alloc) {
size_t new_alloc = MP_STATE_VM(last_pool)->alloc * 2;
#ifdef MICROPY_QSTR_EXTRA_POOL
// Put a lower bound on the allocation size in case the extra qstr pool has few entries
new_alloc = MAX(MICROPY_ALLOC_QSTR_ENTRIES_INIT, new_alloc);
#endif
qstr_pool_t *pool = m_new_obj_var_maybe(qstr_pool_t, const char*, new_alloc);
if (pool == NULL) {
QSTR_EXIT();
m_malloc_fail(new_alloc);
}
pool->prev = MP_STATE_VM(last_pool);
pool->total_prev_len = MP_STATE_VM(last_pool)->total_prev_len + MP_STATE_VM(last_pool)->len;
pool->alloc = new_alloc;
pool->len = 0;
MP_STATE_VM(last_pool) = pool;
DEBUG_printf("QSTR: allocate new pool of size %d\n", MP_STATE_VM(last_pool)->alloc);
}
// add the new qstr
MP_STATE_VM(last_pool)->qstrs[MP_STATE_VM(last_pool)->len++] = q_ptr;
// return id for the newly-added qstr
return MP_STATE_VM(last_pool)->total_prev_len + MP_STATE_VM(last_pool)->len - 1;
}
qstr qstr_find_strn(const char *str, size_t str_len) {
// work out hash of str
mp_uint_t str_hash = qstr_compute_hash((const byte*)str, str_len);
// search pools for the data
for (qstr_pool_t *pool = MP_STATE_VM(last_pool); pool != NULL; pool = pool->prev) {
for (const byte **q = pool->qstrs, **q_top = pool->qstrs + pool->len; q < q_top; q++) {
if (Q_GET_HASH(*q) == str_hash && Q_GET_LENGTH(*q) == str_len && memcmp(Q_GET_DATA(*q), str, str_len) == 0) {
return pool->total_prev_len + (q - pool->qstrs);
}
}
}
// not found; return null qstr
return 0;
}
qstr qstr_from_str(const char *str) {
return qstr_from_strn(str, strlen(str));
}
qstr qstr_from_strn(const char *str, size_t len) {
assert(len < (1 << (8 * MICROPY_QSTR_BYTES_IN_LEN)));
QSTR_ENTER();
qstr q = qstr_find_strn(str, len);
if (q == 0) {
// qstr does not exist in interned pool so need to add it
// compute number of bytes needed to intern this string
size_t n_bytes = MICROPY_QSTR_BYTES_IN_HASH + MICROPY_QSTR_BYTES_IN_LEN + len + 1;
if (MP_STATE_VM(qstr_last_chunk) != NULL && MP_STATE_VM(qstr_last_used) + n_bytes > MP_STATE_VM(qstr_last_alloc)) {
// not enough room at end of previously interned string so try to grow
byte *new_p = m_renew_maybe(byte, MP_STATE_VM(qstr_last_chunk), MP_STATE_VM(qstr_last_alloc), MP_STATE_VM(qstr_last_alloc) + n_bytes, false);
if (new_p == NULL) {
// could not grow existing memory; shrink it to fit previous
(void)m_renew_maybe(byte, MP_STATE_VM(qstr_last_chunk), MP_STATE_VM(qstr_last_alloc), MP_STATE_VM(qstr_last_used), false);
MP_STATE_VM(qstr_last_chunk) = NULL;
} else {
// could grow existing memory
MP_STATE_VM(qstr_last_alloc) += n_bytes;
}
}
if (MP_STATE_VM(qstr_last_chunk) == NULL) {
// no existing memory for the interned string so allocate a new chunk
size_t al = n_bytes;
if (al < MICROPY_ALLOC_QSTR_CHUNK_INIT) {
al = MICROPY_ALLOC_QSTR_CHUNK_INIT;
}
MP_STATE_VM(qstr_last_chunk) = m_new_maybe(byte, al);
if (MP_STATE_VM(qstr_last_chunk) == NULL) {
// failed to allocate a large chunk so try with exact size
MP_STATE_VM(qstr_last_chunk) = m_new_maybe(byte, n_bytes);
if (MP_STATE_VM(qstr_last_chunk) == NULL) {
QSTR_EXIT();
m_malloc_fail(n_bytes);
}
al = n_bytes;
}
MP_STATE_VM(qstr_last_alloc) = al;
MP_STATE_VM(qstr_last_used) = 0;
}
// allocate memory from the chunk for this new interned string's data
byte *q_ptr = MP_STATE_VM(qstr_last_chunk) + MP_STATE_VM(qstr_last_used);
MP_STATE_VM(qstr_last_used) += n_bytes;
// store the interned strings' data
mp_uint_t hash = qstr_compute_hash((const byte*)str, len);
Q_SET_HASH(q_ptr, hash);
Q_SET_LENGTH(q_ptr, len);
memcpy(q_ptr + MICROPY_QSTR_BYTES_IN_HASH + MICROPY_QSTR_BYTES_IN_LEN, str, len);
q_ptr[MICROPY_QSTR_BYTES_IN_HASH + MICROPY_QSTR_BYTES_IN_LEN + len] = '\0';
q = qstr_add(q_ptr);
}
QSTR_EXIT();
return q;
}
mp_uint_t qstr_hash(qstr q) {
const byte *qd = find_qstr(q);
return Q_GET_HASH(qd);
}
size_t qstr_len(qstr q) {
const byte *qd = find_qstr(q);
return Q_GET_LENGTH(qd);
}
const char *qstr_str(qstr q) {
const byte *qd = find_qstr(q);
return (const char*)Q_GET_DATA(qd);
}
const byte *qstr_data(qstr q, size_t *len) {
const byte *qd = find_qstr(q);
*len = Q_GET_LENGTH(qd);
return Q_GET_DATA(qd);
}
void qstr_pool_info(size_t *n_pool, size_t *n_qstr, size_t *n_str_data_bytes, size_t *n_total_bytes) {
QSTR_ENTER();
*n_pool = 0;
*n_qstr = 0;
*n_str_data_bytes = 0;
*n_total_bytes = 0;
for (qstr_pool_t *pool = MP_STATE_VM(last_pool); pool != NULL && pool != &CONST_POOL; pool = pool->prev) {
*n_pool += 1;
*n_qstr += pool->len;
for (const byte **q = pool->qstrs, **q_top = pool->qstrs + pool->len; q < q_top; q++) {
*n_str_data_bytes += Q_GET_ALLOC(*q);
}
#if MICROPY_ENABLE_GC
*n_total_bytes += gc_nbytes(pool); // this counts actual bytes used in heap
#else
*n_total_bytes += sizeof(qstr_pool_t) + sizeof(qstr) * pool->alloc;
#endif
}
*n_total_bytes += *n_str_data_bytes;
QSTR_EXIT();
}
#if MICROPY_PY_MICROPYTHON_MEM_INFO
void qstr_dump_data(void) {
QSTR_ENTER();
for (qstr_pool_t *pool = MP_STATE_VM(last_pool); pool != NULL && pool != &CONST_POOL; pool = pool->prev) {
for (const byte **q = pool->qstrs, **q_top = pool->qstrs + pool->len; q < q_top; q++) {
mp_printf(&mp_plat_print, "Q(%s)\n", Q_GET_DATA(*q));
}
}
QSTR_EXIT();
}
#endif
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