tal/str: new module.

[ccan] / ccan / tal / str / str.h

diff --git a/ccan/tal/str/str.h b/ccan/tal/str/str.h
new file mode 100644 (file)
index 0000000..30086fd
--- /dev/null
+++ b/ccan/tal/str/str.h
@@ -0,0 +1,119 @@
+/* Licensed under BSD-MIT - see LICENSE file for details */
+#ifndef CCAN_STR_TAL_H
+#define CCAN_STR_TAL_H
+#include <ccan/tal/tal.h>
+#include <ccan/tal/tal.h>
+#include <string.h>
+#include <stdbool.h>
+
+enum strsplit {
+       STR_EMPTY_OK,
+       STR_NO_EMPTY
+};
+
+/**
+ * strsplit - Split string into an array of substrings
+ * @ctx: the parent to tal from (often NULL)
+ * @string: the string to split
+ * @delims: delimiters where lines should be split.
+ * @flags: whether to include empty substrings.
+ *
+ * This function splits a single string into multiple strings.  The
+ * original string is untouched: an array is allocated (using tal)
+ * pointing to copies of each substring.  Multiple delimiters result
+ * in empty substrings.  By definition, no delimiters will appear in
+ * the substrings.
+ *
+ * The final char * in the array will be NULL.
+ *
+ * Example:
+ *     #include <ccan/tal/str/str.h>
+ *     ...
+ *     static unsigned int count_long_lines(const char *string)
+ *     {
+ *             char **lines;
+ *             unsigned int i, long_lines = 0;
+ *
+ *             // Can only fail on out-of-memory.
+ *             lines = strsplit(NULL, string, "\n", STR_NO_EMPTY);
+ *             for (i = 0; lines[i] != NULL; i++)
+ *                     if (strlen(lines[i]) > 80)
+ *                             long_lines++;
+ *             tal_free(lines);
+ *             return long_lines;
+ *     }
+ */
+char **strsplit(const void *ctx, const char *string, const char *delims,
+               enum strsplit flags);
+
+enum strjoin {
+       STR_TRAIL,
+       STR_NO_TRAIL
+};
+
+/**
+ * strjoin - Join an array of substrings into one long string
+ * @ctx: the context to tal from (often NULL)
+ * @strings: the NULL-terminated array of strings to join
+ * @delim: the delimiter to insert between the strings
+ * @flags: whether to add a delimieter to the end
+ *
+ * This function joins an array of strings into a single string.  The
+ * return value is allocated using tal.  Each string in @strings is
+ * followed by a copy of @delim.
+ *
+ * Example:
+ *     // Append the string "--EOL" to each line.
+ *     static char *append_to_all_lines(const char *string)
+ *     {
+ *             char **lines, *ret;
+ *
+ *             lines = strsplit(NULL, string, "\n", STR_EMPTY_OK);
+ *             ret = strjoin(NULL, lines, "-- EOL\n", STR_TRAIL);
+ *             tal_free(lines);
+ *             return ret;
+ *     }
+ */
+char *strjoin(const void *ctx, char *strings[], const char *delim,
+             enum strjoin flags);
+
+/**
+ * strreg - match and extract from a string via (extended) regular expressions.
+ * @ctx: the context to tal from (often NULL)
+ * @string: the string to try to match.
+ * @regex: the regular expression to match.
+ * ...: pointers to strings to allocate for subexpressions.
+ *
+ * Returns true if we matched, in which case any parenthesized
+ * expressions in @regex are allocated and placed in the char **
+ * arguments following @regex.  NULL arguments mean the match is not
+ * saved.  The order of the strings is the order
+ * of opening braces in the expression: in the case of repeated
+ * expressions (eg "([a-z])*") the last one is saved, in the case of
+ * non-existent matches (eg "([a-z]*)?") the pointer is set to NULL.
+ *
+ * Allocation failures or malformed regular expressions return false.
+ *
+ * See Also:
+ *     regcomp(3), regex(3).
+ *
+ * Example:
+ *     // Given 'My name is Rusty' outputs 'Hello Rusty!'
+ *     // Given 'my first name is Rusty Russell' outputs 'Hello Rusty Russell!'
+ *     // Given 'My name isnt Rusty Russell' outputs 'Hello there!'
+ *     int main(int argc, char *argv[])
+ *     {
+ *             char *person, *input;
+ *
+ *             // Join args and trim trailing space.
+ *             input = strjoin(NULL, argv+1, " ", STR_NO_TRAIL);
+ *             if (strreg(NULL, input, "[Mm]y (first )?name is ([A-Za-z ]+)",
+ *                        NULL, &person))
+ *                     printf("Hello %s!\n", person);
+ *             else
+ *                     printf("Hello there!\n");
+ *             return 0;
+ *     }
+ */
+bool strreg(const void *ctx, const char *string, const char *regex, ...);
+#endif /* CCAN_STR_TAL_H */