diff options
author | Guy Harris <guy@alum.mit.edu> | 2014-10-06 18:00:57 -0700 |
---|---|---|
committer | Guy Harris <guy@alum.mit.edu> | 2014-10-07 01:01:59 +0000 |
commit | 670ebda4a6af0d30e033b0af48cfd15ce52c10eb (patch) | |
tree | b092e44c944c4eb7566964da4cfb914e6002bd6d /wiretap/mpeg.c | |
parent | 6397ad43c2374ebde388041f2bd7ac925606a51e (diff) |
Add some higher-level file-read APIs and use them.
Add wtap_read_bytes(), which takes a FILE_T, a pointer, a byte count, an
error number pointer, and an error string pointer as arguments, and that
treats a short read of any sort, including a read that returns 0 bytes,
as a WTAP_ERR_SHORT_READ error, and that returns the error number and
string through its last two arguments.
Add wtap_read_bytes_or_eof(), which is similar, but that treats a read
that returns 0 bytes as an EOF, supplying an error number of 0 as an EOF
indication.
Use those in file readers; that simplifies the code and makes it less
likely that somebody will fail to supply the error number and error
string on a file read error.
Change-Id: Ia5dba2a6f81151e87b614461349d611cffc16210
Reviewed-on: https://code.wireshark.org/review/4512
Reviewed-by: Guy Harris <guy@alum.mit.edu>
Diffstat (limited to 'wiretap/mpeg.c')
-rw-r--r-- | wiretap/mpeg.c | 83 |
1 files changed, 27 insertions, 56 deletions
diff --git a/wiretap/mpeg.c b/wiretap/mpeg.c index 05ac414260..681e4baa50 100644 --- a/wiretap/mpeg.c +++ b/wiretap/mpeg.c @@ -70,25 +70,6 @@ mpeg_resync(FILE_T fh, int *err) return count; } -static int -mpeg_read_header(FILE_T fh, int *err, gchar **err_info, guint32 *n) -{ - int bytes_read; - - errno = WTAP_ERR_CANT_READ; - bytes_read = file_read(n, sizeof *n, fh); - if (bytes_read != sizeof *n) { - *err = file_error(fh, err_info); - if (*err == 0 && bytes_read != 0) - *err = WTAP_ERR_SHORT_READ; - return -1; - } - *n = g_ntohl(*n); - if (file_seek(fh, -(gint64)(sizeof *n), SEEK_CUR, err) == -1) - return -1; - return bytes_read; -} - #define SCRHZ 27000000 static gboolean @@ -97,25 +78,35 @@ mpeg_read_packet(wtap *wth, FILE_T fh, struct wtap_pkthdr *phdr, Buffer *buf, { mpeg_t *mpeg = (mpeg_t *)wth->priv; guint32 n; - int bytes_read; unsigned int packet_size; nstime_t ts = mpeg->now; - bytes_read = mpeg_read_header(fh, err, err_info, &n); - if (bytes_read == -1) + /* + * All packets have at least 4 bytes in them. Read the first + * 4 bytes and determine whether it's a PES packet or not + * based on that. + * + * XXX - can an MPEG file contain a mixture of PES and non-PES + * packets? If not, can we determine whether the packets will + * be PES packets or not based on the magic number (i.e., if the + * file begins with 0x00 0x00 0x01, it contains PES packets, + * otherwise it doesn't)? + */ + errno = WTAP_ERR_CANT_READ; + if (!wtap_read_bytes_or_eof(fh, &n, sizeof n, err, err_info)) return FALSE; + if (file_seek(fh, -(gint64)(sizeof n), SEEK_CUR, err) == -1) + return FALSE; + n = g_ntohl(n); if (PES_VALID(n)) { gint64 offset = file_tell(fh); guint8 stream; - if (file_seek(fh, 3, SEEK_CUR, err) == -1) + if (!file_skip(fh, 3, err)) return FALSE; - bytes_read = file_read(&stream, sizeof stream, fh); - if (bytes_read != sizeof stream) { - *err = file_error(fh, err_info); + if (!wtap_read_bytes(fh, &stream, sizeof stream, err, err_info)) return FALSE; - } if (stream == 0xba) { guint32 pack1; @@ -123,32 +114,19 @@ mpeg_read_packet(wtap *wth, FILE_T fh, struct wtap_pkthdr *phdr, Buffer *buf, guint64 pack; guint8 stuffing; - bytes_read = file_read(&pack1, sizeof pack1, fh); - if (bytes_read != sizeof pack1) { - *err = file_error(fh, err_info); - if (*err == 0 && bytes_read != 0) - *err = WTAP_ERR_SHORT_READ; + if (!wtap_read_bytes(fh, &pack1, sizeof pack1, err, err_info)) return FALSE; - } - bytes_read = file_read(&pack0, sizeof pack0, fh); - if (bytes_read != sizeof pack0) { - *err = file_error(fh, err_info); - if (*err == 0 && bytes_read != 0) - *err = WTAP_ERR_SHORT_READ; + if (!wtap_read_bytes(fh, &pack0, sizeof pack0, err, err_info)) return FALSE; - } pack = (guint64)g_ntohl(pack1) << 32 | g_ntohl(pack0); switch (pack >> 62) { case 1: - if (file_seek(fh, 1, SEEK_CUR, err) == -1) + if (!file_skip(fh, 1, err)) return FALSE; - bytes_read = file_read(&stuffing, - sizeof stuffing, fh); - if (bytes_read != sizeof stuffing) { - *err = file_error(fh, err_info); + if (!wtap_read_bytes(fh, &stuffing, + sizeof stuffing, err, err_info)) return FALSE; - } stuffing &= 0x07; packet_size = 14 + stuffing; @@ -173,13 +151,8 @@ mpeg_read_packet(wtap *wth, FILE_T fh, struct wtap_pkthdr *phdr, Buffer *buf, } } else { guint16 length; - bytes_read = file_read(&length, sizeof length, fh); - if (bytes_read != sizeof length) { - *err = file_error(fh, err_info); - if (*err == 0 && bytes_read != 0) - *err = WTAP_ERR_SHORT_READ; + if (!wtap_read_bytes(fh, &length, sizeof length, err, err_info)) return FALSE; - } length = g_ntohs(length); packet_size = 6 + length; } @@ -262,16 +235,14 @@ struct _mpeg_magic { int mpeg_open(wtap *wth, int *err, gchar **err_info) { - int bytes_read; char magic_buf[16]; struct _mpeg_magic* m; mpeg_t *mpeg; errno = WTAP_ERR_CANT_READ; - bytes_read = file_read(magic_buf, sizeof magic_buf, wth->fh); - if (bytes_read != (int) sizeof magic_buf) { - *err = file_error(wth->fh, err_info); - if (*err != 0 && *err != WTAP_ERR_SHORT_READ) + if (!wtap_read_bytes(wth->fh, magic_buf, sizeof magic_buf, + err, err_info)) { + if (*err != WTAP_ERR_SHORT_READ) return -1; return 0; } |