JSON_parser.c

/* Definitions for JSON_Parser */

#include <assert.h>
#include <ctype.h>
#include <float.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <locale.h>

#include "JSON_parser.h"

#ifdef _MSC_VER
#   if _MSC_VER >= 1400 
#      pragma warning(disable:4996) 
#      pragma warning(disable:4127) 
#   endif
#endif


#define true  1
#define false 0
#define __   -1     

#ifndef JSON_PARSER_STACK_SIZE
#   define JSON_PARSER_STACK_SIZE 128
#endif

#ifndef JSON_PARSER_PARSE_BUFFER_SIZE
#   define JSON_PARSER_PARSE_BUFFER_SIZE 3500
#endif

typedef void* (*JSON_debug_malloc_t)(size_t bytes, const char* reason);

#ifdef JSON_PARSER_DEBUG_MALLOC
#   define JSON_parser_malloc(func, bytes, reason) ((JSON_debug_malloc_t)func)(bytes, reason)
#else
#   define JSON_parser_malloc(func, bytes, reason) func(bytes)
#endif

typedef unsigned short UTF16;

struct JSON_parser_struct {
    JSON_parser_callback callback;
    void* ctx;
    signed char state, before_comment_state, type, escaped, comment, allow_comments, handle_floats_manually, error;
    char decimal_point;
    UTF16 utf16_high_surrogate;
    int current_char;
    int depth;
    int top;
    int stack_capacity;
    signed char* stack;
    char* parse_buffer;
    size_t parse_buffer_capacity;
    size_t parse_buffer_count;
    signed char static_stack[JSON_PARSER_STACK_SIZE];
    char static_parse_buffer[JSON_PARSER_PARSE_BUFFER_SIZE];
    JSON_malloc_t malloc;
    JSON_free_t free;
};

#define COUNTOF(x) (sizeof(x)/sizeof(x[0])) 

enum classes {
    C_SPACE,  /* space */
    C_WHITE,  /* other whitespace */
    C_LCURB,  /* {  */
    C_RCURB,  /* } */
    C_LSQRB,  /* [ */
    C_RSQRB,  /* ] */
    C_COLON,  /* : */
    C_COMMA,  /* , */
    C_QUOTE,  /* " */
    C_BACKS,  /* \ */
    C_SLASH,  /* / */
    C_PLUS,   /* + */
    C_MINUS,  /* - */
    C_POINT,  /* . */
    C_ZERO ,  /* 0 */
    C_DIGIT,  /* 123456789 */
    C_LOW_A,  /* a */
    C_LOW_B,  /* b */
    C_LOW_C,  /* c */
    C_LOW_D,  /* d */
    C_LOW_E,  /* e */
    C_LOW_F,  /* f */
    C_LOW_L,  /* l */
    C_LOW_N,  /* n */
    C_LOW_R,  /* r */
    C_LOW_S,  /* s */
    C_LOW_T,  /* t */
    C_LOW_U,  /* u */
    C_ABCDF,  /* ABCDF */
    C_E,      /* E */
    C_ETC,    /* everything else */
    C_STAR,   /* * */   
    NR_CLASSES
};

static const signed char ascii_class[128] = {
    __,      __,      __,      __,      __,      __,      __,      __,
    __,      C_WHITE, C_WHITE, __,      __,      C_WHITE, __,      __,
    __,      __,      __,      __,      __,      __,      __,      __,
    __,      __,      __,      __,      __,      __,      __,      __,

    C_SPACE, C_ETC,   C_QUOTE, C_ETC,   C_ETC,   C_ETC,   C_ETC,   C_ETC,
    C_ETC,   C_ETC,   C_STAR,   C_PLUS,  C_COMMA, C_MINUS, C_POINT, C_SLASH,
    C_ZERO,  C_DIGIT, C_DIGIT, C_DIGIT, C_DIGIT, C_DIGIT, C_DIGIT, C_DIGIT,
    C_DIGIT, C_DIGIT, C_COLON, C_ETC,   C_ETC,   C_ETC,   C_ETC,   C_ETC,

    C_ETC,   C_ABCDF, C_ABCDF, C_ABCDF, C_ABCDF, C_E,     C_ABCDF, C_ETC,
    C_ETC,   C_ETC,   C_ETC,   C_ETC,   C_ETC,   C_ETC,   C_ETC,   C_ETC,
    C_ETC,   C_ETC,   C_ETC,   C_ETC,   C_ETC,   C_ETC,   C_ETC,   C_ETC,
    C_ETC,   C_ETC,   C_ETC,   C_LSQRB, C_BACKS, C_RSQRB, C_ETC,   C_ETC,

