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-rw-r--r--contrib/lua-lpeg/lpvm.c383
1 files changed, 383 insertions, 0 deletions
diff --git a/contrib/lua-lpeg/lpvm.c b/contrib/lua-lpeg/lpvm.c
new file mode 100644
index 0000000..0dfca18
--- /dev/null
+++ b/contrib/lua-lpeg/lpvm.c
@@ -0,0 +1,383 @@
+/*
+** $Id: lpvm.c,v 1.6 2015/09/28 17:01:25 roberto Exp $
+** Copyright 2007, Lua.org & PUC-Rio (see 'lpeg.html' for license)
+*/
+
+#include "config.h"
+
+#include <limits.h>
+#include <string.h>
+
+
+#include "lua.h"
+#include "lauxlib.h"
+
+#include "lpcap.h"
+#include "lptypes.h"
+#include "lpvm.h"
+#include "lpprint.h"
+
+/* initial size for call/backtrack stack */
+#if !defined(INITBACK)
+#define INITBACK MAXBACK
+#endif
+
+
+#define getoffset(p) (((p) + 1)->offset)
+
+static const Instruction giveup = {{IGiveup, 0, 0}};
+
+
+/*
+** {======================================================
+** Virtual Machine
+** =======================================================
+*/
+
+
+typedef struct Stack {
+ const char *s; /* saved position (or NULL for calls) */
+ const Instruction *p; /* next instruction */
+ int caplevel;
+} Stack;
+
+
+#define getstackbase(L, ptop) ((Stack *)lua_touserdata(L, stackidx(ptop)))
+
+
+/*
+** Ensures the size of array 'capture' (with size '*capsize' and
+** 'captop' elements being used) is enough to accomodate 'n' extra
+** elements plus one. (Because several opcodes add stuff to the capture
+** array, it is simpler to ensure the array always has at least one free
+** slot upfront and check its size later.)
+*/
+static Capture *growcap (lua_State *L, Capture *capture, int *capsize,
+ int captop, int n, int ptop) {
+ if (*capsize - captop > n)
+ return capture; /* no need to grow array */
+ else { /* must grow */
+ Capture *newc;
+ int newsize = captop + n + 1; /* minimum size needed */
+ if (newsize < INT_MAX/((int)sizeof(Capture) * 2))
+ newsize *= 2; /* twice that size, if not too big */
+ else if (newsize >= INT_MAX/((int)sizeof(Capture)))
+ luaL_error(L, "too many captures");
+ newc = (Capture *)lua_newuserdata(L, newsize * sizeof(Capture));
+ memcpy(newc, capture, captop * sizeof(Capture));
+ *capsize = newsize;
+ lua_replace(L, caplistidx(ptop));
+ return newc;
+ }
+}
+
+
+/*
+** Double the size of the stack
+*/
+static Stack *doublestack (lua_State *L, Stack **stacklimit, int ptop) {
+ Stack *stack = getstackbase(L, ptop);
+ Stack *newstack;
+ int n = *stacklimit - stack; /* current stack size */
+ int max, newn;
+ lua_getfield(L, LUA_REGISTRYINDEX, MAXSTACKIDX);
+ max = lua_tointeger(L, -1); /* maximum allowed size */
+ lua_pop(L, 1);
+ if (n >= max) /* already at maximum size? */
+ luaL_error(L, "backtrack stack overflow (current limit is %d)", max);
+ newn = 2 * n; /* new size */
+ if (newn > max) newn = max;
+ newstack = (Stack *)lua_newuserdata(L, newn * sizeof(Stack));
+ memcpy(newstack, stack, n * sizeof(Stack));
+ lua_replace(L, stackidx(ptop));
+ *stacklimit = newstack + newn;
+ return newstack + n; /* return next position */
+}
+
+
+/*
+** Interpret the result of a dynamic capture: false -> fail;
+** true -> keep current position; number -> next position.
+** Return new subject position. 'fr' is stack index where
+** is the result; 'curr' is current subject position; 'limit'
+** is subject's size.
+*/
+static int resdyncaptures (lua_State *L, int fr, int curr, int limit) {
+ lua_Integer res;
+ if (!lua_toboolean(L, fr)) { /* false value? */
+ lua_settop(L, fr - 1); /* remove results */
+ return -1; /* and fail */
+ }
+ else if (lua_isboolean(L, fr)) /* true? */
+ res = curr; /* keep current position */
+ else {
+ res = lua_tointeger(L, fr) - 1; /* new position */
+ if (res < curr || res > limit)
+ luaL_error(L, "invalid position returned by match-time capture");
+ }
+ lua_remove(L, fr); /* remove first result (offset) */
+ return res;
+}
+
+
+/*
+** Add capture values returned by a dynamic capture to the list
+** 'capture', nested inside a group. 'fd' indexes the first capture
+** value, 'n' is the number of values (at least 1). The open group
+** capture is already in 'capture', before the place for the new entries.
