diff options
Diffstat (limited to 'contrib/ccan/json/json.c')
| -rw-r--r-- | contrib/ccan/json/json.c | 1381 |
1 files changed, 1381 insertions, 0 deletions
diff --git a/contrib/ccan/json/json.c b/contrib/ccan/json/json.c new file mode 100644 index 0000000..3fd3d43 --- /dev/null +++ b/contrib/ccan/json/json.c @@ -0,0 +1,1381 @@ +/* + Copyright (C) 2011 Joseph A. Adams (joeyadams3.14159@gmail.com) + All rights reserved. + + Permission is hereby granted, free of charge, to any person obtaining a copy + of this software and associated documentation files (the "Software"), to deal + in the Software without restriction, including without limitation the rights + to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + copies of the Software, and to permit persons to whom the Software is + furnished to do so, subject to the following conditions: + + The above copyright notice and this permission notice shall be included in + all copies or substantial portions of the Software. + + THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + THE SOFTWARE. +*/ + +#include "json.h" + +#include <assert.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#define out_of_memory() do { \ + fprintf(stderr, "Out of memory.\n"); \ + exit(EXIT_FAILURE); \ + } while (0) + +/* Sadly, strdup is not portable. */ +static char *json_strdup(const char *str) +{ + char *ret = (char*) malloc(strlen(str) + 1); + if (ret == NULL) + out_of_memory(); + strcpy(ret, str); + return ret; +} + +/* String buffer */ + +typedef struct +{ + char *cur; + char *end; + char *start; +} SB; + +static void sb_init(SB *sb) +{ + sb->start = (char*) malloc(17); + if (sb->start == NULL) + out_of_memory(); + sb->cur = sb->start; + sb->end = sb->start + 16; +} + +/* sb and need may be evaluated multiple times. */ +#define sb_need(sb, need) do { \ + if ((sb)->end - (sb)->cur < (need)) \ + sb_grow(sb, need); \ + } while (0) + +static void sb_grow(SB *sb, int need) +{ + size_t length = sb->cur - sb->start; + size_t alloc = sb->end - sb->start; + + do { + alloc *= 2; + } while (alloc < length + need); + + sb->start = (char*) realloc(sb->start, alloc + 1); + if (sb->start == NULL) + out_of_memory(); + sb->cur = sb->start + length; + sb->end = sb->start + alloc; +} + +static void sb_put(SB *sb, const char *bytes, int count) +{ + sb_need(sb, count); + memcpy(sb->cur, bytes, count); + sb->cur += count; +} + +#define sb_putc(sb, c) do { \ + if ((sb)->cur >= (sb)->end) \ + sb_grow(sb, 1); \ + *(sb)->cur++ = (c); \ + } while (0) + +static void sb_puts(SB *sb, const char *str) +{ + sb_put(sb, str, strlen(str)); +} + +static char *sb_finish(SB *sb) +{ + *sb->cur = 0; + assert(sb->start <= sb->cur && strlen(sb->start) == (size_t)(sb->cur - sb->start)); + return sb->start; +} + +static void sb_free(SB *sb) +{ + free(sb->start); +} + +/* + * Unicode helper functions + * + * These are taken from the ccan/charset module and customized a bit. + * Putting them here means the compiler can (choose to) inline them, + * and it keeps ccan/json from having a dependency. + */ + +/* + * Type for Unicode codepoints. + * We need our own because wchar_t might be 16 bits. + */ +typedef uint32_t uchar_t; + +/* + * Validate a single UTF-8 character starting at @s. + * The string must be null-terminated. + * + * If it's valid, return its length (1 thru 4). + * If it's invalid or clipped, return 0. + * + * This function implements the syntax given in RFC3629, which is + * the same as that given in The Unicode Standard, Version 6.0. + * + * It has the following properties: + * + * * All codepoints U+0000..U+10FFFF may be encoded, + * except