ref: 91fc7321c2b7df934036f7b88ffdd5d6c826e941
parent: eff8fc233ea5bb8d61b5ab53bf66e792eacda7f5
author: henesy <henesy.dev@gmail.com>
date: Fri Feb 25 23:00:22 EST 2022
pt1 content, ex1-[19-20]
--- /dev/null
+++ b/ex/ex1-16.c
@@ -1,0 +1,44 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+
+/*
+Print the length of arbitraryily long input lines
+ and as much as possible of the text.
+*/
+void
+main(int, char*[])
+{+ Biobuf *in, *out;
+ in = Bfdopen(0, OREAD);
+ out = Bfdopen(1, OWRITE);
+
+ u32int len = 0;
+ while(1){+ long r;
+ int n;
+
+ // Read
+ r = Bgetrune(in);
+ if(r == Beof)
+ break;
+ if(r < 0)
+ sysfatal("err: could not read rune → %r\n");+
+ len++;
+ if(r == L'\n'){+ Bprint(out, "\n» Line length = %uld\n", len);
+ len = 0;
+ }
+
+ // Write
+ n = Bputrune(out, r);
+ if(n < 0)
+ sysfatal("err: could not write rune → %r\n");+ }
+
+ Bterm(in);
+ Bterm(out);
+
+ exits(nil);
+}
--- /dev/null
+++ b/ex/ex1-17.c
@@ -1,0 +1,43 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+
+const MIN = 80;
+
+/*
+Print lines greater than 80 runes.
+*/
+void
+main(int, char*[])
+{+ Biobuf *in, *out;
+ in = Bfdopen(0, OREAD);
+ out = Bfdopen(1, OWRITE);
+
+ u32int len = 0;
+ while(1){+ char *line;
+ int len, n;
+
+ // Read
+ line = Brdline(in, '\n');
+ len = Blinelen(in);
+ if(line == 0)
+ break;
+ if(len < 0)
+ sysfatal("err: could not read line → %r\n");+
+ if(len <= 80)
+ continue;
+
+ // Write
+ n = Bwrite(out, line, len);
+ if(n < 0)
+ sysfatal("err: could not write rune → %r\n");+ }
+
+ Bterm(in);
+ Bterm(out);
+
+ exits(nil);
+}
--- /dev/null
+++ b/ex/ex1-18.c
@@ -1,0 +1,59 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+
+const MIN = 80;
+
+/*
+Skip blank lines and trim trailing whitespace.
+*/
+void
+main(int, char*[])
+{+ Biobuf *in, *out;
+ in = Bfdopen(0, OREAD);
+ out = Bfdopen(1, OWRITE);
+
+ u32int len = 0;
+ while(1){+ char *line;
+ int len, n, i, last;
+
+ // Read
+ line = Brdline(in, '\n');
+ len = Blinelen(in);
+ if(line == 0)
+ break;
+ if(len < 0)
+ sysfatal("err: could not read line → %r\n");+
+ if(len < 2)
+ continue;
+
+ last = 0;
+ for(i = 0; i < len-1; i++){+ switch(line[i]){+ case ' ':
+ case '\t':
+ break;
+ default:
+ last = i;
+ }
+ }
+
+ if(last != len-1){+ len = last+2;
+ line[last+1] = '\n';
+ }
+
+ // Write
+ n = Bwrite(out, line, len);
+ if(n < 0)
+ sysfatal("err: could not write line → %r\n");+ }
+
+ Bterm(in);
+ Bterm(out);
+
+ exits(nil);
+}
--- /dev/null
+++ b/ex/ex1-19.c
@@ -1,0 +1,74 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+
+// Return an allocated buffer containing the reversal of 'in'
+Rune*
+reverse(Rune *in, Rune *out, usize len)
+{+ if(in == nil || len < 1)
+ return nil;
+
+ int i;
+
+ //fprint(2, "reversing \"%S\" ;; runelen = %d\n", in, len);
+ int to = 0, from = len-1;
+ while(from >= 0){+ //fprint(2, "out[%d] = in[%d](%C)\n", to, from, in[from]);
+ out[to] = in[from];
+ from--;
+ to++;
+ }
+
+ return out;
+}
+
+/*
+Reverse lines of input using a reverse function.
+*/
+void
+main(int, char*[])
+{+ Biobuf *in, *out;
+ in = Bfdopen(0, OREAD);
+ out = Bfdopen(1, OWRITE);
+
+ while(1){+ long rlen = 0;
+ char *line;
+ int len = 0, n, i;
+ Rune *rev, *rstr;
+
+ // Read
+ line = Brdstr(in, '\n', 1);
+ len = Blinelen(in);
+ if(line == 0)
+ break;
+ if(len < 0)
+ sysfatal("err: could not read line → %r\n");+
+ rstr = runesmprint("%s", line);+ if(rstr == nil)
+ sysfatal("err: UTF8 conversion failed → %r\n");+ rlen = runestrlen(rstr);
+ rev = calloc(rlen+1, sizeof (Rune));
+ reverse(rstr, rev, rlen);
+ if(rev == nil)
+ sysfatal("err: reversal failed\n");+ rev[rlen] = '\0';
+
+ // Write
+ n = Bprint(out, "%S\n", rev);
+ if(n < 0)
+ sysfatal("err: could not write line → %r\n");+
+ free(line);
+ free(rev);
+ free(rstr);
+ }
+
+ Bterm(in);
+ Bterm(out);
+
+ exits(nil);
+}
--- /dev/null
+++ b/ex/ex1-20.c
@@ -1,0 +1,80 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+
+void
+usage(void)
+{+ fprint(2, "usage: %s [-t tabstop]", argv0);
+ exits("usage");+}
+
+/*
+Replace tabs with 'tabstop' number of spaces.
+*/
+void
+main(int argc, char *argv[])
+{+ int tabstop = 4;
+ Biobuf *in, *out;
+ char *aux;
+
+ ARGBEGIN{+ case 't':
+ aux = EARGF(usage());
+ tabstop = atoi(aux);
+ break;
+ default:
+ usage();
+ }ARGEND
+
+ in = Bfdopen(0, OREAD);
+ out = Bfdopen(1, OWRITE);
+
+ while(1){+ char *line;
+ int len, n, i;
+
+ // Read
+ line = Brdline(in, '\n');
+ len = Blinelen(in);
+ if(line == 0)
+ break;
+ if(len < 0)
+ sysfatal("err: could not read line → %r\n");+
+ int ind = -1;
+ for(i = 0; i < len-1; i++){+ if(line[i] != ' ' && line[i] != ' '){+ ind = i;
+ break;
+ }
+
+ if(line[i] == ' '){+ int j;
+ for(j = 0; j < tabstop; j++)
+ Bwrite(out, " ", 1);
+ }
+ }
+
+ // Write
+ char *begin = line;
+ int end = len;
+
+ if(ind > 0){+ ind++;
+ begin = line+ind-1;
+ end = len-ind+1;
+ }
+
+ n = Bwrite(out, begin, end);
+ if(n < 0)
+ sysfatal("err: could not write line → %r\n");+ }
+
+ Bterm(in);
+ Bterm(out);
+
+ exits(nil);
+}
+