    C_ETC,   C_LOW_A, C_LOW_B, C_LOW_C, C_LOW_D, C_LOW_E, C_LOW_F, C_ETC,
    C_ETC,   C_ETC,   C_ETC,   C_ETC,   C_LOW_L, C_ETC,   C_LOW_N, C_ETC,
    C_ETC,   C_ETC,   C_LOW_R, C_LOW_S, C_LOW_T, C_LOW_U, C_ETC,   C_ETC,
    C_ETC,   C_ETC,   C_ETC,   C_LCURB, C_ETC,   C_RCURB, C_ETC,   C_ETC
};

enum states {
    GO,  /* start    */
    OK,  /* ok       */
    OB,  /* object   */
    KE,  /* key      */
    CO,  /* colon    */
    VA,  /* value    */
    AR,  /* array    */
    ST,  /* string   */
    ES,  /* escape   */
    U1,  /* u1       */
    U2,  /* u2       */
    U3,  /* u3       */
    U4,  /* u4       */
    MI,  /* minus    */
    ZE,  /* zero     */
    IT,  /* integer  */
    FR,  /* fraction */
    E1,  /* e        */
    E2,  /* ex       */
    E3,  /* exp      */
    T1,  /* tr       */
    T2,  /* tru      */
    T3,  /* true     */
    F1,  /* fa       */
    F2,  /* fal      */
    F3,  /* fals     */
    F4,  /* false    */
    N1,  /* nu       */
    N2,  /* nul      */
    N3,  /* null     */
    C1,  /* /        */
    C2,  /* / *     */
    C3,  /* *        */
    FX,  /* *.* *eE* */
    D1,  /* second UTF-16 character decoding started by \ */
    D2,  /* second UTF-16 character proceeded by u */
    NR_STATES
};

enum actions
{
    CB = -10, /* comment begin */
    CE = -11, /* comment end */
    FA = -12, /* false */
    TR = -13, /* false */
    NU = -14, /* null */
    DE = -15, /* double detected by exponent e E */
    DF = -16, /* double detected by fraction . */
    SB = -17, /* string begin */
    MX = -18, /* integer detected by minus */
    ZX = -19, /* integer detected by zero */
    IX = -20, /* integer detected by 1-9 */
    EX = -21, /* next char is escaped */
    UC = -22  /* Unicode character read */
};


