From 9453ac360afedb9da323008e816ff238426d4d16 Mon Sep 17 00:00:00 2001 From: Bruce Hill Date: Tue, 8 Sep 2020 19:45:00 -0700 Subject: [PATCH] Cleanup --- bpeg.c | 144 ++++++++++++++++++-------------------------------------- utils.h | 32 +++++++++++++ 2 files changed, 77 insertions(+), 99 deletions(-) diff --git a/bpeg.c b/bpeg.c index 674e1ba..3af2b78 100644 --- a/bpeg.c +++ b/bpeg.c @@ -253,27 +253,6 @@ static void set_range(vm_op_t *op, ssize_t min, ssize_t max, vm_op_t *pat, vm_op op->args.repetitions.sep = sep; } -/* - * Helper function to skip past all spaces (and comments) - * Returns a pointer to the first non-space character. - */ -static inline const char *after_spaces(const char *str) -{ - // Skip whitespace and comments: - skip_whitespace: - switch (*str) { - case ' ': case '\r': case '\n': case '\t': { - ++str; - goto skip_whitespace; - } - case '#': { - while (*str && *str != '\n') ++str; - goto skip_whitespace; - } - } - return str; -} - /* * Take an opcode and expand it into a chain of patterns if it's * followed by any patterns (e.g. "`x `y"), otherwise return @@ -305,9 +284,8 @@ static vm_op_t *expand_chain(vm_op_t *first) static vm_op_t *expand_choices(vm_op_t *first) { first = expand_chain(first); - const char *str = after_spaces(first->end); - if (*str != '/') return first; - ++str; + const char *str = first->end; + if (!matchchar(&str, '/')) return first; debug("Otherwise:\n"); vm_op_t *second = compile_bpeg(str); check(second, "Expected pattern after '/'"); @@ -375,10 +353,11 @@ static vm_op_t *compile_bpeg(const char *str) vm_op_t *op = calloc(sizeof(vm_op_t), 1); op->start = str; op->len = -1; - switch (*str) { + char c = *str; + ++str; + switch (c) { // Any char (dot) case '.': { - ++str; debug("Dot\n"); op->op = VM_ANYCHAR; op->len = 1; @@ -386,46 +365,41 @@ static vm_op_t *compile_bpeg(const char *str) } // Char literals case '`': { + char literal[2] = {*str, '\0'}; ++str; - char c[2] = {*str, '\0'}; - ++str; - check(c[0], "Expected character after '`'\n"); + check(literal[0], "Expected character after '`'\n"); op->len = 1; - if (*str == ',') { // Range + if (matchchar(&str, ',')) { // Range debug("Char range\n"); - ++str; char c2 = *str; check(c2, "Expected character after ','"); op->op = VM_RANGE; - op->args.range.low = c[0]; + op->args.range.low = literal[0]; op->args.range.high = c2; ++str; } else { debug("Char literal\n"); op->op = VM_STRING; - op->args.s = strdup(c); + op->args.s = strdup(literal); } break; } // Escapes case '\\': { - ++str; debug("Escape sequence\n"); check(*str, "Expected escape after '\\'"); op->op = VM_STRING; op->len = 1; - char c[2] = {escapechar(str, &str), '\0'}; - op->args.s = strdup(c); + char literal[2] = {escapechar(str, &str), '\0'}; + op->args.s = strdup(literal); break; } // String literal case '"': case '\'': { - char quote = *str; - ++str; + char quote = c; const char *literal = str; for (; *str && *str != quote; str++) { if (*str == '\\') { - // TODO: handle escape chars like \n check(str[1], "Expected more string contents after backslash"); ++str; } @@ -433,14 +407,13 @@ static vm_op_t *compile_bpeg(const char *str) op->op = VM_STRING; op->len = (ssize_t)(str - literal); op->args.s = strndup(literal, (size_t)op->len); + // TODO: handle escape chars like \n debug("String literal: %c%s%c\n", quote, op->args.s, quote); - check(*str == quote, "Missing closing quote"); - ++str; + check(matchchar(&str, quote), "Missing closing quote"); break; } // Not case '!': { - ++str; debug("Not pattern\n"); vm_op_t *p = compile_bpeg(str); check(p, "Expected pattern after '!'