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/*
* lbp.c - bp library for lua
* API:
* bp.match(str, pat[, start_index]) -> nil or (match_text, start_index, match_len_in_source)
* bp.replace(str, pat, replacement, start_index) -> str with replacements
*/
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include "lua.h"
#include "lauxlib.h"
#include "../pattern.h"
#include "../match.h"
// The C API changed from 5.1 to 5.2, so these shims help the code compile on >=5.2
#if LUA_VERSION_NUM >= 502
#define lua_objlen(L, i) lua_rawlen(L, i)
#define luaL_register(L, _, R) luaL_setfuncs(L, R, 0)
#endif
static const char *builtins_source =
#include "builtins.h"
;
static int MATCH_METATABLE = 0;
static def_t *builtins;
static inline void raise_parse_error(lua_State *L, maybe_pat_t m)
{
size_t err_len = (size_t)(m.value.error.end - m.value.error.start);
char *buf = calloc(err_len+1, sizeof(char));
memcpy(buf, m.value.error.start, err_len);
luaL_error(L, "%s: \"%s\"", m.value.error.msg, buf);
free(buf);
}
static void push_matchstring(lua_State *L, match_t *m)
{
char *buf = NULL;
size_t size = 0;
FILE *out = open_memstream(&buf, &size);
fprint_match(out, m->start, m, NULL);
fflush(out);
lua_pushlstring(L, buf, size);
fclose(out);
}
static void push_match(lua_State *L, match_t *m);
static void set_capture_fields(lua_State *L, match_t *m, int *n)
{
if (m->pat->type == BP_CAPTURE) {
if (m->pat->args.capture.namelen > 0) {
lua_pushlstring(L, m->pat->args.capture.name, m->pat->args.capture.namelen);
push_match(L, m->children[0]);
lua_settable(L, -3);
} else {
push_match(L, m->children[0]);
lua_seti(L, -2, *(n++));
}
} else if (m->children) {
for (int i = 0; m->children[i]; i++)
set_capture_fields(L, m->children[i], n);
}
}
void push_match(lua_State *L, match_t *m)
{
lua_createtable(L, 1, 0);
lua_pushlightuserdata(L, (void*)&MATCH_METATABLE);
lua_gettable(L, LUA_REGISTRYINDEX);
lua_setmetatable(L, -2);
push_matchstring(L, m);
lua_seti(L, -2, 0);
int capture_num = 1;
for (int i = 0; m->children && m->children[i]; i++)
set_capture_fields(L, m->children[i], &capture_num);
}
static int Ltostring(lua_State *L)
{
lua_geti(L, 1, 0);
return 1;
}
static const luaL_Reg Rinstance_metamethods[] =
{
{"__tostring", Ltostring},
{NULL, NULL}
};
static void recursive_free_pat(pat_t *pat)
{
// Do a depth-first traversal, freeing everyting along the way:
if (!pat) return;
switch (pat->type) {
case BP_DEFINITION:
recursive_free_pat(pat->args.def.def);
recursive_free_pat(pat->args.def.pat);
break;
case BP_REPEAT:
recursive_free_pat(pat->args.repetitions.sep);
recursive_free_pat(pat->args.repetitions.repeat_pat);
break;
case BP_CHAIN: case BP_UPTO: case BP_UPTO_STRICT:
case BP_OTHERWISE: case BP_NOT_MATCH: case BP_MATCH:
recursive_free_pat(pat->args.multiple.first);
recursive_free_pat(pat->args.multiple.second);
break;
case BP_REPLACE:
recursive_free_pat(pat->args.replace.pat);
break;
case BP_CAPTURE:
recursive_free_pat(pat->args.capture.capture_pat);
break;
case BP_NOT: case BP_AFTER: case BP_BEFORE:
recursive_free_pat(pat->args.pat);
break;
case BP_LEFTRECURSION:
recursive_free_pat(pat->args.leftrec.fallback);
break;
default: break;
}
free_pat(pat);
}
static int Lmatch(lua_State *L)
{
size_t textlen, patlen;
const char *text = luaL_checklstring(L, 1, &textlen);
const char *pat_text = luaL_checklstring(L, 2, &patlen);
lua_Integer index = luaL_optinteger(L, 3, 1);
if (index > (lua_Integer)strlen(text)+1)
return 0;
maybe_pat_t maybe_pat = bp_pattern(pat_text, pat_text + patlen);
if (!maybe_pat.success) {
raise_parse_error(L, maybe_pat);
return 0;
}
match_t *m = NULL;
int ret = 0;
if (next_match(&m, builtins, text+index-1, &text[textlen], maybe_pat.value.pat, NULL, false)) {
push_match(L, m);
lua_pushinteger(L, (int)(m->start - text) + 1);
lua_pushinteger(L, (int)(m->end - m->start));
stop_matching(&m);
ret = 3;
}
recursive_free_pat(maybe_pat.value.pat);
return ret;
}
static int Lreplace(lua_State *L)
{
size_t textlen, patlen, replen;
const char *text = luaL_checklstring(L, 1, &textlen);
const char *pat_text = luaL_checklstring(L, 2, &patlen);
const char *rep_text = luaL_checklstring(L, 3, &replen);
lua_Integer index = luaL_optinteger(L, 4, 1);
if (index > (lua_Integer)strlen(text)+1)
index = (lua_Integer)strlen(text)+1;
maybe_pat_t maybe_pat = bp_pattern(pat_text, pat_text + patlen);
if (!maybe_pat.success) {
raise_parse_error(L, maybe_pat);
return 0;
}
maybe_pat_t maybe_replacement = bp_replacement(maybe_pat.value.pat, rep_text, rep_text + replen);
if (!maybe_replacement.success) {
recursive_free_pat(maybe_pat.value.pat);
raise_parse_error(L, maybe_replacement);
return 0;
}
char *buf = NULL;
size_t size = 0;
FILE *out = open_memstream(&buf, &size);
int replacements = 0;
const char *prev = text;
for (match_t *m = NULL; next_match(&m, builtins, text, &text[textlen], maybe_replacement.value.pat, NULL, false); ) {
fwrite(prev, sizeof(char), (size_t)(m->start - prev), out);
fprint_match(out, text, m, NULL);
prev = m->end;
++replacements;
}
fwrite(prev, sizeof(char), (size_t)(&text[textlen] - prev), out);
fflush(out);
lua_pushlstring(L, buf, size);
lua_pushinteger(L, replacements);
fclose(out);
// maybe_pat will get freed by this:
recursive_free_pat(maybe_replacement.value.pat);
return 2;
}
LUALIB_API int luaopen_bp(lua_State *L)
{
maybe_pat_t maybe_pat = bp_pattern(builtins_source, builtins_source+strlen(builtins_source));
if (!maybe_pat.success) {
raise_parse_error(L, maybe_pat);
return 0;
}
for (pat_t *p = maybe_pat.value.pat; p && p->type == BP_DEFINITION; p = p->args.def.pat)
builtins = with_def(builtins, p->args.def.namelen, p->args.def.name, p->args.def.def);
lua_pushlightuserdata(L, (void*)&MATCH_METATABLE);
lua_createtable(L, 0, 4);
luaL_register(L, NULL, Rinstance_metamethods);
lua_settable(L, LUA_REGISTRYINDEX);
lua_createtable(L, 0, 2);
lua_pushcfunction(L, Lmatch);
lua_setfield(L, -2, "match");
lua_pushcfunction(L, Lreplace);
lua_setfield(L, -2, "replace");
// lua_pushcfunction(L, Leach);
// lua_setfield(L, -1, "each");
return 1;
}
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