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	json.c - tscrape - twitter scraper (not working anymore)
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	---
	json.c (7806B)
	---
	1 #include <ctype.h>
	2 #include <errno.h>
	3 #include <stdint.h>
	4 #include <stdio.h>
	5 #include <stdlib.h>
	6 #include <string.h>
	7
	8 #define GETNEXT getchar
	9
	10 #include "json.h"
	11
	12 static int
	13 codepointtoutf8(long r, char *s)
	14 {
	15 if (r == 0) {
	16 return 0; /* NUL byte */
	17 } else if (r <= 0x7F) {
	18 /* 1 byte: 0aaaaaaa */
	19 s[0] = r;
	20 return 1;
	21 } else if (r <= 0x07FF) {
	22 /* 2 bytes: 00000aaa aabbbbbb */
	23 s[0] = 0xC0 \| ((r & 0x0007C0) >> 6); /* 110aaaaa */
	24 s[1] = 0x80 \| (r & 0x00003F); /* 10bbbbbb */
	25 return 2;
	26 } else if (r <= 0xFFFF) {
	27 /* 3 bytes: aaaabbbb bbcccccc */
	28 s[0] = 0xE0 \| ((r & 0x00F000) >> 12); /* 1110aaaa */
	29 s[1] = 0x80 \| ((r & 0x000FC0) >> 6); /* 10bbbbbb */
	30 s[2] = 0x80 \| (r & 0x00003F); /* 10cccccc */
	31 return 3;
	32 } else {
	33 /* 4 bytes: 000aaabb bbbbcccc ccdddddd */
	34 s[0] = 0xF0 \| ((r & 0x1C0000) >> 18); /* 11110aaa */
	35 s[1] = 0x80 \| ((r & 0x03F000) >> 12); /* 10bbbbbb */
	36 s[2] = 0x80 \| ((r & 0x000FC0) >> 6); /* 10cccccc */
	37 s[3] = 0x80 \| (r & 0x00003F); /* 10dddddd */
	38 return 4;
	39 }
	40 }
	41
	42 static int
	43 hexdigit(int c)
	44 {
	45 if (c >= '0' && c <= '9')
	46 return c - '0';
	47 else if (c >= 'a' && c <= 'f')
	48 return 10 + (c - 'a');
	49 else if (c >= 'A' && c <= 'F')
	50 return 10 + (c - 'A');
	51 return 0;
	52 }
	53
	54 static int
	55 capacity(char *value, size_t sz, size_t cur, size_t inc)
	56 {
	57 size_t need, newsiz;
	58 char *newp;
	59
	60 /* check for addition overflow */
	61 if (cur > SIZE_MAX - inc) {
	62 errno = EOVERFLOW;
	63 return -1;
	64 }
	65 need = cur + inc;
	66
	67 if (need > *sz) {
	68 if (need > SIZE_MAX / 2) {
	69 newsiz = SIZE_MAX;
	70 } else {
	71 for (newsiz = sz < 64 ? 64 : sz; newsiz <= nee…
	72 ;
	73 }
	74 if (!(newp = realloc(*value, newsiz)))
	75 return -1; /* up to caller to free value /
	76 *value = newp;
	77 *sz = newsiz;
	78 }
	79 return 0;
	80 }
	81
	82 #define EXPECT_VALUE "{[\"-0123456789tfn"
	83 #define EXPECT_STRING "\""
	84 #define EXPECT_END "}],"
	85 #define EXPECT_OBJECT_STRING EXPECT_STRING "}"
	86 #define EXPECT_OBJECT_KEY ":"
	87 #define EXPECT_ARRAY_VALUE EXPECT_VALUE "]"
	88
	89 #define JSON_INVALID() do { ret = JSON_ERROR_INVALID; goto end; } …
	90
	91 int
	92 parsejson(void (cb)(struct json_node , size_t, const char *))
	93 {
	94 struct json_node nodes[JSON_MAX_NODE_DEPTH] = { 0 };
	95 size_t depth = 0, p = 0, len, sz = 0;
	96 long cp, hi, lo;
	97 char pri[128], *str = NULL;
	98 int c, i, escape, iskey = 0, ret = JSON_ERROR_MEM;
	99 const char *expect = EXPECT_VALUE;
	100
	101 if (capacity(&(nodes[0].name), &(nodes[0].namesiz), 0, 1) == -1)
	102 goto end;
	103 nodes[0].name[0] = '\0';
	104
	105 while (1) {
	106 c = GETNEXT();
	107 handlechr:
	108 if (c == EOF)
	109 break;
	110
	111 /* skip JSON white-space, (NOTE: no \v, \f, \b etc) */
	112 if (c == ' ' \|\| c == '\t' \|\| c == '\n' \|\| c == '\r')
	113 continue;
	114
	115 if (!c \|\| !strchr(expect, c))
	116 JSON_INVALID();
	117
	118 switch (c) {
	119 case ':':
	120 iskey = 0;
	121 expect = EXPECT_VALUE;
	122 break;
	123 case '"':
	124 nodes[depth].type = JSON_TYPE_STRING;
	125 escape = 0;
	126 len = 0;
	127 while (1) {
	128 c = GETNEXT();
	129 chr:
	130 /* EOF or control char: 0x7f is not defi…
	131 if (c < 0x20)
	132 JSON_INVALID();
	133
	134 if (escape) {
	135 escchr:
	136 escape = 0;
	137 switch (c) {
	138 case '"': /* FALLTHROUGH */
	139 case '\\':
	140 case '/': break;
	141 case 'b': c = '\b'; break;
	142 case 'f': c = '\f'; break;
	143 case 'n': c = '\n'; break;
	144 case 'r': c = '\r'; break;
	145 case 't': c = '\t'; break;