+*/
+static void adddyncaptures (const char *s, Capture *capture, int n, int fd) {
+ int i;
+ assert(capture[-1].kind == Cgroup && capture[-1].siz == 0);
+ capture[-1].idx = 0; /* make group capture an anonymous group */
+ for (i = 0; i < n; i++) { /* add runtime captures */
+ capture[i].kind = Cruntime;
+ capture[i].siz = 1; /* mark it as closed */
+ capture[i].idx = fd + i; /* stack index of capture value */
+ capture[i].s = s;
+ }
+ capture[n].kind = Cclose; /* close group */
+ capture[n].siz = 1;
+ capture[n].s = s;
+}
+
+
+/*
+** Remove dynamic captures from the Lua stack (called in case of failure)
+*/
+static int removedyncap (lua_State *L, Capture *capture,
+ int level, int last) {
+ int id = finddyncap(capture + level, capture + last); /* index of 1st cap. */
+ int top = lua_gettop(L);
+ if (id == 0) return 0; /* no dynamic captures? */
+ lua_settop(L, id - 1); /* remove captures */
+ return top - id + 1; /* number of values removed */
+}
+
+
+/*
+** Opcode interpreter
+*/
+const char *match (lua_State *L, const char *o, const char *s, const char *e,
+ Instruction *op, Capture *capture, int ptop) {
+ Stack stackbase[INITBACK];
+ Stack *stacklimit = stackbase + INITBACK;
+ Stack *stack = stackbase; /* point to first empty slot in stack */
+ int capsize = INITCAPSIZE;
+ int captop = 0; /* point to first empty slot in captures */
+ int ndyncap = 0; /* number of dynamic captures (in Lua stack) */
+ const Instruction *p = op; /* current instruction */
+ stack->p = &giveup; stack->s = s; stack->caplevel = 0; stack++;
+ lua_pushlightuserdata(L, stackbase);
+ for (;;) {
+#if defined(DEBUG)
+ printf("s: |%s| stck:%d, dyncaps:%d, caps:%d ",
+ s, (int)(stack - getstackbase(L, ptop)), ndyncap, captop);
+ printinst(op, p);
+#endif
+ assert(stackidx(ptop) + ndyncap == lua_gettop(L) && ndyncap <= captop);
+ switch ((Opcode)p->i.code) {
+ case IEnd: {
+ assert(stack == getstackbase(L, ptop) + 1);
+ capture[captop].kind = Cclose;
+ capture[captop].s = NULL;
+ return s;
+ }
+ case IGiveup: {
+ assert(stack == getstackbase(L, ptop));
+ return NULL;
+ }
+ case IRet: {
+ assert(stack > getstackbase(L, ptop) && (stack - 1)->s == NULL);
+ p = (--stack)->p;
+ continue;
+ }
+ case IAny: {
+ if (s < e) { p++; s++; }
+ else goto fail;
+ continue;
+ }
+ case ITestAny: {
+ if (s < e) p += 2;
+ else p += getoffset(p);
+ continue;
+ }
+ case IChar: {
+ if (s < e && (byte)*s == p->i.aux) { p++; s++; }
+ else goto fail;
+ continue;
+ }
+ case ITestChar: {
+ if (s < e && (byte)*s == p->i.aux) p += 2;
+ else p += getoffset(p);
+ continue;
+ }
+ case ISet: {
+ if (s < e) {
+ int c = (byte) *s;
+ if (testchar((p + 1)->buff, c)) {
+ p += CHARSETINSTSIZE;
+ s++;
+ }
+ else goto fail;
+ }
+ else {
+ goto fail;
+ }
+ continue;
+ }
+ case ITestSet: {
+ if (s < e) {
+ int c = (byte) *s;
+ if (testchar((p + 2)->buff, c))
+ p += 1 + CHARSETINSTSIZE;
+ else p += getoffset(p);
+ }
+ else {
+ p += getoffset(p);
+ }
+ continue;
+ }
+ case IBehind: {
+ int n = p->i.aux;
+ if (n > s - o) goto fail;
+ s -= n; p++;
+ continue;
+ }
+ case ISpan: {
+ for (; s < e; s++) {
+ int c = (byte)*s;
+ if (!testchar((p+1)->buff, c)) break;
+ }
+ p += CHARSETINSTSIZE;
+ continue;
+ }
+ case IJmp: {
+ p += getoffset(p);
+ continue;
+ }
+ case IChoice: {
+ if (stack == stacklimit)
+ stack = doublestack(L, &stacklimit, ptop);
+ stack->p = p + getoffset(p);
+ stack->s = s;
