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96 lines
2.0 KiB
C
96 lines
2.0 KiB
C
4 years ago
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#include "parse.h"
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unsigned char bs_peek(struct bytestream* bs) {
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unsigned char r;
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char c;
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if (bs->cur>=bs->max) { // EOF or already error state?
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bs->max=0; // signal error
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bs->cur=1;
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return 0; // return 0
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}
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switch (bs->type) {
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case MEMBUF:
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r=bs->u.base[bs->cur];
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break;
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case IOBUF:
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{
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int ret=buffer_peekc(bs->u.b, &c);
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if (ret==1) {
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r=c;
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} else {
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bs->max=0;
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bs->cur=1;
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return 0;
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}
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}
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break;
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case BSTREAM:
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r=bs_peek(bs->u.bs);
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break;
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default:
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r=0; // cannot happen
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}
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return r;
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}
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#ifdef UNITTEST
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#include <assert.h>
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int main() {
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struct bytestream bs = BS_FROM_MEMBUF("fx", 1);
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/* first test: membuf.
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* See if we get all the bytes we put in and then error is signaled */
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assert(bs_peek(&bs) == 'f');
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assert(bs_peek(&bs) == 'f');
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assert(!bs_err(&bs));
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assert(bs_get(&bs) == 'f');
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assert(!bs_err(&bs));
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assert(bs_peek(&bs) == 0);
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assert(bs_err(&bs));
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/* second test: iobuf with no limit. Otherwise the same. */
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struct buffer b;
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buffer_init_staticcontents(&b, "fx", 1);
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bs_init_iobuf(&bs, &b);
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assert(bs_peek(&bs) == 'f');
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assert(bs_peek(&bs) == 'f');
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assert(!bs_err(&bs));
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assert(bs_get(&bs) == 'f');
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assert(!bs_err(&bs));
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assert(bs_peek(&bs) == 0);
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assert(bs_err(&bs));
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/* third test: iobuf with limit. Otherwise the same. */
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buffer_init_staticcontents(&b, "fx", 2);
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bs_init_iobuf_size(&bs, &b, 1);
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assert(bs_peek(&bs) == 'f');
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assert(bs_peek(&bs) == 'f');
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assert(!bs_err(&bs));
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assert(bs_get(&bs) == 'f');
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assert(!bs_err(&bs));
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assert(bs_peek(&bs) == 0);
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assert(bs_err(&bs));
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/* fourth test: iobuf with EOF */
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buffer_init_staticcontents(&b, "fx", 1);
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bs_init_iobuf(&bs, &b); // bytestream has no limit but will hit EOF in backing buffer
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assert(bs_peek(&bs) == 'f');
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assert(bs_peek(&bs) == 'f');
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assert(!bs_err(&bs));
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assert(bs_get(&bs) == 'f');
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assert(!bs_err(&bs));
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assert(bs_peek(&bs) == 0);
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assert(bs_err(&bs));
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return 0;
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}
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#endif
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