diff options
Diffstat (limited to 'stdio/linewrap.c')
| -rw-r--r-- | stdio/linewrap.c | 183 |
1 files changed, 127 insertions, 56 deletions
diff --git a/stdio/linewrap.c b/stdio/linewrap.c index e821cc3..7f6576f 100644 --- a/stdio/linewrap.c +++ b/stdio/linewrap.c @@ -22,42 +22,27 @@ Cambridge, MA 02139, USA. */ #include <string.h> #include <stdlib.h> -/* We keep this data for each line-wrapping stream. */ - -struct data - { - const size_t *lmargin, *rmargin; /* Left and right margins. */ - const size_t *wrapmargin; /* Margin to wrap to, or null to truncate. */ - size_t point; /* Current column of last chars flushed. */ - - /* Original cookie and hooks from the stream. */ - void *cookie; - void (*output) (FILE *, int); - __io_close_fn *close; - __io_fileno_fn *fileno; - __io_seek_fn *seek; - }; +#include <linewrap.h> + +void __line_wrap_output (FILE *, int); /* Install our hooks into a stream. */ - static inline void -wrap_stream (FILE *stream, struct data *d) +wrap_stream (FILE *stream, struct line_wrap_data *d) { - static void lwoutput (FILE *, int); static __io_close_fn lwclose; static __io_fileno_fn lwfileno; stream->__cookie = d; - stream->__room_funcs.__output = &lwoutput; + stream->__room_funcs.__output = &__line_wrap_output; stream->__io_funcs.__close = &lwclose; stream->__io_funcs.__fileno = &lwfileno; stream->__io_funcs.__seek = NULL; /* Cannot seek. */ } /* Restore a stream to its original state. */ - static inline void -unwrap_stream (FILE *stream, struct data *d) +unwrap_stream (FILE *stream, struct line_wrap_data *d) { stream->__cookie = d->cookie; stream->__room_funcs.__output = d->output; @@ -72,41 +57,40 @@ unwrap_stream (FILE *stream, struct data *d) static int lwclose (void *cookie) { - struct data *d = cookie; + struct line_wrap_data *d = cookie; return (*d->close) (d->cookie); } static int lwfileno (void *cookie) { - struct data *d = cookie; + struct line_wrap_data *d = cookie; return (*d->fileno) (d->cookie); } /* This function is called when STREAM must be flushed. C is EOF or a character to be appended to the buffer contents. */ - -static void -lwoutput (FILE *stream, int c) +void +__line_wrap_output (FILE *stream, int c) { char *buf, *nl; size_t len; /* Extract our data and restore the stream's original cookie and output function so writes we do really go out. */ - struct data *d = stream->__cookie; + struct line_wrap_data *d = stream->__cookie; unwrap_stream (stream, d); /* Scan the buffer for newlines. */ - for (buf = stream->__buffer; - (buf < stream->__bufp || (c != EOF && c != '\n')) && !stream->__error) + buf = stream->__buffer; + while ((buf < stream->__bufp || (c != EOF && c != '\n')) && !stream->__error) { size_t r; - if (d->point == 0 && d->lmargin && *d->lmargin != 0) + if (d->point == 0 && d->lmargin != 0) { /* We are starting a new line. Print spaces to the left margin. */ - const size_t pad = *d->lmargin; + const size_t pad = d->lmargin; if (stream->__bufp + pad < stream->__put_limit) { /* We can fit in them in the buffer by moving the @@ -141,8 +125,7 @@ lwoutput (FILE *stream, int c) { /* The buffer ends in a partial line. */ - if (!d->rmargin || - d->point + len + (c != EOF && c != '\n') <= d->rmargin) + if (d->point + len + (c != EOF && c != '\n') <= d->rmargin) { /* The remaining buffer text is a partial line and fits within the maximum line width. Advance point for the @@ -155,7 +138,7 @@ lwoutput (FILE *stream, int c) the end of the buffer. */ nl = stream->__bufp; } - else if (!d->rmargin || d->point + (nl - buf) <= d->rmargin) + else if (d->point + (nl - buf) <= d->rmargin) { /* The buffer contains a full line that fits within the maximum line width. Reset point and scan the next line. */ @@ -165,9 +148,9 @@ lwoutput (FILE *stream, int c) } /* This line is too long. */ - r = *d->rmargin; + r = d->rmargin; - if (! d->wrapmargin) + if (d->wmargin < 0) { /* Truncate the line by overwriting the excess with the newline and anything after it in the buffer. */ @@ -242,7 +225,7 @@ lwoutput (FILE *stream, int c) /* Temporarily reset bufp to include just the first line. */ stream->__bufp = nl; - if (nextline - (nl + 1) < d->wrap) + if (nextline - (nl + 1) < d->wmargin) /* The margin needs more blanks than we removed. Output the first line so we can use the space. */ (*d->output) (stream, '\n'); @@ -255,7 +238,7 @@ lwoutput (FILE *stream, int c) d->point = 0; /* Add blanks up