static const signed char state_transition_table[NR_STATES][NR_CLASSES] = {
/*
                 white                                      1-9                                   ABCDF  etc
             space |  {  }  [  ]  :  ,  "  \  /  +  -  .  0  |  a  b  c  d  e  f  l  n  r  s  t  u  |  E  |  * */
/*start  GO*/ {GO,GO,-6,__,-5,__,__,__,__,__,CB,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
/*ok     OK*/ {OK,OK,__,-8,__,-7,__,-3,__,__,CB,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
/*object OB*/ {OB,OB,__,-9,__,__,__,__,SB,__,CB,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
/*key    KE*/ {KE,KE,__,__,__,__,__,__,SB,__,CB,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
/*colon  CO*/ {CO,CO,__,__,__,__,-2,__,__,__,CB,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
/*value  VA*/ {VA,VA,-6,__,-5,__,__,__,SB,__,CB,__,MX,__,ZX,IX,__,__,__,__,__,FA,__,NU,__,__,TR,__,__,__,__,__},
/*array  AR*/ {AR,AR,-6,__,-5,-7,__,__,SB,__,CB,__,MX,__,ZX,IX,__,__,__,__,__,FA,__,NU,__,__,TR,__,__,__,__,__},
/*string ST*/ {ST,__,ST,ST,ST,ST,ST,ST,-4,EX,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST},
/*escape ES*/ {__,__,__,__,__,__,__,__,ST,ST,ST,__,__,__,__,__,__,ST,__,__,__,ST,__,ST,ST,__,ST,U1,__,__,__,__},
/*u1     U1*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,U2,U2,U2,U2,U2,U2,U2,U2,__,__,__,__,__,__,U2,U2,__,__},
/*u2     U2*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,U3,U3,U3,U3,U3,U3,U3,U3,__,__,__,__,__,__,U3,U3,__,__},
/*u3     U3*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,U4,U4,U4,U4,U4,U4,U4,U4,__,__,__,__,__,__,U4,U4,__,__},
/*u4     U4*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,UC,UC,UC,UC,UC,UC,UC,UC,__,__,__,__,__,__,UC,UC,__,__},
/*minus  MI*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,ZE,IT,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
/*zero   ZE*/ {OK,OK,__,-8,__,-7,__,-3,__,__,CB,__,__,DF,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
/*int    IT*/ {OK,OK,__,-8,__,-7,__,-3,__,__,CB,__,__,DF,IT,IT,__,__,__,__,DE,__,__,__,__,__,__,__,__,DE,__,__},
/*frac   FR*/ {OK,OK,__,-8,__,-7,__,-3,__,__,CB,__,__,__,FR,FR,__,__,__,__,E1,__,__,__,__,__,__,__,__,E1,__,__},
/*e      E1*/ {__,__,__,__,__,__,__,__,__,__,__,E2,E2,__,E3,E3,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
/*ex     E2*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,E3,E3,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
/*exp    E3*/ {OK,OK,__,-8,__,-7,__,-3,__,__,__,__,__,__,E3,E3,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
/*tr     T1*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,T2,__,__,__,__,__,__,__},
/*tru    T2*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,T3,__,__,__,__},
/*true   T3*/ {__,__,__,__,__,__,__,__,__,__,CB,__,__,__,__,__,__,__,__,__,OK,__,__,__,__,__,__,__,__,__,__,__},
/*fa     F1*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,F2,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
/*fal    F2*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,F3,__,__,__,__,__,__,__,__,__},
/*fals   F3*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,F4,__,__,__,__,__,__},
/*false  F4*/ {__,__,__,__,__,__,__,__,__,__,CB,__,__,__,__,__,__,__,__,__,OK,__,__,__,__,__,__,__,__,__,__,__},
/*nu     N1*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,N2,__,__,__,__},
/*nul    N2*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,N3,__,__,__,__,__,__,__,__,__},
/*null   N3*/ {__,__,__,__,__,__,__,__,__,__,CB,__,__,__,__,__,__,__,__,__,__,__,OK,__,__,__,__,__,__,__,__,__},
/*/      C1*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,C2},
/*/*     C2*/ {C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C3},
/**      C3*/ {C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,CE,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C2,C3},
/*_.     FX*/ {OK,OK,__,-8,__,-7,__,-3,__,__,__,__,__,__,FR,FR,__,__,__,__,E1,__,__,__,__,__,__,__,__,E1,__,__},
/*\      D1*/ {__,__,__,__,__,__,__,__,__,D2,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
/*\      D2*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,U1,__,__,__,__},
};

enum modes {
    MODE_ARRAY = 1, 
    MODE_DONE = 2,  
    MODE_KEY = 3,   
    MODE_OBJECT = 4
};

static void set_error(JSON_parser jc)
{
    switch (jc->state) {
        case GO:
            switch (jc->current_char) {
            case '{': case '}': case '[': case ']': 
                jc->error = JSON_E_UNBALANCED_COLLECTION;
                break;
            default:
                jc->error = JSON_E_INVALID_CHAR;
                break;    
            }
            break;
        case OB:
            jc->error = JSON_E_EXPECTED_KEY;
            break;
        case AR:
            jc->error = JSON_E_UNBALANCED_COLLECTION;
            break;
        case CO:
            jc->error = JSON_E_EXPECTED_COLON;
            break;
        case KE:
            jc->error = JSON_E_EXPECTED_KEY;
            break;
        /* \uXXXX\uYYYY */
        case U1: case U2: case U3: case U4: case D1: case D2:
            jc->error = JSON_E_INVALID_UNICODE_SEQUENCE;
            break;
        /* true, false, null */
        case T1: case T2: case T3: case F1: case F2: case F3: case F4: case N1: case N2: case N3:
            jc->error = JSON_E_INVALID_KEYWORD;
            break;
        /* minus, integer, fraction, exponent */
        case MI: case ZE: case IT: case FR: case E1: case E2: case E3:
            jc->error = JSON_E_INVALID_NUMBER;
            break;
        default:
            jc->error = JSON_E_INVALID_CHAR;
            break;
    }
}

static int
push(JSON_parser jc, int mode)
{
    assert(jc->top <= jc->stack_capacity);
    
