-
-/*
- * m_getfld.c -- read/parse a message
+/* m_getfld.c -- read/parse a message
*
* This code is Copyright (c) 2002, by the authors of nmh. See the
* COPYRIGHT file in the root directory of the nmh distribution for
#include <h/mh.h>
#include <h/mts.h>
#include <h/utils.h>
+#include <inttypes.h>
/*
Purpose
Usage
=====
- m_getfld_state_t gstate = 0;
- ...
- int state = m_getfld (&gstate, ...);
- ...
+ m_getfld_state_t gstate;
+
+ gstate = m_getfld_state_init(mailfp);
+ Perhaps m_getfld_track_filepos2(&gstate);
+ ...
+ state = m_getfld2(&gstate, ...);
+ ...Repeat until finished with mailfp.
m_getfld_state_destroy (&gstate);
The state is retained internally by gstate. To reset its state to FLD:
To speed things up considerably, the routine Eom() was made an auxiliary
function called by the macro eom(). Unless we are bursting a maildrop,
- the eom() macro returns FALSE saying we aren't at the end of the
+ the eom() macro returns false saying we aren't at the end of the
message.
The next thing to do is to read the mts.conf file and initialize
names are typically short (~8 char) and the loop that extracts them
might terminate on a colon, newline or max width. I considered
using a Vax "scanc" to locate the end of the field followed by a
- "bcopy" but the routine call overhead on a Vax is too large for this
+ "memmove" but the routine call overhead on a Vax is too large for this
to work on short names. If Berkeley ever makes "inline" part of the
C optimiser (so things like "scanc" turn into inline instructions) a
change here would be worthwhile.
so message bodies average at least a few hundred characters.
Assuming your system uses reasonably sized stdio buffers (1K or
more), this routine should be able to remove the body in large
- (>500 byte) chunks. The makes the cost of a call to "bcopy"
+ (>500 byte) chunks. The makes the cost of a call to "memmove"
small but there is a premium on checking for the eom in packed
maildrops. The eom pattern is always a simple string so we can
construct an efficient pattern matcher for it (e.g., a Vax "matchc"
/*
* static prototypes
*/
-struct m_getfld_state;
+static void Ungetc(m_getfld_state_t s);
static int m_Eom (m_getfld_state_t);
-static char *matchc(int, char *, int, char *);
#define eom(c,s) (s->msg_style != MS_DEFAULT && \
((c) == *s->msg_delim && m_Eom(s)))
+/*
+ * Maildrop styles
+ */
+#define MS_DEFAULT 0 /* default (one msg per file) */
+#define MS_UNKNOWN 1 /* type not known yet */
+#define MS_MBOX 2 /* Unix-style "from" lines */
+#define MS_MMDF 3 /* string MMDF_DELIM */
+
/* This replaces the old approach, with its direct access to stdio
* internals. It uses one fread() to load a buffer that we manage.
*
#define MAX_DELIMITER_SIZE 5
struct m_getfld_state {
+ /* The file to read from; I/O block. Caller keeps passing it after
+ * initialisation due to historic interface so it keeps getting
+ * updated, presumably to the same value. */
+ FILE *iob;
+
+ /* Holds content of iob. */
char msg_buf[2 * MSG_INPUT_SIZE + MAX_DELIMITER_SIZE];
+ /* Points to the next byte to read from msg_buf. */
char *readpos;
- char *end; /* One past the last character read in. */
- /* The following support tracking of the read position in the
- input file stream so that callers can interleave m_getfld()
- calls with ftell() and fseek(). bytes_read replaces the old
- m_getfld() msg_count global. last_caller_pos is stored when
- leaving m_getfld()/m_unknown(), then checked on the next entry.
- last_internal_pos is used to remember the position used
- internally by m_getfld() (read_more(), actually). */
+ /* Points to just after the last valid byte in msg_buf. If readpos
+ * equals end then msg_buf is empty. */
+ char *end;
+
+ /* Whether the caller intends to ftell(3)/fseek(3) iob's position,
+ * and thus whether m_getfld() needs to detect that and compensate. */
+ int track_filepos;
+ /* Position in iob given what's been consumed ready for returning to
+ * the caller. Further than this may have been read into msg_buf. */
+ off_t total_bytes_read;
+ /* Bytes of iob consumed during this call. */
off_t bytes_read;
- off_t total_bytes_read; /* by caller, not necessarily from input file */
+ /* What fseeko(3) tells us iob's position is having just explicitly
+ * set it to total_bytes_read. Surely always the same? */
off_t last_caller_pos;
+ /* Saved position in iob from filling msg_buf, prior to returning. */
off_t last_internal_pos;
- FILE *iob;
- char **pat_map;
+ /* One of the MS_* macros tracking the type of iob's content and
+ * thus if it's a single email, or several with delimeters. Default
+ * is MS_DEFAULT. */
int msg_style;
- /*
- * The "full" delimiter string for a packed maildrop consists
- * of a newline followed by the actual delimiter. E.g., the
- * full string for a Unix maildrop would be: "\n\nFrom ".
