new.c: Order two return statements to match comment.

[nmh] / sbr / m_getfld.c

diff --git a/sbr/m_getfld.c b/sbr/m_getfld.c
index cc283c2a9248eb27a17a4f81186101ddd67e92a4..f5fa9a4ebe93abfcb585b6375f0be6d0e7309282 100644 (file)
--- a/sbr/m_getfld.c
+++ b/sbr/m_getfld.c
@@ -8,6 +8,7 @@
 #include <h/mh.h>
 #include <h/mts.h>
 #include <h/utils.h>
 #include <h/mh.h>
 #include <h/mts.h>
 #include <h/utils.h>

+#include <inttypes.h>

 
 /*
    Purpose
 
 /*
    Purpose


@@ -59,10 +60,13 @@
 
    Usage
    =====
 
    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:
    m_getfld_state_destroy (&gstate);
 
    The state is retained internally by gstate.  To reset its state to FLD:


@@ -90,7 +94,7 @@
 
    To speed things up considerably, the routine Eom() was made an auxiliary
    function called by the macro eom().  Unless we are bursting a maildrop,
 
    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
    message.
 
    The next thing to do is to read the mts.conf file and initialize


@@ -200,11 +204,20 @@
 /*
  * static prototypes
  */
 /*
  * static prototypes
  */

+static void Ungetc(m_getfld_state_t s);

 static int m_Eom (m_getfld_state_t);
 
 #define eom(c,s)       (s->msg_style != MS_DEFAULT && \
                         ((c) == *s->msg_delim && m_Eom(s)))
 
 static int m_Eom (m_getfld_state_t);
 
 #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.
  *
 /* This replaces the old approach, with its direct access to stdio
  * internals.  It uses one fread() to load a buffer that we manage.
  *


@@ -219,53 +232,88 @@ static int m_Eom (m_getfld_state_t);
 #define MAX_DELIMITER_SIZE 5
 
 struct m_getfld_state {
 #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];
     char msg_buf[2 * MSG_INPUT_SIZE + MAX_DELIMITER_SIZE];

+    /* Points to the next byte to read from msg_buf. */

     char *readpos;
     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 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;
     off_t last_caller_pos;

+    /* Saved position in iob from filling msg_buf, prior to returning. */

     off_t last_internal_pos;
     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;
     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 *msg_delim;

-    char *fdelim;
+    /* The last non-NUL char of msg_delim. */

     char *delimend;
     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;
     int fdelimlen;

+    /* The second char of msg_delim.  Used when the first char has
+     * already been matched to test the rest. */

     char *edelim;
     char *edelim;

+    /* strlen(edelim). */

     int edelimlen;
     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 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);
     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->readpos = s->end = s->msg_buf;
     s->bytes_read = s->total_bytes_read = 0;
     s->last_caller_pos = s->last_internal_pos = 0;


@@ -277,9 +325,11 @@ m_getfld_state_init (m_getfld_state_t *gstate, FILE *iob) {
     s->fdelimlen = s->edelimlen = 0;
     s->state = FLD;
     s->track_filepos = 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_state_reset (m_getfld_state_t *gstate) {
     if (*gstate) {


@@ -293,12 +343,21 @@ m_getfld_state_reset (m_getfld_state_t *gstate) {
 void
 m_getfld_track_filepos (m_getfld_state_t *gstate, FILE *iob) {
     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;
 }
 
     }
 
     (*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;
 
 void m_getfld_state_destroy (m_getfld_state_t *gstate) {
     m_getfld_state_t s = *gstate;
 


@@ -348,7 +407,7 @@ enter_getfld (m_getfld_state_t *gstate, FILE *iob) {
     off_t pos_movement;
 
     if (! *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;
     }
     s = *gstate;
     s->bytes_read = 0;


@@ -364,7 +423,8 @@ enter_getfld (m_getfld_state_t *gstate, FILE *iob) {
     if (!s->track_filepos)
         return;
 
     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;
 
     if (pos == 0 && s->last_internal_pos == 0)
         return;
 


@@ -393,11 +453,15 @@ enter_getfld (m_getfld_state_t *gstate, FILE *iob) {
             s->total_bytes_read += pos_movement;
             pos = s->last_internal_pos;
         } else {
             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. */
             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;
             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;


@@ -405,7 +469,9 @@ enter_getfld (m_getfld_state_t *gstate, FILE *iob) {
         }
     }
 
         }
     }
 

-    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
 }
 
 static void


@@ -414,27 +480,34 @@ leave_getfld (m_getfld_state_t s) {
 
     if (s->track_filepos) {
        /* Save the internal file position that we use for the input buffer. */
 
     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(). */
 
        /* 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) {
     }
 }
 
 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;
 