    if (jc->depth < 0) {
        if (jc->top == jc->stack_capacity) {
            const size_t bytes_to_copy = jc->stack_capacity * sizeof(jc->stack[0]);
            const size_t new_capacity = jc->stack_capacity * 2;
            const size_t bytes_to_allocate = new_capacity * sizeof(jc->stack[0]);
            void* mem = JSON_parser_malloc(jc->malloc, bytes_to_allocate, "stack");
            if (!mem) {
                jc->error = JSON_E_OUT_OF_MEMORY;
                return false;
            }
            jc->stack_capacity = (int)new_capacity;
            memcpy(mem, jc->stack, bytes_to_copy);
            if (jc->stack != &jc->static_stack[0]) {
                jc->free(jc->stack);
            }
            jc->stack = (signed char*)mem;
        }
    } else {
        if (jc->top == jc->depth) {
            jc->error = JSON_E_NESTING_DEPTH_REACHED;
            return false;
        }
    }
    jc->stack[++jc->top] = (signed char)mode;
    return true;
}


static int
pop(JSON_parser jc, int mode)
{
    if (jc->top < 0 || jc->stack[jc->top] != mode) {
        return false;
    }
    jc->top -= 1;
    return true;
}


#define parse_buffer_clear(jc) \
    do {\
        jc->parse_buffer_count = 0;\
        jc->parse_buffer[0] = 0;\
    } while (0)
    
#define parse_buffer_pop_back_char(jc)\
    do {\
        assert(jc->parse_buffer_count >= 1);\
        --jc->parse_buffer_count;\
        jc->parse_buffer[jc->parse_buffer_count] = 0;\
    } while (0)    



void delete_JSON_parser(JSON_parser jc)
{
    if (jc) {
        if (jc->stack != &jc->static_stack[0]) {
            jc->free((void*)jc->stack);
        }
        if (jc->parse_buffer != &jc->static_parse_buffer[0]) {
            jc->free((void*)jc->parse_buffer);
        }
        jc->free((void*)jc);
     }   
}

int JSON_parser_reset(JSON_parser jc)
{
    if (NULL == jc) {
        return false;
    }
    
    jc->state = GO;
    jc->top = -1;

    /* Has the parser has been used previously? */
    if (NULL == jc->parse_buffer) {
    
        /* Do we want a non-bound stack? */
        if (jc->depth > 0) {
            jc->stack_capacity = jc->depth;
            if (jc->depth <= (int)COUNTOF(jc->static_stack)) {
                jc->stack = &jc->static_stack[0];
            } else {
                const size_t bytes_to_alloc = jc->stack_capacity * sizeof(jc->stack[0]);
                jc->stack = (signed char*)JSON_parser_malloc(jc->malloc, bytes_to_alloc, "stack");
                if (jc->stack == NULL) {
                    return false;
                }
            }
        } else {
            jc->stack_capacity = (int)COUNTOF(jc->static_stack);
            jc->depth = -1;
            jc->stack = &jc->static_stack[0];
            jc->type = JSON_T_NONE;
            jc->escaped = 0;
            jc->before_comment_state = 0;
            jc->error = 0;
        }
        
        /* Set up the parse buffer */
        jc->parse_buffer = &jc->static_parse_buffer[0];
        jc->parse_buffer_capacity = COUNTOF(jc->static_parse_buffer);
    }
    
    /* Set parser to start */
    push(jc, MODE_DONE);
    parse_buffer_clear(jc);
    
    return true;
}

JSON_parser
new_JSON_parser(JSON_config const * config)
{
    int use_std_malloc = false;
    JSON_config default_config;
    JSON_parser jc;
    JSON_malloc_t alloc;
    
    /* Set to default configuration if none was provided */
    if (NULL == config) {
        /* initialize configuration */
        init_JSON_config(&default_config);
        config = &default_config;
    }
    
    /* Use std malloc if either the allocator or deallocator function isn't set */
    use_std_malloc = NULL == config->malloc || NULL == config->free;
    
    alloc = use_std_malloc ? malloc : config->malloc;
    
    jc = (JSON_parser)JSON_parser_malloc(alloc, sizeof(*jc), "parser");    
    
    if (NULL == jc) {
        return NULL;
    }
    
    /* Configure the parser */
    memset(jc, 0, sizeof(*jc));
    jc->malloc = alloc;
    jc->free = use_std_malloc ? free : config->free;
    jc->callback = config->callback;
    jc->ctx = config->callback_ctx;
    jc->allow_comments = (signed char)(config->allow_comments != 0);
    jc->handle_floats_manually = (signed char)(config->handle_floats_manually != 0);
    jc->decimal_point = *localeconv()->decimal_point;
    /* We need to be able to push at least one object */
    jc->depth = config->depth == 0 ? 1 : config->depth;
    