to the wrap margin column. */ - for (i = 0; i < d->wrap; ++i) + for (i = 0; i < d->wmargin; ++i) *stream->__bufp++ = ' '; /* Copy the tail of the original buffer into the current buffer @@ -284,19 +267,16 @@ lwoutput (FILE *stream, int c) wrap_stream (stream, d); } -/* Modify STREAM so that it prefixes lines written on it with *LMARGIN - spaces and limits them to *RMARGIN columns total. If WRAP is not null, - words that extend past *RMARGIN are wrapped by replacing the whitespace - before them with a newline and *WRAP spaces. Otherwise, chars beyond - *RMARGIN are simply dropped until a newline. Returns STREAM after - modifying it, or NULL if there was an error. The pointers passed are - stored in the stream and so must remain valid until `line_unwrap_stream' - is called; the values pointed to can be changed between stdio calls. */ - +/* Modify STREAM so that it prefixes lines written on it with LMARGIN spaces + and limits them to RMARGIN columns total. If WMARGIN >= 0, words that + extend past RMARGIN are wrapped by replacing the whitespace before them + with a newline and WMARGIN spaces. Otherwise, chars beyond RMARGIN are + simply dropped until a newline. Returns STREAM after modifying it, or + NULL if there was an error. */ FILE * -line_wrap_stream (FILE *stream, size_t *lmargin, size_t *rmargin, size_t *wrap) +line_wrap_stream (FILE *stream, size_t lmargin, size_t rmargin, size_t wmargin) { - struct data *d = malloc (sizeof *d); + struct line_wrap_data *d = malloc (sizeof *d); if (!d) return NULL; @@ -321,25 +301,116 @@ line_wrap_stream (FILE *stream, size_t *lmargin, size_t *rmargin, size_t *wrap) to work if the stream is switched to full or no buffering. */ stream->__linebuf = 1; -#define ref(arg) d->arg = arg - ref (lmargin); - ref (rmargin); - ref (wrap); -#undef ref + d->lmargin = lmargin; + d->rmargin = rmargin; + d->wmargin = wmargin; return stream; } /* Remove the hooks placed in STREAM by `line_wrap_stream'. */ - void line_unwrap_stream (FILE *stream) { - struct data *d = stream->__cookie; + struct line_wrap_data *d = stream->__cookie; unwrap_stream (stream, d); free (d); } +/* Functions on wrapped streams. */ + +/* Returns true if STREAM is line wrapped. */ +inline int +line_wrapped (FILE *stream) +{ + return (stream->__room_funcs.__output == &__line_wrap_output); +} + +/* If STREAM is not line-wrapped return -1, else return its left margin. */ +size_t +line_wrap_lmargin (FILE *stream) +{ + if (! line_wrapped (stream)) + return -1; + return ((struct line_wrap_data *)stream->__cookie)->lmargin; +} + +/* If STREAM is not line-wrapped return -1, else set its left margin to + LMARGIN and return the old value. */ +size_t +line_wrap_set_lmargin (FILE *stream, size_t lmargin) +{ + if (! line_wrapped (stream)) + return -1; + else + { + struct line_wrap_data *d = stream->__cookie; + size_t old = d->lmargin; + d->lmargin = lmargin; + return old; + } +} + +/* If STREAM is not line-wrapped return -1, else return its left margin. */ +size_t +line_wrap_rmargin (FILE *stream) +{ + if (! line_wrapped (stream)) + return -1; + return ((struct line_wrap_data *)stream->__cookie)->rmargin; +} + +/* If STREAM is not line-wrapped return -1, else set its right margin to + RMARGIN and return the old value. */ +size_t +line_wrap_set_rmargin (FILE *stream, size_t rmargin) +{ + if (! line_wrapped (stream)) + return -1; + else + { + struct line_wrap_data *d = stream->__cookie; + size_t old = d->rmargin; + d->rmargin = rmargin; + return old; + } +} + +/* If STREAM is not line-wrapped return -1, else return its wrap margin. */ +size_t +line_wrap_wmargin (FILE *stream) +{ + if (! line_wrapped (stream)) + return -1; + return ((struct line_wrap_data *)stream->__cookie)->wmargin; +} + +/* If STREAM is not line-wrapped return -1, else set its left margin to + WMARGIN and return the old value. */ +size_t +line_wrap_set_wmargin (FILE *stream, size_t wmargin) +{ + if (! line_wrapped (stream)) + return -1; + else + { + struct line_wrap_data *d = stream->__cookie; + size_t old = d->wmargin; + d->wmargin = wmargin; + return old; + } +} + +/* If STREAM is not line-wrapped return -1, else return the column number of + the current output point. */ +size_t +line_wrap_point (FILE *stream) +{ + if (! line_wrapped (stream)) + return -1; + return ((struct line_wrap_data *)stream->__cookie)->point; +} + #ifdef TEST int main (int argc, char **argv) |