String buffer refactoring, part 2.

Switch to pointers for start/pos/end of buffer.
Abstract out some buffer writers.

1 files changed, 53 insertions, 7 deletions

diff --git a/src/lj_buf.h b/src/lj_buf.h
index 19f2bb0d..5a7eae31 100644
--- a/src/lj_buf.h
+++ b/src/lj_buf.h
@@ -7,21 +7,67 @@
 #define _LJ_BUF_H
 
 #include "lj_obj.h"
+#include "lj_gc.h"
+#include "lj_str.h"
 
 /* Resizable string buffers. Struct definition in lj_obj.h. */
+#define sbufB(sb)       (mref((sb)->b, char))
+#define sbufP(sb)       (mref((sb)->p, char))
+#define sbufE(sb)       (mref((sb)->e, char))
+#define sbufsz(sb)      ((MSize)(sbufE((sb)) - sbufB((sb))))
+#define sbuflen(sb)     ((MSize)(sbufP((sb)) - sbufB((sb))))
+#define setsbufP(sb, q) (setmref((sb)->p, (q)))
+
 LJ_FUNC char *lj_buf_tmp(lua_State *L, MSize sz);
-LJ_FUNC void lj_buf_grow(lua_State *L, SBuf *sb, MSize sz);
+LJ_FUNC void lj_buf_grow(lua_State *L, SBuf *sb, char *en);
 LJ_FUNC void lj_buf_shrink(lua_State *L, SBuf *sb);
 
-#define lj_buf_init(sb)         ((sb)->buf = NULL, (sb)->sz = 0)
-#define lj_buf_reset(sb)        ((sb)->n = 0)
-#define lj_buf_free(g, sb)      lj_mem_free(g, (void *)(sb)->buf, (sb)->sz)
+LJ_FUNC char *lj_buf_wmem(char *p, const void *q, MSize len);
+LJ_FUNC void lj_buf_putmem(lua_State *L, SBuf *sb, const void *q, MSize len);
+LJ_FUNC uint32_t lj_buf_ruleb128(const char **pp);
+LJ_FUNC char *lj_buf_wuleb128(char *p, uint32_t v);
+
+static LJ_AINLINE void lj_buf_init(SBuf *sb)
+{
+  setmref(sb->p, NULL); setmref(sb->e, NULL); setmref(sb->b, NULL);
+}
+
+static LJ_AINLINE void lj_buf_reset(SBuf *sb)
+{
+  setmrefr(sb->p, sb->b);
+}
+
+static LJ_AINLINE void lj_buf_free(global_State *g, SBuf *sb)
+{
+  lj_mem_free(g, sbufB(sb), sbufsz(sb));
+}
+
+static LJ_AINLINE GCstr *lj_buf_str(lua_State *L, SBuf *sb)
+{
+  return lj_str_new(L, sbufB(sb), sbuflen(sb));
+}
 
 static LJ_AINLINE char *lj_buf_need(lua_State *L, SBuf *sb, MSize sz)
 {
-  if (LJ_UNLIKELY(sz > sb->sz))
-    lj_buf_grow(L, sb, sz);
-  return sb->buf;
+  char *en = sbufB(sb) + sz;
+  if (LJ_UNLIKELY(en > sbufE(sb)))
+    lj_buf_grow(L, sb, en);
+  return sbufB(sb);
+}
+
+static LJ_AINLINE char *lj_buf_more(lua_State *L, SBuf *sb, MSize sz)
+{
+  char *en = sbufP(sb) + sz;
+  if (LJ_UNLIKELY(en > sbufE(sb)))
+    lj_buf_grow(L, sb, en);
+  return sbufP(sb);
+}
+
+static LJ_AINLINE void lj_buf_putb(lua_State *L, SBuf *sb, int c)
+{
+  char *p = lj_buf_more(L, sb, 1);
+  *p++ = (char)c;
+  setsbufP(sb, p);
 }
 
 #endif