Reworked enter_getfld() and Peek().

diff --git a/sbr/m_getfld.c b/sbr/m_getfld.c
index cb1918b1a809db7c705b4504136b95fd600e2e10..7268aff3307d26f10acfa1b3e6caf458996b6c09 100644 (file)
--- a/sbr/m_getfld.c
+++ b/sbr/m_getfld.c
@@ -316,45 +316,54 @@ void m_getfld_state_destroy (m_getfld_state_t *s) {
 
 static void
 enter_getfld (m_getfld_state_t s, FILE *iob) {
-    off_t pos;
+    off_t pos = ftello (iob);
 
     /* Ugly.  The parser opens the input file multiple times, so we
-       have to always use the FILE * that's passed to m_getfld(). */
+       have to always use the FILE * that's passed to m_getfld().
+       Though this might not be necessary any more, as long as the
+       parser inits a new m_getfld_state for each file.  See comment
+       below about the readpos shift code being currently unused. */
     s->iob = iob;
 
-    pos = ftello (iob);
-
-    if (pos != 0) {
-       off_t pos_movement = pos - s->last_caller_pos; /* Can be < 0. */
-
-       if (pos_movement == 0) {
-           pos = s->last_internal_pos;
+    if (pos != 0  ||  s->last_internal_pos != 0) {
+       if (s->last_internal_pos == 0) {
+           s->total_bytes_read = pos;
        } else {
-           /* The current file stream position differs from the last
-              one, so caller must have called ftell/o().  Or, this is
-              the first call and the file position was not at 0. */
-
-           if (s->readpos + pos_movement >= s->msg_buf  &&
-               s->readpos + pos_movement < s->end) {
-               /* We can shift readpos and remain within the bounds of
-                  msg_buf. */
-               s->readpos += pos_movement;
-               s->total_bytes_read += pos_movement;
+           off_t pos_movement = pos - s->last_caller_pos; /* Can be < 0. */
+
+           if (pos_movement == 0) {
                pos = s->last_internal_pos;
            } else {
-               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);
-               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;
-               s->total_bytes_read = pos;
+               /* The current file stream position differs from the
+                  last one, so caller must have called ftell/o().
+                  Or, this is the first call and the file position
+                  was not at 0. */
+
+               if (s->readpos + pos_movement >= s->msg_buf  &&
+                   s->readpos + pos_movement < s->end) {
+                   /* This is currently unused.  It could be used by
+                      parse_mime() if it was changed to use a global
+                      m_getfld_state. */
+                   /* We can shift readpos and remain within the
+                      bounds of msg_buf. */
+                   s->readpos += pos_movement;
+                   s->total_bytes_read += pos_movement;
+                   pos = s->last_internal_pos;
+               } else {
+                   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);
+                   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;
+                   s->total_bytes_read = pos;
+               }
            }
-       }
 
-       if (s->last_internal_pos != 0) fseeko (iob, pos, SEEK_SET);
+           fseeko (iob, pos, SEEK_SET);
+       }
     }
 
     s->bytes_read = 0;
@@ -407,11 +416,15 @@ Getc (m_getfld_state_t s) {
 
 static int
 Peek (m_getfld_state_t s) {
-    int next_char = Getc (s);
-    --s->readpos;
-    --s->bytes_read;
+    if (s->end - s->readpos < 1) {
+       if (read_more (s) == 0) {
+           /* Pretend that we read a character.  That's what stdio does. */
+           ++s->readpos;
+           return EOF;
+       }
+    }
 
-    return next_char;
+    return s->readpos < s->end  ?  *s->readpos  :  EOF;
 }
 
 static int
@@ -598,7 +611,7 @@ m_getfld (m_getfld_state_t s, unsigned char name[NAMESZ], unsigned char *buf,
            unsigned char *bp;
 
            max = *bufsz-1;
-           /* Back up and store the current position and update cnt. */
+           /* Back up and store the current position. */
            bp = --s->readpos;
            c = s->end - s->readpos < max  ?  s->end - s->readpos  :  max;
            if (s->msg_style != MS_DEFAULT && c > 1) {