diff options
| -rw-r--r-- | ChangeLog | 22 | ||||
| -rw-r--r-- | generic/tclStringObj.c | 45 |
2 files changed, 46 insertions, 21 deletions
@@ -1,15 +1,21 @@ -2009-02-16 Jan Nijtmans <nijtmans@users.sf.net> +2009-02-17 Don Porter <dgp@users.sourceforge.net> - * generic/tclZlib.c hack needed for official zlib1.dll build. - * win/configure.in fix [Feature Request 2605263] use official - * win/Makefile.in zlib build. - * win/configure (regenerated) - * compat/zlib/zdll.lib new files - * compat/zlib/zlib1.dll + * generic/tclStringObj.c: Revise buffer growth implementation + in ExtendStringRepWithUnicode. Use cheap checks to determine that + no reallocation is necessary without cost of computing the precise + number of bytes needed. Also make use of the string growth algortihm + in the case of repeated appends. 2009-02-16 Jan Nijtmans <nijtmans@users.sf.net> - * win/Makefile.in fix [Bug 2605232] tdbc doesn't build when + * generic/tclZlib.c: hack needed for official zlib1.dll build. + * win/configure.in: fix [Feature Request 2605263] use official + * win/Makefile.in: zlib build. + * win/configure: (regenerated) + * compat/zlib/zdll.lib: new files + * compat/zlib/zlib1.dll: + + * win/Makefile.in: fix [Bug 2605232] tdbc doesn't build when Tcl is compiled with --disable-shared. 2009-02-15 Don Porter <dgp@users.sourceforge.net> diff --git a/generic/tclStringObj.c b/generic/tclStringObj.c index ecea7be..52e6019 100644 --- a/generic/tclStringObj.c +++ b/generic/tclStringObj.c @@ -33,7 +33,7 @@ * See the file "license.terms" for information on usage and redistribution of * this file, and for a DISCLAIMER OF ALL WARRANTIES. * - * RCS: @(#) $Id: tclStringObj.c,v 1.109 2009/02/16 04:06:07 dgp Exp $ */ + * RCS: @(#) $Id: tclStringObj.c,v 1.110 2009/02/17 06:52:05 dgp Exp $ */ #include "tclInt.h" #include "tommath.h" @@ -2897,7 +2897,7 @@ ExtendStringRepWithUnicode( const Tcl_UniChar *unicode, int numChars) { - int i, size = 0; + int i, origLength, size = 0; char *dst, buf[TCL_UTF_MAX]; /* Pre-condition: this is the "string" Tcl_ObjType */ @@ -2918,12 +2918,13 @@ ExtendStringRepWithUnicode( } else { objPtr->length = 0; } + origLength = objPtr->length; - /* - * TODO: Consider fast overallocation of numChars*TCL_UTF_MAX bytes. - * Then we could make one pass instead of two. Trade away memory - * efficiency for speed. - */ + /* Quick cheap check in case we have more than enough room. */ + if (numChars <= (INT_MAX - size)/TCL_UTF_MAX + && stringPtr->allocated >= size + numChars * TCL_UTF_MAX) { + goto copyBytes; + } for (i = 0; i < numChars && size >= 0; i++) { size += Tcl_UniCharToUtf((int) unicode[i], buf); @@ -2934,16 +2935,34 @@ ExtendStringRepWithUnicode( /* Grow space if needed */ if (size > stringPtr->allocated) { - /* TODO: Growth algorithm for appends ? */ - objPtr->bytes = ckrealloc(objPtr->bytes, (unsigned) size+1); - stringPtr->allocated = size; + if (stringPtr->allocated == 0) { + /* First allocation - just big enough */ + objPtr->bytes = ckrealloc(objPtr->bytes, (unsigned) size+1); + stringPtr->allocated = size; + } else { + /* Subsequent appends - apply the growth algorithm. */ + if (Tcl_AttemptSetObjLength(objPtr, 2 * size) == 0) { + /* + * Take care computing the amount of modest growth to avoid + * overflow into invalid argument values for Tcl_SetObjLength. + */ + unsigned int limit = INT_MAX - size; + unsigned int extra = size - objPtr->length + + TCL_GROWTH_MIN_ALLOC; + int growth = (int) ((extra > limit) ? limit : extra); + + Tcl_SetObjLength(objPtr, size + growth); + } + } } - dst = objPtr->bytes + objPtr->length; + + copyBytes: + dst = objPtr->bytes + origLength; for (i = 0; i < numChars; i++) { dst += Tcl_UniCharToUtf((int) unicode[i], dst); } - objPtr->length = size; - objPtr->bytes[size] = '\0'; + *dst = '\0'; + objPtr->length = dst - objPtr->bytes; return numChars; } |