Use internal implementation for converting FP numbers to strings.

Contributed by Peter Cawley.

src/Makefile

@@ -478,7 +478,7 @@ LJLIB_C= $(LJLIB_O:.o=.c)
 LJCORE_O= lj_gc.o lj_err.o lj_char.o lj_bc.o lj_obj.o lj_buf.o \
 	  lj_str.o lj_tab.o lj_func.o lj_udata.o lj_meta.o lj_debug.o \
 	  lj_state.o lj_dispatch.o lj_vmevent.o lj_vmmath.o lj_strscan.o \
-	  lj_strfmt.o lj_api.o lj_profile.o \
+	  lj_strfmt.o lj_strfmt_num.o lj_api.o lj_profile.o \
 	  lj_lex.o lj_parse.o lj_bcread.o lj_bcwrite.o lj_load.o \
 	  lj_ir.o lj_opt_mem.o lj_opt_fold.o lj_opt_narrow.o \
 	  lj_opt_dce.o lj_opt_loop.o lj_opt_split.o lj_opt_sink.o \

src/Makefile.dep

@@ -94,7 +94,7 @@ lj_crecord.o: lj_crecord.c lj_obj.h lua.h luaconf.h lj_def.h lj_arch.h \
  lj_crecord.h lj_strfmt.h
 lj_ctype.o: lj_ctype.c lj_obj.h lua.h luaconf.h lj_def.h lj_arch.h \
  lj_gc.h lj_err.h lj_errmsg.h lj_str.h lj_tab.h lj_strfmt.h lj_ctype.h \
- lj_ccallback.h
+ lj_ccallback.h lj_buf.h
 lj_debug.o: lj_debug.c lj_obj.h lua.h luaconf.h lj_def.h lj_arch.h \
  lj_err.h lj_errmsg.h lj_debug.h lj_buf.h lj_gc.h lj_str.h lj_tab.h \
  lj_state.h lj_frame.h lj_bc.h lj_strfmt.h lj_jit.h lj_ir.h
@@ -188,6 +188,8 @@ lj_str.o: lj_str.c lj_obj.h lua.h luaconf.h lj_def.h lj_arch.h lj_gc.h \
  lj_err.h lj_errmsg.h lj_str.h lj_char.h
 lj_strfmt.o: lj_strfmt.c lj_obj.h lua.h luaconf.h lj_def.h lj_arch.h \
  lj_buf.h lj_gc.h lj_str.h lj_state.h lj_char.h lj_strfmt.h
+lj_strfmt_num.o: lj_strfmt_num.c lj_obj.h lua.h luaconf.h lj_def.h \
+ lj_arch.h lj_buf.h lj_gc.h lj_str.h lj_strfmt.h
 lj_strscan.o: lj_strscan.c lj_obj.h lua.h luaconf.h lj_def.h lj_arch.h \
  lj_char.h lj_strscan.h
 lj_tab.o: lj_tab.c lj_obj.h lua.h luaconf.h lj_def.h lj_arch.h lj_gc.h \

src/lib_base.c

@@ -495,11 +495,10 @@ LJLIB_CF(print)
   shortcut = (tvisfunc(tv) && funcV(tv)->c.ffid == FF_tostring);
   for (i = 0; i < nargs; i++) {
     cTValue *o = &L->base[i];
-    char buf[STRFMT_MAXBUF_NUM];
     const char *str;
     size_t size;
     MSize len;
-    if (shortcut && (str = lj_strfmt_wstrnum(buf, o, &len)) != NULL) {
+    if (shortcut && (str = lj_strfmt_wstrnum(L, o, &len)) != NULL) {
       size = len;
     } else {
       copyTV(L, L->top+1, o);