	146 case 'u': /* hex hex hex hex */
	147 if (capacity(&str, &sz, …
	148 goto end;
	149 for (i = 12, cp = 0; i >…
	150 if ((c = GETNEXT…
	151 JSON_INV…
	152 cp \|= (hexdigit(…
	153 }
	154 /* RFC8259 - 7. Strings …
	155 * 0xd800 - 0xdb7f - hig…
	156 if (cp >= 0xd800 && cp <…
	157 if ((c = GETNEXT…
	158 len += c…
	159 goto chr;
	160 }
	161 if ((c = GETNEXT…
	162 len += c…
	163 goto esc…
	164 }
	165 for (hi = cp, i …
	166 if ((c =…
	167 …
	168 lo \|= (h…
	169 }
	170 /* 0xdc00 - 0xdf…
	171 if (lo >= 0xdc00…
	172 cp = (hi…
	173 } else {
	174 /* handl…
	175 len += c…
	176 if (capa…
	177 …
	178 len += c…
	179 continue;
	180 }
	181 }
	182 len += codepointtoutf8(c…
	183 continue;
	184 default:
	185 JSON_INVALID(); /* inval…
	186 }
	187 if (capacity(&str, &sz, len, 1) …
	188 goto end;
	189 str[len++] = c;
	190 } else if (c == '\\') {
	191 escape = 1;
	192 } else if (c == '"') {
	193 if (capacity(&str, &sz, len, 1) …
	194 goto end;
	195 str[len++] = '\0';
	196
	197 if (iskey) {
	198 /* copy string as key, i…
	199 if (capacity(&(nodes[dep…
	200 goto end;
	201 memcpy(nodes[depth].name…
	202 } else {
	203 cb(nodes, depth + 1, str…
	204 }
	205 break;
	206 } else {
	207 if (capacity(&str, &sz, len, 1) …
	208 goto end;
	209 str[len++] = c;
	210 }
	211 }
	212 if (iskey)
	213 expect = EXPECT_OBJECT_KEY;
	214 else
	215 expect = EXPECT_END;
	216 break;
	217 case '[':
	218 case '{':
	219 if (depth + 1 >= JSON_MAX_NODE_DEPTH)
	220 JSON_INVALID(); /* too deep */
	221
	222 nodes[depth].index = 0;
	223 if (c == '[') {
	224 nodes[depth].type = JSON_TYPE_ARRAY;
	225 expect = EXPECT_ARRAY_VALUE;
	226 } else if (c == '{') {
	227 iskey = 1;
	228 nodes[depth].type = JSON_TYPE_OBJECT;
	229 expect = EXPECT_OBJECT_STRING;
	230 }
	231
	232 cb(nodes, depth + 1, "");
	233
	234 depth++;
	235 nodes[depth].index = 0;
	236 if (capacity(&(nodes[depth].name), &(nodes[depth…
	237 goto end;
	238 nodes[depth].name[0] = '\0';
	239 break;
	240 case ']':
	241 case '}':
	242 if (!depth \|\|
	243 (c == ']' && nodes[depth - 1].type != JSON_TY…
	244 (c == '}' && nodes[depth - 1].type != JSON_TY…
	245 JSON_INVALID(); /* unbalanced nodes */
	246
	247 nodes[--depth].index++;
	248 expect = EXPECT_END;
	249 break;
	250 case ',':
	251 if (!depth)
	252 JSON_INVALID(); /* unbalanced nodes */
	253
	254 nodes[depth - 1].index++;
	255 if (nodes[depth - 1].type == JSON_TYPE_OBJECT) {
	256 iskey = 1;
	257 expect = EXPECT_STRING;
	258 } else {
	259 expect = EXPECT_VALUE;
	260 }
	261 break;
	262 case 't': /* true */
	263 if (GETNEXT() != 'r' \|\| GETNEXT() != 'u' \|\| GETN…
	264 JSON_INVALID();
	265 nodes[depth].type = JSON_TYPE_BOOL;
	266 cb(nodes, depth + 1, "true");
	267 expect = EXPECT_END;
	268 break;
	269 case 'f': /* false */
	270 if (GETNEXT() != 'a' \|\| GETNEXT() != 'l' \|\| GETN…
	271 GETNEXT() != 'e')
	272 JSON_INVALID();
	273 nodes[depth].type = JSON_TYPE_BOOL;
	274 cb(nodes, depth + 1, "false");
	275 expect = EXPECT_END;
	276 break;
	277 case 'n': /* null */
	278 if (GETNEXT() != 'u' \|\| GETNEXT() != 'l' \|\| GETN…
	279 JSON_INVALID();
	280 nodes[depth].type = JSON_TYPE_NULL;
	281 cb(nodes, depth + 1, "null");
	282 expect = EXPECT_END;
	283 break;
	284 default: /* number */
	285 nodes[depth].type = JSON_TYPE_NUMBER;
	286 p = 0;
	287 pri[p++] = c;
	288 expect = EXPECT_END;
	289 while (1) {
	290 c = GETNEXT();
	291 if (c == EOF \|\|
	292 !c \|\| !strchr("0123456789eE+-.", c) …
	293 p + 1 >= sizeof(pri)) {
	294 pri[p] = '\0';
	295 cb(nodes, depth + 1, pri);
	296 goto handlechr; /* do not read n…
	297 } else {
	298 pri[p++] = c;
	299 }
	300 }
	301 }
	302 }
	303 if (depth)
	304 JSON_INVALID(); /* unbalanced nodes */
	305
	306 ret = 0; /* success */
	307 end:
	308 for (depth = 0; depth < sizeof(nodes) / sizeof(nodes[0]); depth+…
	309 free(nodes[depth].name);
	310 free(str);
	311
	312 return ret;
	313 }