     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);
 
     s->readpos = s->msg_buf + retain;
     num_read = fread (s->readpos, 1, MSG_INPUT_SIZE, s->iob);


@@ -443,9 +516,8 @@ read_more (m_getfld_state_t s) {
     return num_read;
 }
 
     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) ||
 static int
 Getc (m_getfld_state_t s) {
     if ((s->end - s->readpos < 1 && read_more (s) == 0) ||


@@ -456,21 +528,29 @@ Getc (m_getfld_state_t s) {
     return (unsigned char)*s->readpos++;
 }
 
     return (unsigned char)*s->readpos++;
 }
 

+/* Return the next character that Getc() would return, which may be EOF. */

 static int
 static int

-Peek (m_getfld_state_t s) {
-    if (s->end - s->readpos < 1  &&  read_more (s) == 0) {
-        return EOF;
-    }
-    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;
-    }
-    --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--;

 }
 
 
 }
 
 


@@ -496,7 +576,7 @@ m_getfld (m_getfld_state_t *gstate, char name[NAMESZ], char *buf, int *bufsz,
            ;
 
        if (c != EOF)
            ;
 
        if (c != EOF)

-           Ungetc(c, s);
+            Ungetc(s);

        *bufsz = *buf = 0;
        leave_getfld (s);
        return s->state = FILEEOF;
        *bufsz = *buf = 0;
        leave_getfld (s);
        return s->state = FILEEOF;


@@ -514,7 +594,7 @@ m_getfld (m_getfld_state_t *gstate, char name[NAMESZ], char *buf, int *bufsz,
                    while ((c = Getc(s)) != EOF && eom (c, s))
                        ;
                    if (c != EOF)
                    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;
                    *bufsz = *buf = 0;
                    leave_getfld (s);
                    return s->state = FILEEOF;


@@ -681,6 +761,9 @@ m_getfld (m_getfld_state_t *gstate, char name[NAMESZ], char *buf, int *bufsz,
                char *ep;
 
                 if ((ep = memmem(bp, c, s->fdelim, s->fdelimlen)))
                char *ep;
 
                 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 {
                    /*
                    c = ep - bp + 1;
                else {
                    /*


@@ -698,7 +781,7 @@ m_getfld (m_getfld_state_t *gstate, char name[NAMESZ], char *buf, int *bufsz,
                     */
                    char *sp;
 
                     */
                    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
                    if ((sp = s->pat_map[(unsigned char) *ep])) {
                        do {
                            /* This if() is true unless (a) the buffer is too


@@ -760,6 +843,16 @@ m_getfld (m_getfld_state_t *gstate, char name[NAMESZ], char *buf, int *bufsz,
 }
 
 
 }
 
 

+/* 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)
 {
 void
 m_unknown(m_getfld_state_t *gstate, FILE *iob)
 {


@@ -810,6 +903,10 @@ m_unknown(m_getfld_state_t *gstate, FILE *iob)
        s->msg_style = MS_MMDF;
     }
 
        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); /* \0, \n, delimstr, \0 */
     *s->fdelim++ = '\0';
     c = strlen (delimstr);
     s->fdelim = mh_xmalloc (c + 3); /* \0, \n, delimstr, \0 */
     *s->fdelim++ = '\0';


@@ -823,24 +920,6 @@ m_unknown(m_getfld_state_t *gstate, FILE *iob)
     if (s->edelimlen <= 1)
        adios (NULL, "maildrop delimiter must be at least 2 bytes");
 
     if (s->edelimlen <= 1)
        adios (NULL, "maildrop delimiter must be at least 2 bytes");
 

-    /* Now malloc'd memory at s->fdelim-1 is referenced several times,
-     * containing a copy of the string constant from delimstr.
-     *
-     *     "\nFrom \0"   7                  "\001\001\001\001\n\0"  6
-     *       |                                  |
-     *       delimstr   c=6                     delimstr   c=5
-     *
-     *     "\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
-     */
-

     /*
      * 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
     /*
      * 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


@@ -857,13 +936,23 @@ m_unknown(m_getfld_state_t *gstate, FILE *iob)
        while ((c = Getc(s)) != EOF && eom (c, s))
            ;
        if (c != EOF)
        while ((c = Getc(s)) != EOF && eom (c, s))
            ;
        if (c != EOF)

-           Ungetc(c, s);
+            Ungetc(s);

     }
 
     leave_getfld (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
  */
 /*
  * test for msg delimiter string
  */


@@ -895,10 +984,11 @@ m_Eom (m_getfld_state_t s)
            return 1;
        }
 
            return 1;
        }
 

-       if (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. */
+       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;
        }
 
            adjust = 2;
        }