Added JSON_checker source
This commit is contained in:
Jordan Cristiano
parent
f4cd7f96e2
commit
b763712020
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/* JSON_checker.c */
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/* 2007-08-24 */
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/*
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Copyright (c) 2005 JSON.org
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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The Software shall be used for Good, not Evil.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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*/
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#include <stdlib.h>
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#include "JSON_checker.h"
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#define true 1
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#define false 0
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#define __ -1 /* the universal error code */
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/*
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Characters are mapped into these 31 character classes. This allows for
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a significant reduction in the size of the state transition table.
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*/
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enum classes {
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C_SPACE, /* space */
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C_WHITE, /* other whitespace */
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C_LCURB, /* { */
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C_RCURB, /* } */
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C_LSQRB, /* [ */
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C_RSQRB, /* ] */
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C_COLON, /* : */
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C_COMMA, /* , */
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C_QUOTE, /* " */
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C_BACKS, /* \ */
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C_SLASH, /* / */
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C_PLUS, /* + */
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C_MINUS, /* - */
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C_POINT, /* . */
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C_ZERO , /* 0 */
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C_DIGIT, /* 123456789 */
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C_LOW_A, /* a */
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C_LOW_B, /* b */
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C_LOW_C, /* c */
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C_LOW_D, /* d */
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C_LOW_E, /* e */
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C_LOW_F, /* f */
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C_LOW_L, /* l */
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C_LOW_N, /* n */
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C_LOW_R, /* r */
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C_LOW_S, /* s */
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C_LOW_T, /* t */
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C_LOW_U, /* u */
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C_ABCDF, /* ABCDF */
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C_E, /* E */
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C_ETC, /* everything else */
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NR_CLASSES
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};
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static int ascii_class[128] = {
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/*
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This array maps the 128 ASCII characters into character classes.
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The remaining Unicode characters should be mapped to C_ETC.
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Non-whitespace control characters are errors.
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*/
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__, __, __, __, __, __, __, __,
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__, C_WHITE, C_WHITE, __, __, C_WHITE, __, __,
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__, __, __, __, __, __, __, __,
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__, __, __, __, __, __, __, __,
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C_SPACE, C_ETC, C_QUOTE, C_ETC, C_ETC, C_ETC, C_ETC, C_ETC,
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C_ETC, C_ETC, C_ETC, C_PLUS, C_COMMA, C_MINUS, C_POINT, C_SLASH,
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C_ZERO, C_DIGIT, C_DIGIT, C_DIGIT, C_DIGIT, C_DIGIT, C_DIGIT, C_DIGIT,
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C_DIGIT, C_DIGIT, C_COLON, C_ETC, C_ETC, C_ETC, C_ETC, C_ETC,
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C_ETC, C_ABCDF, C_ABCDF, C_ABCDF, C_ABCDF, C_E, C_ABCDF, C_ETC,
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C_ETC, C_ETC, C_ETC, C_ETC, C_ETC, C_ETC, C_ETC, C_ETC,
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C_ETC, C_ETC, C_ETC, C_ETC, C_ETC, C_ETC, C_ETC, C_ETC,
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C_ETC, C_ETC, C_ETC, C_LSQRB, C_BACKS, C_RSQRB, C_ETC, C_ETC,
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C_ETC, C_LOW_A, C_LOW_B, C_LOW_C, C_LOW_D, C_LOW_E, C_LOW_F, C_ETC,
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C_ETC, C_ETC, C_ETC, C_ETC, C_LOW_L, C_ETC, C_LOW_N, C_ETC,
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C_ETC, C_ETC, C_LOW_R, C_LOW_S, C_LOW_T, C_LOW_U, C_ETC, C_ETC,
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C_ETC, C_ETC, C_ETC, C_LCURB, C_ETC, C_RCURB, C_ETC, C_ETC
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};
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/*
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The state codes.
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*/
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enum states {
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GO, /* start */
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OK, /* ok */
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OB, /* object */
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KE, /* key */
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CO, /* colon */
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VA, /* value */
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AR, /* array */
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ST, /* string */
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ES, /* escape */
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U1, /* u1 */
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U2, /* u2 */
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U3, /* u3 */
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U4, /* u4 */
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MI, /* minus */
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ZE, /* zero */
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IN, /* integer */
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FR, /* fraction */
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E1, /* e */
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E2, /* ex */
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E3, /* exp */
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T1, /* tr */
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T2, /* tru */
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T3, /* true */
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F1, /* fa */
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F2, /* fal */
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F3, /* fals */
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F4, /* false */
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N1, /* nu */
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N2, /* nul */
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N3, /* null */
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NR_STATES
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};
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static int state_transition_table[NR_STATES][NR_CLASSES] = {
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/*
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The state transition table takes the current state and the current symbol,
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and returns either a new state or an action. An action is represented as a
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negative number. A JSON text is accepted if at the end of the text the
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state is OK and if the mode is MODE_DONE.
