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Diffstat (limited to 'src/util/mac_parse.c')
| -rw-r--r-- | src/util/mac_parse.c | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/src/util/mac_parse.c b/src/util/mac_parse.c new file mode 100644 index 0000000..45b717a --- /dev/null +++ b/src/util/mac_parse.c @@ -0,0 +1,199 @@ +/*++ +/* NAME +/* mac_parse 3 +/* SUMMARY +/* locate macro references in string +/* SYNOPSIS +/* #include <mac_parse.h> +/* +/* int mac_parse(string, action, context) +/* const char *string; +/* int (*action)(int type, VSTRING *buf, void *context); +/* DESCRIPTION +/* This module recognizes macro expressions in null-terminated +/* strings. Macro expressions have the form $name, $(text) or +/* ${text}. A macro name consists of alphanumerics and/or +/* underscore. Text other than macro expressions is treated +/* as literal text. +/* +/* mac_parse() breaks up its string argument into macro references +/* and other text, and invokes the \fIaction\fR routine for each item +/* found. With each action routine call, the \fItype\fR argument +/* indicates what was found, \fIbuf\fR contains a copy of the text +/* found, and \fIcontext\fR is passed on unmodified from the caller. +/* The application is at liberty to clobber \fIbuf\fR. +/* .IP MAC_PARSE_LITERAL +/* The content of \fIbuf\fR is literal text. +/* .IP MAC_PARSE_EXPR +/* The content of \fIbuf\fR is a macro expression: either a +/* bare macro name without the preceding "$", or all the text +/* inside $() or ${}. +/* .PP +/* The action routine result value is the bit-wise OR of zero or more +/* of the following: +/* .IP MAC_PARSE_ERROR +/* A parsing error was detected. +/* .IP MAC_PARSE_UNDEF +/* A macro was expanded but not defined. +/* .PP +/* Use the constant MAC_PARSE_OK when no error was detected. +/* SEE ALSO +/* dict(3) dictionary interface. +/* DIAGNOSTICS +/* Fatal errors: out of memory. malformed macro name. +/* +/* The result value is the bit-wise OR of zero or more of the +/* following: +/* .IP MAC_PARSE_ERROR +/* A parsing error was detected. +/* .IP MAC_PARSE_UNDEF +/* A macro was expanded but not defined. +/* LICENSE +/* .ad +/* .fi +/* The Secure Mailer license must be distributed with this software. +/* AUTHOR(S) +/* Wietse Venema +/* IBM T.J. Watson Research +/* P.O. Box 704 +/* Yorktown Heights, NY 10598, USA +/*--*/ + +/* System library. */ + +#include <sys_defs.h> +#include <ctype.h> + +/* Utility library. */ + +#include <msg.h> +#include <mac_parse.h> + + /* + * Helper macro for consistency. Null-terminate the temporary buffer, + * execute the action, and reset the temporary buffer for re-use. + */ +#define MAC_PARSE_ACTION(status, type, buf, context) \ + do { \ + VSTRING_TERMINATE(buf); \ + status |= action((type), (buf), (context)); \ + VSTRING_RESET(buf); \ + } while(0) + +/* mac_parse - split string into literal text and macro references */ + +int mac_parse(const char *value, MAC_PARSE_FN action, void *context) +{ + const char *myname = "mac_parse"; + VSTRING *buf = vstring_alloc(1); /* result buffer */ + const char *vp; /* value pointer */ + const char *pp; /* open_paren pointer */ + const char *ep; /* string end pointer */ + static char open_paren[] = "({"; + static char close_paren[] = ")}"; + int level; + int status = 0; + +#define SKIP(start, var, cond) do { \ + for (var = start; *var && (cond); var++) \ + /* void */; \ + } while (0) + + if (msg_verbose > 1) + msg_info("%s: %s", myname, value); + + for (vp = value; *vp;) { + if (*vp != '$') { /* ordinary character */ + VSTRING_ADDCH(buf, *vp); + vp += 1; + } else if (vp[1] == '$') { /* $$ becomes $ */ + VSTRING_ADDCH(buf, *vp); + vp += 2; + } else { /* found bare $ */ + if (VSTRING_LEN(buf) > 0) + MAC_PARSE_ACTION(status, MAC_PARSE_LITERAL, buf, context); + vp += 1; + pp = open_paren; + if (*vp == *pp || *vp == *++pp) { /* ${x} or $(x) */ + level = 1; + vp += 1; + for (ep = vp; level > 0; ep++) { + if (*ep == 0) { + msg_warn("truncated macro reference: \"%s\"", value); + status |= MAC_PARSE_ERROR; + break; + } + if (*ep == *pp) + level++; + if (*ep == close_paren[pp - open_paren]) + level--; + } + if (status & MAC_PARSE_ERROR) + break; + vstring_strncat(buf, vp, level > 0 ? ep - vp : ep - vp - 1); + vp = ep; + } else { /* plain $x */ + SKIP(vp, ep, ISALNUM(*ep) || *ep == '_'); + vstring_strncat(buf, vp, ep - vp); + vp = ep; + } + if (VSTRING_LEN(buf) == 0) { + status |= MAC_PARSE_ERROR; + msg_warn("empty macro name: \"%s\"", value); + break; + } + MAC_PARSE_ACTION(status, MAC_PARSE_EXPR, buf, context); + } + } + if (VSTRING_LEN(buf) > 0 && (status & MAC_PARSE_ERROR) == 0) + MAC_PARSE_ACTION(status, MAC_PARSE_LITERAL, buf, context); + + /* + * Cleanup. + */ + vstring_free(buf); + + return (status); +} + +#ifdef TEST + + /* + * Proof-of-concept test program. Read strings from stdin, print parsed + * result to stdout. + */ +#include <vstring_vstream.h> + +/* mac_parse_print - print parse tree */ + +static int mac_parse_print(int type, VSTRING *buf, void *unused_context) +{ + char *type_name; + + switch (type) { + case MAC_PARSE_EXPR: + type_name = "MAC_PARSE_EXPR"; + break; + case MAC_PARSE_LITERAL: + type_name = "MAC_PARSE_LITERAL"; + break; + default: + msg_panic("unknown token type %d", type); + } + vstream_printf("%s \"%s\"\n", type_name, vstring_str(buf)); + return (0); +} + +int main(int unused_argc, char **unused_argv) +{ + VSTRING *buf = vstring_alloc(1); + + while (vstring_fgets_nonl(buf, VSTREAM_IN)) { + mac_parse(vstring_str(buf), mac_parse_print, (void *) 0); + vstream_fflush(VSTREAM_OUT); + } + vstring_free(buf); + return (0); +} + +#endif |