2132e0221
Denis Vlasenko
2008-07-15
Subject
libbb: experimental faster string reading routines.
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include/libbb.h+5 -1
| @@ -607,6 +607,8 @@ extern void xopen_xwrite_close(const char* file, const char *str) FAST_FUNC; | |
| /* Reads and prints to stdout till eof, then closes FILE. Exits on error: */ | |
| extern void xprint_and_close_file(FILE *file) FAST_FUNC; | |
| + | |
| + | extern char *bb_get_chunk_from_file(FILE *file, int *end) FAST_FUNC; |
| /* Reads up to (and including) TERMINATING_STRING: */ | |
| extern char *xmalloc_fgets_str(FILE *file, const char *terminating_string) FAST_FUNC; | |
| /* Chops off TERMINATING_STRING from the end: */ | |
| @@ -615,7 +617,9 @@ extern char *xmalloc_fgetline_str(FILE *file, const char *terminating_string) FA | |
| extern char *xmalloc_fgets(FILE *file) FAST_FUNC; | |
| /* Chops off '\n' from the end, unlike fgets: */ | |
| extern char *xmalloc_fgetline(FILE *file) FAST_FUNC; | |
| - | extern char *bb_get_chunk_from_file(FILE *file, int *end) 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 void die_if_ferror(FILE *file, const char *msg) FAST_FUNC; | |
| extern void die_if_ferror_stdout(void) FAST_FUNC; | |
| extern void xfflush_stdout(void) FAST_FUNC; | |
libbb/get_line_from_file.c+70 -0
| @@ -67,3 +67,73 @@ char* FAST_FUNC xmalloc_fgetline(FILE *file) | |
| return c; | |
| } | |
| + | |
| + | /* 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. |
| + | * We sorely need C lib to provide fgets which reports size! |
| + | */ |
| + | |
| + | static char* xmalloc_fgets_internal(FILE *file, int *sizep) |
| + | { |
| + | int len; |
| + | int idx = 0; |
| + | char *linebuf = NULL; |
| + | |
| + | while (1) { |
| + | char *r; |
| + | |
| + | linebuf = xrealloc(linebuf, idx + 0x100); |
| + | r = fgets(&linebuf[idx], 0x100, file); |
| + | if (!r) { |
| + | /* need to terminate in case this is error |
| + | * (EOF puts NUL itself) */ |
| + | linebuf[idx] = '\0'; |
| + | break; |
| + | } |
| + | /* stupid. fgets knows the len, it should report it somehow */ |
| + | len = strlen(&linebuf[idx]); |
| + | idx += len; |
| + | if (len != 0xff || linebuf[idx - 1] == '\n') |
| + | break; |
| + | } |
| + | *sizep = idx; |
| + | if (idx) { |
| + | /* xrealloc(linebuf, idx + 1) is up to caller */ |
| + | return linebuf; |
| + | } |
| + | free(linebuf); |
| + | return NULL; |
| + | } |
| + | |
| + | /* Get line, remove trailing \n */ |
| + | char* FAST_FUNC xmalloc_fgetline_fast(FILE *file) |
| + | { |
| + | int sz; |
| + | char *r = xmalloc_fgets_internal(file, &sz); |
| + | if (r && r[sz - 1] == '\n') |
| + | r[--sz] = '\0'; |
| + | return r; /* not xrealloc(r, sz + 1)! */ |
| + | } |
| + | |
| + | #if 0 |
| + | char* FAST_FUNC xmalloc_fgets(FILE *file) |
| + | { |
| + | int sz; |
| + | return xmalloc_fgets_internal(file, &sz); |
| + | } |
| + | |
| + | /* Get line, remove trailing \n */ |
| + | char* FAST_FUNC xmalloc_fgetline(FILE *file) |
| + | { |
| + | int sz; |
| + | char *r = xmalloc_fgets_internal(file, &sz); |
| + | if (!r) |
| + | return r; |
| + | if (r[sz - 1] == '\n') |
| + | r[--sz] = '\0'; |
| + | return xrealloc(r, sz + 1); |
| + | } |
| + | #endif |