From a1a448347e71c9899ad1500cbd8739fd82e1bb91 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Fri, 17 Jun 2011 03:37:43 +0200 Subject: libbb: split bb_get_chunk_from_file and bb_get_chunk_with_continuation This also moves bb_get_chunk_with_continuation into its sole user, parse_config.c. This allows to optimize both functions separately, they need to be optimized for speed. (this need was highlighted by slow modprobe caused in part by slow bb_get_chunk_with_continuation in config parser). function old new delta bb_get_chunk_from_file 7 130 +123 config_read 457 558 +101 bb_get_chunk_with_continuation 194 - -194 ------------------------------------------------------------------------------ (add/remove: 0/1 grow/shrink: 2/0 up/down: 224/-194) Total: 30 bytes Signed-off-by: Denys Vlasenko --- libbb/parse_config.c | 52 +++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 43 insertions(+), 9 deletions(-) (limited to 'libbb/parse_config.c') diff --git a/libbb/parse_config.c b/libbb/parse_config.c index 4b0236028..769ae5103 100644 --- a/libbb/parse_config.c +++ b/libbb/parse_config.c @@ -104,6 +104,44 @@ void FAST_FUNC config_close(parser_t *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. + * Trailing '\' is recognized as line continuation. + * Returns NULL if EOF/error. + */ +static char* get_line_with_continuation(FILE *file, int *lineno) +{ + 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; + } + idx++; + } + if (ch == EOF) { + /* handle corner case when the file is not ended with '\n' */ + (*lineno)++; + if (linebuf) + linebuf[idx] = '\0'; + } + return linebuf; +} + + /* 0. If parser is NULL return 0. 1. Read a line from config file. If nothing to read then return 0. @@ -132,28 +170,24 @@ int FAST_FUNC config_read(parser_t *parser, char **tokens, unsigned flags, const { char *line; int ntokens, mintokens; - int t, len; + int t; + + if (!parser) + return 0; ntokens = (uint8_t)flags; mintokens = (uint8_t)(flags >> 8); - if (parser == NULL) - return 0; - again: memset(tokens, 0, sizeof(tokens[0]) * ntokens); config_free_data(parser); /* Read one line (handling continuations with backslash) */ - line = bb_get_chunk_with_continuation(parser->fp, &len, &parser->lineno); + line = get_line_with_continuation(parser->fp, &parser->lineno); if (line == NULL) return 0; parser->line = line; - /* Strip trailing line-feed if any */ - if (len && line[len-1] == '\n') - line[len-1] = '\0'; - /* Skip token in the start of line? */ if (flags & PARSE_TRIM) line += strspn(line, delims + 1); -- cgit v1.2.3