    /* Reset the parser */
    if (!JSON_parser_reset(jc)) {
        jc->free(jc);
        return NULL;
    }
    
    return jc;
}

static int parse_buffer_grow(JSON_parser jc)
{
    const size_t bytes_to_copy = jc->parse_buffer_count * sizeof(jc->parse_buffer[0]);
    const size_t new_capacity = jc->parse_buffer_capacity * 2;
    const size_t bytes_to_allocate = new_capacity * sizeof(jc->parse_buffer[0]);
    void* mem = JSON_parser_malloc(jc->malloc, bytes_to_allocate, "parse buffer");
    
    if (mem == NULL) {
        jc->error = JSON_E_OUT_OF_MEMORY;
        return false;
    }
    
    assert(new_capacity > 0);
    memcpy(mem, jc->parse_buffer, bytes_to_copy);
    
    if (jc->parse_buffer != &jc->static_parse_buffer[0]) {
        jc->free(jc->parse_buffer);
    }
    
    jc->parse_buffer = (char*)mem;
    jc->parse_buffer_capacity = new_capacity;
    
    return true;
}

static int parse_buffer_reserve_for(JSON_parser jc, unsigned chars)
{
    while (jc->parse_buffer_count + chars + 1 > jc->parse_buffer_capacity) {
        if (!parse_buffer_grow(jc)) {
            assert(jc->error == JSON_E_OUT_OF_MEMORY);
            return false;
        }
    }
    
    return true;
}

#define parse_buffer_has_space_for(jc, count) \
    (jc->parse_buffer_count + (count) + 1 <= jc->parse_buffer_capacity)

#define parse_buffer_push_back_char(jc, c)\
    do {\
        assert(parse_buffer_has_space_for(jc, 1)); \
        jc->parse_buffer[jc->parse_buffer_count++] = c;\
        jc->parse_buffer[jc->parse_buffer_count]   = 0;\
    } while (0)

#define assert_is_non_container_type(jc) \
    assert( \
        jc->type == JSON_T_NULL || \
        jc->type == JSON_T_FALSE || \
        jc->type == JSON_T_TRUE || \
        jc->type == JSON_T_FLOAT || \
        jc->type == JSON_T_INTEGER || \
        jc->type == JSON_T_STRING)
    

static int parse_parse_buffer(JSON_parser jc)
{
    if (jc->callback) {
        JSON_value value, *arg = NULL;
        
        if (jc->type != JSON_T_NONE) {
            assert_is_non_container_type(jc);
        
            switch(jc->type) {
                case JSON_T_FLOAT:
                    arg = &value;
                    if (jc->handle_floats_manually) {
                        value.vu.str.value = jc->parse_buffer;
                        value.vu.str.length = jc->parse_buffer_count;
                    } else { 
                        value.vu.float_value = strtod(jc->parse_buffer, NULL);
                    }
                    break;
                case JSON_T_INTEGER:
                    arg = &value;
                    sscanf(jc->parse_buffer, JSON_PARSER_INTEGER_SSCANF_TOKEN, &value.vu.integer_value);
                    break;
                case JSON_T_STRING:
                    arg = &value;
                    value.vu.str.value = jc->parse_buffer;
                    value.vu.str.length = jc->parse_buffer_count;
                    break;
            }
            
            if (!(*jc->callback)(jc->ctx, jc->type, arg)) {
                return false;
            }
        }
    }
    
    parse_buffer_clear(jc);
    
    return true;
}

#define IS_HIGH_SURROGATE(uc) (((uc) & 0xFC00) == 0xD800)
#define IS_LOW_SURROGATE(uc)  (((uc) & 0xFC00) == 0xDC00)
#define DECODE_SURROGATE_PAIR(hi,lo) ((((hi) & 0x3FF) << 10) + ((lo) & 0x3FF) + 0x10000)
static const unsigned char utf8_lead_bits[4] = { 0x00, 0xC0, 0xE0, 0xF0 };

static int decode_unicode_char(JSON_parser jc)
{
    int i;
    unsigned uc = 0;
    char* p;
    int trail_bytes;
    
