libbb: document plans to speed up line-based input

This commit is contained in:
Denis Vlasenko 2008-07-15 21:29:44 +00:00
parent e559e0a757
commit 5e476bab9c
2 changed files with 15 additions and 3 deletions

View File

@ -618,7 +618,7 @@ extern char *xmalloc_fgets(FILE *file) FAST_FUNC;
/* Chops off '\n' from the end, unlike fgets: */
extern char *xmalloc_fgetline(FILE *file) FAST_FUNC;
/* Same, but doesn't try to conserve space (may have some slack after the end) */
extern char *xmalloc_fgetline_fast(FILE *file) FAST_FUNC;
/* extern char *xmalloc_fgetline_fast(FILE *file) FAST_FUNC; */
extern void die_if_ferror(FILE *file, const char *msg) FAST_FUNC;
extern void die_if_ferror_stdout(void) FAST_FUNC;
@ -1006,6 +1006,7 @@ typedef struct parser_t {
} parser_t;
extern FILE* config_open(parser_t *parser, const char *filename) FAST_FUNC;
#endif
/* TODO: add define magic to collapse ntokens/mintokens/comment into one int param */
extern char* config_read(parser_t *parser, char **tokens, int ntokens, int mintokens, const char *delims, char comment) FAST_FUNC;
extern void config_close(parser_t *parser) FAST_FUNC;

View File

@ -68,12 +68,24 @@ char* FAST_FUNC xmalloc_fgetline(FILE *file)
return c;
}
#if 0
/* Faster routines (~twice as fast). +170 bytes. Unused as of 2008-07.
*
* NB: they stop at NUL byte too.
* Performance is important here. Think "grep 50gigabyte_file"...
* Iironically, grep can't use it because of NUL issue.
* Ironically, grep can't use it because of NUL issue.
* We sorely need C lib to provide fgets which reports size!
*
* Update:
* Actually, uclibc and glibc have it. man getline. It's GNUism,
* but very useful one (if it's as fast as this code).
* TODO:
* - currently, sed and sort use bb_get_chunk_from_file and heavily
* depend on its "stop on \n or \0" behavior, and STILL they fail
* to handle all cases with embedded NULs correctly. So:
* - audit sed and sort; convert them to getline FIRST.
* - THEN ditch bb_get_chunk_from_file, replace it with getline.
* - provide getline implementation for non-GNU systems.
*/
static char* xmalloc_fgets_internal(FILE *file, int *sizep)
@ -118,7 +130,6 @@ char* FAST_FUNC xmalloc_fgetline_fast(FILE *file)
return r; /* not xrealloc(r, sz + 1)! */
}
#if 0
char* FAST_FUNC xmalloc_fgets(FILE *file)
{
int sz;