diff options
Diffstat (limited to 'src/contrib/json.c')
| -rw-r--r-- | src/contrib/json.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/src/contrib/json.c b/src/contrib/json.c new file mode 100644 index 0000000..8b8bda4 --- /dev/null +++ b/src/contrib/json.c @@ -0,0 +1,237 @@ +/* Copyright (C) 2022 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <assert.h> +#include <stdlib.h> +#include <string.h> + +#include "contrib/json.h" + +#include "contrib/string.h" + +#define MAX_DEPTH 8 + +enum { + BLOCK_INVALID = 0, + BLOCK_OBJECT, + BLOCK_LIST, +}; + +/*! One indented block of JSON. */ +struct block { + /*! Block type. */ + int type; + /*! Number of elements written. */ + int count; +}; + +struct jsonw { + /*! Output file stream. */ + FILE *out; + /*! Indentaiton string. */ + const char *indent; + /*! List to be used as a stack of blocks in progress. */ + struct block stack[MAX_DEPTH]; + /*! Index pointing to the top of the stack. */ + int top; + /*! Newline needed indication. */ + bool wrap; +}; + +static const char *DEFAULT_INDENT = "\t"; + +static void start_block(jsonw_t *w, int type) +{ + assert(w->top > 0); + + struct block b = { + .type = type, + .count = 0, + }; + + w->top -= 1; + w->stack[w->top] = b; +} + +static struct block *cur_block(jsonw_t *w) +{ + if (w && w->top < MAX_DEPTH) { + return &w->stack[w->top]; + } + return NULL; +} + +/*! Insert new line and indent for the next write. */ +static void wrap(jsonw_t *w) +{ + if (!w->wrap) { + w->wrap = true; + return; + } + + fputc('\n', w->out); + int level = MAX_DEPTH - w->top; + for (int i = 0; i < level; i++) { + fprintf(w->out, "%s", w->indent); + } +} + +static void end_block(jsonw_t *w) +{ + assert(w->top < MAX_DEPTH); + + w->top += 1; +} + +static void escaped_print(jsonw_t *w, const char *str) +{ + fputc('"', w->out); + for (const char *pos = str; *pos != '\0'; pos++) { + char c = *pos; + if (c == '\\' || c == '\"') { + fputc('\\', w->out); + } + fputc(c, w->out); + } + fputc('"', w->out); +} + +static void align_key(jsonw_t *w, const char *key) +{ + struct block *top = cur_block(w); + if (top && top->count++) { + fputc(',', w->out); + } + + wrap(w); + + if (key && key[0]) { + escaped_print(w, key); + fprintf(w->out, ": "); + } +} + +jsonw_t *jsonw_new(FILE *out, const char *indent) +{ + assert(out); + + jsonw_t *w = calloc(1, sizeof(*w)); + if (w == NULL) { + return w; + } + + w->out = out; + w->indent = indent ? indent : DEFAULT_INDENT; + w->top = MAX_DEPTH; + + return w; +} + +void jsonw_free(jsonw_t **w) +{ + if (w == NULL) { + return; + } + + wrap(*w); + + free(*w); + *w = NULL; +} + +void jsonw_object(jsonw_t *w, const char *key) +{ + assert(w); + + align_key(w, key); + fprintf(w->out, "{"); + start_block(w, BLOCK_OBJECT); +} + +void jsonw_list(jsonw_t *w, const char *key) +{ + assert(w); + + align_key(w, key); + fprintf(w->out, "["); + start_block(w, BLOCK_LIST); +} + +void jsonw_str(jsonw_t *w, const char *key, const char *value) +{ + assert(w); + + align_key(w, key); + escaped_print(w, value); +} + +void jsonw_ulong(jsonw_t *w, const char *key, unsigned long value) +{ + assert(w); + + align_key(w, key); + fprintf(w->out, "%lu", value); +} + +void jsonw_int(jsonw_t *w, const char *key, int value) +{ + assert(w); + + align_key(w, key); + fprintf(w->out, "%d", value); +} + + +void jsonw_bool(jsonw_t *w, const char *key, bool value) +{ + assert(w); + + align_key(w, key); + fprintf(w->out, "%s", value ? "true" : "false"); +} + +void jsonw_hex(jsonw_t *w, const char *key, const uint8_t *data, size_t len) +{ + assert(w); + + char *hex = bin_to_hex(data, len, true); + if (hex != NULL) { + jsonw_str(w, key, hex); + } + free(hex); +} + +void jsonw_end(jsonw_t *w) +{ + assert(w); + + struct block *top = cur_block(w); + if (top == NULL) { + return; + } + + end_block(w); + wrap(w); + + switch (top->type) { + case BLOCK_OBJECT: + fprintf(w->out, "}"); + break; + case BLOCK_LIST: + fprintf(w->out, "]"); + break; + } +} |