From: David Levine Date: Tue, 25 Dec 2012 17:57:31 +0000 (-0600) Subject: Replaced all the stdio buffer access in m_getfld.c with a single call X-Git-Url: https://diplodocus.org/git/nmh/commitdiff_plain/9db3474c4cfc16b01d132e03ddf2c91b8db8b594?ds=inline;hp=d3d007e835e9eb1a0e797bd3a58d5295a079c40b Replaced all the stdio buffer access in m_getfld.c with a single call to fread() and then some almost straightforward buffer manipulations. --- diff --git a/sbr/m_getfld.c b/sbr/m_getfld.c index 0eed0a55..b02acd58 100644 --- a/sbr/m_getfld.c +++ b/sbr/m_getfld.c @@ -125,7 +125,7 @@ it knows that _filbuf ignores the _ptr & _cnt and simply fills the buffer. If stdio on your system doesn't work this way, you may have to make small changes in this routine. - + This routine also "knows" that an EOF indication on a stream is "sticky" (i.e., you will keep getting EOF until you reposition the stream). If your system doesn't work this way it is broken and you @@ -178,16 +178,18 @@ char * msg_delim int msg_style int (*eom_action)(int) -Restriction -=========== +Restrictions +============ m_getfld() is restricted to operate on one file stream at a time because of -the retained state (see "State variables" above). +the retained state (see "State variables" above). Also, if m_getfld() is +used to read a file stream, then only m_getfld() should be used to read that +file stream. Current usage ============= The first call to m_getfld() on a file stream is with a state of FLD. Subsequent calls provide the state returned by the previous call. -(Therefore, given the Restriction above, the state variable could be +(Therefore, given the Restrictions above, the state variable could be removed from the signature and just retained internally.) */ @@ -198,7 +200,6 @@ static int m_Eom (int, FILE *); static unsigned char *matchc(int, char *, int, char *); static unsigned char *locc(int, unsigned char *, unsigned char); -#define Getc(iob) getc(iob) #define eom(c,iob) (msg_style != MS_DEFAULT && \ (((c) == *msg_delim && m_Eom(c,iob)) ||\ (eom_action && (*eom_action)(c)))) @@ -228,21 +229,66 @@ static int edelimlen; static int (*eom_action)(int) = NULL; -#ifdef _FSTDIO -# define _ptr _p /* Gag */ -# define _cnt _r /* Retch */ -# define _filbuf __srget /* Puke */ -# define DEFINED__FILBUF_TO_SOMETHING_SPECIFIC +/* This replaces the old approach, which included direct access to + stdio internals. It uses one fread() to load a buffer that we + manage. */ +#define MSG_INPUT_SIZE 8192 +static struct m_getfld_buffer { + unsigned char msg_buf[2 * MSG_INPUT_SIZE]; + unsigned char *readpos; + unsigned char *end; /* One past, like C++, the last character read in. */ +} m; + +static void +setup_buffer (FILE *iob, struct m_getfld_buffer *m) { + /* Rely on Restrictions that m_getfld() calls on different file + streams are not interleaved, and no other file stream read + methods are used. And, the first call to m_getfld (), etc., on + a stream always reads at least 1 byte. + I don't think it's necessary to use ftello() because we just + need to determine whether the current offset is 0 or not. */ + if (ftell (iob) == 0) { + /* A new file stream, so reset the buffer state. */ + m->readpos = m->end = m->msg_buf; + } +} -# if defined __CYGWIN__ - /* Cygwin's stdio.h does not declare __srget(). */ - int __srget(FILE *); -# endif /* __CYGWIN__ */ -#endif +static size_t +read_more (struct m_getfld_buffer *m, FILE *iob) { + size_t num_read; + + /* Move any leftover at the end of buf to the beginning. */ + if (m->end > m->readpos) { + memmove (m->msg_buf, m->readpos, m->end - m->readpos); + } + + m->readpos = m->msg_buf + (m->end - m->readpos); + num_read = fread (m->readpos, 1, MSG_INPUT_SIZE, iob); + + m->end = m->readpos + num_read; + + return num_read; +} + +static int +Getc (FILE *iob) { + if (m.end - m.readpos < 1) { + if (read_more (&m, iob) == 0) { + /* Pretend that we read a character. That's what stdio does. */ + ++m.readpos; + return EOF; + } + } + + return m.readpos < m.end ? *m.readpos++ : EOF; +} + +static int +Ungetc (int c, FILE *iob) { + NMH_UNUSED (iob); -#ifndef DEFINED__FILBUF_TO_SOMETHING_SPECIFIC -extern int _filbuf(FILE*); -#endif + return m.readpos == m.msg_buf ? EOF : (*--m.readpos = c); +} int @@ -250,7 +296,9 @@ m_getfld (int state, unsigned char name[NAMESZ], unsigned char *buf, int *bufsz, FILE *iob) { register unsigned char *bp, *cp, *ep, *sp; - register int cnt, c, i, j; + register int cnt, c, i, j, k; + + setup_buffer (iob, &m); if ((c = Getc(iob)) < 0) { *bufsz = 0; @@ -262,8 +310,9 @@ m_getfld (int state, unsigned char name[NAMESZ], unsigned char *buf, /* flush null messages */ while ((c = Getc(iob)) >= 0 && eom (c, iob)) ; + if (c >= 0) - ungetc(c, iob); + Ungetc(c, iob); } *bufsz = 0; *buf = 0; @@ -271,9 +320,9 @@ m_getfld (int state, unsigned char name[NAMESZ], unsigned char *buf, } switch (state) { - case FLDEOF: - case BODYEOF: - case FLD: + case FLDEOF: + case BODYEOF: + case FLD: if (c == '\n' || c == '-') { /* we hit the header/body separator */ while (c != '\n' && (c = Getc(iob)) >= 0) @@ -285,7 +334,7 @@ m_getfld (int state, unsigned char name[NAMESZ], unsigned char *buf, while ((c = Getc(iob)) >= 0 && eom (c, iob)) ; if (c >= 0) - ungetc(c, iob); + Ungetc(c, iob); } *bufsz = 0; *buf = 0; @@ -297,52 +346,29 @@ m_getfld (int state, unsigned char name[NAMESZ], unsigned char *buf, /* * get the name of this component. take characters up * to a ':', a newline or NAMESZ-1 characters, whichever - * comes first. + * comes first. */ cp = name; i = NAMESZ - 1; for (;;) { -#ifdef LINUX_STDIO - bp = sp = (unsigned char *) iob->_IO_read_ptr - 1; - j = (cnt = ((long) iob->_IO_read_end - - (long) iob->_IO_read_ptr) + 1) < i ? cnt : i; -#elif defined(__DragonFly__) - bp = sp = (unsigned char *) ((struct __FILE_public *)iob)->_p - 1; - j = (cnt = ((struct __FILE_public *)iob)->_r+1) < i ? cnt : i; -#else - bp = sp = (unsigned char *) iob->_ptr - 1; - j = (cnt = iob->_cnt+1) < i ? cnt : i; -#endif + /* Store current position, ungetting the last character. */ + bp = sp = (unsigned char *) m.readpos - 1; + j = (cnt = m.end - m.readpos + 1) < i ? cnt : i; while (--j >= 0 && (c = *bp++) != ':' && c != '\n') *cp++ = c; j = bp - sp; if ((cnt -= j) <= 0) { -#ifdef LINUX_STDIO - iob->_IO_read_ptr = iob->_IO_read_end; - if (__underflow(iob) == EOF) { -#elif defined(__DragonFly__) - if (__srget(iob) == EOF) { -#else - if (_filbuf(iob) == EOF) { -#endif + /* Used to explicitly force refill of the buffer + here, but Getc() will do that if necessary. */ + if (Getc (iob) == EOF) { *cp = *buf = 0; advise (NULL, "eof encountered in field \"%s\"", name); return FMTERR; } -#ifdef LINUX_STDIO - iob->_IO_read_ptr++; /* NOT automatic in __underflow()! */ -#endif } else { -#ifdef LINUX_STDIO - iob->_IO_read_ptr = bp + 1; -#elif defined(__DragonFly__) - ((struct __FILE_public *)iob)->_p = bp + 1; - ((struct __FILE_public *)iob)->_r = cnt - 1; -#else - iob->_ptr = bp + 1; - iob->_cnt = cnt - 1; -#endif + /* Restore the current offset. */ + m.readpos = bp + 1; } if (c == ':') break; @@ -381,7 +407,12 @@ m_getfld (int state, unsigned char name[NAMESZ], unsigned char *buf, * blank line in this case. Simpler parsers (e.g. mhl) * get extra newlines, but that should be harmless enough, * right? This is a corrupt message anyway. */ - fseek (iob, ftell (iob) - 2, SEEK_SET); + /* emulates: fseek (iob, ftell (iob) -(-2 + cnt + 1), + SEEK_SET) */ + m.readpos += cnt - 1; + /* Reset file stream position so caller, e.g., + get_content, can use ftell(), etc. */ + fseek (iob, -cnt - 1, SEEK_CUR); return BODY; } if ((i -= j) <= 0) { @@ -397,7 +428,7 @@ m_getfld (int state, unsigned char