    assert(jc->parse_buffer_count >= 6);
    
    p = &jc->parse_buffer[jc->parse_buffer_count - 4];
    
    for (i = 12; i >= 0; i -= 4, ++p) {
        unsigned x = *p;
        
        if (x >= 'a') {
            x -= ('a' - 10);
        } else if (x >= 'A') {
            x -= ('A' - 10);
        } else {
            x &= ~0x30u;
        }
        
        assert(x < 16);
        
        uc |= x << i;
    }
    
    jc->parse_buffer_count -= 6;
    jc->parse_buffer[jc->parse_buffer_count] = 0;
    
    if (jc->utf16_high_surrogate) {
        if (IS_LOW_SURROGATE(uc)) {
            uc = DECODE_SURROGATE_PAIR(jc->utf16_high_surrogate, uc);
            trail_bytes = 3;
            jc->utf16_high_surrogate = 0;
        } else {
            return false;
        }
    } else {
        if (uc < 0x80) {
            trail_bytes = 0;
        } else if (uc < 0x800) {
            trail_bytes = 1;
        } else if (IS_HIGH_SURROGATE(uc)) {
            jc->utf16_high_surrogate = (UTF16)uc;
            return true;
        } else if (IS_LOW_SURROGATE(uc)) {
            return false;
        } else {
            trail_bytes = 2;
        }
    }
    
    jc->parse_buffer[jc->parse_buffer_count++] = (char) ((uc >> (trail_bytes * 6)) | utf8_lead_bits[trail_bytes]);
    
    for (i = trail_bytes * 6 - 6; i >= 0; i -= 6) {
        jc->parse_buffer[jc->parse_buffer_count++] = (char) (((uc >> i) & 0x3F) | 0x80);
    }

    jc->parse_buffer[jc->parse_buffer_count] = 0;
    
    return true;
}

static int add_escaped_char_to_parse_buffer(JSON_parser jc, int next_char)
{
    assert(parse_buffer_has_space_for(jc, 1));
    
    jc->escaped = 0;
    /* Remove the backslash */
    parse_buffer_pop_back_char(jc);
    switch(next_char) {
        case 'b':
            parse_buffer_push_back_char(jc, '\b');
            break;
        case 'f':
            parse_buffer_push_back_char(jc, '\f');
            break;
        case 'n':
            parse_buffer_push_back_char(jc, '\n');
            break;
        case 'r':
            parse_buffer_push_back_char(jc, '\r');
            break;
        case 't':
            parse_buffer_push_back_char(jc, '\t');
            break;
        case '"':
            parse_buffer_push_back_char(jc, '"');
            break;
        case '\\':
            parse_buffer_push_back_char(jc, '\\');
            break;
        case '/':
            parse_buffer_push_back_char(jc, '/');
            break;
        case 'u':
            parse_buffer_push_back_char(jc, '\\');
            parse_buffer_push_back_char(jc, 'u');
            break;
        default:
            return false;
    }

    return true;
}

static int add_char_to_parse_buffer(JSON_parser jc, int next_char, int next_class)
{
    if (!parse_buffer_reserve_for(jc, 1)) {
        assert(JSON_E_OUT_OF_MEMORY == jc->error);
        return false;
    }
    
    if (jc->escaped) {
        if (!add_escaped_char_to_parse_buffer(jc, next_char)) {
            jc->error = JSON_E_INVALID_ESCAPE_SEQUENCE;
            return false; 
        }
    } else if (!jc->comment) {
        if ((jc->type != JSON_T_NONE) | !((next_class == C_SPACE) | (next_class == C_WHITE)) /* non-white-space */) {
            parse_buffer_push_back_char(jc, (char)next_char);
        }
    }
    
    return true;
}

#define assert_type_isnt_string_null_or_bool(jc) \
    assert(jc->type != JSON_T_FALSE); \
    assert(jc->type != JSON_T_TRUE); \
    assert(jc->type != JSON_T_NULL); \
    assert(jc->type != JSON_T_STRING)


int
JSON_parser_char(JSON_parser jc, int next_char)
{
    int next_class, next_state;  
    jc->current_char = next_char;
    if (next_char < 0) {
        jc->error = JSON_E_INVALID_CHAR;
        return false;
    }
    if (next_char >= 128) {
        next_class = C_ETC;
    } else {
        next_class = ascii_class[next_char];
        if (next_class <= __) {
            set_error(jc);
            return false;
        }
    }
    
