From 60fb31cfdd625ea3bc4a12a8440715c8ff0c9242 Mon Sep 17 00:00:00 2001 From: Mark Pulford Date: Sun, 1 May 2011 02:11:10 +0930 Subject: Create "cjson" Lua module, support UCS-2 escapes - Convert lua_json_init() into luaopen_cjson() to support dynamic .so loading. - Rename "json" to "cjson" to reduce conflicts with other JSON modules. - Remove unnecessary *_pcall_* API. Lua calls are fast enough, even through C. - Encode empty tables as objects - Add support for decoding all UCS-2 escape codes. --- lua_json.c | 726 ------------------------------------------------------------- 1 file changed, 726 deletions(-) delete mode 100644 lua_json.c (limited to 'lua_json.c') diff --git a/lua_json.c b/lua_json.c deleted file mode 100644 index 77a8d90..0000000 --- a/lua_json.c +++ /dev/null @@ -1,726 +0,0 @@ -/* Lua JSON routines - */ - -/* Caveats: - * - No unicode support - * - JSON "null" values are represented as lightuserdata. Compare with - * json.null. - * - Parsing comments is not support. According to json.org, this isn't - * part of the spec. - * - * Note: lua_json_decode() probably spends significant time rehashing - * tables since it is difficult to know their size ahead of time. - * Earlier JSON libaries didn't have this problem but the intermediate - * storage (and their implementations) were much slower anyway.. - */ - -/* FIXME: - * - Ensure JSON data is UTF-8. Fail otherwise. - * - Alternatively, dynamically support Unicode in JSON string. Return current locale. - * - Consider implementing other Unicode standards. - * - Option to encode non-printable characters? Only \" \\ are required - */ - -#include -#include -#include - -#include - -#include -#include - -#include "lua_json.h" -#include "strbuf.h" - -#include "die.h" - - -static void verify_arg_count(lua_State *l, int nargs) -{ - luaL_argcheck(l, lua_gettop(l) <= nargs, nargs + 1, "too many arguments"); -} - -/* ===== ENCODING ===== */ - -static void json_encode_exception(lua_State *l, strbuf_t *json, - char *location, int lindex) - -{ - strbuf_free(json); - - luaL_error(l, "Cannot serialise %s: %s", location, - lua_typename(l, lua_type(l, lindex))); -} - -/* JSON escape a character if required, or return NULL */ -static inline char *json_escape_char(int c) -{ - switch(c) { - case 0: - return "\\u0000"; - case '\\': - return "\\\\"; - case '"': - return "\\\""; - case '\b': - return "\\b"; - case '\t': - return "\\t"; - case '\n': - return "\\n"; - case '\f': - return "\\f"; - case '\r': - return "\\r"; - } - - return NULL; -} - -/* json_append_string args: - * - lua_State - * - JSON strbuf - * - String (Lua stack index) - * - * Returns nothing. Doesn't remove string from Lua stack */ -static void json_append_string(lua_State *l, strbuf_t *json, int lindex) -{ - char *p; - int i; - const char *str; - size_t len; - - str = lua_tolstring(l, lindex, &len); - - /* Worst case is len * 6 (all unicode escapes). - * This buffer is reused constantly for small strings - * If there are any excess pages, they won't be hit anyway. - * This gains ~5% speedup. */ - strbuf_ensure_empty_length(json, len * 6); - - strbuf_append_char(json, '\"'); - for (i = 0; i < len; i++) { - p = json_escape_char(str[i]); - if (p) - strbuf_append_string(json, p); - else - strbuf_append_char_unsafe(json, str[i]); - } - strbuf_append_char(json, '\"'); -} - -/* Find the size of the array on the top of the Lua stack - * -1 object (not a pure array) - * >=0 elements in array - */ -static int