113 lines
3.1 KiB
C++
113 lines
3.1 KiB
C++
#include <cubescript/cubescript.hh>
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#include "cs_strman.hh"
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namespace cscript {
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struct cs_strref_state {
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std::size_t length;
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std::size_t refcount;
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};
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inline cs_strref_state *get_ref_state(char const *ptr) {
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return const_cast<cs_strref_state *>(
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reinterpret_cast<cs_strref_state const *>(ptr)
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) - 1;
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}
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char const *cs_strman::add(std::string_view str) {
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auto it = counts.find(str);
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/* already present: just increment ref */
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if (it != counts.end()) {
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auto *st = it->second;
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/* having a null pointer is the same as non-existence */
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if (st) {
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++st->refcount;
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return reinterpret_cast<char const *>(st + 1);
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}
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}
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/* not present: allocate brand new data */
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auto ss = str.size();
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auto strp = alloc_buf(ss);
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/* write string data, it's already pre-terminated */
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memcpy(strp, str.data(), ss);
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/* store it */
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counts.emplace(std::string_view{strp, ss}, get_ref_state(strp));
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return strp;
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}
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char const *cs_strman::ref(char const *ptr) {
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auto *ss = get_ref_state(ptr);
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++ss->refcount;
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return ptr;
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}
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char const *cs_strman::steal(char *ptr) {
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auto *ss = get_ref_state(ptr);
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auto sr = std::string_view{ptr, ss->length};
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/* much like add(), but we already have memory */
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auto it = counts.find(sr);
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if (it != counts.end()) {
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auto *st = it->second;
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if (st) {
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++st->refcount;
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/* the buffer is superfluous now */
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cstate->alloc(ss, ss->length + sizeof(cs_strref_state) + 1, 0);
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return reinterpret_cast<char const *>(st + 1);
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}
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}
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ss->refcount = 1;
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counts.emplace(sr, ss);
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return ptr;
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}
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void cs_strman::unref(char const *ptr) {
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auto *ss = get_ref_state(ptr);
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if (!--ss->refcount) {
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/* refcount zero, so ditch it
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* this path is a little slow...
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*/
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auto sr = std::string_view{ptr, ss->length};
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auto it = counts.find(sr);
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if (it == counts.end()) {
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/* internal error: this should *never* happen */
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throw cs_internal_error{"no refcount"};
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}
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/* we're freeing the key */
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counts.erase(it);
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/* dealloc */
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cstate->alloc(ss, ss->length + sizeof(cs_strref_state) + 1, 0);
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}
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}
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char const *cs_strman::find(std::string_view str) const {
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auto it = counts.find(str);
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if (it == counts.end()) {
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return nullptr;
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}
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return reinterpret_cast<char const *>(it->second + 1);
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}
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std::string_view cs_strman::get(char const *ptr) const {
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auto *ss = get_ref_state(ptr);
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return std::string_view{ptr, ss->length};
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}
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char *cs_strman::alloc_buf(std::size_t len) const {
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auto mem = cstate->alloc(nullptr, 0, len + sizeof(cs_strref_state) + 1);
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if (!mem) {
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throw cs_internal_error{"allocation failed"};
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}
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/* write length and initial refcount */
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auto *sst = static_cast<cs_strref_state *>(mem);
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sst->length = len;
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sst->refcount = 1;
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/* pre-terminate */
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auto *strp = reinterpret_cast<char *>(sst + 1);
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strp[len] = '\0';
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/* now the user can fill it */
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return strp;
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};
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} /* namespace cscript */
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