X-Git-Url: http://git.marmaro.de/?a=blobdiff_plain;f=sbr%2Ffmt_compile.c;h=ee495f1463e87db72b981d17fa9defe554bfcd51;hb=57cd23b8807fa351800ba7277c5636a133241166;hp=836872892d15937e2260fc664b4c02e6ae731db9;hpb=162f2a7d23a18a87cad101f68ab27de057de533d;p=mmh diff --git a/sbr/fmt_compile.c b/sbr/fmt_compile.c index 8368728..ee495f1 100644 --- a/sbr/fmt_compile.c +++ b/sbr/fmt_compile.c @@ -5,6 +5,38 @@ * This code is Copyright (c) 2002, by the authors of nmh. See the * COPYRIGHT file in the root directory of the nmh distribution for * complete copyright information. + * + * This code compiles the format strings (documented in mh-format(5)) into + * an internal form to be later processed by fmt_scan.c. + * + * What happens here is that the format strings are parsed and an array + * of struct format structures are returned. Each format structure is + * a single operation interpreted by the the routines in fmt_scan.c. + * + * There is a NOT a one-to-one correspondence between format strings and + * format instructions; some functions have side effects that can result + * in multiple instructions being generated. The exact list of instructions + * generated by a format string can be seem with the nmh fmtdump utility. + * + * A list of format instructions can be found in fmt_compile.h. + * + * If you wish to add a new function, you will need to do the following + * things: + * + * - Add a new instruction to the list of instructions in fmt_compile.h. + * Note that test instructions (starting with FT_IF_S_NULL) have special + * handling, so if you are NOT writing a test function then you need + * to insert it into the list before that _and_ bump all of the + * following instruction numbers. + * + * - Add the function name to the functable[] array below, and write any + * special code that your function may require in terms of parsing + * (it very well may not need anything). + * + * - Add the code in fmt_scan.c to handle your new function. + * + * - Document the new function in the mh-format(5) man page. + * */ #include @@ -12,6 +44,7 @@ #include #include #include +#include #ifdef HAVE_SYS_TIME_H # include @@ -43,6 +76,9 @@ extern struct mailname fmt_mnull; #define TF_NOW 6 /* special - get current unix time */ #define TF_EXPR_SV 7 /* like expr but save current str reg */ #define TF_NOP 8 /* like expr but no result */ +#define TF_MYNAME 9 /* special - get current name of user */ +#define TF_MYHOST 10 /* special - get "local" hostname */ +#define TF_LMBOX 11 /* special - get full local mailbox */ /* ftable->flags */ /* NB that TFL_PUTS is also used to decide whether the test @@ -51,6 +87,31 @@ extern struct mailname fmt_mnull; #define TFL_PUTS 1 /* implicit putstr if top level */ #define TFL_PUTN 2 /* implicit putnum if top level */ +/* + * The functable array maps between the text names of format functions and + * the format instructions interpreted by the engine in fmt_scan.c. + * + * The elements of this structure are as follows: + * + * name - The name of the function as seen in the format string. This is + * what maps a particular function name into a format instruction. + * type - The type of argument this function expects. Those types are + * listed above (with the TF_ prefix). This affects what gets + * placed in the format instruction (the f_un union). + * f_type - The instruction corresponding to this function (from the list + * in fmt_compile.h). + * extra - Used by some functions to provide extra data to the compiler. + * Uses include: + * - Providing an alternate instruction to combine a load + * and test operation (see do_if()). + * - Passed in f_value in the format instruction to provide + * extra information for the engine (see FT_LV_DAT handling + * in fmt_scan.c). + * - Provide