- * "fdelim" points to the start of the full string and is used
- * in the BODY case of the main routine to search the buffer for
- * a possible eom. Msg_delim points to the first character of
- * the actual delim. string (i.e., fdelim+1). edelim
- * points to the 2nd character of actual delimiter string. It
- * is used in m_Eom because the first character of the string
- * has been read and matched before m_Eom is called.
- */
+
+ /* The message delimeter if iob has multiple emails, else NULL. For
+ * MS_MBOX it's the string that separates two emails, "\nFrom ",
+ * i.e. the terminating blank line of the previous email, and the
+ * starting From_ line of the next, but for MS_MMDF it's
+ * "\001\001\001\001\n" that may start or terminate an email. */
char *msg_delim;
- char *fdelim;
+ /* The last non-NUL char of msg_delim. */
char *delimend;
+ /* When searching for msg_delim after an email, it's only of
+ * interest at the start of the line, i.e. when preceded by a
+ * linefeed. fdelim points to msg_delim[-1] that contains '\n' so
+ * it can be used as the needle. */
+ char *fdelim;
+ /* strlen(fdelim). */
int fdelimlen;
+ /* The second char of msg_delim. Used when the first char has
+ * already been matched to test the rest. */
char *edelim;
+ /* strlen(edelim). */
int edelimlen;
+ /* The relationship between all of these pointers and lengths for
+ * the two possible msg_delim values.
+ *
+ * "\0\n\nFrom \0" 9 "\0\n\001\001\001\001\n\0" 8
+ * | || | | | | |
+ * | || s->delimend | | | s->delimend
+ * | || | | |
+ * | |s->edelim s->edelimlen=5 | | s->edelim s->edelimlen=4
+ * | | | |
+ * | s->msg_delim | s->msg_delim
+ * | |
+ * s->fdelim s->fdelimlen=7 s->fdelim s->fdelimlen=6
+ */
+
+ /* Maps all the bytes of msg_delim, apart from the last two,
+ * including the NUL, onto the last position in msg_delim where they
+ * occur. Bytes not present are NULL. */
+ char **pat_map;
+
+ /* The parser's current state. Also returned to the caller, amongst
+ * other possible values, to indicate the token consumed. One of
+ * FLD, FLDPLUS, BODY, or FILEEOF. */
int state;
- int track_filepos;
};
-static
-void
-m_getfld_state_init (m_getfld_state_t *gstate, FILE *iob) {
+m_getfld_state_t m_getfld_state_init(FILE *iob)
+{
m_getfld_state_t s;
NEW(s);
- *gstate = s;
s->readpos = s->end = s->msg_buf;
s->bytes_read = s->total_bytes_read = 0;
s->last_caller_pos = s->last_internal_pos = 0;
s->fdelimlen = s->edelimlen = 0;
s->state = FLD;
s->track_filepos = 0;
+
+ return s;
}
-/* scan() needs to force a state an initial state of FLD for each message. */
+/* scan() needs to force an initial state of FLD for each message. */
void
m_getfld_state_reset (m_getfld_state_t *gstate) {
if (*gstate) {
void
m_getfld_track_filepos (m_getfld_state_t *gstate, FILE *iob) {
if (! *gstate) {
- m_getfld_state_init (gstate, iob);
+ *gstate = m_getfld_state_init(iob);
}
(*gstate)->track_filepos = 1;
}
+/* m_getfld_track_filepos() with the existing iob. */
+void m_getfld_track_filepos2(m_getfld_state_t *gstate)
+{
+ if (!*gstate)
+ adios(NULL, "m_getfld_track_filepos2 without gstate");
+
+ m_getfld_track_filepos(gstate, (*gstate)->iob);
+}
+
void m_getfld_state_destroy (m_getfld_state_t *gstate) {
m_getfld_state_t s = *gstate;
off_t pos_movement;
if (! *gstate) {
- m_getfld_state_init (gstate, iob);
+ *gstate = m_getfld_state_init(iob);
}
s = *gstate;
s->bytes_read = 0;
if (!s->track_filepos)
return;
- pos = ftello(iob);
+ if ((pos = ftello(iob)) == -1)
+ adios("getfld's iob", "failed to get offset on entry");
