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less: optional support of -R

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Based on patches by Lubomir Rintel <lkundrak@v3.sk>

function                                             old     new   delta
read_lines                                           653     722     +69
less_main                                           2464    2531     +67
packed_usage                                       32202   32239     +37
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/0 up/down: 173/0)             Total: 173 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2018-01-22 14:38:51 +01:00
parent e411cd071a
commit 8528d3d4f8
1 changed files with 63 additions and 1 deletions
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64
miscutils/less.c
View File

@ -99,6 +99,22 @@
//config: bool "Enable -N (dynamic switching of line numbers)"
//config: default y
//config: depends on FEATURE_LESS_DASHCMD
//config:
//config:config FEATURE_LESS_RAW
//config: bool "Enable -R ('raw control characters')"
//config: default y
//config: depends on FEATURE_LESS_DASHCMD
//config: help
//config: This is essential for less applet to work with tools that use colors
//config: and paging, such as git, systemd tools or nmcli.
//config:
//config:config FEATURE_LESS_ENV
//config: bool "Take options from $LESS environment variable"
//config: default y
//config: depends on FEATURE_LESS_DASHCMD
//config: help
//config: This is essential for less applet to work with tools that use colors
//config: and paging, such as git, systemd tools or nmcli.
//applet:IF_LESS(APPLET(less, BB_DIR_USR_BIN, BB_SUID_DROP))
@ -106,7 +122,7 @@
//usage:#define less_trivial_usage
//usage: "[-E" IF_FEATURE_LESS_REGEXP("I")IF_FEATURE_LESS_FLAGS("Mm")
//usage: "N" IF_FEATURE_LESS_TRUNCATE("S") "h~] [FILE]..."
//usage: "N" IF_FEATURE_LESS_TRUNCATE("S") IF_FEATURE_LESS_TRUNCATE("R") "h~] [FILE]..."
//usage:#define less_full_usage "\n\n"
//usage: "View FILE (or stdin) one screenful at a time\n"
//usage: "\n -E Quit once the end of a file is reached"
@ -121,6 +137,9 @@
//usage: IF_FEATURE_LESS_TRUNCATE(
//usage: "\n -S Truncate long lines"
//usage: )
//usage: IF_FEATURE_LESS_RAW(
//usage: "\n -R Remove color escape codes in input"
//usage: )
//usage: "\n -~ Suppress ~s displayed past EOF"
#include <sched.h> /* sched_yield() */
@ -157,6 +176,7 @@ enum {
FLAG_TILDE = 1 << 4,
FLAG_I = 1 << 5,
FLAG_S = (1 << 6) * ENABLE_FEATURE_LESS_TRUNCATE,
FLAG_R = (1 << 7) * ENABLE_FEATURE_LESS_RAW,
/* hijack command line options variable for internal state vars */
LESS_STATE_MATCH_BACKWARDS = 1 << 15,
};
@ -207,6 +227,9 @@ struct globals {
regex_t pattern;
smallint pattern_valid;
#endif
#if ENABLE_FEATURE_LESS_RAW
smallint in_escape;
#endif
#if ENABLE_FEATURE_LESS_ASK_TERMINAL
smallint winsize_err;
#endif
@ -513,6 +536,26 @@ static void read_lines(void)
*--p = '\0';
continue;
}
#if ENABLE_FEATURE_LESS_RAW
if (option_mask32 & FLAG_R) {
if (c == '\033')
goto discard;
if (G.in_escape) {
if (isdigit(c)
|| c == '['
|| c == ';'
|| c == 'm'
) {
discard:
G.in_escape = (c != 'm');
readpos++;
continue;
}
/* Hmm, unexpected end of "ESC [ N ; N m" sequence */
G.in_escape = 0;
}
}
#endif
{
size_t new_last_line_pos = last_line_pos + 1;
if (c == '\t') {
@ -1776,6 +1819,25 @@ int less_main(int argc, char **argv)
num_files = argc - optind;
files = argv;
/* Tools typically pass LESS="FRSXMK".
* The options we don't understand are ignored. */
if (ENABLE_FEATURE_LESS_ENV) {
char *c = getenv("LESS");
if (c) while (*c) switch (*c++) {
case 'M':
option_mask32 |= FLAG_M;
break;
case 'R':
option_mask32 |= FLAG_R;
break;
case 'S':
option_mask32 |= FLAG_S;
break;
default:
break;
}
}
/* Another popular pager, most, detects when stdout
* is not a tty and turns into cat. This makes sense. */
if (!isatty(STDOUT_FILENO))