for U+D800..U+DFFF, which are reserved + * for UTF-16 surrogate pair encoding. + * * UTF-8 byte sequences longer than 4 bytes are not permitted, + * as they exceed the range of Unicode. + * * The sixty-six Unicode "non-characters" are permitted + * (namely, U+FDD0..U+FDEF, U+xxFFFE, and U+xxFFFF). + */ +static int utf8_validate_cz(const char *s) +{ + unsigned char c = *s++; + + if (c <= 0x7F) { /* 00..7F */ + return 1; + } else if (c <= 0xC1) { /* 80..C1 */ + /* Disallow overlong 2-byte sequence. */ + return 0; + } else if (c <= 0xDF) { /* C2..DF */ + /* Make sure subsequent byte is in the range 0x80..0xBF. */ + if (((unsigned char)*s++ & 0xC0) != 0x80) + return 0; + + return 2; + } else if (c <= 0xEF) { /* E0..EF */ + /* Disallow overlong 3-byte sequence. */ + if (c == 0xE0 && (unsigned char)*s < 0xA0) + return 0; + + /* Disallow U+D800..U+DFFF. */ + if (c == 0xED && (unsigned char)*s > 0x9F) + return 0; + + /* Make sure subsequent bytes are in the range 0x80..0xBF. */ + if (((unsigned char)*s++ & 0xC0) != 0x80) + return 0; + if (((unsigned char)*s++ & 0xC0) != 0x80) + return 0; + + return 3; + } else if (c <= 0xF4) { /* F0..F4 */ + /* Disallow overlong 4-byte sequence. */ + if (c == 0xF0 && (unsigned char)*s < 0x90) + return 0; + + /* Disallow codepoints beyond U+10FFFF. */ + if (c == 0xF4 && (unsigned char)*s > 0x8F) + return 0; + + /* Make sure subsequent bytes are in the range 0x80..0xBF. */ + if (((unsigned char)*s++ & 0xC0) != 0x80) + return 0; + if (((unsigned char)*s++ & 0xC0) != 0x80) + return 0; + if (((unsigned char)*s++ & 0xC0) != 0x80) + return 0; + + return 4; + } else { /* F5..FF */ + return 0; + } +} + +/* Validate a null-terminated UTF-8 string. */ +static bool utf8_validate(const char *s) +{ + int len; + + for (; *s != 0; s += len) { + len = utf8_validate_cz(s); + if (len == 0) + return false; + } + + return true; +} + +/* + * Read a single UTF-8 character starting at @s, + * returning the length, in bytes, of the character read. + * + * This function assumes input is valid UTF-8, + * and that there are enough characters in front of @s. + */ +static int utf8_read_char(const char *s, uchar_t *out) +{ + const unsigned char *c = (const unsigned char*) s; + + assert(utf8_validate_cz(s)); + + if (c[0] <= 0x7F) { + /* 00..7F */ + *out = c[0]; + return 1; + } else if (c[0] <= 0xDF) { + /* C2..DF (unless input is invalid) */ + *out = ((uchar_t)c[0] & 0x1F) << 6 | + ((uchar_t)c[1] & 0x3F); + return 2; + } else if (c[0] <= 0xEF) { + /* E0..EF */ + *out = ((uchar_t)c[0] & 0xF) << 12 | + ((uchar_t)c[1] & 0x3F) << 6 | + ((uchar_t)c[2] & 0x3F); + return 3; + } else { + /* F0..F4 (unless input is invalid) */ + *out = ((uchar_t)c[0] & 0x7) << 18 | + ((uchar_t)c[1] & 0x3F) << 12 | + ((uchar_t)c[2] & 0x3F) << 6 | + ((uchar_t)c[3] & 0x3F); + return 4; + } +} + +/* + * Write a single UTF-8 character to @s, + * returning the length, in bytes, of the character written. + * + * @unicode must be U+0000..U+10FFFF, but not U+D800..U+DFFF. + * + * This function will write up to 4 bytes to @out. + */ +static int utf8_write_char(uchar_t unicode, char *out) +{ + unsigned char *o = (unsigned char*) out; + + assert(unicode <= 0x10FFFF && !