if (pos == 0 && s->last_internal_pos == 0)
return;
s->total_bytes_read += pos_movement;
pos = s->last_internal_pos;
} else {
+ off_t off;
size_t num_read;
/* This seek skips past an integral number of
chunks of size MSG_INPUT_SIZE. */
- fseeko (iob, pos/MSG_INPUT_SIZE * MSG_INPUT_SIZE, SEEK_SET);
+ off = pos / MSG_INPUT_SIZE * MSG_INPUT_SIZE;
+ if (fseeko(iob, off, SEEK_SET) == -1)
+ adios("getfld's iob", "failed to set offset to skip: "
+ "%" PRIdMAX, (intmax_t)off);
num_read = fread (s->msg_buf, 1, MSG_INPUT_SIZE, iob);
s->readpos = s->msg_buf + pos % MSG_INPUT_SIZE;
s->end = s->msg_buf + num_read;
}
}
- fseeko (iob, pos, SEEK_SET);
+ if (fseeko(iob, pos, SEEK_SET) == -1)
+ adios("getfld's iob", "failed to set offset on entry: %" PRIdMAX,
+ (intmax_t)pos);
}
static void
if (s->track_filepos) {
/* Save the internal file position that we use for the input buffer. */
- s->last_internal_pos = ftello (s->iob);
+ if ((s->last_internal_pos = ftello(s->iob)) == -1)
+ adios("getfld's iob", "failed to get offset before seek");
/* Set file stream position so that callers can use ftell(). */
- fseeko (s->iob, s->total_bytes_read, SEEK_SET);
- s->last_caller_pos = ftello (s->iob);
+ if (fseeko(s->iob, s->total_bytes_read, SEEK_SET) == -1)
+ adios("getfld's iob", "failed to set offset: %" PRIdMAX,
+ (intmax_t)s->total_bytes_read);
+
+ s->last_caller_pos = s->total_bytes_read;
}
}
static size_t
read_more (m_getfld_state_t s) {
- /* Retain at least edelimlen characters that have already been
- read so that we can back up to them in m_Eom(). */
- ssize_t retain = s->edelimlen;
+ /* Retain at least edelimlen characters that have already been read,
+ if at least edelimlen have been read, so that we can back up to them
+ in m_Eom(). */
+ ssize_t retain = s->end - s->msg_buf < s->edelimlen ? 0 : s->edelimlen;
size_t num_read;
- if (retain < s->end - s->readpos) retain = s->end - s->readpos;
- assert (retain <= s->readpos - s->msg_buf);
+ if (retain > 0) {
+ if (retain < s->end - s->readpos)
+ retain = s->end - s->readpos;
+ assert (retain <= s->readpos - s->msg_buf);
- /* Move what we want to retain at end of the buffer to the beginning. */
- memmove (s->msg_buf, s->readpos - retain, retain);
+ /* Move what we want to retain at end of the buffer to the beginning. */
+ memmove (s->msg_buf, s->readpos - retain, retain);
+ }
s->readpos = s->msg_buf + retain;
num_read = fread (s->readpos, 1, MSG_INPUT_SIZE, s->iob);
return num_read;
}
-/* The return values of the following functions are a bit
- subtle. They can return 0x00 - 0xff as a valid character,
- but EOF is typically 0xffffffff. */
+/* Return the next character consumed from the input, fetching more of
+ * the input for the buffer if required, or EOF on end of file. */
static int
Getc (m_getfld_state_t s) {
if ((s->end - s->readpos < 1 && read_more (s) == 0) ||
return (unsigned char)*s->readpos++;
}
+/* Return the next character that Getc() would return, which may be EOF. */
static int
-Peek (m_getfld_state_t s) {
- if (s->end - s->readpos < 1 && read_more (s) == 0) {
- return EOF;
- } else {
- return s->readpos < s->end ? (unsigned char) *s->readpos : EOF;
- }
+Peek (m_getfld_state_t s)
+{
+ int c;
+
+ c = Getc(s);
+ if (c != EOF)
+ Ungetc(s);
+
+ return c;
}
-static int
-Ungetc (int c, m_getfld_state_t s) {
- if (s->readpos == s->msg_buf) {
- return EOF;
- } else {
- --s->bytes_read;
- return *--s->readpos = (unsigned char) c;
- }
+/* If there's room, undo the consumption of one character from msg_buf,