    if (!add_char_to_parse_buffer(jc, next_char, next_class)) {
        return false;
    }
    next_state = state_transition_table[jc->state][next_class];

    if (next_state >= 0) {
        jc->state = (signed char)next_state;
    } else {
   switch (next_state) {      
        case UC:
            if(!decode_unicode_char(jc)) {
                jc->error = JSON_E_INVALID_UNICODE_SEQUENCE;
                return false;
            }
            /* check if we need to read a second UTF-16 char */
            if (jc->utf16_high_surrogate) {
                jc->state = D1;
            } else {
                jc->state = ST;
            }
            break;
/* escaped char */
        case EX:
            jc->escaped = 1;
            jc->state = ES;
            break;
/* integer detected by minus */
        case MX:
            jc->type = JSON_T_INTEGER;
            jc->state = MI;
            break;  
/* integer detected by zero */            
        case ZX:
            jc->type = JSON_T_INTEGER;
            jc->state = ZE;
            break;  
/* integer detected by 1-9 */            
        case IX:
            jc->type = JSON_T_INTEGER;
            jc->state = IT;
            break;  
            
/* floating point number detected by exponent*/
        case DE:
            assert_type_isnt_string_null_or_bool(jc);
            jc->type = JSON_T_FLOAT;
            jc->state = E1;
            break;   
        
/* floating point number detected by fraction */
        case DF:
            assert_type_isnt_string_null_or_bool(jc);
            if (!jc->handle_floats_manually) {
/*
    Some versions of strtod (which underlies sscanf) don't support converting 
    C-locale formated floating point values.
*/           
                assert(jc->parse_buffer[jc->parse_buffer_count-1] == '.');
                jc->parse_buffer[jc->parse_buffer_count-1] = jc->decimal_point;
            }            
            jc->type = JSON_T_FLOAT;
            jc->state = FX;
            break;   
/* string begin " */
        case SB:
            parse_buffer_clear(jc);
            assert(jc->type == JSON_T_NONE);
            jc->type = JSON_T_STRING;
            jc->state = ST;
            break;        
        
/* n */
        case NU:
            assert(jc->type == JSON_T_NONE);
            jc->type = JSON_T_NULL;
            jc->state = N1;
            break;        
/* f */
        case FA:
            assert(jc->type == JSON_T_NONE);
            jc->type = JSON_T_FALSE;
            jc->state = F1;
            break;        
/* t */
        case TR:
            assert(jc->type == JSON_T_NONE);
            jc->type = JSON_T_TRUE;
            jc->state = T1;
            break;        
        
/* closing comment */
        case CE:
            jc->comment = 0;
            assert(jc->parse_buffer_count == 0);
            assert(jc->type == JSON_T_NONE);
            jc->state = jc->before_comment_state;
            break;        
        
/* opening comment  */
        case CB:
            if (!jc->allow_comments) {
                return false;
            }
            parse_buffer_pop_back_char(jc);
            if (!parse_parse_buffer(jc)) {
                return false;
            }
            assert(jc->parse_buffer_count == 0);
            assert(jc->type != JSON_T_STRING);
            switch (jc->stack[jc->top]) {
            case MODE_ARRAY:
            case MODE_OBJECT:   
                switch(jc->state) {
                case VA:
                case AR:
                    jc->before_comment_state = jc->state;
                    break;
                default:
                    jc->before_comment_state = OK;
                    break;
                }
                break;
            default:
                jc->before_comment_state = jc->state;
                break;
            }
            jc->type = JSON_T_NONE;
            jc->state = C1;
            jc->comment = 1;
            break;
/* empty } */
        case -9:        
            parse_buffer_clear(jc);
            if (jc->callback && !(*jc->callback)(jc->ctx, JSON_T_OBJECT_END, NULL)) {
                return false;
            }
            if (!pop(jc, MODE_KEY)) {
                return false;
            }
            jc->state = OK;
            break;

/* } */ case -8:
            parse_buffer_pop_back_char(jc);
            if (!parse_parse_buffer(jc)) {
                return false;
            }
            if (jc->callback && !(*jc->callback)(jc->ctx, JSON_T_OBJECT_END, NULL)) {
                return false;
            }
            if (!pop(jc, MODE_OBJECT)) {
                jc->error = JSON_E_UNBALANCED_COLLECTION;
                return false;
            }
            jc->type = JSON_T_NONE;
            jc->state = OK;
            break;