lua_array_length(lua_State *l) -{ - double k; - int max; - - max = 0; - - lua_pushnil(l); - /* table, startkey */ - while (lua_next(l, -2) != 0) { - /* table, key, value */ - if ((k = lua_tonumber(l, -2))) { - /* Integer >= 1 ? */ - if (floor(k) == k && k >= 1) { - if (k > max) - max = k; - lua_pop(l, 1); - continue; - } - } - - /* Must not be an array (non integer key) */ - lua_pop(l, 2); - return -1; - } - - return max; -} - -static void json_append_data(lua_State *l, strbuf_t *json); - -/* json_append_array args: - * - lua_State - * - JSON strbuf - * - Size of passwd Lua array (top of stack) */ -static void json_append_array(lua_State *l, strbuf_t *json, int array_length) -{ - int comma, i; - - strbuf_append_string(json, "[ "); - - comma = 0; - for (i = 1; i <= array_length; i++) { - if (comma) - strbuf_append_string(json, ", "); - else - comma = 1; - - lua_rawgeti(l, -1, i); - json_append_data(l, json); - lua_pop(l, 1); - } - - strbuf_append_string(json, " ]"); -} - -static void json_append_object(lua_State *l, strbuf_t *json) -{ - int comma, keytype; - - /* Object */ - strbuf_append_string(json, "{ "); - - lua_pushnil(l); - /* table, startkey */ - comma = 0; - while (lua_next(l, -2) != 0) { - if (comma) - strbuf_append_string(json, ", "); - else - comma = 1; - - /* table, key, value */ - keytype = lua_type(l, -2); - if (keytype == LUA_TNUMBER) { - strbuf_append_fmt(json, "\"" LUA_NUMBER_FMT "\": ", - lua_tonumber(l, -2)); - } else if (keytype == LUA_TSTRING) { - json_append_string(l, json, -2); - strbuf_append_string(json, ": "); - } else { - json_encode_exception(l, json, "table key", -2); - /* never returns */ - } - - /* table, key, value */ - json_append_data(l, json); - lua_pop(l, 1); - /* table, key */ - } - - strbuf_append_string(json, " }"); -} - -/* Serialise Lua data into JSON string. */ -static void json_append_data(lua_State *l, strbuf_t *json) -{ - int len; - - switch (lua_type(l, -1)) { - case LUA_TSTRING: - json_append_string(l, json, -1); - break; - case LUA_TNUMBER: - strbuf_append_fmt(json, "%lf", lua_tonumber(l, -1)); - break; - case LUA_TBOOLEAN: - if (lua_toboolean(l, -1)) - strbuf_append_string(json, "true"); - else - strbuf_append_string(json, "false"); - break; - case LUA_TTABLE: - len = lua_array_length(l); - if (len >= 0) - json_append_array(l, json, len); - else - json_append_object(l, json); - break; - case LUA_TNIL: - strbuf_append_string(json, "null"); - break; - case LUA_TLIGHTUSERDATA: - if (lua_touserdata(l, -1) == NULL) { - strbuf_append_string(json, "null"); - break; - } - default: - /* Remaining types (LUA_TFUNCTION, LUA_TUSERDATA, LUA_TTHREAD, - * and LUA_TLIGHTUSERDATA) cannot be serialised */ - json_encode_exception(l, json, "value", -1); - /* never returns */ - } -} - -/* lua_json_encode can throw an exception */ -char *lua_json_encode(lua_State *l, int *len) -{ - strbuf_t buf; - char *json; - - strbuf_init(&buf, 0); - json_append_data(l, &buf); - json = strbuf_free_to_string(&buf, len); - - return json; -} - -/* lua_json_pcall_encode(object) must be called via lua_pcall(). - * This allows a C caller to catch any errors without needing - * to register the string with Lua for garbage collection. */ -int lua_json_pcall_encode(lua_State *l) -{ - char *json; - int len; - - verify_arg_count(l, 1); - - json = lua_json_encode(l, &len); - - lua_pushlightuserdata(l, json); - lua_pushnumber(l, len); - - return 2; -} - -int lua_api_json_encode(lua_State *l) -{ - char *json; - int len; - - json = lua_json_encode(l, &len); - lua_pushlstring(l, json, len); - free(json); - - return 1; -} - -/* ===== DECODING ===== */ - -typedef struct { - const char *data; - int index; - strbuf_t *tmp; /* Temporary storage for strings */ -} json_parse_t; - -typedef enum { - T_OBJ_BEGIN, - T_OBJ_END, - T_ARR_BEGIN, - T_ARR_END, - T_STRING, - T_NUMBER, - T_BOOLEAN, - T_NULL, - T_COLON, - T_COMMA, - T_END, - T_WHITESPACE, - T_ERROR, - T_UNKNOWN -} json_token_type_t; - -static const char *json_token_type_name[] = { - "T_OBJ_BEGIN", - "T_OBJ_END", - "T_ARR_BEGIN", - "T_ARR_END", - "T_STRING", - "T_NUMBER", - "T_BOOLEAN", - "T_NULL", - "T_COLON", - "T_COMMA", - "T_END", - "T_WHITESPACE", - "T_ERROR", - "T_UNKNOWN", - NULL -}; - -typedef struct { - json_token_type_t type; - int index; - union { - char *string; - double number; - int boolean; - } value; - int length; /* FIXME: Merge into union? Won't save memory, but more logical */ -} json_token_t; - -static void json_process_value(lua_State *l, json_parse_t *json, json_token_t *token); - -static json_token_type_t json_ch2token[256]; -static char json_ch2escape[256]; - -static void json_global_init() -{ - int i; - - /* Tag all characters as an error */ - for (i = 0; i < 256; i++) - json_ch2token[i] = T_ERROR; - - /* Set tokens that require no further processing */ - json_ch2token['{'] = T_OBJ_BEGIN; - json_ch2token['}'] = T_OBJ_END; - json_ch2token['['] = T_ARR_BEGIN; - json_ch2token[']'] = T_ARR_END; - json_ch2token[','] = T_COMMA; - json_ch2token[':'] = T_COLON; - json_ch2token['\0'] = T_END; - json_ch2token[' '] = T_WHITESPACE; - json_ch2token['\t'] = T_WHITESPACE; - json_ch2token['\n'] = T_WHITESPACE; - json_ch2token['\r'] = T_WHITESPACE; - - /* Update characters that require further processing */ - json_ch2token['n'] = T_UNKNOWN; - json_ch2token['t'] = T_UNKNOWN; - json_ch2token['f'] = T_UNKNOWN; - json_ch2token['"'] = T_UNKNOWN; - json_ch2token['-'] = T_UNKNOWN; - for (i = 0; i < 10; i++) - json_ch2token['0' + i] = T_UNKNOWN; - - for (i = 0; i < 256; i++) - json_ch2escape[i] = 0; /* String error */ - - json_ch2escape['"'] = '"'; - json_ch2escape['\\'] = '\\'; - json_ch2escape['/'] = '/'; - json_ch2escape['b'] = '\b'; - json_ch2escape['t'] = '\t'; - json_ch2escape['n'] = '\n'; - json_ch2escape['f'] = '\f'; - json_ch2escape['r'] = '\r'; - json_ch2escape['u'] = 'u'; /* This needs to be parsed as unicode */ -} - -static void json_next_string_token(json_parse_t *json, json_token_t *token) -{ - char ch; - - /* Caller must ensure a string is next */ - assert(json->data[json->index] == '"'); - - /* Gobble string. FIXME, ugly */ - - json->tmp->length = 0; - while ((ch = json->data[++json->index]) != '"') { - /* Handle escapes */ - if (ch == '\\') { - /* Translate escape code */ - ch = json_ch2escape[(unsigned char)json->data[++json->index]]; - if (!ch) { - /* Invalid escape code */ - token->type = T_ERROR; - return; - } - if (ch == 'u') { - /* Process unicode */ - /* FIXME: cleanup memory handling. Implement iconv(3) - * conversion from UCS-2 -> UTF-8 - */ - if (!memcmp(&json->data[json->index], "u0000", 5)) { - /* Handle NULL */ - ch = 0; - json->index += 4; - } else { - /* Remaining codepoints unhandled */ - token->type = T_ERROR; - return; - } - } - } - strbuf_append_char(json->tmp, ch); - } - json->index++; /* Eat final quote (") */ - - strbuf_ensure_null(json->tmp); - - token->type = T_STRING; - token->value.string = strbuf_string(json->tmp, NULL); - token->length = json->tmp->length; -} - -static void json_next_number_token(json_parse_t *json, json_token_t *token) -{ - const char *startptr; - char *endptr; - - /* FIXME: - * Verify that the number takes the following form: - * -?