src/lib_io.c

@@ -232,9 +232,8 @@ static int io_file_write(lua_State *L, FILE *fp, int start)
   cTValue *tv;
   int status = 1;
   for (tv = L->base+start; tv < L->top; tv++) {
-    char buf[STRFMT_MAXBUF_NUM];
     MSize len;
-    const char *p = lj_strfmt_wstrnum(buf, tv, &len);
+    const char *p = lj_strfmt_wstrnum(L, tv, &len);
     if (!p)
       lj_err_argt(L, (int)(tv - L->base) + 1, LUA_TSTRING);
     status = status && (fwrite(p, 1, len, fp) == len);

src/lj_buf.c

@@ -186,7 +186,7 @@ SBuf *lj_buf_puttab(SBuf *sb, GCtab *t, GCstr *sep, int32_t i, int32_t e)
       } else if (tvisint(o)) {
 	p = lj_strfmt_wint(lj_buf_more(sb, STRFMT_MAXBUF_INT+seplen), intV(o));
       } else if (tvisnum(o)) {
-	p = lj_strfmt_wnum(lj_buf_more(sb, STRFMT_MAXBUF_NUM+seplen), o);
+	p = lj_buf_more(lj_strfmt_putfnum(sb, STRFMT_G14, numV(o)), seplen);
       } else {
 	goto badtype;
       }

src/lj_ctype.c

@@ -14,6 +14,7 @@
 #include "lj_strfmt.h"
 #include "lj_ctype.h"
 #include "lj_ccallback.h"
+#include "lj_buf.h"
 
 /* -- C type definitions -------------------------------------------------- */
 
@@ -571,19 +572,18 @@ GCstr *lj_ctype_repr_int64(lua_State *L, uint64_t n, int isunsigned)
 /* Convert complex to string with 'i' or 'I' suffix. */
 GCstr *lj_ctype_repr_complex(lua_State *L, void *sp, CTSize size)
 {
-  char buf[2*STRFMT_MAXBUF_NUM+2+1], *p = buf;
+  SBuf *sb = lj_buf_tmp_(L);
   TValue re, im;
   if (size == 2*sizeof(double)) {
     re.n = *(double *)sp; im.n = ((double *)sp)[1];
   } else {
     re.n = (double)*(float *)sp; im.n = (double)((float *)sp)[1];
   }
-  p = lj_strfmt_wnum(p, &re);
-  if (!(im.u32.hi & 0x80000000u) || im.n != im.n) *p++ = '+';
-  p = lj_strfmt_wnum(p, &im);
-  *p = *(p-1) >= 'a' ? 'I' : 'i';
-  p++;
-  return lj_str_new(L, buf, p-buf);
+  lj_strfmt_putfnum(sb, STRFMT_G14, re.n);
+  if (!(im.u32.hi & 0x80000000u) || im.n != im.n) lj_buf_putchar(sb, '+');
+  lj_strfmt_putfnum(sb, STRFMT_G14, im.n);
+  lj_buf_putchar(sb, sbufP(sb)[-1] >= 'a' ? 'I' : 'i');
+  return lj_buf_str(L, sb);
 }
 
 /* -- C type state -------------------------------------------------------- */

src/lj_meta.c

@@ -278,25 +278,25 @@ TValue *lj_meta_cat(lua_State *L, TValue *top, int left)
       */
       TValue *e, *o = top;
       uint64_t tlen = tvisstr(o) ? strV(o)->len : STRFMT_MAXBUF_NUM;
-      char *p, *buf;
+      SBuf *sb;
       do {
 	o--; tlen += tvisstr(o) ? strV(o)->len : STRFMT_MAXBUF_NUM;
       } while (--left > 0 && (tvisstr(o-1) || tvisnumber(o-1)));
       if (tlen >= LJ_MAX_STR) lj_err_msg(L, LJ_ERR_STROV);
-      p = buf = lj_buf_tmp(L, (MSize)tlen);
+      sb = lj_buf_tmp_(L);
+      lj_buf_more(sb, (MSize)tlen);
       for (e = top, top = o; o <= e; o++) {
 	if (tvisstr(o)) {
 	  GCstr *s = strV(o);
 	  MSize len = s->len;
-	  p = lj_buf_wmem(p, strdata(s), len);
+	  lj_buf_putmem(sb, strdata(s), len);
 	} else if (tvisint(o)) {
-	  p = lj_strfmt_wint(p, intV(o));
+	  lj_strfmt_putint(sb, intV(o));
 	} else {
-	  lua_assert(tvisnum(o));
-	  p = lj_strfmt_wnum(p, o);
+	  lj_strfmt_putfnum(sb, STRFMT_G14, numV(o));
 	}
       }
-      setstrV(L, top, lj_str_new(L, buf, (size_t)(p-buf)));
+      setstrV(L, top, lj_buf_str(L, sb));
     }
   } while (left >= 1);
   if (LJ_UNLIKELY(G(L)->gc.total >= G(L)->gc.threshold)) {