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white 1-9 ABCDF etc
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space | { } [ ] : , " \ / + - . 0 | a b c d e f l n r s t u | E |*/
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/*start GO*/ {GO,GO,-6,__,-5,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
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/*ok OK*/ {OK,OK,__,-8,__,-7,__,-3,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
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/*object OB*/ {OB,OB,__,-9,__,__,__,__,ST,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
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/*key KE*/ {KE,KE,__,__,__,__,__,__,ST,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
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/*colon CO*/ {CO,CO,__,__,__,__,-2,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
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/*value VA*/ {VA,VA,-6,__,-5,__,__,__,ST,__,__,__,MI,__,ZE,IN,__,__,__,__,__,F1,__,N1,__,__,T1,__,__,__,__},
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/*array AR*/ {AR,AR,-6,__,-5,-7,__,__,ST,__,__,__,MI,__,ZE,IN,__,__,__,__,__,F1,__,N1,__,__,T1,__,__,__,__},
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/*string ST*/ {ST,__,ST,ST,ST,ST,ST,ST,-4,ES,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST,ST},
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/*escape ES*/ {__,__,__,__,__,__,__,__,ST,ST,ST,__,__,__,__,__,__,ST,__,__,__,ST,__,ST,ST,__,ST,U1,__,__,__},
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/*u1 U1*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,U2,U2,U2,U2,U2,U2,U2,U2,__,__,__,__,__,__,U2,U2,__},
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/*u2 U2*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,U3,U3,U3,U3,U3,U3,U3,U3,__,__,__,__,__,__,U3,U3,__},
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/*u3 U3*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,U4,U4,U4,U4,U4,U4,U4,U4,__,__,__,__,__,__,U4,U4,__},
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/*u4 U4*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,ST,ST,ST,ST,ST,ST,ST,ST,__,__,__,__,__,__,ST,ST,__},
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/*minus MI*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,ZE,IN,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
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/*zero ZE*/ {OK,OK,__,-8,__,-7,__,-3,__,__,__,__,__,FR,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
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/*int IN*/ {OK,OK,__,-8,__,-7,__,-3,__,__,__,__,__,FR,IN,IN,__,__,__,__,E1,__,__,__,__,__,__,__,__,E1,__},
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/*frac FR*/ {OK,OK,__,-8,__,-7,__,-3,__,__,__,__,__,__,FR,FR,__,__,__,__,E1,__,__,__,__,__,__,__,__,E1,__},
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/*e E1*/ {__,__,__,__,__,__,__,__,__,__,__,E2,E2,__,E3,E3,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
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/*ex E2*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,E3,E3,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
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/*exp E3*/ {OK,OK,__,-8,__,-7,__,-3,__,__,__,__,__,__,E3,E3,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
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/*tr T1*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,T2,__,__,__,__,__,__},
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/*tru T2*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,T3,__,__,__},
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/*true T3*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,OK,__,__,__,__,__,__,__,__,__,__},
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/*fa F1*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,F2,__,__,__,__,__,__,__,__,__,__,__,__,__,__},
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/*fal F2*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,F3,__,__,__,__,__,__,__,__},
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/*fals F3*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,F4,__,__,__,__,__},
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/*false F4*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,OK,__,__,__,__,__,__,__,__,__,__},
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/*nu N1*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,N2,__,__,__},
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/*nul N2*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,N3,__,__,__,__,__,__,__,__},
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/*null N3*/ {__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,__,OK,__,__,__,__,__,__,__,__},
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};
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/*
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These modes can be pushed on the stack.
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*/
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enum modes {
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MODE_ARRAY,
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MODE_DONE,
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MODE_KEY,
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MODE_OBJECT,
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};
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static int
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reject(JSON_checker jc)
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{
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/*
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Delete the JSON_checker object.
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*/
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free((void*)jc->stack);
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free((void*)jc);
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return false;
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}
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static int
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push(JSON_checker jc, int mode)
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{
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/*
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Push a mode onto the stack. Return false if there is overflow.
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*/
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jc->top += 1;
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if (jc->top >= jc->depth) {
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return false;
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}
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jc->stack[jc->top] = mode;
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return true;
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}
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static int
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pop(JSON_checker jc, int mode)
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{
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/*
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Pop the stack, assuring that the current mode matches the expectation.
