Added regex backend, does not compile

2013-01-13 17:01:10 +01:00 · 2013-01-13 17:01:10 +01:00 · b8314f6662
commit b8314f6662
parent ca8751bcfe
6 changed files with 206 additions and 0 deletions
--- a/src/backends/regex.c
+++ b/src/backends/regex.c
@ -0,0 +1,138 @@
+#include "../internal.h"
+#include "../parsers/parser_internal.h"
+
+#undef a_new
+#define a_new(typ, count) a_new_(arena, typ, count);
+// Stack VM
+typedef enum HSVMOp_ {
+  SVM_PUSH, // Push a mark. There is no VM insn to push an object.
+  SVM_NOP, // Used to start the chain, and possibly elsewhere. Does nothing.
+  SVM_ACTION, // Same meaning as RVM_ACTION
+  SVM_CAPTURE, // Same meaning as RVM_CAPTURE
+  SVM_ACCEPT,
+} HSVMOp;
+
+typedef struct HRVMTrace_ {
+  struct HRVMTrace_ *next; // When parsing, these are
+			   // reverse-threaded. There is a postproc
+			   // step that inverts all the pointers.
+  uint16_t arg;
+  uint8_t opcode;
+} HRVMTrace;
+
+typedef struct HRVMThread_ {
+  HRVMTrace *trace;
+  uint16_t ip;
+} HRVMThread;
+    
+void* h_rvm_run__m(HAllocator *mm__, HRVMProg *prog, const char* input, size_t len) {
+  HArena *arena = h_new_arena(mm__, 0);
+  HRVMTrace **heads_p = a_new(HRVMTrace*, prog->length),
+    **heads_n = a_new(HRVMTrace*, prog->length), **heads_t;
+
+  
+  uint8_t *insn_seen = a_new(uint8_t, prog->length); // 0 -> not seen, 1->processed, 2->queued
+  HRVMThread *ip_queue = a_new(HRVMThread, prog->length);
+  size_t ipq_top;
+
+#define THREAD ip_queue[ipq_top-1]
+#define PUSH_SVM(op_, arg_) do { \
+	  HRVMTrace *nt = a_new(HRVMTrace, 1); \
+	  nt->arg = (arg_);		       \
+	  nt->opcode = (op_);		       \
+	  nt->next = THREAD.trace;	       \
+	  THREAD.trace = nt;		       \
+  } while(0)
+    
+  heads_n[0] = a_new(HRVMTrace, 1); // zeroing
+  heads_n[0]->opcode = SVM_NOP;
+
+  size_t off = 0;
+  int live_threads = 1;
+  for (off = 0; off <= len; off++) {
+    uint8_t ch = ((off == len) ? 0 : input[off]);
+    size_t ip_s, ip;
+    /* scope */ {
+      HRVMTrace **heads_t;
+      heads_t = heads_n;
+      heads_n = heads_p;
+      heads_p = heads_t;
+      memset(heads_n, 0, prog->length * sizeof(*heads_n));
+    }
+    memset(insn_seen, 0, prog->length); // no insns seen yet
+    if (!live_threads)
+      return NULL;
+    live_threads = 0;
+    for (ip_s = 0; ip_s < prog->length; ip_s++) {
+      ipq_top = 1;
+      // TODO: Write this as a threaded VM
+      if (!heads_p[ip_s])
+	continue;
+      THREAD.ip = ip_s;
+
+      uint8_t hi, lo;
+      uint16_t arg;
+      while(ipq_top > 0) {
+	if (insns_seen[THREAD.ip] == 1)
+	  continue;
+	insns_seen[THREAD.ip] = 1;
+	arg = prog->insns[THREAD.ip].arg;
+	switch(prog->insns[THREAD.ip].op) {
+	case RVM_ACCEPT:
+	  // TODO: save current SVM pos, and jump to end
+	  abort();
+	case RVM_MATCH:
+	  // Doesn't actually validate the "must be followed by MATCH
+	  // or STEP. It should. Preproc perhaps?
+	  hi = (arg >> 8) & 0xff;
+	  lo = arg & 0xff;
+	  THREAD.ip++;
+	  if (ch < lo && ch > hi)
+	    ipq_top--; // terminate thread
+	  goto next_insn;
+	case RVM_GOTO:
+	  THREAD.ip = arg;
+	  goto next_insn;
+	case RVM_FORK:
+	  THREAD.ip++;
+	  if (!insns_seen[arg]) {
+	    insns_seen[THREAD.ip] = 2;
+	    HRVMTrace* tr = THREAD.trace;
+	    ipq_top++;
+	    THREAD.ip = arg;
+	    THREAD.trace = tr;
+	  }
+	  goto next_insn;
+	case RVM_PUSH:
+	  PUSH_SVM(SVM_PUSH, off);
+	  THREAD.ip++;
+	  goto next_insn;
+	case RVM_ACTION:
+	  PUSH_SVM(SVM_ACTION, arg);
+	  THREAD.ip++;
+	  goto next_insn;
+	case RVM_CAPTURE:
+	  PUSH_SVM(SVM_CAPTURE, 0);
+	  THREAD.ip++;
+	  goto next_insn;
+	case RVM_EOF:
+	  THREAD.ip++;
+	  if (off != len)
+	    ipq_top--; // Terminate thread
+	  goto next_insn;
+	case RVM_STEP:
+	  // save thread
+	  live_threads++;
+	  heads_n[THREAD.ip++] = THREAD.trace;
+	  ipq_top--;
+	  goto next_insn;
+	}
+      next_insn:
+	
+      }
+      
+      
+      
+      
+  
+}