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Diffstat (limited to 'color/parse_ansi.c')
| -rw-r--r-- | color/parse_ansi.c | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/color/parse_ansi.c b/color/parse_ansi.c new file mode 100644 index 000000000..d61570875 --- /dev/null +++ b/color/parse_ansi.c @@ -0,0 +1,259 @@ +/** + * @file + * Parse ANSI Sequences + * + * @authors + * Copyright (C) 2023 Richard Russon <rich@flatcap.org> + * + * @copyright + * This program is free software: you can redistribute it and/or modify it under + * the terms of the GNU General Public License as published by the Free Software + * Foundation, either version 2 of the License, or (at your option) any later + * version. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS + * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more + * details. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see <http://www.gnu.org/licenses/>. + */ + +/** + * @page color_parse_ansi Parse ANSI Sequences + * + * Parse ANSI Sequences + */ + +#include "config.h" +#include <stddef.h> +#include <ctype.h> +#include <stdbool.h> +#include <stdlib.h> +#include "mutt/lib.h" +#include "gui/lib.h" +#include "parse_ansi.h" +#include "ansi.h" +#include "color.h" + +/** + * ansi_is_end_char - Is this the end of a sequence? + * @param c Character to test + * @retval true Is it a valid end char + */ +static inline bool ansi_is_end_char(char c) +{ + return ((c == 'm') || (c == ';')); +} + +/** + * ansi_skip_sequence - Skip an unrecognised sequence + * @param str String to examine + * @retval num Number of characters to skip over + */ +int ansi_skip_sequence(const char *str) +{ + if (!str || (str[0] == '\0')) + return 0; + + int count = 1; + while ((str[0] != '\0') && !ansi_is_end_char(str[0])) + { + str++; + count++; + } + + return count; +} + +/** + * ansi_color_seq_length - Is this an ANSI escape sequence? + * @param str String to test + * @retval 0 No, not an ANSI sequence + * @retval >0 Length of the ANSI sequence + * + * Match ANSI escape sequences of type 'm', e.g. + * - `<esc>[1;32m` + */ +int ansi_color_seq_length(const char *str) +{ + if (!str || !*str) + return 0; + + if ((str[0] != '\033') || (str[1] != '[')) // Escape + return 0; + + int i = 2; + while ((str[i] != '\0') && (isdigit(str[i]) || (str[i] == ';'))) + { + i++; + } + + if (str[i] == 'm') + return i + 1; + + return 0; +} + +/** + * ansi_color_parse_single - Parse a single ANSI escape sequence + * @param buf String to parse + * @param ansi AnsiColor for the result + * @param dry_run Don't parse anything, just skip over + * @retval num Length of the escape sequence + * + * Parse an ANSI escape sequence into @a ansi. + * Calling this function repeatedly, will accumulate sequences in @a ansi. + */ +int ansi_color_parse_single(const char *buf, struct AnsiColor *ansi, bool dry_run) +{ + int seq_len = ansi_color_seq_length(buf); + if (seq_len == 0) + return 0; + + if (dry_run || !ansi) + return seq_len; + + int pos = 2; // Skip '<esc>[' + + while (pos < seq_len) + { + if ((buf[pos] == '0') && isdigit(buf[pos + 1])) + { + pos++; // Skip the leading zero + } + else if ((buf[pos] == '0') && ansi_is_end_char(buf[pos + 1])) + { + ansi->fg = COLOR_DEFAULT; + ansi->bg = COLOR_DEFAULT; + ansi->attrs = 0; + ansi->attr_color = NULL; + pos += 2; + } + else if ((buf[pos] == '1') && ansi_is_end_char(buf[pos + 1])) + { + ansi->attrs |= A_BOLD; + pos += 2; + } + else if ((buf[pos] == '3') && ansi_is_end_char(buf[pos + 1])) + { + ansi->attrs |= A_ITALIC; + pos += 2; + } + else if (buf[pos] == '3') + { + // 30-37 basic foreground + if ((buf[pos + 1] >= '0') && (buf[pos + 1] < '8') && ansi_is_end_char(buf[pos + 2])) + { + ansi->fg = buf[pos + 1] - '0'; + pos += 3; + } + else if (buf[pos + 1] == '8') + { + if (mutt_str_startswith(buf + pos, "38;5;") && isdigit(buf[pos + 5])) + { + // 38;5;n palette foreground + char *end = NULL; + int value = strtoul(buf + pos + 5, &end, 10); + if ((value >= 0) && (value < 256) && end && ansi_is_end_char(end[0])) + { + ansi->fg = value; + pos += end - &buf[pos]; + } + else + { + pos += ansi_skip_sequence(buf + pos); + } + } + else if (mutt_str_startswith(buf + pos, "38;2;") && isdigit(buf[pos + 5])) + { + // 38;2;R;G;B true colour foreground + pos += ansi_skip_sequence(buf + pos + 5); + pos += ansi_skip_sequence(buf + pos); + pos += ansi_skip_sequence(buf + pos); + } + else + { + return pos; + } + } + else if ((buf[pos + 1] == '9') && ansi_is_end_char(buf[pos + 2])) + { + // default fg + ansi->fg = COLOR_DEFAULT; + pos += 2; + } + else + { + pos += ansi_skip_sequence(buf + pos); + } + } + else if ((buf[pos] == '4') && ansi_is_end_char(buf[pos + 1])) + { + ansi->attrs |= A_UNDERLINE; + pos += 2; + } + else if (buf[pos] == '4') + { + // 40-47 basic background + if ((buf[pos + 1] >= '0') && (buf[pos + 1] < '8')) + { + ansi->bg = buf[pos + 1] - '0'; + pos += 3; + } + else if (buf[pos + 1] == '8') + { + if (mutt_str_startswith(buf + pos, "48;5;") && isdigit(buf[pos + 5])) + { + // 48;5;n palette background + char *end = NULL; + int value = strtoul(buf + pos + 5, &end, 10); + if ((value >= 0) && (value < 256) && end && ansi_is_end_char(end[0])) + { + ansi->bg = value; + pos += end - &buf[pos]; + } + else + { + pos += ansi_skip_sequence(buf + pos); + } + } + else if (mutt_str_startswith(buf + pos, "48;2;") && isdigit(buf[pos + 5])) + { + // 48;2;R;G;B true colour background + pos += ansi_skip_sequence(buf + pos + 5); + pos += ansi_skip_sequence(buf + pos); + pos += ansi_skip_sequence(buf + pos); + } + else + { + pos += ansi_skip_sequence(buf + pos); + } + } + else if ((buf[pos + 1] == '9') && ansi_is_end_char(buf[pos + 2])) + { + // default background + ansi->bg = COLOR_DEFAULT; + pos += 2; + } + } + else if ((buf[pos] == '5') && ansi_is_end_char(buf[pos + 1])) + { + ansi->attrs |= A_BLINK; + pos += 2; + } + else if ((buf[pos] == '7') && ansi_is_end_char(buf[pos + 1])) + { + ansi->attrs |= A_REVERSE; + pos += 2; + } + else + { + while ((pos < seq_len) && (buf[pos] != ';')) + pos++; + } + } + + return pos; +} |