src/lj_strfmt.c

@@ -18,7 +18,7 @@
 /* -- Format parser ------------------------------------------------------- */
 
 static const uint8_t strfmt_map[('x'-'A')+1] = {
-  STRFMT_A,0,0,0,STRFMT_E,0,STRFMT_G,0,0,0,0,0,0,
+  STRFMT_A,0,0,0,STRFMT_E,STRFMT_F,STRFMT_G,0,0,0,0,0,0,
   0,0,0,0,0,0,0,0,0,0,STRFMT_X,0,0,
   0,0,0,0,0,0,
   STRFMT_A,0,STRFMT_C,STRFMT_D,STRFMT_E,STRFMT_F,STRFMT_G,0,STRFMT_I,0,0,0,0,
@@ -89,24 +89,6 @@ SFormat LJ_FASTCALL lj_strfmt_parse(FormatState *fs)
 
 /* -- Raw conversions ----------------------------------------------------- */
 
-/* Write number to bufer. */
-char * LJ_FASTCALL lj_strfmt_wnum(char *p, cTValue *o)
-{
-  if (LJ_LIKELY((o->u32.hi << 1) < 0xffe00000)) {  /* Finite? */
-#if __BIONIC__
-    if (tvismzero(o)) { *p++ = '-'; *p++ = '0'; return p; }
-#endif
-    return p + lua_number2str(p, o->n);
-  } else if (((o->u32.hi & 0x000fffff) | o->u32.lo) != 0) {
-    *p++ = 'n'; *p++ = 'a'; *p++ = 'n';
-  } else if ((o->u32.hi & 0x80000000) == 0) {
-    *p++ = 'i'; *p++ = 'n'; *p++ = 'f';
-  } else {
-    *p++ = '-'; *p++ = 'i'; *p++ = 'n'; *p++ = 'f';
-  }
-  return p;
-}
-
 #define WINT_R(x, sh, sc) \
   { uint32_t d = (x*(((1<<sh)+sc-1)/sc))>>sh; x -= d*sc; *p++ = (char)('0'+d); }
 
@@ -168,21 +150,22 @@ char * LJ_FASTCALL lj_strfmt_wuleb128(char *p, uint32_t v)
   return p;
 }
 
-/* Return string or write number to buffer and return pointer to start. */
-const char *lj_strfmt_wstrnum(char *buf, cTValue *o, MSize *lenp)
+/* Return string or write number to tmp buffer and return pointer to start. */
+const char *lj_strfmt_wstrnum(lua_State *L, cTValue *o, MSize *lenp)
 {
+  SBuf *sb;
   if (tvisstr(o)) {
     *lenp = strV(o)->len;
     return strVdata(o);
   } else if (tvisint(o)) {
-    *lenp = (MSize)(lj_strfmt_wint(buf, intV(o)) - buf);
-    return buf;
+    sb = lj_strfmt_putint(lj_buf_tmp_(L), intV(o));
   } else if (tvisnum(o)) {
-    *lenp = (MSize)(lj_strfmt_wnum(buf, o) - buf);
-    return buf;
+    sb = lj_strfmt_putfnum(lj_buf_tmp_(L), STRFMT_G14, o->n);
   } else {
     return NULL;
   }
+  *lenp = sbuflen(sb);
+  return sbufB(sb);
 }
 
