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Diffstat (limited to '')
| -rw-r--r-- | src/util/format.c | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/src/util/format.c b/src/util/format.c new file mode 100644 index 000000000..66243c8ec --- /dev/null +++ b/src/util/format.c @@ -0,0 +1,259 @@ +/* + * music player command (mpc) + * Copyright (C) 2003-2015 The Music Player Daemon Project + * http://www.musicpd.org + * + * 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, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "format.h" + +#include <stdbool.h> +#include <stdio.h> +#include <string.h> +#include <stdlib.h> + +/** + * Reallocate the given string and append the source string. + */ +gcc_malloc +static char * +string_append(char *dest, const char *src, size_t len) +{ + size_t destlen = dest != NULL + ? strlen(dest) + : 0; + + dest = realloc(dest, destlen + len + 1); + memcpy(dest + destlen, src, len); + dest[destlen + len] = '\0'; + + return dest; +} + +/** + * Skip the format string until the current group is closed by either + * '&', '|' or ']' (supports nesting). + */ +gcc_pure +static const char * +skip_format(const char *p) +{ + unsigned stack = 0; + + while (*p != '\0') { + if (*p == '[') + stack++; + else if (*p == '#' && p[1] != '\0') + /* skip escaped stuff */ + ++p; + else if (stack > 0) { + if (*p == ']') + --stack; + } else if (*p == '&' || *p == '|' || *p == ']') + break; + + ++p; + } + + return p; +} + +static bool +is_name_char(char ch) +{ + return (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') || + (ch >= '0' && ch <= '9') || ch == '_'; +} + +static char * +format_object2(const char *format, const char **last, const void *object, + const char *(*getter)(const void *object, const char *name)) +{ + char *ret = NULL; + const char *p; + bool found = false; + + for (p = format; *p != '\0';) { + switch (p[0]) { + case '|': + ++p; + if (!found) { + /* nothing found yet: try the next + section */ + free(ret); + ret = NULL; + } else + /* already found a value: skip the + next section */ + p = skip_format(p); + break; + + case '&': + ++p; + if (!found) + /* nothing found yet, so skip this + section */ + p = skip_format(p); + else + /* we found something yet, but it will + only be used if the next section + also found something, so reset the + flag */ + found = false; + break; + + case '[': { + char *t = format_object2(p + 1, &p, object, getter); + if (t != NULL) { + ret = string_append(ret, t, strlen(t)); + free(t); + found = true; + } + } + break; + + case ']': + if (last != NULL) + *last = p + 1; + if (!found) { + free(ret); + ret = NULL; + } + return ret; + + case '\\': { + /* take care of escape sequences */ + char ltemp; + switch (p[1]) { + case 'a': + ltemp = '\a'; + break; + + case 'b': + ltemp = '\b'; + break; + + case 't': + ltemp = '\t'; + break; + + case 'n': + ltemp = '\n'; + break; + + case 'v': + ltemp = '\v'; + break; + + case 'f': + ltemp = '\f'; + break; + + case 'r': + ltemp = '\r'; + break; + + case '[': + case ']': + ltemp = p[1]; + break; + + default: + /* unknown escape: copy the + backslash */ + ltemp = p[0]; + --p; + break; + } + + ret = string_append(ret, <emp, 1); + p += 2; + } + break; + + case '%': { + /* find the extent of this format specifier + (stop at \0, ' ', or esc) */ + const char *end = p + 1; + while (is_name_char(*end)) + ++end; + + const size_t length = end - p + 1; + + if (*end != '%') { + ret = string_append(ret, p, length - 1); + p = end; + continue; + } + + char name[32]; + if (length > (int)sizeof(name)) { + ret = string_append(ret, p, length); + p = end + 1; + continue; + } + + memcpy(name, p + 1, length - 2); + name[length - 2] = 0; + + const char *value = getter(object, name); + size_t value_length; + if (value != NULL) { + if (*value != 0) + found = true; + value_length = strlen(value); + } else { + /* unknown variable: copy verbatim + from format string */ + value = p; + value_length = length; + } + + ret = string_append(ret, value, value_length); + + /* advance past the specifier */ + p = end + 1; + } + break; + + case '#': + /* let the escape character escape itself */ + if (p[1] != '\0') { + ret = string_append(ret, p + 1, 1); + p += 2; + break; + } + + /* fall through */ + + default: + /* pass-through non-escaped portions of the format string */ + ret = string_append(ret, p, 1); + ++p; + } + } + + if (last != NULL) + *last = p; + return ret; +} + +char * +format_object(const char *format, const void *object, + const char *(*getter)(const void *object, const char *name)) +{ + return format_object2(format, NULL, object, getter); +} |