Experimental lexer generator: Misc fixes.

tools/lexer_generator/code_generator.jinja

 #include "lexer/even-more-experimental-scanner.h"
 
-
 {# TODO implement CLASS checks #}
 {%- macro do_key(key) -%}
   {%- for r in key -%}
     {%- if not loop.first %} || {% endif -%}
     {%- if r[0] == 'LATIN_1' -%}
       {%- if r[1][0] == r[1][1] -%}
         yych == {{r[1][0]}}
       {%- elif r[1][0] == 0 -%}
         yych <= {{r[1][1]}}
       {%- elif r[1][1] == 255 -%}
         yych >= {{r[1][0]}}
       {%- else -%}
         ({{r[1][0]}} <= yych && yych <= {{r[1][1]}})
       {%- endif -%}
     {%- elif r[0] == 'CLASS' -%}
-      {%- if r[1] == 'eof' -%}
-        (yych == 0 && cursor_ == buffer_end_)
+      {%- if r[1] == 'eos' -%}
+        (yych == 0 && cursor_ >= buffer_end_)
+      {%- elif r[1] == 'zero' -%}
+        (yych == 0 && cursor_ < buffer_end_)
       {%- else -%}
         false
       {%- endif -%}
     {%- else -%}
       false
     {%- endif -%}
   {%- endfor -%}
 {%- endmacro -%}
 
 
@@ skipping 104 matching lines @@
   return T;                           \
 }
 
 #define PUSH_TOKEN_AND_GO_FORWARD(T) {\
   PREPARE_PUSH_TOKEN();               \
   FORWARD();                          \
   return T;                           \
 }
 
 #define PUSH_EOS() {                  \
-  --cursor_;                          \
+  --start_;                           \
+  cursor_ -= 2;                       \
   PUSH_TOKEN(Token::EOS);             \
 }
 
 #define PUSH_LINE_TERMINATOR(s) {     \
   start_ = cursor_;                   \
   just_seen_line_terminator_ = true;  \
 }
 
 #define FORWARD() {                   \
-  yych = *(++cursor_);                \
+  if (++cursor_ >= buffer_end_) yych = 0; \
+  else yych = *(cursor_);                 \
 }
 
 #define BACKWARD() {                  \
-  yych = *(--cursor_);                \
+  if (--cursor_ >= buffer_end_) yych = 0; \
+  else yych = *(cursor_);                 \
 }
 
 #define SKIP() {                      \
   start_ = cursor_;                   \
 }
 
 namespace v8 {
 namespace internal {
 Token::Value EvenMoreExperimentalScanner::Next(int* beg_pos_to_return,
                                                int* end_pos_to_return) {
@@ skipping 17 matching lines @@
 {% endif -%}
     {{dispatch_action(default_action[0], default_action[1])}}
   FORWARD();
   goto code_start;
 
   fell_through:
   CHECK(false);
 }
 } }