 /* -- Unformatted conversions to buffer ----------------------------------- */
@@ -198,8 +181,7 @@ SBuf * LJ_FASTCALL lj_strfmt_putint(SBuf *sb, int32_t k)
 /* Add number to buffer. */
 SBuf * LJ_FASTCALL lj_strfmt_putnum(SBuf *sb, cTValue *o)
 {
-  setsbufP(sb, lj_strfmt_wnum(lj_buf_more(sb, STRFMT_MAXBUF_NUM), o));
-  return sb;
+  return lj_strfmt_putfnum(sb, STRFMT_G14, o->n);
 }
 #endif
 
@@ -360,63 +342,6 @@ SBuf *lj_strfmt_putfnum_uint(SBuf *sb, SFormat sf, lua_Number n)
   return lj_strfmt_putfxint(sb, sf, (uint64_t)k);
 }
 
-/* Max. sprintf buffer size needed. At least #string.format("%.99f", -1e308). */
-#define STRFMT_FMTNUMBUF	512
-
-/* Add formatted floating-point number to buffer. */
-SBuf *lj_strfmt_putfnum(SBuf *sb, SFormat sf, lua_Number n)
-{
-  TValue tv;
-  tv.n = n;
-  if (LJ_UNLIKELY((tv.u32.hi << 1) >= 0xffe00000)) {
-    /* Canonicalize output of non-finite values. */
-    MSize width = STRFMT_WIDTH(sf), len = 3;
-    int prefix = 0, ch = (sf & STRFMT_F_UPPER) ? 0x202020 : 0;
-    char *p;
-    if (((tv.u32.hi & 0x000fffff) | tv.u32.lo) != 0) {
-      ch ^= ('n' << 16) | ('a' << 8) | 'n';
-      if ((sf & STRFMT_F_SPACE)) prefix = ' ';
-    } else {
-      ch ^= ('i' << 16) | ('n' << 8) | 'f';
-      if ((tv.u32.hi & 0x80000000)) prefix = '-';
-      else if ((sf & STRFMT_F_PLUS)) prefix = '+';
-      else if ((sf & STRFMT_F_SPACE)) prefix = ' ';
-    }
-    if (prefix) len = 4;
-    p = lj_buf_more(sb, width > len ? width : len);
-    if (!(sf & STRFMT_F_LEFT)) while (width-- > len) *p++ = ' ';
-    if (prefix) *p++ = prefix;
-    *p++ = (char)(ch >> 16); *p++ = (char)(ch >> 8); *p++ = (char)ch;
-    if ((sf & STRFMT_F_LEFT)) while (width-- > len) *p++ = ' ';
-    setsbufP(sb, p);
-  } else {  /* Delegate to sprintf() for now. */
-    uint8_t width = (uint8_t)STRFMT_WIDTH(sf), prec = (uint8_t)STRFMT_PREC(sf);
-    char fmt[1+5+2+3+1+1], *p = fmt;
-    *p++ = '%';
-    if ((sf & STRFMT_F_LEFT)) *p++ = '-';
-    if ((sf & STRFMT_F_PLUS)) *p++ = '+';
-    if ((sf & STRFMT_F_ZERO)) *p++ = '0';
-    if ((sf & STRFMT_F_SPACE)) *p++ = ' ';
-    if ((sf & STRFMT_F_ALT)) *p++ = '#';
-    if (width) {
-      uint8_t x = width / 10, y = width % 10;
-      if (x) *p++ = '0' + x;
-      *p++ = '0' + y;
-    }
-    if (prec != 255) {
-      uint8_t x = prec / 10, y = prec % 10;
-      *p++ = '.';
-      if (x) *p++ = '0' + x;
-      *p++ = '0' + y;
-    }
-    *p++ = (0x67666561 >> (STRFMT_FP(sf)<<3)) ^ ((sf & STRFMT_F_UPPER)?0x20:0);
-    *p = '\0';
-    p = lj_buf_more(sb, STRFMT_FMTNUMBUF);
-    setsbufP(sb, p + sprintf(p, fmt, n));
-  }
-  return sb;
-}
-
 /* -- Conversions to strings ---------------------------------------------- */
 
