parse_config: use getline. BIG speedup with glibc (~40%).

function                                             old     new   delta
config_read                                          559     604     +45
getline                                                -      23     +23
config_close                                          29      49     +20
find_pair                                            169     187     +18
showmode                                             330     338      +8
hash_find                                            233     234      +1
builtin_umask                                        133     132      -1
lzo1x_optimize                                      1434    1429      -5
test_main                                            253     247      -6
buffer_fill_and_print                                196     179     -17
create_J                                            1849    1826     -23
config_free_data                                      37       -     -37
------------------------------------------------------------------------------
(add/remove: 3/1 grow/shrink: 5/5 up/down: 138/-89)            Total: 26 bytes

Signed-off-by: Timo Teras <timo.teras@iki.fi>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/include/libbb.h b/include/libbb.h
index 2cac7e6..953bec3 100644 (file)
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -1184,8 +1184,9 @@ enum {
 };
 typedef struct parser_t {
        FILE *fp;
-       char *line;
        char *data;
+       char *line, *nline;
+       size_t line_alloc, nline_alloc;
        int lineno;
 } parser_t;
 parser_t* config_open(const char *filename) FAST_FUNC;

diff --git a/libbb/parse_config.c b/libbb/parse_config.c
index c0c34f3..cf5ba4d 100644 (file)
--- a/libbb/parse_config.c
+++ b/libbb/parse_config.c
@@ -83,60 +83,55 @@ parser_t* FAST_FUNC config_open(const char *filename)
        return config_open2(filename, fopen_or_warn_stdin);
 }
 
-static void config_free_data(parser_t *parser)
-{
-       free(parser->line);
-       parser->line = NULL;
-       if (PARSE_KEEP_COPY) { /* compile-time constant */
-               free(parser->data);
-               parser->data = NULL;
-       }
-}
-
 void FAST_FUNC config_close(parser_t *parser)
 {
        if (parser) {
-               config_free_data(parser);
+               if (PARSE_KEEP_COPY) /* compile-time constant */
+                       free(parser->data);
                fclose(parser->fp);
+               free(parser->line);
+               free(parser->nline);
                free(parser);
        }
 }
 
-/* This function reads an entire line from a text file, up to a newline
- * or NUL byte, exclusive.  It returns a malloc'ed char*.
- * *lineno is incremented for each line.
+/* This function reads an entire line from a text file,
+ * up to a newline, exclusive.
  * Trailing '\' is recognized as line continuation.
- * Returns NULL if EOF/error.
+ * Returns -1 if EOF/error.
  */
-static char* get_line_with_continuation(FILE *file, int *lineno)
+static int get_line_with_continuation(parser_t *parser)
 {
-       int ch;
-       unsigned idx = 0;
-       char *linebuf = NULL;
-
-       while ((ch = getc(file)) != EOF) {
-               /* grow the line buffer as necessary */
-               if (!(idx & 0xff))
-                       linebuf = xrealloc(linebuf, idx + 0x101);
-               if (ch == '\n')
-                       ch = '\0';
-               linebuf[idx] = (char) ch;
-               if (ch == '\0') {
-                       (*lineno)++;
-                       if (idx == 0 || linebuf[idx-1] != '\\')
-                               break;
-                       idx--; /* go back to '/' */
-                       continue;
+       ssize_t len, nlen;
+       char *line;
+
+       len = getline(&parser->line, &parser->line_alloc, parser->fp);
+       if (len <= 0)
+               return len;
+
+       line = parser->line;
+       for (;;) {
+               parser->lineno++;
+               if (line[len - 1] == '\n')
+                       len--;
+               if (len == 0 || line[len - 1] != '\\')
+                       break;
+               len--;
+
+               nlen = getline(&parser->nline, &parser->nline_alloc, parser->fp);
+               if (nlen <= 0)
+                       break;
+
+               if (parser->line_alloc < len + nlen + 1) {
+                       parser->line_alloc = len + nlen + 1;
+                       line = parser->line = xrealloc(line, parser->line_alloc);
                }
-               idx++;
-       }
-       if (ch == EOF) {
-               /* handle corner case when the file is not ended with '\n' */
-               (*lineno)++;
-               if (linebuf)
-                       linebuf[idx] = '\0';
+               memcpy(&line[len], parser->nline, nlen);
+               len += nlen;
        }
-       return linebuf;
+
+       line[len] = '\0';
+       return len;
 }
 
 
@@ -176,15 +171,14 @@ int FAST_FUNC config_read(parser_t *parser, char **tokens, unsigned flags, const
        ntokens = (uint8_t)flags;
        mintokens = (uint8_t)(flags >> 8);
 
-again:
+ again:
        memset(tokens, 0, sizeof(tokens[0]) * ntokens);
-       config_free_data(parser);
 
        /* Read one line (handling continuations with backslash) */
-       line = get_line_with_continuation(parser->fp, &parser->lineno);
-       if (line == NULL)
+       if (get_line_with_continuation(parser) < 0)
                return 0;
-       parser->line = line;
+
+       line = parser->line;
 
        /* Skip token in the start of line? */
        if (flags & PARSE_TRIM)
@@ -193,8 +187,10 @@ again:
        if (line[0] == '\0' || line[0] == delims[0])
                goto again;
 
-       if (flags & PARSE_KEEP_COPY)
+       if (flags & PARSE_KEEP_COPY) {
+               free(parser->data);
                parser->data = xstrdup(line);
+       }
 
        /* Tokenize the line */
        t = 0;
@@ -240,8 +236,6 @@ again:
                                parser->lineno, t, mintokens);
                if (flags & PARSE_MIN_DIE)
                        xfunc_die();
-               if (flags & PARSE_KEEP_COPY)
-                       free(parser->data);
                goto again;
        }