name[NAMESZ], unsigned char *buf, *++cp = 0; /* fall through */ - case FLDPLUS: + case FLDPLUS: /* * get (more of) the text of a field. take * characters up to the end of this field (newline @@ -405,37 +436,19 @@ m_getfld (int state, unsigned char name[NAMESZ], unsigned char *buf, */ cp = buf; i = *bufsz-1; for (;;) { -#ifdef LINUX_STDIO - cnt = (long) iob->_IO_read_end - (long) iob->_IO_read_ptr; - bp = (unsigned char *) --iob->_IO_read_ptr; -#elif defined(__DragonFly__) - cnt = ((struct __FILE_public *)iob)->_r++; - bp = (unsigned char *) --((struct __FILE_public *)iob)->_p; -#else - cnt = iob->_cnt++; - bp = (unsigned char *) --iob->_ptr; -#endif + /* Set, and save, the current position, and update cnt. */ + cnt = m.end - m.readpos; + bp = --m.readpos; c = cnt < i ? cnt : i; while ((ep = locc( c, bp, '\n' ))) { /* * if we hit the end of this field, return. */ if ((j = *++ep) != ' ' && j != '\t') { -#ifdef LINUX_STDIO - j = ep - (unsigned char *) iob->_IO_read_ptr; - memcpy (cp, iob->_IO_read_ptr, j); - iob->_IO_read_ptr = ep; -#elif defined(__DragonFly__) - j = ep - (unsigned char *) ((struct __FILE_public *)iob)->_p; - memcpy (cp, ((struct __FILE_public *)iob)->_p, j); - ((struct __FILE_public *)iob)->_p = ep; - ((struct __FILE_public *)iob)->_r -= j; -#else - j = ep - (unsigned char *) iob->_ptr; - memcpy (cp, iob->_ptr, j); - iob->_ptr = ep; - iob->_cnt -= j; -#endif + /* Save the text and update the current position. */ + j = ep - m.readpos; + memcpy (cp, m.readpos, j); + m.readpos = ep; cp += j; state = FLD; goto finish; @@ -446,63 +459,30 @@ m_getfld (int state, unsigned char name[NAMESZ], unsigned char *buf, /* * end of input or dest buffer - copy what we've found. */ -#ifdef LINUX_STDIO - c += bp - (unsigned char *) iob->_IO_read_ptr; - memcpy( cp, iob->_IO_read_ptr, c); -#elif defined(__DragonFly__) - c += bp - (unsigned char *) ((struct __FILE_public *)iob)->_p; - memcpy( cp, ((struct __FILE_public *)iob)->_p, c); -#else - c += bp - (unsigned char *) iob->_ptr; - memcpy( cp, iob->_ptr, c); -#endif - i -= c; - cp += c; + c += bp - m.readpos; + for (k = 0; k < c; ++k, --i) { + *cp++ = Getc (iob); + } if (i <= 0) { /* the dest buffer is full */ -#ifdef LINUX_STDIO - iob->_IO_read_ptr += c; -#elif defined(__DragonFly__) - ((struct __FILE_public *)iob)->_r -= c; - ((struct __FILE_public *)iob)->_p += c; -#else - iob->_cnt -= c; - iob->_ptr += c; -#endif state = FLDPLUS; break; } - /* + /* * There's one character left in the input buffer. - * Copy it & fill the buffer. If the last char + * Copy it & fill the buffer (that fill used to be + * explicit, but now Getc() does it). If the last char * was a newline and the next char is not whitespace, * this is the end of the field. Otherwise loop. */ --i; -#ifdef LINUX_STDIO - *cp++ = j = *(iob->_IO_read_ptr + c); - iob->_IO_read_ptr = iob->_IO_read_end; - c = __underflow(iob); - iob->_IO_read_ptr++; /* NOT automatic! */ -#elif defined(__DragonFly__) - *cp++ =j = *(((struct __FILE_public *)iob)->_p + c); - c = __srget(iob); -#else - *cp++ = j = *(iob->_ptr + c); - c = _filbuf(iob); -#endif - if (c == EOF || + *cp++ = j = Getc (iob); + c = Getc (iob); + if (c == EOF || ((j == '\0' || j == '\n') && c != ' ' && c != '\t')) { if (c != EOF) { -#ifdef LINUX_STDIO - --iob->_IO_read_ptr; -#elif defined(__DragonFly__) - --((struct __FILE_public *)iob)->_p; - ++((struct __FILE_public *)iob)->_r; -#else - --iob->_ptr; - ++iob->_cnt; -#endif + /* Put the character back for the next call. */ + --m.readpos; } state = FLD; break; @@ -510,7 +490,7 @@ m_getfld (int state, unsigned char name[NAMESZ], unsigned char *buf, } break; - case BODY: + case BODY: body: /* * get the message body up to bufsz characters or the @@ -519,17 +499,10 @@ m_getfld (int state, unsigned char name[NAMESZ], unsigned char *buf, * the output buffer