 /* Convert integer to string. */
@@ -427,14 +352,6 @@ GCstr * LJ_FASTCALL lj_strfmt_int(lua_State *L, int32_t k)
   return lj_str_new(L, buf, len);
 }
 
-/* Convert number to string. */
-GCstr * LJ_FASTCALL lj_strfmt_num(lua_State *L, cTValue *o)
-{
-  char buf[STRFMT_MAXBUF_NUM];
-  MSize len = (MSize)(lj_strfmt_wnum(buf, o) - buf);
-  return lj_str_new(L, buf, len);
-}
-
 /* Convert integer or number to string. */
 GCstr * LJ_FASTCALL lj_strfmt_number(lua_State *L, cTValue *o)
 {
@@ -510,12 +427,9 @@ const char *lj_strfmt_pushvf(lua_State *L, const char *fmt, va_list argp)
     case STRFMT_UINT:
       lj_strfmt_putfxint(sb, sf, va_arg(argp, uint32_t));
       break;
-    case STRFMT_NUM: {
-      TValue tv;
-      tv.n = va_arg(argp, lua_Number);
-      setsbufP(sb, lj_strfmt_wnum(lj_buf_more(sb, STRFMT_MAXBUF_NUM), &tv));
+    case STRFMT_NUM:
+      lj_strfmt_putfnum(sb, STRFMT_G14, va_arg(argp, lua_Number));
       break;
-      }
     case STRFMT_STR: {
       const char *s = va_arg(argp, char *);
       if (s == NULL) s = "(null)";

src/lj_strfmt.h

@@ -64,11 +64,12 @@ typedef enum FormatType {
 #define STRFMT_S	(STRFMT_STR)
 #define STRFMT_U	(STRFMT_UINT)
 #define STRFMT_X	(STRFMT_UINT|STRFMT_T_HEX)
+#define STRFMT_G14	(STRFMT_G | ((14+1) << STRFMT_SH_PREC))
 
 /* Maximum buffer sizes for conversions. */
 #define STRFMT_MAXBUF_XINT	(1+22)  /* '0' prefix + uint64_t in octal. */
 #define STRFMT_MAXBUF_INT	(1+10)  /* Sign + int32_t in decimal. */
-#define STRFMT_MAXBUF_NUM	LUAI_MAXNUMBER2STR
+#define STRFMT_MAXBUF_NUM	32  /* Must correspond with STRFMT_G14. */
 #define STRFMT_MAXBUF_PTR	(2+2*sizeof(ptrdiff_t))  /* "0x" + hex ptr. */
 
 /* Format parser. */
@@ -83,10 +84,9 @@ static LJ_AINLINE void lj_strfmt_init(FormatState *fs, const char *p, MSize len)
 
 /* Raw conversions. */
 LJ_FUNC char * LJ_FASTCALL lj_strfmt_wint(char *p, int32_t k);
-LJ_FUNC char * LJ_FASTCALL lj_strfmt_wnum(char *p, cTValue *o);
 LJ_FUNC char * LJ_FASTCALL lj_strfmt_wptr(char *p, const void *v);
 LJ_FUNC char * LJ_FASTCALL lj_strfmt_wuleb128(char *p, uint32_t v);
-LJ_FUNC const char *lj_strfmt_wstrnum(char *buf, cTValue *o, MSize *lenp);
+LJ_FUNC const char *lj_strfmt_wstrnum(lua_State *L, cTValue *o, MSize *lenp);
 
 /* Unformatted conversions to buffer. */
 LJ_FUNC SBuf * LJ_FASTCALL lj_strfmt_putint(SBuf *sb, int32_t k);