diff options
Diffstat (limited to 'src/benc.c')
| -rw-r--r-- | src/benc.c | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/src/benc.c b/src/benc.c new file mode 100644 index 0000000..4f61ff7 --- /dev/null +++ b/src/benc.c @@ -0,0 +1,232 @@ +#include "benc.h" +#include "log.h" + +#include <errno.h> +#include <stdlib.h> +#include <assert.h> +#include <ctype.h> +#include <string.h> + + +#define MAX(a, b) \ + ({ \ + __typeof__ (a) _a = (a); \ + __typeof__ (b) _b = (b); \ + _a > _b ? _a : _b; \ + }) + +#define MIN(a, b) \ + ({ \ + __typeof__ (a) _a = (a); \ + __typeof__ (b) _b = (b); \ + _a < _b ? _a : _b; \ + }) + +bool readint(const char** loc, int64_t* val) { + char* end = NULL; + errno = 0; + *val = strtol(*loc, &end, 10); + *loc = end; + + return errno == 0; +} + +bool digit(const char c) { + return c >= '0' && c <= '9'; +} + +char* nodenames[] = { + "INT", + "STR", + "LIST", + "DICT", + "END", +}; + +void indent(int depth) { + for(int i = 0; i < depth; i++) { + printf(" "); + } +} + +void benc_print(const struct benc_node* stream, size_t stream_len, int* depth) { + const struct benc_node* cursor = stream; + for(; cursor < stream + stream_len; cursor++) { + switch(cursor->type) { + case BNT_INT: + indent(*depth); + printf("INT %.*s\n", cursor->size, cursor->loc); + break; + case BNT_STRING: + indent(*depth); + bool allprint = true; + for (const char* c = cursor->loc; c < cursor->loc + cursor->size; c++) { + if(!isalnum(*c)) { + allprint = false; + break; + } + } + printf("STR "); + if(allprint) { + printf("%.*s", cursor->size, cursor->loc); + } else { + for (const unsigned char* c = (const unsigned char*)cursor->loc; c < (unsigned char*)(cursor->loc + cursor->size); c++) { + printf("\\x%02X", *c); + } + } + printf("\n"); + break; + case BNT_LIST: + indent(*depth); + printf("LIST\n"); + *depth = cursor->depth + 1; + break; + case BNT_DICT: + indent(*depth); + printf("DICT\n"); + *depth = cursor->depth + 1; + break; + case BNT_END: + *depth = cursor->depth; + indent(*depth); + printf("END\n"); + break; + } + } +} + +int64_t benc_decode(const char** cursor, const char* end, int* depth, struct benc_node* stream, size_t stream_len) { + size_t cursor_out = 0; + + while(cursor_out < stream_len) { + struct benc_node* node = &stream[cursor_out]; + + if(**cursor == 'i') { + node->type = BNT_INT; + (*cursor)++; + if(*cursor >= end) { + return -cursor_out; + } + node->loc = *cursor; + while(**cursor != 'e') { + if(**cursor != '-' && !digit(**cursor)) { + return -cursor_out; + } + (*cursor)++; + if(*cursor >= end) { + return -cursor_out; + } + } + node->size = *cursor - node->loc; + (*cursor)++; + } else if(**cursor == 'l') { + node->type = BNT_LIST; + node->depth = *depth; + (*depth)++; + node->loc = *cursor; + (*cursor)++; + if(*cursor >= end) { + return -cursor_out; + } + } else if(**cursor == 'd') { + node->type = BNT_DICT; + node->depth = *depth; + (*depth)++; + node->loc = *cursor; + (*cursor)++; + if(*cursor >= end) { + return -cursor_out; + } + } else if(**cursor == 'e') { + node->type = BNT_END; + (*depth)--; + node->depth = *depth; + node->loc = *cursor; + (*cursor)++; + } else if(digit(**cursor)) { + node->type = BNT_STRING; + int64_t val; + bool rc = readint(cursor, &val); + node->size = val; + if(*cursor >= end) { + return -cursor_out; + } + assert(rc); + if(**cursor != ':') { + return -cursor_out; + } + (*cursor)++; + if(*cursor >= end) { + return -cursor_out; + } + node->loc = *cursor; + (*cursor) += node->size; + if(*cursor > end) { + return -cursor_out; + } + } else { + return -cursor_out; + dbg("Failing on char \"%c\"", **cursor); + assert(false); + } + cursor_out++; + if(*depth == 0) break; + } + return cursor_out; +} + +void skip_sibling(const struct benc_node** cursor, const struct benc_node* end) { + assert((*cursor)->type == BNT_LIST || (*cursor)->type == BNT_DICT); + + if((*cursor)->type == BNT_LIST || (*cursor)->type == BNT_DICT) { + uint32_t tdepth = (*cursor)->depth; + (*cursor)++; + while(true) { + if(*cursor == end) { + fatal("Invalid dict"); + } + + if((*cursor)->type == BNT_END && (*cursor)->depth == tdepth) { + break; + } + + (*cursor)++; + } + (*cursor)++; + } else { + (*cursor)++; + } +} + +// All the arrays should be equal length +ssize_t skip_to_key(const struct benc_node** cursor, const struct benc_node* end, const enum benc_nodetype* keyTypes, const char** keyValues, const size_t* keyLengths, const size_t keys) { + // @ROBUSTNESS: Check if keytypes are anything but strings and ints because that is not supported + + while(true) { + if(*cursor > end-1) { + fatal("Invalid dict"); + } + + // Skip lists + if((*cursor)->type == BNT_LIST || (*cursor)->type == BNT_DICT) { + skip_sibling(cursor, end); + } else { + for(size_t i = 0; i < keys; i++) { + if((*cursor)->type == keyTypes[i] && memcmp((*cursor)->loc, keyValues[i], MIN((*cursor)->size, keyLengths[i])) == 0) { + return i; + } + } + } + + (*cursor) += 2; + + if((*cursor-1)->type == BNT_LIST || (*cursor-1)->type == BNT_DICT) { + (*cursor)--; + skip_sibling(cursor, end); + } + + if((*cursor)->type == BNT_END) { + return -1; + } + } +} |