and we don't add an eos. */ i = (*bufsz < 0) ? -*bufsz : *bufsz-1; -#ifdef LINUX_STDIO - bp = (unsigned char *) --iob->_IO_read_ptr; - cnt = (long) iob->_IO_read_end - (long) iob->_IO_read_ptr; -#elif defined(__DragonFly__) - bp = (unsigned char *) --((struct __FILE_public *)iob)->_p; - cnt = ++((struct __FILE_public *)iob)->_r; -#else - bp = (unsigned char *) --iob->_ptr; - cnt = ++iob->_cnt; -#endif - c = (cnt < i ? cnt : i); + /* Back up and store the current position and update cnt. */ + bp = --m.readpos; + cnt = m.end - m.readpos; + c = cnt < i ? cnt : i; if (msg_style != MS_DEFAULT && c > 1) { /* * packed maildrop - only take up to the (possible) @@ -598,15 +571,8 @@ m_getfld (int state, unsigned char name[NAMESZ], unsigned char *buf, } } memcpy( buf, bp, c ); -#ifdef LINUX_STDIO - iob->_IO_read_ptr += c; -#elif defined(__DragonFly__) - ((struct __FILE_public *)iob)->_r -= c; - ((struct __FILE_public *)iob)->_p += c; -#else - iob->_cnt -= c; - iob->_ptr += c; -#endif + /* Advance the current position to reflect the copy out. */ + m.readpos += c; if (*bufsz < 0) { *bufsz = c; return (state); @@ -614,7 +580,7 @@ m_getfld (int state, unsigned char name[NAMESZ], unsigned char *buf, cp = buf + c; break; - default: + default: adios (NULL, "m_getfld() called with bogus state of %d", state); } finish: @@ -628,11 +594,13 @@ void m_unknown(FILE *iob) { register int c; - register long pos; + unsigned char *pos; char text[10]; register char *cp; register char *delimstr; + setup_buffer (iob, &m); + /* * Figure out what the message delimitter string is for this * maildrop. (This used to be part of m_Eom but I didn't like @@ -648,16 +616,21 @@ m_unknown(FILE *iob) msg_style = MS_UNKNOWN; - pos = ftell (iob); - if (fread (text, sizeof(*text), 5, iob) == 5 - && strncmp (text, "From ", 5) == 0) { + pos = m.readpos; /* ftell */ + for (c = 0, cp = text; c < 5; ++c, ++cp) { + if ((*cp = Getc (iob)) == EOF) { + break; + } + } + + if (c == 5 && strncmp (text, "From ", 5) == 0) { msg_style = MS_MBOX; delimstr = "\nFrom "; - while ((c = getc (iob)) != '\n' && c >= 0) + while ((c = Getc (iob)) != '\n' && c >= 0) ; } else { /* not a Unix style maildrop */ - fseek (iob, pos, SEEK_SET); + m.readpos = pos; /* fseek (iob, pos, SEEK_SET) */ if (mmdlm2 == NULL || *mmdlm2 == 0) mmdlm2 = "\001\001\001\001\n"; delimstr = mmdlm2; @@ -691,7 +664,7 @@ m_unknown(FILE *iob) while ((c = Getc(iob)) >= 0 && eom (c, iob)) ; if (c >= 0) - ungetc(c, iob); + Ungetc(c, iob); } } @@ -720,30 +693,31 @@ m_eomsbr (int (*action)(int)) static int m_Eom (int c, FILE *iob) { - register long pos = 0L; + unsigned char *pos; register int i; char text[10]; + char *cp; + + pos = m.readpos; /* ftell */ + for (i = 0, cp = text; i < edelimlen; ++i, ++cp) { + if ((*cp = Getc (iob)) == EOF) { + break; + } + } - pos = ftell (iob); - if ((i = fread (text, sizeof *text, edelimlen, iob)) != edelimlen - || strncmp (text, (char *)edelim, edelimlen)) { + if (i != edelimlen || strncmp (text, (char *)edelim, edelimlen)) { if (i == 0 && msg_style == MS_MBOX) /* the final newline in the (brain damaged) unix-format * maildrop is part of the delimitter - delete it. */ return 1; - -#if 0 - fseek (iob, pos, SEEK_SET); -#endif - - fseek (iob, (long)(pos-1), SEEK_SET); - getc (iob); /* should be OK */ + m.readpos = pos - 1; /* fseek (iob, pos - 1, SEEK_SET) */ + Getc (iob); /* should be OK */ return 0; } if (msg_style == MS_MBOX) { - while ((c = getc (iob)) != '\n') + while ((c = Getc (iob)) != '\n') if (c < 0) break; } @@ -770,7 +744,7 @@ matchc(int patln, char *pat, int strln, char *str) sp = str; pp = pat; while (pp < ep && *sp++ == *pp) pp++; - if (pp >= ep) + if (pp >= ep) return ((unsigned char *)--str); } } @@ -788,4 +762,3 @@ locc(int cnt, unsigned char *src, unsigned char term) return (cnt > 0 ? --src : (unsigned char *)0); } -