mirror of https://github.com/GnoConsortium/gno.git
541 lines
11 KiB
C
541 lines
11 KiB
C
/*
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* Routines to manipulate the "line buffer".
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* The line buffer holds a line of output as it is being built
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* in preparation for output to the screen.
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*/
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#pragma noroot
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#include "less.h"
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#ifdef _ORCAC_
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segment "LoadSegONE";
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#endif
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static char linebuf[1024]; /* Buffer which holds the current output line */
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static char attr[1024]; /* Extension of linebuf to hold attributes */
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static int curr; /* Index into linebuf */
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static int column; /* Printable length, accounting for
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backspaces, etc. */
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static int overstrike; /* Next char should overstrike previous char */
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static int is_null_line; /* There is no current line */
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static char pendc;
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extern int bs_mode;
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extern int tabstop;
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extern int linenums;
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extern int ctldisp;
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extern int twiddle;
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extern int binattr;
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extern int auto_wrap, ignaw;
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extern int bo_s_width, bo_e_width;
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extern int ul_s_width, ul_e_width;
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extern int bl_s_width, bl_e_width;
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extern int sc_width, sc_height;
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static int pwidth(int c, int a);
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static void backc(void);
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static int storec(int c, int a);
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static int do_append(int c);
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/*
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* Rewind the line buffer.
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*/
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public void
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prewind(void)
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{
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curr = 0;
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column = 0;
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overstrike = 0;
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is_null_line = 0;
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pendc = '\0';
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}
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/*
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* Insert the line number (of the given position) into the line buffer.
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*/
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public void
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plinenum(pos)
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POSITION pos;
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{
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register int lno;
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register int i;
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register int n;
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/*
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* We display the line number at the start of each line
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* only if the -N option is set.
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*/
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if (linenums != 2)
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return;
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/*
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* Get the line number and put it in the current line.
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* {{ Note: since find_linenum calls forw_raw_line,
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* it may seek in the input file, requiring the caller
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* of plinenum to re-seek if necessary. }}
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*/
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lno = find_linenum(pos);
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sprintf(&linebuf[curr], "%6d", lno);
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n = strlen(&linebuf[curr]);
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column += n;
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for (i = 0; i < n; i++)
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attr[curr++] = 0;
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/*
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* Append enough spaces to bring us to the next tab stop.
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* {{ We could avoid this at the cost of adding some
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* complication to the tab stop logic in pappend(). }}
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*/
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do
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{
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linebuf[curr] = ' ';
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attr[curr++] = 0;
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column++;
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} while ((column % tabstop) != 0);
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}
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/*
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* Return the printing width of the start (enter) sequence
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* for a given character attribute.
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*/
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int
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attr_swidth(a)
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int a;
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{
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switch (a)
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{
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case BOLD: return (bo_s_width);
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case UNDERLINE: return (ul_s_width);
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case BLINK: return (bl_s_width);
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}
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return (0);
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}
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/*
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* Return the printing width of the end (exit) sequence
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* for a given character attribute.
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*/
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int
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attr_ewidth(a)
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int a;
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{
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switch (a)
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{
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case BOLD: return (bo_e_width);
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case UNDERLINE: return (ul_e_width);
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case BLINK: return (bl_e_width);
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}
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return (0);
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}
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/*
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* Return the printing width of a given character and attribute,
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* if the character were added to the current position in the line buffer.
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* Adding a character with a given attribute may cause an enter or exit
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* attribute sequence to be inserted, so this must be taken into account.
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*/
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static int
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pwidth(c, a)
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int c;
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int a;
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{
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register int w;
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if (c == '\b')
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/*
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* Backspace moves backwards one position.
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*/
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return (-1);
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if (control_char(c))
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/*
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* Control characters do unpredicatable things,
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* so we don't even try to guess; say it doesn't move.
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* This can only happen if the -r flag is in effect.
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*/
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return (0);
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/*
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* Other characters take one space,
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* plus the width of any attribute enter/exit sequence.
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*/
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w = 1;
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if (curr > 0 && attr[curr-1] != a)
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w += attr_ewidth(attr[curr-1]);
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if (a && (curr == 0 || attr[curr-1] != a))
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w += attr_swidth(a);
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return (w);
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}
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/*
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* Delete the previous character in the line buffer.
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*/
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static void
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backc(void)
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{
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curr--;
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column -= pwidth(linebuf[curr], attr[curr]);
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}
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/*
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* Append a character and attribute to the line buffer.
