diff options
Diffstat (limited to 'Modules/regexpr.c')
| -rw-r--r-- | Modules/regexpr.c | 384 |
1 files changed, 267 insertions, 117 deletions
diff --git a/Modules/regexpr.c b/Modules/regexpr.c index 87f747f..0b6ec8b 100644 --- a/Modules/regexpr.c +++ b/Modules/regexpr.c @@ -1,3 +1,7 @@ +/* + * -*- mode: c-mode; c-file-style: python -*- + */ + /* regexpr.c * * Author: Tatu Ylonen <ylo@ngs.fi> @@ -57,6 +61,12 @@ char *realloc(); #endif /* __STDC__ */ #endif /* THINK_C */ +/* The original code blithely assumed that sizeof(short) == 2. Not + * always true. Original instances of "(short)x" were replaced by + * SHORT(x), where SHORT is #defined below. */ + +#define SHORT(x) ((x) & 0x8000 ? (x) - 0x10000 : (x)) + /* The stack implementation is taken from an idea by Andrew Kuchling. * It's a doubly linked list of arrays. The advantages of this over a * simple linked list are that the number of mallocs required are @@ -75,27 +85,27 @@ char *realloc(); typedef union item_t { - struct - { - int num; - int level; - char *start; - char *end; - } reg; - struct - { - int count; - int level; - int phantom; - char *code; - char *text; - } fail; - struct - { - int num; - int level; - int count; - } cntr; + struct + { + int num; + int level; + char *start; + char *end; + } reg; + struct + { + int count; + int level; + int phantom; + char *code; + char *text; + } fail; + struct + { + int num; + int level; + int count; + } cntr; } item_t; #define STACK_PAGE_SIZE 256 @@ -105,43 +115,98 @@ typedef union item_t typedef struct item_page_t { - item_t items[STACK_PAGE_SIZE]; - struct item_page_t *prev; - struct item_page_t *next; + item_t items[STACK_PAGE_SIZE]; + struct item_page_t *prev; + struct item_page_t *next; } item_page_t; typedef struct match_state { - /* Structure to encapsulate the stack. */ - struct - { - /* index into the curent page. If index == 0 and you need - * to pop and item, move to the previous page and set - * index = STACK_PAGE_SIZE - 1. Otherwise decrement index - * to push a page. If index == STACK_PAGE_SIZE and you - * need to push a page move to the next page and set index - * = 0. If there is no new next page, allocate a new page - * and link it in. Otherwise, increment index to push a - * page. */ - int index; - item_page_t *current; /* Pointer to the current page. */ - item_page_t first; /* First page is statically allocated. */ - } stack; - char *start[NUM_REGISTERS]; - char *end[NUM_REGISTERS]; - - int changed[NUM_REGISTERS]; - /* The number of registers that have been pushed onto the stack - * since the last failure point. */ - int count; - /* Used to control when registers need to be pushed onto the - * stack. */ - int level; - /* The number of failure points on the stack. */ - int point; + /* The number of registers that have been pushed onto the stack + * since the last failure point. */ + + int count; + + /* Used to control when registers need to be pushed onto the + * stack. */ + + int level; + + /* The number of failure points on the stack. */ + + int point; + + /* Storage for the registers. Each register consists of two + * pointers to characters. So register N is represented as + * start[N] and end[N]. The pointers must be converted to + * offsets from the beginning of the string before returning the + * registers to the calling program. */ + + char *start[NUM_REGISTERS]; + char *end[NUM_REGISTERS]; + + /* Keeps track of whether a register has changed recently. */ + + int