Mercurial > hg > toybox
view toys/posix/echo.c @ 818:264b9da809df
Simplify license text, as mentioned on the mailing list.
Reasoning: it was never my intent to require anybody to copy license
text into another project if they cut and pasted something out of
toybox. The "permission for any purpose" is as close to public domain
as you can get in our current screwed up legal system without making
people uncomfortable the _other_ way. (Besides, my initial reading of
that was "all copies of the source code" but that's not what it says,
and somebody pointed out that Android has "show license text" options
because paranoid lawyers think that sort of thing applies to the BINARY
version, which is nuts.)
author | Rob Landley <rob@landley.net> |
---|---|
date | Thu, 14 Mar 2013 09:02:37 -0500 |
parents | 786841fdb1e0 |
children | 95cb37adb024 |
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/* echo.c - echo supporting -n and -e. * * Copyright 2007 Rob Landley <rob@landley.net> * * See http://opengroup.org/onlinepubs/9699919799/utilities/echo.html USE_ECHO(NEWTOY(echo, "^?en", TOYFLAG_BIN)) config ECHO bool "echo" default y help usage: echo [-ne] [args...] Write each argument to stdout, with one space between each, followed by a newline. -n No trailing newline. -e Process the following escape sequences: \\ backslash \0NNN octal values (1 to 3 digits) \a alert (beep/flash) \b backspace \c stop output here (avoids trailing newline) \f form feed \n newline \r carriage return \t horizontal tab \v vertical tab \xHH hexadecimal values (1 to 2 digits) */ #define FOR_echo #include "toys.h" void echo_main(void) { int i = 0, out; char *arg, *from = "\\abfnrtv", *to = "\\\a\b\f\n\r\t\v", *c; for (;;) { arg = toys.optargs[i]; if (!arg) break; if (i++) xputc(' '); // Should we output arg verbatim? if (!(toys.optflags & FLAG_e)) { xprintf("%s", arg); continue; } // Handle -e for (c=arg;;) { if (!(out = *(c++))) break; // handle \escapes if (out == '\\' && *c) { int n = 0, slash = *(c++); char *found = strchr(from, slash); if (found) out = to[found-from]; else if (slash == 'c') goto done; else if (slash == '0') { out = 0; while (*c>='0' && *c<='7' && n++<3) out = (out*8)+*(c++)-'0'; } else if (slash == 'x') { out = 0; while (n++<2) { if (*c>='0' && *c<='9') out = (out*16)+*(c++)-'0'; else { int temp = tolower(*c); if (temp>='a' && temp<='f') { out = (out*16)+temp-'a'+10; c++; } else break; } } // Slash in front of unknown character, print literal. } else c--; } xputc(out); } } // Output "\n" if no -n if (!(toys.optflags&FLAG_n)) xputc('\n'); done: xflush(); }