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*/
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static int
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storec(c, a)
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int c;
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int a;
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{
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register int w;
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w = pwidth(c, a);
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if (ctldisp > 0 && column + w + attr_ewidth(a) > sc_width)
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/*
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* Won't fit on screen.
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*/
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return (1);
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if (curr >= sizeof(linebuf)-2)
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/*
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* Won't fit in line buffer.
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*/
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return (1);
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/*
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* Special handling for "magic cookie" terminals.
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* If an attribute enter/exit sequence has a printing width > 0,
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* and the sequence is adjacent to a space, delete the space.
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* We just mark the space as invisible, to avoid having too
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* many spaces deleted.
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* {{ Note that even if the attribute width is > 1, we
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* delete only one space. It's not worth trying to do more.
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* It's hardly worth doing this much. }}
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*/
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if (curr > 0 && a != NORMAL &&
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linebuf[curr-1] == ' ' && attr[curr-1] == NORMAL &&
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attr_swidth(a) > 0)
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{
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/*
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* We are about to append an enter-attribute sequence
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* just after a space. Delete the space.
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*/
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attr[curr-1] = INVIS;
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column--;
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} else if (curr > 0 && attr[curr-1] != NORMAL &&
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attr[curr-1] != INVIS && c == ' ' && a == NORMAL &&
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attr_ewidth(attr[curr-1]) > 0)
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{
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/*
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* We are about to append a space just after an
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* exit-attribute sequence. Delete the space.
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*/
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a = INVIS;
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column--;
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}
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/* End of magic cookie handling. */
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linebuf[curr] = c;
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attr[curr] = a;
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column += w;
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return (0);
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}
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/*
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* Append a character to the line buffer.
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* Expand tabs into spaces, handle underlining, boldfacing, etc.
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* Returns 0 if ok, 1 if couldn't fit in buffer.
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*/
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public int
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pappend(c)
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register int c;
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{
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if (pendc)
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{
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if (do_append(pendc))
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/*
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* Oops. We've probably lost the char which
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* was in pendc, since caller won't back up.
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*/
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return (1);
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pendc = '\0';
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}
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/* if (c == '\r' && bs_mode == BS_SPECIAL)*/
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if ((c == '\r' || c == '\n') && bs_mode == BS_SPECIAL)
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{
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/*
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* Don't put the CR into the buffer until we see
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* the next char. If the next char is a newline,
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* discard the CR.
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*/
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pendc = c;
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return (0);
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}
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return (do_append(c));
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}
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static int
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do_append(c)
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int c;
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{
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register char *s;
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register int a;
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#define STOREC(c,a) if (storec((c),(a))) return (1); else curr++
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if (overstrike)
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{
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/*
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* Overstrike the character at the current position
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* in the line buffer. This will cause either
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* underline (if a "_" is overstruck),
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* bold (if an identical character is overstruck),
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* or just deletion of the character in the buffer.
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*/
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overstrike = 0;
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if (c == linebuf[curr])
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STOREC(linebuf[curr], BOLD);
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else if (c == '_')
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STOREC(linebuf[curr], UNDERLINE);
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else if (linebuf[curr] == '_')
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STOREC(c, UNDERLINE);
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else if (control_char(c))
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goto do_control_char;
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else
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STOREC(c, NORMAL);
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} else if (c == '\b')
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{
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switch (bs_mode)
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{
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case BS_NORMAL:
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STOREC(c, NORMAL);
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break;
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case BS_CONTROL:
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goto do_control_char;
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case BS_SPECIAL:
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if (curr == 0)
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break;
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backc();
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overstrike = 1;
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break;
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}
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} else if (c == '\t')
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{
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/*
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* Expand a tab into spaces.
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*/
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do
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{
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STOREC(' ', NORMAL);
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} while ((column % tabstop) != 0);
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} else if (control_char(c))
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{
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do_control_char:
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if (ctldisp == 0)
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{
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/*
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* Output as a normal character.
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*/
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STOREC(c, NORMAL);
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} else
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{
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/*
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* Output in the (blinking) ^X format.
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*/
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s = prchar(c);
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a = binattr;
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/*
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* Make sure we can get the entire representation
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* the character on this line.
