| /* |
| * This file is part of the Micro Python 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 "mpconfig.h" |
| #include "misc.h" |
| #include "qstr.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 0 // 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). |
| // For now we use very simple encoding, just to get the framework correct: |
| // - hash is 2 bytes (see function below) |
| // - length is 2 bytes |
| // - data follows |
| // - \0 terminated (for now, so they can be printed using printf) |
| |
| #define Q_GET_HASH(q) ((q)[0] | ((q)[1] << 8)) |
| #define Q_GET_ALLOC(q) (4 + Q_GET_LENGTH(q) + 1) |
| #define Q_GET_LENGTH(q) ((q)[2] | ((q)[3] << 8)) |
| #define Q_GET_DATA(q) ((q) + 4) |
| |
| // this must match the equivalent function in makeqstrdata.py |
| mp_uint_t qstr_compute_hash(const byte *data, uint 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 &= 0xffff; |
| // Make sure that valid hash is never zero, zero means "hash not computed" |
| if (hash == 0) { |
| hash++; |
| } |
| return hash; |
| } |
| |
| typedef struct _qstr_pool_t { |
| struct _qstr_pool_t *prev; |
| uint total_prev_len; |
| uint alloc; |
| uint len; |
| const byte *qstrs[]; |
| } qstr_pool_t; |
| |
| STATIC const qstr_pool_t const_pool = { |
| NULL, // no previous pool |
| 0, // no previous pool |
| 10, // set so that the first dynamically allocated pool is twice this size; must be <= the len (just below) |
| MP_QSTR_number_of, // corresponds to number of strings in array just below |
| { |
| (const byte*) "\0\0\0\0", // invalid/no qstr has empty data |
| (const byte*) "\0\0\0\0", // empty qstr |
| #define Q(id, str) str, |
| #include "genhdr/qstrdefs.generated.h" |
| #undef Q |
| }, |
| }; |
| |
| STATIC qstr_pool_t *last_pool; |
| |
| void qstr_init(void) { |
| last_pool = (qstr_pool_t*)&const_pool; // we won't modify the const_pool since it has no allocated room left |
| } |
| |
| STATIC const byte *find_qstr(qstr q) { |
| // search pool for this qstr |
| for (qstr_pool_t *pool = last_pool; pool != NULL; pool = pool->prev) { |
| if (q >= pool->total_prev_len) { |
| return pool->qstrs[q - pool->total_prev_len]; |
| } |
| } |
| |
| // not found |
| return 0; |
| } |
| |
| 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 (last_pool->len >= last_pool->alloc) { |
| qstr_pool_t *pool = m_new_obj_var(qstr_pool_t, const char*, last_pool->alloc * 2); |
| pool->prev = last_pool; |
| pool->total_prev_len = last_pool->total_prev_len + last_pool->len; |
| pool->alloc = last_pool->alloc * 2; |
| pool->len = 0; |
| last_pool = pool; |
| DEBUG_printf("QSTR: allocate new pool of size %d\n", last_pool->alloc); |
| } |
| |
| // add the new qstr |
| last_pool->qstrs[last_pool->len++] = q_ptr; |
| |
| // return id for the newly-added qstr |
| return last_pool->total_prev_len + last_pool->len - 1; |
| } |
| |
| qstr qstr_find_strn(const char *str, uint 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 = 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, uint len) { |
| qstr q = qstr_find_strn(str, len); |
| if (q == 0) { |
| mp_uint_t hash = qstr_compute_hash((const byte*)str, len); |
| byte *q_ptr = m_new(byte, 4 + len + 1); |
| q_ptr[0] = hash; |
| q_ptr[1] = hash >> 8; |
| q_ptr[2] = len; |
| q_ptr[3] = len >> 8; |
| memcpy(q_ptr + 4, str, len); |
| q_ptr[4 + len] = '\0'; |
| q = qstr_add(q_ptr); |
| } |
| return q; |
| } |
| |
| byte *qstr_build_start(uint len, byte **q_ptr) { |
| assert(len <= 65535); |
| *q_ptr = m_new(byte, 4 + len + 1); |
| (*q_ptr)[2] = len; |
| (*q_ptr)[3] = len >> 8; |
| return Q_GET_DATA(*q_ptr); |
| } |
| |
| qstr qstr_build_end(byte *q_ptr) { |
| qstr q = qstr_find_strn((const char*)Q_GET_DATA(q_ptr), Q_GET_LENGTH(q_ptr)); |
| if (q == 0) { |
| mp_uint_t len = Q_GET_LENGTH(q_ptr); |
| mp_uint_t hash = qstr_compute_hash(Q_GET_DATA(q_ptr), len); |
| q_ptr[0] = hash; |
| q_ptr[1] = hash >> 8; |
| q_ptr[4 + len] = '\0'; |
| q = qstr_add(q_ptr); |
| } else { |
| m_del(byte, q_ptr, Q_GET_ALLOC(q_ptr)); |
| } |
| return q; |
| } |
| |
| mp_uint_t qstr_hash(qstr q) { |
| return Q_GET_HASH(find_qstr(q)); |
| } |
| |
| uint qstr_len(qstr q) { |
| const byte *qd = find_qstr(q); |
| return Q_GET_LENGTH(qd); |
| } |
| |
| // XXX to remove! |
| 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, uint *len) { |
| const byte *qd = find_qstr(q); |
| *len = Q_GET_LENGTH(qd); |
| return Q_GET_DATA(qd); |
| } |
| |
| void qstr_pool_info(uint *n_pool, uint *n_qstr, uint *n_str_data_bytes, uint *n_total_bytes) { |
| *n_pool = 0; |
| *n_qstr = 0; |
| *n_str_data_bytes = 0; |
| *n_total_bytes = 0; |
| for (qstr_pool_t *pool = 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); |
| } |
| *n_total_bytes += sizeof(qstr_pool_t) + sizeof(qstr) * pool->alloc; |
| } |
| *n_total_bytes += *n_str_data_bytes; |
| } |