+ stack->caplevel = captop;
+ stack++;
+ p += 2;
+ continue;
+ }
+ case ICall: {
+ if (stack == stacklimit)
+ stack = doublestack(L, &stacklimit, ptop);
+ stack->s = NULL;
+ stack->p = p + 2; /* save return address */
+ stack++;
+ p += getoffset(p);
+ continue;
+ }
+ case ICommit: {
+ assert(stack > getstackbase(L, ptop) && (stack - 1)->s != NULL);
+ stack--;
+ p += getoffset(p);
+ continue;
+ }
+ case IPartialCommit: {
+ assert(stack > getstackbase(L, ptop) && (stack - 1)->s != NULL);
+ (stack - 1)->s = s;
+ (stack - 1)->caplevel = captop;
+ p += getoffset(p);
+ continue;
+ }
+ case IBackCommit: {
+ assert(stack > getstackbase(L, ptop) && (stack - 1)->s != NULL);
+ s = (--stack)->s;
+ captop = stack->caplevel;
+ p += getoffset(p);
+ continue;
+ }
+ case IFailTwice:
+ assert(stack > getstackbase(L, ptop));
+ stack--;
+ /* go through */
+ case IFail:
+ fail: { /* pattern failed: try to backtrack */
+ do { /* remove pending calls */
+ assert(stack > getstackbase(L, ptop));
+ s = (--stack)->s;
+ } while (s == NULL);
+ if (ndyncap > 0) /* is there matchtime captures? */
+ ndyncap -= removedyncap(L, capture, stack->caplevel, captop);
+ captop = stack->caplevel;
+ p = stack->p;
+ continue;
+ }
+ case ICloseRunTime: {
+ CapState cs;
+ int rem, res, n;
+ int fr = lua_gettop(L) + 1; /* stack index of first result */
+ cs.reclevel = 0; cs.L = L;
+ cs.s = o; cs.ocap = capture; cs.ptop = ptop;
+ n = runtimecap(&cs, capture + captop, s, &rem); /* call function */
+ captop -= n; /* remove nested captures */
+ ndyncap -= rem; /* update number of dynamic captures */
+ fr -= rem; /* 'rem' items were popped from Lua stack */
+ res = resdyncaptures(L, fr, s - o, e - o); /* get result */
+ if (res == -1) /* fail? */
+ goto fail;
+ s = o + res; /* else update current position */
+ n = lua_gettop(L) - fr + 1; /* number of new captures */
+ ndyncap += n; /* update number of dynamic captures */
+ if (n == 0) /* no new captures? */
+ captop--; /* remove open group */
+ else { /* new captures; keep original open group */
+ if (fr + n >= SHRT_MAX)
+ luaL_error(L, "too many results in match-time capture");
+ /* add new captures + close group to 'capture' list */
+ capture = growcap(L, capture, &capsize, captop, n + 1, ptop);
+ adddyncaptures(s, capture + captop, n, fr);
+ captop += n + 1; /* new captures + close group */
+ }
+ p++;
+ continue;
+ }
+ case ICloseCapture: {
+ const char *s1 = s;
+ assert(captop > 0);
+ /* if possible, turn capture into a full capture */
+ if (capture[captop - 1].siz == 0 &&
+ s1 - capture[captop - 1].s < UCHAR_MAX) {
+ capture[captop - 1].siz = s1 - capture[captop - 1].s + 1;
+ p++;
+ continue;
+ }
+ else {
+ capture[captop].siz = 1; /* mark entry as closed */
+ capture[captop].s = s;
+ goto pushcapture;
+ }
+ }
+ case IOpenCapture:
+ capture[captop].siz = 0; /* mark entry as open */
+ capture[captop].s = s;
+ goto pushcapture;
+ case IFullCapture:
+ capture[captop].siz = getoff(p) + 1; /* save capture size */
+ capture[captop].s = s - getoff(p);
+ /* goto pushcapture; */
+ pushcapture: {
+ capture[captop].idx = p->i.key;
+ capture[captop].kind = getkind(p);
+ captop++;
+ capture = growcap(L, capture, &capsize, captop, 0, ptop);
+ p++;
+ continue;
+ }
+ default: assert(0); return NULL;
+ }
+ }
+
+}
+
+/* }====================================================== */
+
+
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