changed[NUM_REGISTERS]; + + /* Structure to encapsulate the stack. */ + struct + { + /* index into the curent page. If index == 0 and you need + * to pop an item, move to the previous page and set index + * = STACK_PAGE_SIZE - 1. Otherwise decrement index to + * push a page. If index == STACK_PAGE_SIZE and you need + * to push a page move to the next page and set index = + * 0. If there is no new next page, allocate a new page + * and link it in. Otherwise, increment index to push a + * page. */ + + int index; + item_page_t *current; /* Pointer to the current page. */ + item_page_t first; /* First page is statically allocated. */ + } stack; } match_state; +/* Initialize a state object */ + +/* #define NEW_STATE(state) \ */ +/* memset(&state, 0, (void *)(&state.stack) - (void *)(&state)); \ */ +/* state.stack.current = &state.stack.first; \ */ +/* state.stack.first.prev = NULL; \ */ +/* state.stack.first.next = NULL; \ */ +/* state.stack.index = 0; \ */ +/* state.level = 1 */ + +#define NEW_STATE(state, nregs) \ +{ \ + int i; \ + for (i = 0; i < nregs; i++) \ + { \ + state.start[i] = NULL; \ + state.end[i] = NULL; \ + state.changed[i] = 0; \ + } \ + state.stack.current = &state.stack.first; \ + state.stack.first.prev = NULL; \ + state.stack.first.next = NULL; \ + state.stack.index = 0; \ + state.level = 1; \ + state.count = 0; \ + state.level = 0; \ + state.point = 0; \ +} + +/* Free any memory that might have been malloc'd */ + +#define FREE_STATE(state) \ +while(state.stack.first.next != NULL) \ +{ \ + state.stack.current = state.stack.first.next; \ + state.stack.first.next = state.stack.current->next; \ + free(state.stack.current); \ +} + /* Discard the top 'count' stack items. */ #define STACK_DISCARD(stack, count, on_error) \ @@ -226,24 +291,6 @@ else \ #define STACK_EMPTY(stack) ((stack.index == 0) && \ (stack.current->prev == NULL)) - -/* Initialize a state object */ - -#define NEW_STATE(state) \ -memset(&state, 0, sizeof(match_state)); \ -state.stack.current = &state.stack.first; \ -state.level = 1 - -/* Free any memory that might have been malloc'd */ - -#define FREE_STATE(state) \ -while(state.stack.first.next != NULL) \ -{ \ - state.stack.current = state.stack.first.next; \ - state.stack.first.next = state.stack.current->next; \ - free(state.stack.current); \ -} - /* Return the start of register 'reg' */ #define GET_REG_START(state, reg) (state.start[reg]) @@ -302,22 +349,6 @@ state.end[reg] = text /* Update the last failure point with a new position in the text. */ -/* #define UPDATE_FAILURE(state, xtext, on_error) \ */ -/* { \ */ -/* item_t *item; \ */ -/* STACK_DISCARD(state.stack, state.count, on_error); \ */ -/* STACK_TOP(state.stack, item, on_error); \ */ -/* item->fail.text = xtext; \ */ -/* state.count = 0; \ */ -/* } */ - -/* #define UPDATE_FAILURE(state, xtext, on_error) \ */ -/* { \ */ -/* item_t *item; \ */ -/* STACK_BACK(state.stack, item, state.count + 1, on_error); \ */ -/* item->fail.text = xtext; \ */ -/* } */ - #define UPDATE_FAILURE(state, xtext, on_error) \ { \ item_t *item; \ @@ -391,7 +422,8 @@ enum regexp_compiled_ops /* opcodes for compiled regexp */ Cwordbound, /* match if at word boundary */ Cnotwordbound, /* match if not at word boundary */ Csyntaxspec, /* matches syntax code (1 byte follows) */ - Cnotsyntaxspec /* matches if syntax code does not match (1 byte foll)*/ + Cnotsyntaxspec, /* matches if syntax code does not match (1 byte foll)*/ + Crepeat1 }; enum regexp_syntax_op /* syntax codes for plain and quoted characters */ @@ -581,6 +613,8 @@ static void re_compile_fastmap_aux(char *code, case Cwordbound: case Cnotwordbound: { + for (a = 0; a < 256; a++) + fastmap[a] = 1; break; } case Csyntaxspec: @@ -648,7 +682,7 @@ static void re_compile_fastmap_aux(char *code, { a = (unsigned char)code[pos++]; a |= (unsigned char)code[pos++] << 8; - pos += (int)(short)a; + pos += (int)SHORT(a); if (visited[pos]) { /* argh... the regexp contains empty loops. This is not @@ -664,10 +698,15 @@ static void re_compile_fastmap_aux(char *code, { a = (unsigned char)code[pos++]; a |= (unsigned char)code[pos++] << 8; - a = pos + (int)(short)a; + a = pos + (int)SHORT(a); re_compile_fastmap_aux(code, a, visited, can_be_null, fastmap); break; } + case Crepeat1: + { + pos += 2; + break; + } default: { abort(); /* probably some opcode is missing from this switch */ @@ -754,10 +793,11 @@ static int re_optimize_star_jump(regexp_t bufp, char *code) char ch; int a; int b; + int num_instructions = 0; a = (unsigned char)*code++; a |= (unsigned char)*code++ << 8; - a = (int)(short)a; + a = (int)SHORT(a); p1 = code + a + 3; /* skip the failure_jump */ assert(p1[-3] == Cfailure_jump); @@ -775,6 +815,7 @@ static int re_optimize_star_jump(regexp_t bufp, char *code) /* loop until we find something that consumes a character */ loop_p1: + num_instructions++; switch (*p1++) { case Cbol: @@ -824,6 +865,7 @@ static int re_optimize_star_jump(regexp_t bufp, char *code) /* now we know that we can't backtrack. */ while (p1 != p2 - 3) { + num_instructions++; switch (*p1++) { case Cend: @@ -873,11 +915,22 @@ static int re_optimize_star_jump(regexp_t bufp, char *code) } } + make_update_jump: code -= 3; a += 3; /* jump to after the Cfailure_jump */ code[0] = Cupdate_failure_jump; code[1] = a & 0xff; code[2] = a >> 8; + if (num_instructions > 1) + return 1; + assert(num_instructions == 1); + /* if the only instruction matches a single character, we can do + * better + */ + p1 = code + 3 + a; /* start of sole instruction */ + if (*p1 == Cset || *p1 == Cexact || *p1 == Canychar || + *p1 == Csyntaxspec || *p1 == Cnotsyntaxspec) + code[0] = Crepeat1; return 1; make_normal_jump: @@ -939,6 +992,7 @@ static int re_optimize(regexp_t bufp) case Cjump: case Cdummy_failure_jump: case Cfailure_jump: + case Crepeat1: { code += 2; break; @@ -1111,7 +1165,8 @@ char *re_compile_pattern(char *regex, int size, regexp_t bufp) re_compile_initialize(); bufp->used = 0; bufp->fastmap_accurate = 0; - bufp->uses_registers = 0; + bufp->uses_registers = 1; + bufp->num_registers = 1; translate = bufp->translate; pattern = bufp->buffer; alloc = bufp->allocated; @@ -1289,6 +1344,7 @@ char *re_compile_pattern(char *regex, int size, regexp_t bufp) STORE(Cstart_memory); STORE(next_register); open_registers[num_open_registers++] = next_register; + bufp->num_registers++; next_register++; } paren_depth++; @@ -1545,27 +1601,8 @@ int re_match(regexp_t bufp, code = bufp->buffer; translate = bufp->translate; -/* translated = NULL; */ -/* if (bufp->translate) */ -/* { */ -/* char *t1; */ -/* char *t2; */ - -/* translated = malloc(size); */ -/* if (translated == NULL) */ -/* goto error; */ - -/* t1 = string; */ -/* t2 = translated; */ -/* while(t1 < textend) */ -/* *t2++ = bufp->translate[*t1++]; */ - -/* text = translated + pos; */ -/* textstart = translated; */ -/* textend = translated + size; */ -/* } */ - NEW_STATE(state); + NEW_STATE(state, bufp->num_registers); continue_matching: switch (*code++) @@ -1587,7 +1624,7 @@ int re_match(regexp_t bufp, } else { - for (a = 1; a < RE_NREGS; a++) + for (a = 1; a < bufp->num_registers; a++) { if ((GET_REG_START(state, a) == NULL) || (GET_REG_END(state, a) == NULL)) @@ -1599,10 +1636,13 @@ int re_match(regexp_t bufp, old_regs->start[a] = GET_REG_START(state, a) - textstart; old_regs->end[a] = GET_REG_END(state, a) - textstart; } + for (; a < RE_NREGS; a++) + { + old_regs->start[a] = -1; + old_regs->end[a] = -1; + } } } -/* if(translated) */ -/* free(translated); */ FREE_STATE(state); return match_end - pos; } @@ -1703,18 +1743,18 @@ int re_match(regexp_t bufp, { a = (unsigned char)*code++; a |= (unsigned char)*code++ << 8; - code += (int)(short)a; + code += (int)SHORT(a); goto continue_matching; } case Cdummy_failure_jump: { a = (unsigned char)*code++; a |= (unsigned char)*code++ << 8; - a = (int)(short)a; + a = (int)SHORT(a); assert(*code == Cfailure_jump); b = (unsigned char)code[1]; b |= (unsigned char)code[2] << 8; - PUSH_FAILURE(state, code + (int)(short)b + 3, NULL, goto error); + PUSH_FAILURE(state, code + (int)SHORT(b) + 3, NULL, goto error); code += a; goto continue_matching; } @@ -1722,10 +1762,120 @@ int re_match(regexp_t bufp, { a = (unsigned char)*code++; a |= (unsigned char)*code++ << 8; - a = (int)(short)a; + a = (int)SHORT(a); PUSH_FAILURE(state, code + a, text, goto error); goto continue_matching; } + case Crepeat1: + { + char *pinst; + a = (unsigned char)*code++; + a |= (unsigned char)*code++ << 8; + a = (int)SHORT(a); + pinst = code + a; + /* pinst is sole instruction in loop, and it matches a + * single character. Since Crepeat1 was originally a + * Cupdate_failure_jump, we also know that backtracking is + * useless: so long as the single-character expression matches, + * it must be used. Also, in the case of +, we've already + * matched one character, so + can't fail: nothing here can + * cause a failure. + */ + switch (*pinst++) + { + case Cset: + { + if (translate) + { + while (text < textend) + { + ch = translate[(unsigned char)*text]; + if (pinst[ch/8] & (1<<(ch & 7))) + text++; + else + break; + } + } + else + { + while (text < textend) + { + ch = (unsigned char)*text; + if (pinst[ch/8] & (1<<(ch & 7))) + text++; + else + break; + } + } + break; + } + case Cexact: + { + ch = (unsigned char)*pinst; + if (translate) + { + while (text < textend && + translate[(unsigned char)*text] == ch) + text++; + } + else + { + while (text < textend && (unsigned char)*text == ch) + text++; + } + break; + } + case Canychar: + { + while (text < textend && (unsigned char)*text != '\n') + text++; + break; + } + case Csyntaxspec: + { + a = (unsigned char)*pinst; + if (translate) + { + while (text < textend && + translate[SYNTAX(*text)] == a) + text++; + } + else + { + while (text < textend && SYNTAX(*text) == a) + text++; + } + break; + } + case Cnotsyntaxspec: + { + a = (unsigned char)*pinst; + if (translate) + { + while (text < textend && + translate[SYNTAX(*text)] != a) + text++; + } + else + { + while (text < textend && SYNTAX(*text) != a) + text++; + } + break; + } + default: + { + abort(); + /*NOTREACHED*/ + } + } + /* due to the funky way + and * are compiled, the top failure- + * stack entry at this point is actually a success entry -- + * update it & pop it + */ + UPDATE_FAILURE(state, text, goto error); + goto fail; /* i.e., succeed <wink/sigh> */ + } case Cbegbuf: { if (text == textstart) |