(0|[1-9]|[1-9][0-9]+)(.[0-9]+)?([eE][-+]?[0-9]+)? - * strtod() below allows other forms (Hex, infinity, NaN,..) */ - /* i = json->index; - if (json->data[i] == '-') - i++; - j = i; - while ('0' <= json->data[i] && json->data[i] <= '9') - i++; - if (i == j) - return T_ERROR; */ - - token->type = T_NUMBER; - startptr = &json->data[json->index]; - token->value.number = strtod(&json->data[json->index], &endptr); - if (startptr == endptr) - token->type = T_ERROR; - else - json->index += endptr - startptr; /* Skip the processed number */ - - return; -} - -/* Fills in the token struct. - * T_STRING will return a pointer to the json_parse_t temporary string - * T_ERROR will leave the json->index pointer at the error. - */ -static void json_next_token(json_parse_t *json, json_token_t *token) -{ - int ch; - - /* Eat whitespace. FIXME: UGLY */ - token->type = json_ch2token[(unsigned char)json->data[json->index]]; - while (token->type == T_WHITESPACE) - token->type = json_ch2token[(unsigned char)json->data[++json->index]]; - - token->index = json->index; - - /* Don't advance the pointer for an error or the end */ - if (token->type == T_ERROR || token->type == T_END) - return; - - /* Found a known token, advance index and return */ - if (token->type != T_UNKNOWN) { - json->index++; - return; - } - - /* Process characters which triggered T_UNKNOWN */ - ch = json->data[json->index]; - - if (ch == '"') { - json_next_string_token(json, token); - return; - } else if (ch == '-' || ('0' <= ch && ch <= '9')) { - json_next_number_token(json, token); - return; - } else if (!strncmp(&json->data[json->index], "true", 4)) { - token->type = T_BOOLEAN; - token->value.boolean = 1; - json->index += 4; - return; - } else if (!strncmp(&json->data[json->index], "false", 5)) { - token->type = T_BOOLEAN; - token->value.boolean = 0; - json->index += 5; - return; - } else if (!strncmp(&json->data[json->index], "null", 4)) { - token->type = T_NULL; - json->index += 4; - return; - } - - token->type = T_ERROR; -} - -/* This function does not return. - * DO NOT CALL WITH DYNAMIC MEMORY ALLOCATED. - * The only supported exception is the temporary parser string - * json->tmp struct. - * json and token should exist on the stack somewhere. - * luaL_error() will long_jmp and release the stack */ -static void json_throw_parse_error(lua_State *l, json_parse_t *json, - const char *exp, json_token_t *token) -{ - strbuf_free(json->tmp); - luaL_error(l, "Expected %s but found type <%s> at character %d", - exp, json_token_type_name[token->type], token->index); -} - -static void json_parse_object_context(lua_State *l, json_parse_t *json) -{ - json_token_t token; - - /* 3 slots required: - * .., table, key, value */ - luaL_checkstack(l, 3, "too many nested data structures"); - - lua_newtable(l); - - json_next_token(json, &token); - - /* Handle empty objects */ - if (token.type == T_OBJ_END) - return; - - while (1) { - if (token.type != T_STRING) - json_throw_parse_error(l, json, "object key", &token); - - lua_pushlstring(l, token.value.string, token.length); /* Push key */ - - json_next_token(json, &token); - if (token.type != T_COLON) - json_throw_parse_error(l, json, "colon", &token); - - json_next_token(json, &token); - json_process_value(l, json, &token); - lua_rawset(l, -3); /* Set