(unicode >= 0xD800 && unicode <= 0xDFFF)); + + if (unicode <= 0x7F) { + /* U+0000..U+007F */ + *o++ = unicode; + return 1; + } else if (unicode <= 0x7FF) { + /* U+0080..U+07FF */ + *o++ = 0xC0 | unicode >> 6; + *o++ = 0x80 | (unicode & 0x3F); + return 2; + } else if (unicode <= 0xFFFF) { + /* U+0800..U+FFFF */ + *o++ = 0xE0 | unicode >> 12; + *o++ = 0x80 | (unicode >> 6 & 0x3F); + *o++ = 0x80 | (unicode & 0x3F); + return 3; + } else { + /* U+10000..U+10FFFF */ + *o++ = 0xF0 | unicode >> 18; + *o++ = 0x80 | (unicode >> 12 & 0x3F); + *o++ = 0x80 | (unicode >> 6 & 0x3F); + *o++ = 0x80 | (unicode & 0x3F); + return 4; + } +} + +/* + * Compute the Unicode codepoint of a UTF-16 surrogate pair. + * + * @uc should be 0xD800..0xDBFF, and @lc should be 0xDC00..0xDFFF. + * If they aren't, this function returns false. + */ +static bool from_surrogate_pair(uint16_t uc, uint16_t lc, uchar_t *unicode) +{ + if (uc >= 0xD800 && uc <= 0xDBFF && lc >= 0xDC00 && lc <= 0xDFFF) { + *unicode = 0x10000 + ((((uchar_t)uc & 0x3FF) << 10) | (lc & 0x3FF)); + return true; + } else { + return false; + } +} + +/* + * Construct a UTF-16 surrogate pair given a Unicode codepoint. + * + * @unicode must be U+10000..U+10FFFF. + */ +static void to_surrogate_pair(uchar_t unicode, uint16_t *uc, uint16_t *lc) +{ + uchar_t n; + + assert(unicode >= 0x10000 && unicode <= 0x10FFFF); + + n = unicode - 0x10000; + *uc = ((n >> 10) & 0x3FF) | 0xD800; + *lc = (n & 0x3FF) | 0xDC00; +} + +#define is_space(c) ((c) == '\t' || (c) == '\n' || (c) == '\r' || (c) == ' ') +#define is_digit(c) ((c) >= '0' && (c) <= '9') + +static bool parse_value (const char **sp, JsonNode **out); +static bool parse_string (const char **sp, char **out); +static bool parse_number (const char **sp, double *out); +static bool parse_array (const char **sp, JsonNode **out); +static bool parse_object (const char **sp, JsonNode **out); +static bool parse_hex16 (const char **sp, uint16_t *out); + +static bool expect_literal (const char **sp, const char *str); +static void skip_space (const char **sp); + +static void emit_value (SB *out, const JsonNode *node); +static void emit_value_indented (SB *out, const JsonNode *node, const char *space, int indent_level); +static void emit_string (SB *out, const char *str); +static void emit_number (SB *out, double num); +static void emit_array (SB *out, const JsonNode *array); +static void emit_array_indented (SB *out, const JsonNode *array, const char *space, int indent_level); +static void emit_object (SB *out, const JsonNode *object); +static void emit_object_indented (SB *out, const JsonNode *object, const char *space, int indent_level); + +static int write_hex16(char *out, uint16_t val); + +static JsonNode *mknode(JsonTag tag); +static void append_node(JsonNode *parent, JsonNode *child); +static void prepend_node(JsonNode *parent, JsonNode *child); +static void append_member(JsonNode *object, char *key, JsonNode *value); + +/* Assertion-friendly validity checks */ +static bool tag_is_valid(unsigned int tag); +static bool number_is_valid(const char *num); + +JsonNode *json_decode(const char *json) +{ + const char *s = json; + JsonNode *ret; + + skip_space(&s); + if (!parse_value(&s, &ret)) + return NULL; + + skip_space(&s); + if (*s != 0) { + json_delete(ret); + return NULL; + } + + return ret; +} + +char *json_encode(const JsonNode *node) +{ + return json_stringify(node, NULL); +} + +char *json_encode_string(const char *str) +{ + SB sb; + sb_init(&sb); + + emit_string(&sb, str); + + return sb_finish(&sb); +} + +char *json_stringify(const JsonNode *node, const char *space) +{ + SB sb; + sb_init(&sb); + + if (space != NULL) + emit_value_indented(&sb, node, space, 0); + else + emit_value(&sb, node); + + return sb_finish(&sb); +} + +void json_delete(JsonNode *node) +{ + if (node != NULL) { + json_remove_from_parent(node); + + switch (node->tag) { + case JSON_STRING: + free(node->string_); + break; + case JSON_ARRAY: + case JSON_OBJECT: + { + JsonNode *child, *next; + for (child = node->children.head; child != NULL; child = next) { + next = child->next; + json_delete(child); + } + break; + } + default:; + } + + free(node); + } +} + +bool json_validate(const char *json) +{ + const char *s = json; + + skip_space(&s); + if (!parse_value(&s, NULL)) + return false; + + skip_space(&s); + if (*s != 0) + return false; + + return true; +} + +JsonNode *json_find_element(JsonNode *array, int index) +{ + JsonNode *element; + int i = 0; + + if (array == NULL || array->tag != JSON_ARRAY) + return NULL; + + json_foreach(element, array) { + if (i == index) + return element; + i++; + } + + return NULL; +} + +JsonNode *json_find_member(JsonNode *object, const char *name) +{ + JsonNode *member; + + if (object == NULL || object->tag != JSON_OBJECT) + return NULL; + + json_foreach(member, object) + if (strcmp(member->key, name) == 0) + return member; + + return NULL; +} + +JsonNode *json_first_child(const JsonNode *node) +{ + if (node != NULL && (node->tag == JSON_ARRAY || node->tag == JSON_OBJECT)) + return node->children.head; + return NULL; +} + +static JsonNode *mknode(JsonTag tag) +{ + JsonNode *ret = (JsonNode*) calloc(1, sizeof(JsonNode)); + if (ret == NULL) + out_of_memory(); + ret->tag = tag; + return ret; +} + +JsonNode *json_mknull(void) +{ + return mknode(JSON_NULL); +} + +JsonNode *json_mkbool(bool b) +{ + JsonNode *ret = mknode(JSON_BOOL); + ret->bool_ = b; + return ret; +} + +static JsonNode *mkstring(char *s) +{ + JsonNode *ret = mknode(JSON_STRING); + ret->string_ = s; + return ret; +} + +JsonNode *json_mkstring(const char *s) +{ + return mkstring(json_strdup(s)); +} + +JsonNode *json_mknumber(double n) +{ + JsonNode *node = mknode(JSON_NUMBER); + node->number_ = n; + return node; +} + +JsonNode *json_mkarray(void) +{ + return mknode(JSON_ARRAY); +} + +JsonNode *json_mkobject(void) +{ + return mknode(JSON_OBJECT); +} + +static void append_node(JsonNode *parent, JsonNode *child) +{ + child->parent = parent; + child->prev = parent->children.tail; + child->next = NULL; + + if (parent->children.tail != NULL) + parent->children.tail->next = child; + else + parent->children.head = child; + parent->children.tail = child; +} + +static void prepend_node(JsonNode *parent, JsonNode *child) +{ + child->parent = parent; + child->prev = NULL; + child->next = parent->children.head; + + if (parent->children.head != NULL) + parent->children.head->prev = child; + else + parent->children.tail = child; + parent->children.head = child; +} + +static void append_member(JsonNode *object, char *key, JsonNode *value) +{ + value->key = key; + append_node(object, value); +} + +void json_append_element(JsonNode *array, JsonNode *element) +{ + assert(array->tag == JSON_ARRAY); + assert(element->parent == NULL); + + append_node(array, element); +} + +void json_prepend_element(JsonNode *array, JsonNode *element) +{ + assert(array->tag == JSON_ARRAY); + assert(element->parent == NULL); + + prepend_node(array, element); +} + +void json_append_member(JsonNode *object, const char *key, JsonNode *value) +{ + assert(object->tag == JSON_OBJECT); + assert(value->parent == NULL); + + append_member(object, json_strdup(key), value); +} + +void json_prepend_member(JsonNode *object, const char *key, JsonNode *value) +{ + assert(object->tag == JSON_OBJECT); + assert(value->parent == NULL); + + value->key = json_strdup(key); + prepend_node(object, value); +} + +void json_remove_from_parent(JsonNode *node) +{ + JsonNode *parent = node->parent; + + if (parent != NULL) { + if (node->prev != NULL) + node->prev->next = node->next; + else + parent->children.head = node->next; + if (node->next != NULL) + node->next->prev = node->prev; + else + parent->children.tail = node->prev; + + free(node->key); + + node->parent = NULL; + node->prev = node->next = NULL; + node->key = NULL; + } +} + +static bool parse_value(const char **sp, JsonNode **out) +{ + const char *s = *sp; + + switch (*s) { + case 'n': + if (expect_literal(&s, "null")) { + if (out) + *out = json_mknull(); + *sp = s; + return true; + } + return false; + + case 'f': + if (expect_literal(&s, "false")) { + if (out) + *out = json_mkbool(false); + *sp = s; + return true; + } + return false; + + case 't': + if (expect_literal(&s, "true")) { + if (out) + *out = json_mkbool(true); + *sp = s; + return true; + } + return false; + + case '"': { + char *str; + if (parse_string(&s, out ? &str : NULL)) { + if (out) + *out = mkstring(str); + *sp = s; + return true; + } + return false; + } + + case '[': + if (parse_array(&s, out)) { + *sp = s; + return true; + } + return false; + + case '{': + if (parse_object(&s, out)) { + *sp = s; + return true; + } + return false; + + default: { + double num; + if (parse_number(&s, out ? &num : NULL)) { + if (out) + *out = json_mknumber(num); + *sp = s; + return true; + } + return false; + } + } +} + +static bool parse_array(const char **sp, JsonNode **out) +{ + const char *s = *sp; + JsonNode *ret = out ? json_mkarray() : NULL; + JsonNode *element; + + if (*s++ != '[') + goto failure; + skip_space(&s); + + if (*s == ']') { + s++; + goto success; + } + + for (;;) { + if (!parse_value(&s, out ? &element : NULL)) + goto failure; + skip_space(&s); + + if (out) + json_append_element(ret, element); + + if (*s == ']') { + s++; + goto success; + } + + if (*s++ != ',') + goto failure; + skip_space(&s); + } + +success: + *sp = s; + if (out) + *out = ret; + return true; + +failure: + json_delete(ret); + return false; +} + +static bool parse_object(const char **sp, JsonNode **out) +{ + const char *s = *sp; + JsonNode *ret = out ? json_mkobject() : NULL; + char *key; + JsonNode *value; + + if (*s++ != '{') + goto failure; + skip_space(&s); + + if (*s == '}') { + s++; + goto success; + } + + for (;;) { + if (!parse_string(&s, out ? &key : NULL)) + goto failure; + skip_space(&s); + + if (*s++ != ':') + goto failure_free_key; + skip_space(&s); + + if (!parse_value(&s, out ? &value : NULL)) + goto failure_free_key; + skip_space(&s); + + if (out) + append_member(ret, key, value); + + if (*s == '}') { + s++; + goto success; + } + + if (*s++ != ',') + goto failure; + skip_space(&s); + } + +success: + *sp = s; + if (out) + *out = ret; + return true; + +failure_free_key: + if (out) + free(key); +failure: + json_delete(ret); + return false; +} + +bool parse_string(const char **sp, char **out) +{ + const char *s = *sp; + SB sb = { NULL, NULL, NULL }; + char throwaway_buffer[4]; + /* enough space for a UTF-8 character */ + char *b; + + if (*s++ != '"') + return false; + + if (out) { + sb_init(&sb); + sb_need(&sb, 4); + b = sb.cur; + } else { + b = throwaway_buffer; + } + + while (*s != '"') { + unsigned char c = *s++; + + /* Parse next character, and write it to b. */ + if (c == '\\') { + c = *s++; + switch (c) { + case '"': + case '\\': + case '/': + *b++ = c; + break; + case 'b': + *b++ = '\b'; + break; + case 'f': + *b++ = '\f'; + break; + case 'n': + *b++ = '\n'; + break; + case 'r': + *b++ = '\r'; + break; + case 't': + *b++ = '\t'; + break; + case 'u': + { + uint16_t uc, lc; + uchar_t unicode; + + if (!parse_hex16(&s, &uc)) + goto failed; + + if (uc >= 0xD800 && uc <= 0xDFFF) { + /* Handle UTF-16 surrogate pair. */ + if (*s++ != '\\' || *s++ != 'u' || !parse_hex16(&s, &lc)) + goto