+ * rewinding so it's read next, else die. */
+static void
+Ungetc(m_getfld_state_t s)
+{
+ if (s->readpos == s->msg_buf)
+ adios(NULL, "Ungetc() at start of message buffer.");
+
+ s->readpos--;
+ s->bytes_read--;
}
FILE *iob)
{
m_getfld_state_t s;
- register char *cp;
- register int max, n, c;
+ char *cp;
+ int max, n, c;
enter_getfld (gstate, iob);
s = *gstate;
;
if (c != EOF)
- Ungetc(c, s);
+ Ungetc(s);
*bufsz = *buf = 0;
leave_getfld (s);
return s->state = FILEEOF;
while ((c = Getc(s)) != EOF && eom (c, s))
;
if (c != EOF)
- Ungetc(c, s);
+ Ungetc(s);
*bufsz = *buf = 0;
leave_getfld (s);
return s->state = FILEEOF;
int next_char;
if (c == EOF || (next_char = Peek (s)) == EOF) {
*bufsz = *cp = *buf = 0;
- advise (NULL, "eof encountered in field \"%s\"", name);
+ inform("eof encountered in field \"%s\"", name);
leave_getfld (s);
return s->state = FMTERR;
}
if (*bufsz < n + 1) {
/* No, it can't. Oh well, guess we'll blow up. */
*bufsz = *cp = *buf = 0;
- advise (NULL, "eol encountered in field \"%s\"", name);
+ inform("eol encountered in field \"%s\"", name);
s->state = FMTERR;
break;
}
memcpy (buf, name, n - 1);
buf[n - 1] = '\n';
buf[n] = '\0';
+ /* Indicate this wasn't a header field using a character
+ that can't appear in a header field. */
+ name[0] = ':';
/* The last character read was '\n'. s->bytes_read
(and n) include that, but it was not put into the
name array in the for loop above. So subtract 1. */
*bufsz = --s->bytes_read; /* == n - 1 */
leave_getfld (s);
return s->state = BODY;
- } else if (max <= n) {
+ }
+ if (max <= n) {
/* By design, the loop above discards the last character
it had read. It's in c, use it. */
*cp++ = c;
*bufsz = *cp = *buf = 0;
- advise (NULL, "field name \"%s\" exceeds %d bytes", name,
+ inform("field name \"%s\" exceeds %d bytes", name,
NAMESZ - 2);
s->state = LENERR;
break;
while (isspace ((unsigned char) *--cp) && cp >= name) continue;
*++cp = 0;
/* readpos points to the first character of the field body. */
- /* fall through */
+ /* FALLTHRU */
case FLDPLUS: {
/*
n = 0;
for (finished = 0; ! finished; ) {
while (c != '\n' && c != EOF && n++ < max) {
- if ((c = Getc (s)) != EOF) { *cp++ = c; }
+ if ((c = Getc (s)) != EOF)
+ *cp++ = c;
}
- if (c != EOF) c = Peek (s);
+ if (c != EOF)
+ c = Peek (s);
if (max < n) {
/* The dest buffer is full. Need to back the read
pointer up by one because when m_getfld() is
*/
char *bp;
+ name[0] = '\0';
max = *bufsz-1;
/* Back up and store the current position. */
bp = --s->readpos;
- c = s->end - s->readpos < max ? s->end - s->readpos : max;
+ c = min(s->end - s->readpos, max);
if (s->msg_style != MS_DEFAULT && c > 1) {
/*
* packed maildrop - only take up to the (possible)
*/
char *ep;
- if ((ep = matchc( s->fdelimlen, s->fdelim, c, bp )))
+ if ((ep = memmem(bp, c, s->fdelim, s->fdelimlen)))
+ /* Plus one to nab the '\n' that starts fdelim as
+ * that ends the previous line; it isn't part of
+ * msg_delim. */
c = ep - bp + 1;
else {
/*
*/
char *sp;
- ep = bp + c - 1;
+ ep = bp + c - 1; /* The last byte. */
if ((sp = s->pat_map[(unsigned char) *ep])) {
do {
/* This if() is true unless (a) the buffer is too
}
+/* m_getfld() with the existing iob. */
+int m_getfld2(m_getfld_state_t *gstate, char name[NAMESZ], char *buf, int *bufsz)
+{
+ if (!*gstate)
+ adios(NULL, "m_getfld2 without gstate");
+
+ return m_getfld(gstate, name, buf, bufsz, (*gstate)->iob);
+}
+
+
void
m_unknown(m_getfld_state_t *gstate, FILE *iob)
{
m_getfld_state_t s;
- register int c;
+ int c;
char text[MAX_DELIMITER_SIZE];