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*/
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if (column + strlen(s) +
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attr_swidth(a) + attr_ewidth(a) > sc_width)
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return (1);
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for ( ; *s != 0; s++)
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STOREC(*s, a);
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}
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} else
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{
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STOREC(c, NORMAL);
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}
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return (0);
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}
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/*
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* Terminate the line in the line buffer.
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*/
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public void
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pdone(endline)
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int endline;
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{
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/* if (pendc && (pendc != '\r' || !endline)) */
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if (pendc && ((pendc != '\n' && pendc != '\n') || !endline))
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/*
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* If we had a pending character, put it in the buffer.
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* But discard a pending CR if we are at end of line
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* (that is, discard the CR in a CR/LF sequence).
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*/
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(void) do_append(pendc);
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/*
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* Add a newline if necessary,
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* and append a '\0' to the end of the line.
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*/
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if (column < sc_width || !auto_wrap || ignaw || ctldisp == 0)
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{
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/* linebuf[curr] = '\n'; */
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linebuf[curr] = '\r';
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attr[curr] = NORMAL;
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curr++;
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}
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linebuf[curr] = '\0';
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attr[curr] = NORMAL;
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}
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/*
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* Get a character from the current line.
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* Return the character as the function return value,
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* and the character attribute in *ap.
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*/
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public int
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gline(i, ap)
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register int i;
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register int *ap;
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{
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if (is_null_line)
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{
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/*
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* If there is no current line, we pretend the line is
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* either "~" or "", depending on the "twiddle" flag.
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*/
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*ap = NORMAL;
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if (twiddle)
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/* return ("~\n"[i]);
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return ("\n"[i]); */
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return ("~\r"[i]);
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return ("\r"[i]);
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}
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*ap = attr[i];
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return (linebuf[i] & 0377);
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}
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/*
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* Indicate that there is no current line.
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*/
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public void
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null_line(void)
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{
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is_null_line = 1;
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}
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/*
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* Analogous to forw_line(), but deals with "raw lines":
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* lines which are not split for screen width.
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* {{ This is supposed to be more efficient than forw_line(). }}
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*/
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public POSITION
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forw_raw_line(curr_pos, linep)
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POSITION curr_pos;
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char **linep;
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{
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register char *p;
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register int c;
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POSITION new_pos;
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if (curr_pos == NULL_POSITION || ch_seek(curr_pos) ||
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(c = ch_forw_get()) == EOI)
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return (NULL_POSITION);
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p = linebuf;
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for (;;)
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{
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/* if (c == '\n' || c == EOI) */
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if (c == '\r' || c == '\n' || c == EOI)
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{
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new_pos = ch_tell();
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break;
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}
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if (p >= &linebuf[sizeof(linebuf)-1])
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{
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/*
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* Overflowed the input buffer.
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* Pretend the line ended here.
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* {{ The line buffer is supposed to be big
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* enough that this never happens. }}
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*/
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new_pos = ch_tell() - 1;
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break;
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}
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*p++ = c;
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c = ch_forw_get();
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}
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*p = '\0';
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if (linep != NULL)
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*linep = linebuf;
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return (new_pos);
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}
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/*
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* Analogous to back_line(), but deals with "raw lines".
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* {{ This is supposed to be more efficient than back_line(). }}
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*/
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public POSITION
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back_raw_line(curr_pos, linep)
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POSITION curr_pos;
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char **linep;
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{
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register char *p;
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register int c;
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POSITION new_pos;
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if (curr_pos == NULL_POSITION || curr_pos <= ch_zero() ||
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ch_seek(curr_pos-1))
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return (NULL_POSITION);
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p = &linebuf[sizeof(linebuf)];
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*--p = '\0';
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for (;;)
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{
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c = ch_back_get();
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/* if (c == '\n') */
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if (c == '\r' || c == '\n')
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{
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/*
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* This is the newline ending the previous line.
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* We have hit the beginning of the line.
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*/
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new_pos = ch_tell() + 1;
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break;
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}
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if (c == EOI)
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{
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/*
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* We have hit the beginning of the file.
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* This must be the first line in the file.
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* This must, of course, be the beginning of the line.
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*/
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new_pos = ch_zero();
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break;
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}
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if (p <= linebuf)
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{
|
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/*
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* Overflowed the input buffer.
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* Pretend the line ended here.
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|
*/
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new_pos = ch_tell() + 1;
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break;
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}
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*--p = c;
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}
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if (linep != NULL)
|
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*linep = p;
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return (new_pos);
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}
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