failed; /* Incomplete surrogate pair. */ + if (!from_surrogate_pair(uc, lc, &unicode)) + goto failed; /* Invalid surrogate pair. */ + } else if (uc == 0) { + /* Disallow "\u0000". */ + goto failed; + } else { + unicode = uc; + } + + b += utf8_write_char(unicode, b); + break; + } + default: + /* Invalid escape */ + goto failed; + } + } else if (c <= 0x1F) { + /* Control characters are not allowed in string literals. */ + goto failed; + } else { + /* Validate and echo a UTF-8 character. */ + int len; + + s--; + len = utf8_validate_cz(s); + if (len == 0) + goto failed; /* Invalid UTF-8 character. */ + + while (len--) + *b++ = *s++; + } + + /* + * Update sb to know about the new bytes, + * and set up b to write another character. + */ + if (out) { + sb.cur = b; + sb_need(&sb, 4); + b = sb.cur; + } else { + b = throwaway_buffer; + } + } + s++; + + if (out) + *out = sb_finish(&sb); + *sp = s; + return true; + +failed: + if (out) + sb_free(&sb); + return false; +} + +/* + * The JSON spec says that a number shall follow this precise pattern + * (spaces and quotes added for readability): + * '-'? (0 | [1-9][0-9]*) ('.' [0-9]+)? ([Ee] [+-]? [0-9]+)? + * + * However, some JSON parsers are more liberal. For instance, PHP accepts + * '.5' and '1.'. JSON.parse accepts '+3'. + * + * This function takes the strict approach. + */ +bool parse_number(const char **sp, double *out) +{ + const char *s = *sp; + + /* '-'? */ + if (*s == '-') + s++; + + /* (0 | [1-9][0-9]*) */ + if (*s == '0') { + s++; + } else { + if (!is_digit(*s)) + return false; + do { + s++; + } while (is_digit(*s)); + } + + /* ('.' [0-9]+)? */ + if (*s == '.') { + s++; + if (!is_digit(*s)) + return false; + do { + s++; + } while (is_digit(*s)); + } + + /* ([Ee] [+-]? [0-9]+)? */ + if (*s == 'E' || *s == 'e') { + s++; + if (*s == '+' || *s == '-') + s++; + if (!is_digit(*s)) + return false; + do { + s++; + } while (is_digit(*s)); + } + + if (out) + *out = strtod(*sp, NULL); + + *sp = s; + return true; +} + +static void skip_space(const char **sp) +{ + const char *s = *sp; + while (is_space(*s)) + s++; + *sp = s; +} + +static void emit_value(SB *out, const JsonNode *node) +{ + assert(tag_is_valid(node->tag)); + switch (node->tag) { + case JSON_NULL: + sb_puts(out, "null"); + break; + case JSON_BOOL: + sb_puts(out, node->bool_ ? "true" : "false"); + break; + case JSON_STRING: + emit_string(out, node->string_); + break; + case JSON_NUMBER: + emit_number(out, node->number_); + break; + case JSON_ARRAY: + emit_array(out, node); + break; + case JSON_OBJECT: + emit_object(out, node); + break; + default: + assert(false); + } +} + +void emit_value_indented(SB *out, const JsonNode *node, const char *space, int indent_level) +{ + assert(tag_is_valid(node->tag)); + switch (node->tag) { + case JSON_NULL: + sb_puts(out, "null"); + break; + case JSON_BOOL: + sb_puts(out, node->bool_ ? "true" : "false"); + break; + case JSON_STRING: + emit_string(out, node->string_); + break; + case JSON_NUMBER: + emit_number(out, node->number_); + break; + case JSON_ARRAY: + emit_array_indented(out, node, space, indent_level); + break; + case JSON_OBJECT: + emit_object_indented(out, node, space, indent_level); + break; + default: + assert(false); + } +} + +static void emit_array(SB *out, const JsonNode *array) +{ + const JsonNode *element; + + sb_putc(out, '['); + json_foreach(element, array) { + emit_value(out, element); + if (element->next != NULL) + sb_putc(out, ','); + } + sb_putc(out, ']'); +} + +static void emit_array_indented(SB *out, const JsonNode *array, const char *space, int indent_level) +{ + const