diff options
| -rw-r--r-- | doc/channelvariables.txt | 8 | ||||
| -rw-r--r-- | pbx.c | 22 |
2 files changed, 19 insertions, 11 deletions
diff --git a/doc/channelvariables.txt b/doc/channelvariables.txt index 4de93e7dd..061fa4261 100644 --- a/doc/channelvariables.txt +++ b/doc/channelvariables.txt @@ -139,8 +139,12 @@ previous example). ;Save the numbers 555 to the 'number' variable exten => _9X.,1,Set(number=${EXTEN:-7:3}) -If a negative length value is entered, it is ignored and Asterisk will match -to the end of the string. +If a negative length value is entered, Asterisk will remove that many characters +from the end of the string. + + ;Set pin to everything but the trailing #. + exten => _XXXX#,1,Set(pin=${EXTEN:0:-1}) + ___________________________ EXPRESSIONS: --------------------------- @@ -36,6 +36,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$") #include <errno.h> #include <time.h> #include <sys/time.h> +#include <limits.h> #include "asterisk/lock.h" #include "asterisk/cli.h" @@ -1020,9 +1021,6 @@ static struct ast_exten *pbx_find_extension(struct ast_channel *chan, return NULL; } -/* Note that it's negative -- that's important later. */ -#define DONT_HAVE_LENGTH 0x80000000 - /*! \brief extract offset:length from variable name. * Returns 1 if there is a offset:length part, which is * trimmed off (values go into variables) @@ -1032,7 +1030,7 @@ static int parse_variable_name(char *var, int *offset, int *length, int *isfunc) int parens=0; *offset = 0; - *length = DONT_HAVE_LENGTH; + *length = INT_MAX; *isfunc = 0; for (; *var; var++) { if (*var == '(') { @@ -1053,8 +1051,8 @@ static int parse_variable_name(char *var, int *offset, int *length, int *isfunc) * * offset < 0 means start from the end of the string and set the beginning * to be that many characters back. - * length is the length of the substring, -1 means unlimited - * (we take any negative value). + * length is the length of the substring. A value less than 0 means to leave + * that many off the end. * Always return a copy in workspace. */ static char *substring(const char *value, int offset, int length, char *workspace, size_t workspace_len) @@ -1064,12 +1062,12 @@ static char *substring(const char *value, int offset, int length, char *workspac ast_copy_string(workspace, value, workspace_len); /* always make a copy */ + lr = strlen(ret); /* compute length after copy, so we never go out of the workspace */ + /* Quick check if no need to do anything */ - if (offset == 0 && length < 0) /* take the whole string */ + if (offset == 0 && length >= lr) /* take the whole string */ return ret; - lr = strlen(ret); /* compute length after copy, so we never go out of the workspace */ - if (offset < 0) { /* translate negative offset into positive ones */ offset = lr + offset; if (offset < 0) /* If the negative offset was greater than the length of the string, just start at the beginning */ @@ -1083,6 +1081,12 @@ static char *substring(const char *value, int offset, int length, char *workspac ret += offset; /* move to the start position */ if (length >= 0 && length < lr - offset) /* truncate if necessary */ ret[length] = '\0'; + else if (length < 0) { + if (lr > offset - length) /* After we remove from the front and from the rear, is there anything left? */ + ret[lr + length - offset] = '\0'; + else + ret[0] = '\0'; + } return ret; } |