\n"); @@ -452,7 +425,6 @@ static vm_op_t *compile_bpeg(const char *str) } // Upto case '^': { - ++str; debug("Upto pattern\n"); vm_op_t *p = compile_bpeg(str); check(p, "Expected pattern after '^'\n"); @@ -464,7 +436,6 @@ static vm_op_t *compile_bpeg(const char *str) } // Upto and including case '&': { - ++str; debug("Upto-and pattern\n"); vm_op_t *p = compile_bpeg(str); check(p, "Expected pattern after '&'\n"); @@ -479,34 +450,24 @@ static vm_op_t *compile_bpeg(const char *str) case '6': case '7': case '8': case '9': { debug("Repetitions\n"); ssize_t min = -1, max = -1; + --str; long n1 = strtol(str, (char**)&str, 10); - str = after_spaces(str); - switch (*str) { - case '-': { - ++str; - str = after_spaces(str); - const char *start = str; - long n2 = strtol(str, (char**)&str, 10); - if (str == start) min = 0, max = n1; - else min = n1, max = n2; - break; - } - case '+': { - ++str; - min = n1, max = -1; - break; - } - default: { - min = n1, max = n1; - break; - } + if (matchchar(&str, '-')) { + str = after_spaces(str); + const char *start = str; + long n2 = strtol(str, (char**)&str, 10); + if (str == start) min = 0, max = n1; + else min = n1, max = n2; + } else if (matchchar(&str, '+')) { + min = n1, max = -1; + } else { + min = n1, max = n1; } vm_op_t *pat = compile_bpeg(str); check(pat, "Expected pattern after repetition count"); str = pat->end; str = after_spaces(str); - if (*str == '%') { - ++str; + if (matchchar(&str, '%')) { vm_op_t *sep = compile_bpeg(str); check(sep, "Expected pattern for separator after '%%'"); str = sep->end; @@ -521,18 +482,16 @@ static vm_op_t *compile_bpeg(const char *str) case '+': case '*': case '?': { debug("Special repetitions\n"); ssize_t min = -1, max = -1; - switch (*str) { + switch (c) { case '+': min = 1, max = -1; break; case '*': min = 0, max = -1; break; case '?': min = 0, max = 1; break; } - ++str; vm_op_t *pat = compile_bpeg(str); check(pat, "Expected pattern after +"); str = pat->end; str = after_spaces(str); - if (*str == '%') { - ++str; + if (matchchar(&str, '%')) { vm_op_t *sep = compile_bpeg(str); check(sep, "Expected pattern for separator after '%%'"); str = sep->end; @@ -545,7 +504,6 @@ static vm_op_t *compile_bpeg(const char *str) } // Lookbehind case '<': { - ++str; debug("Lookbehind\n"); vm_op_t *pat = compile_bpeg(str); check(pat, "Expected pattern after <"); @@ -559,7 +517,6 @@ static vm_op_t *compile_bpeg(const char *str) } // Lookahead case '>': { - ++str; debug("Lookahead\n"); vm_op_t *pat = compile_bpeg(str); check(pat, "Expected pattern after >"); @@ -572,32 +529,28 @@ static vm_op_t *compile_bpeg(const char *str) // Parentheses case '(': { debug("Open paren (\n"); - ++str; free(op); op = compile_bpeg(str); check(op, "Expected pattern inside parentheses"); op = expand_choices(op); str = op->end; str = after_spaces(str); - check(*str == ')', "Expected closing parenthesis"); - ++str; + check(matchchar(&str, ')'), "Expected closing parenthesis"); debug(")\n"); break; } // Capture case '@': { debug("Capture\n"); - ++str; op->op = VM_CAPTURE; str = after_spaces(str); - if (*str == '[') { - ++str; + if (matchchar(&str, '[')) { char *closing = strchr(str, ']'); check(closing, "Expected closing ']'"); op->args.capture.name = strndup(str, (size_t)(closing-str)); debug("named \"%s\"\n", op->args.capture.name); str = closing; - ++str; + check(matchchar(&str, ']'), "Expected closing ']'"); } vm_op_t *pat = compile_bpeg(str); check(pat, "Expected pattern after @"); @@ -609,27 +562,24 @@ static