key = value */ - - json_next_token(json, &token); - - if (token.type == T_OBJ_END) - return; - - if (token.type != T_COMMA) - json_throw_parse_error(l, json, "comma or object end", &token); - - json_next_token(json, &token); - } -} - -/* Handle the array context */ -static void json_parse_array_context(lua_State *l, json_parse_t *json) -{ - json_token_t token; - int i; - - /* 2 slots required: - * .., table, value */ - luaL_checkstack(l, 2, "too many nested data structures"); - - lua_newtable(l); - - json_next_token(json, &token); - - /* Handle empty arrays */ - if (token.type == T_ARR_END) - return; - - i = 1; - while (1) { - json_process_value(l, json, &token); - lua_rawseti(l, -2, i); /* arr[i] = value */ - - json_next_token(json, &token); - - if (token.type == T_ARR_END) - return; - - if (token.type != T_COMMA) - json_throw_parse_error(l, json, "comma or array end", &token); - - json_next_token(json, &token); - i++; - } -} - -/* Handle the "value" context */ -static void json_process_value(lua_State *l, json_parse_t *json, json_token_t *token) -{ - switch (token->type) { - case T_STRING: - lua_pushlstring(l, token->value.string, token->length); - break;; - case T_NUMBER: - lua_pushnumber(l, token->value.number); - break;; - case T_BOOLEAN: - lua_pushboolean(l, token->value.boolean); - break;; - case T_OBJ_BEGIN: - json_parse_object_context(l, json); - break;; - case T_ARR_BEGIN: - json_parse_array_context(l, json); - break;; - case T_NULL: - /* In Lua, setting "t[k] = nil" will delete k from the table. - * Hence a NULL pointer lightuserdata object is used instead */ - lua_pushlightuserdata(l, NULL); - break;; - default: - json_throw_parse_error(l, json, "value", token); - } -} - -/* json_text must be null terminated string */ -void lua_json_decode(lua_State *l, const char *json_text) -{ - json_parse_t json; - json_token_t token; - - json.data = json_text; - json.index = 0; - json.tmp = strbuf_new(0); - - json_next_token(&json, &token); - json_process_value(l, &json, &token); - - /* Ensure there is no more input left */ - json_next_token(&json, &token); - - if (token.type != T_END) - json_throw_parse_error(l, &json, "the end", &token); - - strbuf_free(json.tmp); -} - -/* lua_json_pcall_decode(string) must be called via lua_pcall(). - * This allows a C caller to catch any errors so the string can - * be freed before returning to Lua. */ -int lua_json_pcall_decode(lua_State *l) -{ - const char *json; - - verify_arg_count(l, 1); - luaL_argcheck(l, lua_islightuserdata(l, 1), 1, - "missing lightuserdata"); - - json = lua_touserdata(l, 1); - lua_pop(l, 1); - - lua_json_decode(l, json); - - return 1; -} - -static int lua_api_json_decode(lua_State *l) -{ - const char *json; - - verify_arg_count(l, 1); - json = luaL_checkstring(l, 1); - - lua_json_decode(l, json); - - lua_remove(l, 1); - - return 1; -} - -/* ===== INITIALISATION ===== */ - -static pthread_once_t json_global_init_once = PTHREAD_ONCE_INIT; - -void lua_json_init(lua_State *l) -{ - luaL_Reg reg[] = { - { "encode", lua_api_json_encode }, - { "decode", lua_api_json_decode }, - { NULL, NULL } - }; - - luaL_register(l, "json", reg); - - /* Set json.null, and pop "json" table from the stack */ - lua_pushlightuserdata(l, NULL); - lua_setfield(l, -2, "null"); - lua_pop(l, 1); - - SYS_NOFAIL(pthread_once(&json_global_init_once, json_global_init)); -} - -/* vi:ai et sw=4 ts=4: - */ -- cgit v1.2.3-55-g6feb