musl libc 源码实现

/* regcomp.c - TRE POSIX compatible regex compilation functions. Copyright (c) 2001-2009 Ville Laurikari <vl@iki.fi> All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include <string.h> #include <stdlib.h> #include <regex.h> #include <limits.h> #include <stdint.h> #include <ctype.h> #include "tre.h" #include <assert.h> /*********************************************************************** from tre-compile.h ***********************************************************************/ typedef struct { int position; int code_min; int code_max; int *tags; int assertions; tre_ctype_t class; tre_ctype_t *neg_classes; int backref; } tre_pos_and_tags_t; /*********************************************************************** from tre-ast.c and tre-ast.h ***********************************************************************/ /* The different AST node types. */ typedef enum { LITERAL, CATENATION, ITERATION, UNION } tre_ast_type_t; /* Special subtypes of TRE_LITERAL. */ #define EMPTY -1 /* Empty leaf (denotes empty string). */ #define ASSERTION -2 /* Assertion leaf. */ #define TAG -3 /* Tag leaf. */ #define BACKREF -4 /* Back reference leaf. */ #define IS_SPECIAL(x) ((x)->code_min < 0) #define IS_EMPTY(x) ((x)->code_min == EMPTY) #define IS_ASSERTION(x) ((x)->code_min == ASSERTION) #define IS_TAG(x) ((x)->code_min == TAG) #define IS_BACKREF(x) ((x)->code_min == BACKREF) /* A generic AST node. All AST nodes consist of this node on the top level with `obj' pointing to the actual content. */ typedef struct { tre_ast_type_t type; /* Type of the node. */ void *obj; /* Pointer to actual node. */ int nullable; int submatch_id; int num_submatches; int num_tags; tre_pos_and_tags_t *firstpos; tre_pos_and_tags_t *lastpos; } tre_ast_node_t; /* A "literal" node. These are created for assertions, back references, tags, matching parameter settings, and all expressions that match one character. */ typedef struct { long code_min; long code_max; int position; tre_ctype_t class; tre_ctype_t *neg_classes; } tre_literal_t; /* A "catenation" node. These are created when two regexps are concatenated. If there are more than one subexpressions in sequence, the `left' part holds all but the last, and `right' part holds the last subexpression (catenation is left associative). */ typedef struct { tre_ast_node_t *left; tre_ast_node_t *right; } tre_catenation_t; /* An "iteration" node. These are created for the "*", "+", "?", and "{m,n}" operators. */ typedef struct { /* Subexpression to match. */ tre_ast_node_t *arg; /* Minimum number of consecutive matches. */ int min; /* Maximum number of consecutive matches. */ int max; /* If 0, match as many characters as possible, if 1 match as few as possible. Note that this does not always mean the same thing as matching as many/few repetitions as possible. */ unsigned int minimal:1; } tre_iteration_t; /* An "union" node. These are created for the "|" operator. */ typedef struct { tre_ast_node_t *left; tre_ast_node_t *right; } tre_union_t; static tre_ast_node_t * tre_ast_new_node(tre_mem_t mem, int type, void *obj) { tre_ast_node_t *node = tre_mem_calloc(mem, sizeof *node); if (!node || !obj) return 0; node->obj = obj; node->type = type; node->nullable = -1; node->submatch_id = -1; return node; } static tre_ast_node_t * tre_ast_new_literal(tre_mem_t mem, int code_min, int code_max, int position) { tre_ast_node_t *node; tre_literal_t *lit; lit = tre_mem_calloc(mem, sizeof *lit); node = tre_ast_new_node(mem, LITERAL, lit); if (!node) return 0; lit->code_min = code_min; lit->code_max = code_max; lit->position = position; return node; } static tre_ast_node_t * tre_ast_new_iter(tre_mem_t mem, tre_ast_node_t *arg, int min, int max, int minimal) { tre_ast_node_t *node; tre_iteration_t *iter; iter = tre_mem_calloc(mem, sizeof *iter); node = tre_ast_new_node(mem, ITERATION, iter); if (!node) return 0; iter->arg = arg; iter->min = min; iter->max = max; iter->minimal = minimal; node->num_submatches = arg->num_submatches; return node; } static tre_ast_node_t * tre_ast_new_union(tre_mem_t mem, tre_ast_node_t *left, tre_ast_node_t *right) { tre_ast_node_t *node; tre_union_t *un; if (!left) return right; un = tre_mem_calloc(mem, sizeof *un); node = tre_ast_new_node(mem, UNION, un); if (!node || !right) return 0; un->left = left; un->right = right; node->num_submatches = left->num_submatches + right->num_submatches; return node; } static tre_ast_node_t * tre_ast_new_catenation(tre_mem_t mem, tre_ast_node_t *left, tre_ast_node_t *right) { tre_ast_node_t *node; tre_catenation_t *cat; if (!left) return right; cat = tre_mem_calloc(mem, sizeof *cat); node = tre_ast_new_node(mem, CATENATION, cat); if (!node) return 0; cat->left = left; cat->right = right; node->num_submatches = left->num_submatches + right->num_submatches; return node; } /*********************************************************************** from tre-stack.c and tre-stack.h ***********************************************************************/ typedef struct tre_stack_rec tre_stack_t; /* Creates a new stack object. `size' is initial size in bytes, `max_size' is maximum size, and `increment' specifies how much more space will be allocated with realloc() if all space gets used up. Returns the stack object or NULL if out of memory. */ static tre_stack_t * tre_stack_new(int size, int max_size, int increment); /* Frees the stack object. */ static void tre_stack_destroy(tre_stack_t *s); /* Returns the current number of objects in the stack. */ static int tre_stack_num_objects(tre_stack_t *s); /* Each tre_stack_push_*(tre_stack_t *s, <type> value) function pushes `value' on top of stack `s'. Returns REG_ESPACE if out of memory. This tries to realloc() more space before failing if maximum size has not yet been reached. Returns REG_OK if successful. */ #define declare_pushf(typetag, type) \ static reg_errcode_t tre_stack_push_ ## typetag(tre_stack_t *s, type value) declare_pushf(voidptr, void *); declare_pushf(int, int); /* Each tre_stack_pop_*(tre_stack_t *s) function pops the topmost element off of stack `s' and returns it. The stack must not be empty. */ #define declare_popf(typetag, type) \ static type tre_stack_pop_ ## typetag(tre_stack_t *s) declare_popf(voidptr, void *); declare_popf(int, int); /* Just to save some typing. */ #define STACK_PUSH(s, typetag, value) \ do \ { \ status = tre_stack_push_ ## typetag(s, value);