a hint as to preprocessing that is required for + * this instruction (see do_name()). + * flags - See the definitions for TFL_PUTS & TFL_PUTN above. + */ + struct ftable { char *name; /* function name */ char type; /* argument type */ @@ -96,6 +157,9 @@ static struct ftable functable[] = { { "dat", TF_NUM, FT_LV_DAT, 0, TFL_PUTN }, { "strlen", TF_NONE, FT_LV_STRLEN, 0, TFL_PUTN }, { "me", TF_MYBOX, FT_LS_LIT, 0, TFL_PUTS }, + { "myname", TF_MYNAME, FT_LS_LIT, 0, TFL_PUTS }, + { "myhost", TF_MYHOST, FT_LS_LIT, 0, TFL_PUTS }, + { "localmbox", TF_LMBOX, FT_LS_LIT, 0, TFL_PUTS }, { "plus", TF_NUM, FT_LV_PLUS_L, 0, TFL_PUTN }, { "minus", TF_NUM, FT_LV_MINUS_L, 0, TFL_PUTN }, { "divide", TF_NUM, FT_LV_DIVIDE_L, 0, TFL_PUTN }, @@ -182,17 +246,12 @@ static struct ftable functable[] = { #define PUTLIT(str) do { NEW(FT_LIT,0,0); fp->f_text = (str); } while (0) #define PUTC(c) do { NEW(FT_CHAR,0,0); fp->f_char = (c); } while (0) -static char *format_string; +char *format_string; static unsigned char *usr_fstring; /* for CERROR */ #define CERROR(str) compile_error (str, cp) /* - * external prototypes - */ -extern char *getusername(void); - -/* * static prototypes */ static struct ftable *lookup(char *); @@ -206,6 +265,9 @@ static char *do_loop(char *); static char *do_if(char *); +/* + * Lookup a function name in the functable + */ static struct ftable * lookup(char *name) { @@ -256,7 +318,7 @@ int fmt_compile(char *fstring, struct format **fmt) { register char *cp; - int i; + size_t i; if (format_string) free (format_string); @@ -353,6 +415,9 @@ compile (char *sp) } +/* + * Process functions & components (handle field width here as well + */ static char * do_spec(char *sp) { @@ -404,6 +469,11 @@ do_spec(char *sp) return (cp); } +/* + * Process a component name. Normally this involves generating an FT_COMP + * instruction for the specified component. If preprocess is set, then we + * do some extra processing. + */ static char * do_name(char *sp, int preprocess) { @@ -458,6 +528,10 @@ do_name(char *sp, int preprocess) return (cp); } +/* + * Generate one or more instructions corresponding to the named function. + * The different type of function arguments are handled here. + */ static char * do_func(char *sp) { @@ -521,6 +595,18 @@ do_func(char *sp) LS(t->f_type, getusername()); break; + case TF_MYNAME: + LS(t->f_type, getfullname()); + break; + + case TF_MYHOST: + LS(t->f_type, LocalName(0)); + break; + + case TF_LMBOX: + LS(t->f_type, getlocalmbox()); + break; + case TF_NOW: LV(t->f_type, time((time_t *) 0)); break; @@ -550,6 +636,10 @@ do_func(char *sp) return (cp); } +/* + * Handle an expression as an argument. Basically we call one of do_name(), + * do_func(), or do_if() + */ static char * do_expr (char *sp, int preprocess) { @@ -571,6 +661,15 @@ do_expr (char *sp, int preprocess) return (cp); } +/* + * I am guessing this was for some kind of loop statement, which would have + * looked like %[ .... %]. It looks like the way this would have worked + * is that the format engine would have seen that FT_DONE had a 1 in the + * f_un.f_un_value and then decided whether or not to continue the loop. + * There is no support for this in the format engine, so right now if + * you try using it you will reach the FT_DONE and simply stop. I'm leaving + * this here in case someone wants to continue the work. + */ static char * do_loop(char *sp) { @@ -589,6 +688,12 @@ do_loop(char *sp) return cp; } +/* + * Handle an if-elsif-endif statement. Note here that the branching + * is handled by the f_skip member of the struct format (which is really + * just f_width overloaded). This number controls how far to move forward + * (or back) in the format instruction array. + */ static char * do_if(char *sp) {