/* ] */ case -7:
            parse_buffer_pop_back_char(jc);
            if (!parse_parse_buffer(jc)) {
                return false;
            }
            if (jc->callback && !(*jc->callback)(jc->ctx, JSON_T_ARRAY_END, NULL)) {
                return false;
            }
            if (!pop(jc, MODE_ARRAY)) {
                jc->error = JSON_E_UNBALANCED_COLLECTION;
                return false;
            }
            
            jc->type = JSON_T_NONE;
            jc->state = OK;
            break;

/* { */ case -6:
            parse_buffer_pop_back_char(jc);
            if (jc->callback && !(*jc->callback)(jc->ctx, JSON_T_OBJECT_BEGIN, NULL)) {
                return false;
            }
            if (!push(jc, MODE_KEY)) {
                return false;
            }
            assert(jc->type == JSON_T_NONE);
            jc->state = OB;
            break;

/* [ */ case -5:
            parse_buffer_pop_back_char(jc);
            if (jc->callback && !(*jc->callback)(jc->ctx, JSON_T_ARRAY_BEGIN, NULL)) {
                return false;
            }
            if (!push(jc, MODE_ARRAY)) {
                return false;
            }
            assert(jc->type == JSON_T_NONE);
            jc->state = AR;
            break;

/* string end " */ case -4:
            parse_buffer_pop_back_char(jc);
            switch (jc->stack[jc->top]) {
            case MODE_KEY:
                assert(jc->type == JSON_T_STRING);
                jc->type = JSON_T_NONE;
                jc->state = CO;
                
                if (jc->callback) {
                    JSON_value value;
                    value.vu.str.value = jc->parse_buffer;
                    value.vu.str.length = jc->parse_buffer_count;
                    if (!(*jc->callback)(jc->ctx, JSON_T_KEY, &value)) {
                        return false;
                    }
                }
                parse_buffer_clear(jc);
                break;
            case MODE_ARRAY:
            case MODE_OBJECT:
                assert(jc->type == JSON_T_STRING);
                if (!parse_parse_buffer(jc)) {
                    return false;
                }
                jc->type = JSON_T_NONE;
                jc->state = OK;
                break;
            default:
                return false;
            }
            break;

/* , */ case -3:
            parse_buffer_pop_back_char(jc);
            if (!parse_parse_buffer(jc)) {
                return false;
            }
            switch (jc->stack[jc->top]) {
            case MODE_OBJECT:
/*
    A comma causes a flip from object mode to key mode.
*/
                if (!pop(jc, MODE_OBJECT) || !push(jc, MODE_KEY)) {
                    return false;
                }
                assert(jc->type != JSON_T_STRING);
                jc->type = JSON_T_NONE;
                jc->state = KE;
                break;
            case MODE_ARRAY:
                assert(jc->type != JSON_T_STRING);
                jc->type = JSON_T_NONE;
                jc->state = VA;
                break;
            default:
                return false;
            }
            break;

/* : */ case -2:
/*
    A colon causes a flip from key mode to object mode.
*/
            parse_buffer_pop_back_char(jc);
            if (!pop(jc, MODE_KEY) || !push(jc, MODE_OBJECT)) {
                return false;
            }
            assert(jc->type == JSON_T_NONE);
            jc->state = VA;
            break;
/*
    Bad action.
*/
        default:
            set_error(jc);
            return false;
        }
    }
    return true;
}

int
JSON_parser_done(JSON_parser jc)
{
    if ((jc->state == OK || jc->state == GO) && pop(jc, MODE_DONE))
    {
        return true;
    }

    jc->error = JSON_E_UNBALANCED_COLLECTION;
    return false;
}


int JSON_parser_is_legal_white_space_string(const char* s)
{
    int c, char_class;
    
    if (s == NULL) {
        return false;
    }
    
    for (; *s; ++s) {   
        c = *s;
        
        if (c < 0 || c >= 128) {
            return false;
        }
        
        char_class = ascii_class[c];
        
        if (char_class != C_SPACE && char_class != C_WHITE) {
            return false;
        }
    }
    
    return true;
}

int JSON_parser_get_last_error(JSON_parser jc)
{
    return jc->error;
}


void init_JSON_config(JSON_config* config)
{
    if (config) {
        memset(config, 0, sizeof(*config));
        
        config->depth = JSON_PARSER_STACK_SIZE - 1;
        config->malloc = malloc;
        config->free = free;
    }
}