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Return false if there is underflow or if the modes mismatch.
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*/
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if (jc->top < 0 || jc->stack[jc->top] != mode) {
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return false;
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}
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jc->top -= 1;
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return true;
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}
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JSON_checker
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new_JSON_checker(int depth)
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{
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/*
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new_JSON_checker starts the checking process by constructing a JSON_checker
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object. It takes a depth parameter that restricts the level of maximum
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nesting.
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To continue the process, call JSON_checker_char for each character in the
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JSON text, and then call JSON_checker_done to obtain the final result.
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These functions are fully reentrant.
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The JSON_checker object will be deleted by JSON_checker_done.
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JSON_checker_char will delete the JSON_checker object if it sees an error.
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*/
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JSON_checker jc = (JSON_checker)malloc(sizeof(struct JSON_checker_struct));
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jc->state = GO;
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jc->depth = depth;
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jc->top = -1;
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jc->stack = (int*)calloc(depth, sizeof(int));
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push(jc, MODE_DONE);
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return jc;
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}
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int
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JSON_checker_char(JSON_checker jc, int next_char)
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{
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/*
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After calling new_JSON_checker, call this function for each character (or
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partial character) in your JSON text. It can accept UTF-8, UTF-16, or
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UTF-32. It returns true if things are looking ok so far. If it rejects the
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text, it deletes the JSON_checker object and returns false.
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*/
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int next_class, next_state;
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/*
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Determine the character's class.
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*/
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if (next_char < 0) {
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return reject(jc);
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}
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if (next_char >= 128) {
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next_class = C_ETC;
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} else {
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next_class = ascii_class[next_char];
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if (next_class <= __) {
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return reject(jc);
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}
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}
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/*
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Get the next state from the state transition table.
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*/
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next_state = state_transition_table[jc->state][next_class];
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if (next_state >= 0) {
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/*
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Change the state.
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*/
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jc->state = next_state;
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} else {
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/*
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Or perform one of the actions.
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*/
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switch (next_state) {
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/* empty } */
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case -9:
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if (!pop(jc, MODE_KEY)) {
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return reject(jc);
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}
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jc->state = OK;
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break;
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/* } */ case -8:
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if (!pop(jc, MODE_OBJECT)) {
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return reject(jc);
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}
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jc->state = OK;
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break;
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/* ] */ case -7:
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if (!pop(jc, MODE_ARRAY)) {
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return reject(jc);
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}
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jc->state = OK;
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break;
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/* { */ case -6:
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if (!push(jc, MODE_KEY)) {
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return reject(jc);
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}
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jc->state = OB;
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break;
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/* [ */ case -5:
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if (!push(jc, MODE_ARRAY)) {
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return reject(jc);
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}
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jc->state = AR;
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break;
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/* " */ case -4:
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switch (jc->stack[jc->top]) {
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case MODE_KEY:
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jc->state = CO;
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break;
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case MODE_ARRAY:
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case MODE_OBJECT:
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jc->state = OK;
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break;
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default:
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return reject(jc);
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}
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break;
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/* , */ case -3:
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switch (jc->stack[jc->top]) {
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case MODE_OBJECT:
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/*
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A comma causes a flip from object mode to key mode.
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*/
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if (!pop(jc, MODE_OBJECT) || !push(jc, MODE_KEY)) {
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return reject(jc);
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}
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jc->state = KE;
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break;
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case MODE_ARRAY:
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jc->state = VA;
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break;
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default:
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return reject(jc);
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}
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break;
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/* : */ case -2:
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/*
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A colon causes a flip from key mode to object mode.
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*/
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if (!pop(jc, MODE_KEY) || !push(jc, MODE_OBJECT)) {
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return reject(jc);
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}
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jc->state = VA;
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break;
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/*
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Bad action.
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*/
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default:
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return reject(jc);
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}
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}
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return true;
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}
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int
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JSON_checker_done(JSON_checker jc)
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{
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/*
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The JSON_checker_done function should be called after all of the characters
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have been processed, but only if every call to JSON_checker_char returned
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true. This function deletes the JSON_checker and returns true if the JSON
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text was accepted.
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*/
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int result = jc->state == OK && pop(jc, MODE_DONE);
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reject(jc);
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return result;
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}
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@ -0,0 +1,13 @@
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/* JSON_checker.h */
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typedef struct JSON_checker_struct {
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int state;
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int depth;
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int top;
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int* stack;
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} * JSON_checker;
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extern JSON_checker new_JSON_checker(int depth);
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extern int JSON_checker_char(JSON_checker jc, int next_char);
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extern int JSON_checker_done(JSON_checker jc);
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