diff options
Diffstat (limited to 'gas/sb.c')
| -rw-r--r-- | gas/sb.c | 43 |
1 files changed, 31 insertions, 12 deletions
@@ -25,6 +25,13 @@ #include "as.h" #include "sb.h" +#ifdef HAVE_LIMITS_H +#include <limits.h> +#endif +#ifndef CHAR_BIT +#define CHAR_BIT 8 +#endif + /* These routines are about manipulating strings. They are managed in things called `sb's which is an abbreviation @@ -39,7 +46,13 @@ use foo->ptr[*]; sb_kill (&foo); */ -static size_t dsize = 32; +/* Buffers start at INIT_ALLOC size, and roughly double each time we + go over the current allocation. MALLOC_OVERHEAD is a guess at the + system malloc overhead. We aim to not waste any memory in the + underlying page/chunk allocated by the system malloc. */ +#define MALLOC_OVERHEAD (2 * sizeof (size_t)) +#define INIT_ALLOC (64 - MALLOC_OVERHEAD - 1) + static void sb_check (sb *, size_t); /* Initializes an sb. */ @@ -55,7 +68,7 @@ sb_build (sb *ptr, size_t size) void sb_new (sb *ptr) { - sb_build (ptr, dsize); + sb_build (ptr, INIT_ALLOC); } /* Deallocate the sb at ptr. */ @@ -114,16 +127,23 @@ sb_scrub_and_add_sb (sb *ptr, sb *s) static void sb_check (sb *ptr, size_t len) { - size_t max = ptr->max; + size_t want = ptr->len + len; - while (ptr->len + len >= max) + if (want > ptr->max) { - max <<= 1; - if (max == 0) + size_t max; + + want += MALLOC_OVERHEAD + 1; + if ((ssize_t) want < 0) as_fatal ("string buffer overflow"); - } - if (max != ptr->max) - { +#if GCC_VERSION >= 3004 + max = (size_t) 1 << (CHAR_BIT * sizeof (want) - __builtin_clzl (want)); +#else + max = 128; + while (want > max) + max <<= 1; +#endif + max -= MALLOC_OVERHEAD + 1; ptr->max = max; ptr->ptr = xrealloc (ptr->ptr, max + 1); } @@ -167,13 +187,12 @@ sb_add_buffer (sb *ptr, const char *s, size_t len) ptr->len += len; } -/* Like sb_name, but don't include the null byte in the string. */ +/* Write terminating NUL and return string. */ char * sb_terminate (sb *in) { - sb_add_char (in, 0); - --in->len; + in->ptr[in->len] = 0; return in->ptr; } |