JsonNode *element = array->children.head; + int i; + + if (element == NULL) { + sb_puts(out, "[]"); + return; + } + + sb_puts(out, "[\n"); + while (element != NULL) { + for (i = 0; i < indent_level + 1; i++) + sb_puts(out, space); + emit_value_indented(out, element, space, indent_level + 1); + + element = element->next; + sb_puts(out, element != NULL ? ",\n" : "\n"); + } + for (i = 0; i < indent_level; i++) + sb_puts(out, space); + sb_putc(out, ']'); +} + +static void emit_object(SB *out, const JsonNode *object) +{ + const JsonNode *member; + + sb_putc(out, '{'); + json_foreach(member, object) { + emit_string(out, member->key); + sb_putc(out, ':'); + emit_value(out, member); + if (member->next != NULL) + sb_putc(out, ','); + } + sb_putc(out, '}'); +} + +static void emit_object_indented(SB *out, const JsonNode *object, const char *space, int indent_level) +{ + const JsonNode *member = object->children.head; + int i; + + if (member == NULL) { + sb_puts(out, "{}"); + return; + } + + sb_puts(out, "{\n"); + while (member != NULL) { + for (i = 0; i < indent_level + 1; i++) + sb_puts(out, space); + emit_string(out, member->key); + sb_puts(out, ": "); + emit_value_indented(out, member, space, indent_level + 1); + + member = member->next; + sb_puts(out, member != NULL ? ",\n" : "\n"); + } + for (i = 0; i < indent_level; i++) + sb_puts(out, space); + sb_putc(out, '}'); +} + +void emit_string(SB *out, const char *str) +{ + bool escape_unicode = false; + const char *s = str; + char *b; + + assert(utf8_validate(str)); + + /* + * 14 bytes is enough space to write up to two + * \uXXXX escapes and two quotation marks. + */ + sb_need(out, 14); + b = out->cur; + + *b++ = '"'; + while (*s != 0) { + unsigned char c = *s++; + + /* Encode the next character, and write it to b. */ + switch (c) { + case '"': + *b++ = '\\'; + *b++ = '"'; + break; + case '\\': + *b++ = '\\'; + *b++ = '\\'; + break; + case '\b': + *b++ = '\\'; + *b++ = 'b'; + break; + case '\f': + *b++ = '\\'; + *b++ = 'f'; + break; + case '\n': + *b++ = '\\'; + *b++ = 'n'; + break; + case '\r': + *b++ = '\\'; + *b++ = 'r'; + break; + case '\t': + *b++ = '\\'; + *b++ = 't'; + break; + default: { + int len; + + s--; + len = utf8_validate_cz(s); + + if (len == 0) { + /* + * Handle invalid UTF-8 character gracefully in production + * by writing a replacement character (U+FFFD) + * and skipping a single byte. + * + * This should never happen when assertions are enabled + * due to the assertion at the beginning of this function. + */ + assert(false); + if (escape_unicode) { + strcpy(b, "\\uFFFD"); + b += 6; + } else { + *b++ = (char)0xEF; + *b++ = (char)0xBF; + *b++ = (char)0xBD; + } + s++; + } else if (c < 0x1F || (c >= 0x80 && escape_unicode)) { + /* Encode using \u.... */ + uint32_t unicode; + + s += utf8_read_char(s, &unicode); + + if (unicode <= 0xFFFF) { + *b++ = '\\'; + *b++ = 'u'; + b += write_hex16(b, unicode); + } else { + /* Produce a surrogate pair. */ + uint16_t uc, lc; + assert(unicode <= 0x10FFFF); + to_surrogate_pair(unicode, &uc, &lc); + *b++ = '\\'; + *b++ = 'u'; + b += write_hex16(b, uc); + *b++ = '\\'; + *b++ = 'u'; + b += write_hex16(b, lc); + } + } else { + /* Write the character directly. */ + while (len--) + *b++ = *s++; + } + + break; + } + } + + /* + * Update *out to know about the new bytes, + * and set up b to write another encoded character. + */ + out->cur = b; + sb_need(out, 14); + b = out->cur; + } + *b++ = '"'; + + out->cur = b; +} + +static void emit_number(SB *out, double num) +{ + /* + * This isn't exactly how JavaScript renders numbers, + * but it should produce valid JSON