char from[] = "From ";
- register char *cp;
- register char *delimstr;
+ char *cp;
+ char *delimstr;
unsigned int i;
enter_getfld (gstate, iob);
s = *gstate;
/*
- * Figure out what the message delimitter string is for this
+ * Figure out what the message delimiter string is for this
* maildrop. (This used to be part of m_Eom but I didn't like
* the idea of an "if" statement that could only succeed on the
* first call to m_Eom getting executed on each call, i.e., at
if ((c = Getc (s)) == EOF) {
*cp = '\0';
break;
- } else {
- *cp = c;
}
+ *cp = c;
}
if (i == sizeof from-1 && strncmp (text, "From ", sizeof from-1) == 0) {
/* not a Unix style maildrop */
s->readpos -= s->bytes_read;
s->bytes_read = 0;
- delimstr = mmdlm2;
+ delimstr = MMDF_DELIM;
s->msg_style = MS_MMDF;
}
+
+ /* "\nFrom \0" 7 "\001\001\001\001\n\0" 6
+ * | |
+ * delimstr c=6 delimstr c=5
+ */
c = strlen (delimstr);
- s->fdelim = mh_xmalloc (c + 3);
+ s->fdelim = mh_xmalloc (c + 3); /* \0, \n, delimstr, \0 */
*s->fdelim++ = '\0';
*s->fdelim = '\n';
- s->msg_delim = s->fdelim+1;
- s->edelim = s->msg_delim+1;
s->fdelimlen = c + 1;
- s->edelimlen = c - 1; /* == strlen (delimstr) */
+ s->msg_delim = s->fdelim+1;
strcpy (s->msg_delim, delimstr);
+ s->edelim = s->msg_delim+1;
+ s->edelimlen = c - 1;
s->delimend = s->msg_delim + s->edelimlen;
if (s->edelimlen <= 1)
adios (NULL, "maildrop delimiter must be at least 2 bytes");
+
/*
* build a Boyer-Moore end-position map for the matcher in m_getfld.
* N.B. - we don't match just the first char (since it's the newline
while ((c = Getc(s)) != EOF && eom (c, s))
;
if (c != EOF)
- Ungetc(c, s);
+ Ungetc(s);
}
leave_getfld (s);
}
+/* m_unknown() with the existing iob. */
+void m_unknown2(m_getfld_state_t *gstate)
+{
+ if (!*gstate)
+ adios(NULL, "m_unknown2 without gstate");
+
+ m_unknown(gstate, (*gstate)->iob);
+}
+
+
/*
* test for msg delimiter string
*/
static int
m_Eom (m_getfld_state_t s)
{
- register int i;
+ int i;
char text[MAX_DELIMITER_SIZE];
char *cp;
+ int adjust = 1;
for (i = 0, cp = text; i < s->edelimlen; ++i, ++cp) {
int c2;
if ((c2 = Getc (s)) == EOF) {
*cp = '\0';
break;
- } else {
- *cp = c2;
}
+ *cp = c2;
}
if (i != s->edelimlen ||
strncmp (text, (char *)s->edelim, s->edelimlen)) {
- if (i == 0 && s->msg_style == MS_MBOX)
+ if (i == 0 && s->msg_style == MS_MBOX) {
/* the final newline in the (brain damaged) unix-format
- * maildrop is part of the delimitter - delete it.
+ * maildrop is part of the delimiter - delete it.
*/
return 1;
+ }
+
+ if (i <= 2 && s->msg_style == MS_MBOX &&
+ i != s->edelimlen && ! strncmp(text, s->fdelim, i)) {
+ /* If all or part of fdelim appeared at the end of the file,
+ back up even more so that the bytes are included in the
+ message. */
+ adjust = 2;
+ }
/* Did not find delimiter, so restore the read position.
Note that on input, a character had already been read
with Getc(). It will be unget by m_getfld () on return. */
- s->readpos -= s->bytes_read - 1;
- s->bytes_read = 1;
+ s->readpos -= s->bytes_read - adjust;
+ s->bytes_read = adjust;
return 0;
}
return 1;
}
-
-
-static char *
-matchc(int patln, char *pat, int strln, char *str)
-{
- register char *es = str + strln - patln;
- register char *sp;
- register char *pp;
- register char *ep = pat + patln;
- register char pc = *pat++;
-
- for(;;) {
- while (pc != *str++)
- if (str > es)
- return 0;
- if (str > es+1)
- return 0;
- sp = str; pp = pat;
- while (pp < ep && *sp++ == *pp)
- pp++;
- if (pp >= ep)
- return --str;
- }
-}
projects / nmh / blobdiff