vm_op_t *compile_bpeg(const char *str) // Replacement case '{': { debug("Replacement {\n"); - ++str; str = after_spaces(str); vm_op_t *pat = NULL; - if (*str != '~') { + if (!matchchar(&str, '~')) { pat = compile_bpeg(str); check(pat, "Expected pattern after '{'"); pat = expand_choices(pat); str = pat->end; str = after_spaces(str); - check(*str == '~', "Expected '~' after pattern in replacement"); + check(matchchar(&str, '~'), "Expected '~' after pattern in replacement"); } - ++str; str = after_spaces(str); char quote = *str; const char *replacement; - if (quote == '}') { + if (matchchar(&str, '}')) { replacement = strdup(""); } else { - ++str; - check(quote == '\'' || quote == '"', + check(matchchar(&str, '"') || matchchar(&str, '\''), "Expected string literal for replacement"); replacement = str; for (; *str && *str != quote; str++) { @@ -639,11 +589,9 @@ static vm_op_t *compile_bpeg(const char *str) } } replacement = strndup(replacement, (size_t)(str-replacement)); - ++str; - str = after_spaces(str); + check(matchchar(&str, quote), "Expected closing quote"); } - check(*str == '}', "Expected a closing '}'"); - ++str; + check(matchchar(&str, '}'), "Expected a closing '}'"); op->op = VM_REPLACE; op->args.replace.replace_pat = pat; op->args.replace.replacement = replacement; @@ -655,14 +603,14 @@ static vm_op_t *compile_bpeg(const char *str) // Whitespace case '_': { debug("Whitespace\n"); - ++str; op->op = VM_REF; op->args.s = strdup("_"); break; } default: { // Reference - if (isalpha(*str)) { + if (isalpha(c)) { + --str; const char *refname = str; size_t len = 1; for (++str; isalnum(*str); ++str) @@ -770,8 +718,7 @@ static void print_match(match_t *m, const char *color) print_match(cap, "\033[0;35m"); printf("\033[0;34m"); } - } else if (*r == '\\') { - ++r; + } else if (matchchar(&r, '\\')) { fputc(escapechar(r, &r), stdout); --r; } else { @@ -819,16 +766,15 @@ int main(int argc, char *argv[]) check(op, "Failed to compile_bpeg input"); op = expand_choices(op); - const char *defs = after_spaces(op->end); - while (*defs == ';') { - defs = after_spaces(++defs); + const char *defs = op->end; + while (matchchar(&defs, ';')) { + defs = after_spaces(defs); const char *name = defs; check(isalpha(*name), "Definition must begin with a name"); while (isalpha(*defs)) ++defs; name = strndup(name, (size_t)(defs-name)); defs = after_spaces(defs); - check(*defs == '=', "Expected '=' in definition"); - ++defs; + check(matchchar(&defs, '='), "Expected '=' in definition"); vm_op_t *def = load_def(name, defs); check(def, "Couldn't load definition"); defs = def->end; diff --git a/utils.h b/utils.h index 8723516..96c6de2 100644 --- a/utils.h +++ b/utils.h @@ -5,3 +5,35 @@ // TODO: better error reporting #define check(cond, ...) do { if (!(cond)) { fprintf(stderr, __VA_ARGS__); fwrite("\n", 1, 1, stderr); _exit(1); } } while(0) #define debug(...) do { if (verbose) fprintf(stderr, __VA_ARGS__); } while(0) + +/* + * Helper function to skip past all spaces (and comments) + * Returns a pointer to the first non-space character. + */ +static inline const char *after_spaces(const char *str) +{ + // Skip whitespace and comments: + skip_whitespace: + switch (*str) { + case ' ': case '\r': case '\n': case '\t': { + ++str; + goto skip_whitespace; + } + case '#': { + while (*str && *str != '\n') ++str; + goto skip_whitespace; + } + } + return str; +} + +static inline int matchchar(const char **str, char c) +{ + *str = after_spaces(*str); + if (**str == c) { + ++(*str); + return 1; + } else { + return 0; + } +}