From 9b978282144d6bab479c042070c66bdfcdae6b02 Mon Sep 17 00:00:00 2001 From: Nick Clifton Date: Tue, 26 Mar 2013 14:16:59 +0000 Subject: PR gas/15295 * listing.c (rebuffer_line): Rewrite to avoid seeking back to the start of the file each time. --- gas/ChangeLog | 4 +++ gas/listing.c | 86 ++++++++++++++++++++++++++++++++++++++++++----------------- 2 files changed, 65 insertions(+), 25 deletions(-) (limited to 'gas') diff --git a/gas/ChangeLog b/gas/ChangeLog index 583655c..bb9367d 100644 --- a/gas/ChangeLog +++ b/gas/ChangeLog @@ -1,5 +1,9 @@ 2013-03-26 Nick Clifton + PR gas/15295 + * listing.c (rebuffer_line): Rewrite to avoid seeking back to the + start of the file each time. + PR gas/15178 * config/tc-sparc.h (ELF_TARGET_FORMAT): Set to elf32-sparc for FreeBSD targets. diff --git a/gas/listing.c b/gas/listing.c index 38518e4..182d504 100644 --- a/gas/listing.c +++ b/gas/listing.c @@ -553,7 +553,8 @@ buffer_line (file_info_type *file, char *line, unsigned int size) /* This function rewinds the requested file back to the line requested, reads it in again into the buffer provided and then restores the file - back to its original location. */ + back to its original location. Returns the buffer pointer upon success + or an empty string if an error occurs. */ static char * rebuffer_line (file_info_type * file, @@ -562,13 +563,15 @@ rebuffer_line (file_info_type * file, unsigned int size) { unsigned int count = 0; - unsigned int current_line = 1; + unsigned int current_line; char * p = buffer; long pos; + long pos2; int c; + bfd_boolean found = FALSE; /* Sanity checks. */ - if (file == NULL || buffer == NULL || size == 0 || file->linenum <= linenum) + if (file == NULL || buffer == NULL || size <= 1 || file->linenum <= linenum) return ""; /* Check the cache and see if we last used this file. */ @@ -596,39 +599,72 @@ rebuffer_line (file_info_type * file, } /* Remember where we are in the current file. */ - pos = ftell (last_open_file); + pos2 = pos = ftell (last_open_file); + if (pos < 3) + return ""; + current_line = file->linenum; - /* Go back to the beginning. */ - fseek (last_open_file, 0, SEEK_SET); + /* Leave room for the nul at the end of the buffer. */ + size -= 1; + buffer[size] = 0; - /* Skip lines prior to the one we are interested in. */ - while (current_line < linenum) + /* Increment the current line count by one. + This is to allow for the fact that we are searching for the + start of a previous line, but we do this by detecting end-of-line + character(s) not start-of-line characters. */ + ++ current_line; + + while (pos2 > 0 && ! found) { - /* fgets only stops on newlines and has a size limit, - so we read one character at a time instead. */ - do + char * ptr; + + /* Move backwards through the file, looking for earlier lines. */ + pos2 = (long) size > pos2 ? 0 : pos2 - size; + fseek (last_open_file, pos2, SEEK_SET); + + /* Our caller has kindly provided us with a buffer, so we use it. */ + if (fread (buffer, 1, size, last_open_file) != size) { - c = fgetc (last_open_file); + as_warn (_("unable to rebuffer file: %s\n"), file->filename); + return ""; } - while (c != EOF && c != '\n' && c != '\r'); - ++ current_line; - - if (c == '\r' || c == '\n') + for (ptr = buffer + size; ptr >= buffer; -- ptr) { - int next = fgetc (last_open_file); + if (*ptr == '\n') + { + -- current_line; - /* If '\r' is followed by '\n', swallow that. Likewise, if '\n' - is followed by '\r', swallow that as well. */ - if ((c == '\r' && next != '\n') - || (c == '\n' && next != '\r')) - ungetc (next, last_open_file); + if (current_line == linenum) + { + /* We have found the start of the line we seek. */ + found = TRUE; + + /* FIXME: We could skip the read-in-the-line code + below if we know that we already have the whole + line in the buffer. */ + + /* Advance pos2 to the newline character we have just located. */ + pos2 += (ptr - buffer); + + /* Skip the newline and, if present, the carriage return. */ + if (ptr + 1 == buffer + size) + { + ++pos2; + if (fgetc (last_open_file) == '\r') + ++ pos2; + } + else + pos2 += (ptr[1] == '\r' ? 2 : 1); + + /* Move the file pointer to this location. */ + fseek (last_open_file, pos2, SEEK_SET); + break; + } + } } } - /* Leave room for the nul at the end of the buffer. */ - size -= 1; - /* Read in the line. */ c = fgetc (last_open_file); -- cgit v1.1