for reasonable numbers + * preserve precision well enough, and avoid some oddities + * like 0.3 -> 0.299999999999999988898 . + */ + char buf[64]; + sprintf(buf, "%.16g", num); + + if (number_is_valid(buf)) + sb_puts(out, buf); + else + sb_puts(out, "null"); +} + +static bool tag_is_valid(unsigned int tag) +{ + return (/* tag >= JSON_NULL && */ tag <= JSON_OBJECT); +} + +static bool number_is_valid(const char *num) +{ + return (parse_number(&num, NULL) && *num == '\0'); +} + +static bool expect_literal(const char **sp, const char *str) +{ + const char *s = *sp; + + while (*str != '\0') + if (*s++ != *str++) + return false; + + *sp = s; + return true; +} + +/* + * Parses exactly 4 hex characters (capital or lowercase). + * Fails if any input chars are not [0-9A-Fa-f]. + */ +static bool parse_hex16(const char **sp, uint16_t *out) +{ + const char *s = *sp; + uint16_t ret = 0; + uint16_t i; + uint16_t tmp; + char c; + + for (i = 0; i < 4; i++) { + c = *s++; + if (c >= '0' && c <= '9') + tmp = c - '0'; + else if (c >= 'A' && c <= 'F') + tmp = c - 'A' + 10; + else if (c >= 'a' && c <= 'f') + tmp = c - 'a' + 10; + else + return false; + + ret <<= 4; + ret += tmp; + } + + if (out) + *out = ret; + *sp = s; + return true; +} + +/* + * Encodes a 16-bit number into hexadecimal, + * writing exactly 4 hex chars. + */ +static int write_hex16(char *out, uint16_t val) +{ + const char *hex = "0123456789ABCDEF"; + + *out++ = hex[(val >> 12) & 0xF]; + *out++ = hex[(val >> 8) & 0xF]; + *out++ = hex[(val >> 4) & 0xF]; + *out++ = hex[ val & 0xF]; + + return 4; +} + +bool json_check(const JsonNode *node, char errmsg[256]) +{ + #define problem(...) do { \ + if (errmsg != NULL) \ + snprintf(errmsg, 256, __VA_ARGS__); \ + return false; \ + } while (0) + + if (node->key != NULL && !utf8_validate(node->key)) + problem("key contains invalid UTF-8"); + + if (!tag_is_valid(node->tag)) + problem("tag is invalid (%u)", node->tag); + + if (node->tag == JSON_BOOL) { + if (node->bool_ != false && node->bool_ != true) + problem("bool_ is neither false (%d) nor true (%d)", (int)false, (int)true); + } else if (node->tag == JSON_STRING) { + if (node->string_ == NULL) + problem("string_ is NULL"); + if (!utf8_validate(node->string_)) + problem("string_ contains invalid UTF-8"); + } else if (node->tag == JSON_ARRAY || node->tag == JSON_OBJECT) { + JsonNode *head = node->children.head; + JsonNode *tail = node->children.tail; + + if (head == NULL || tail == NULL) { + if (head != NULL) + problem("tail is NULL, but head is not"); + if (tail != NULL) + problem("head is NULL, but tail is not"); + } else { + JsonNode *child; + JsonNode *last = NULL; + + if (head->prev != NULL) + problem("First child's prev pointer is not NULL"); + + for (child = head; child != NULL; last = child, child = child->next) { + if (child == node) + problem("node is its own child"); + if (child->next == child) + problem("child->next == child (cycle)"); + if (child->next == head) + problem("child->next == head (cycle)"); + + if (child->parent != node) + problem("child does not point back to parent"); + if (child->next != NULL && child->next->prev != child) + problem("child->next does not point back to child"); + + if (node->tag == JSON_ARRAY && child->key != NULL) + problem("Array element's key is not NULL"); + if (node->tag == JSON_OBJECT && child->key == NULL) + problem("Object member's key is NULL"); + + if (!json_check(child, errmsg)) + return false; + } + + if (last != tail) + problem("tail does not match pointer found by starting at head and following next links"); + } + } + + return true; + + #undef problem +} |