From ae4da6d73d784adc69c1a6e460ebb87cc9cca6de Mon Sep 17 00:00:00 2001
From: alessandrobason <1902881@uad.ac.uk>
Date: Mon, 22 Aug 2022 18:27:41 +0100
Subject: [PATCH] added a few function to str_istream_t

---
 src/strstream.c | 22 ++++++++++++++++++++++
 src/strstream.h |  7 +++++++
 2 files changed, 29 insertions(+)

diff --git a/src/strstream.c b/src/strstream.c
index aa3485c..2ddc40d 100644
--- a/src/strstream.c
+++ b/src/strstream.c
@@ -22,6 +22,17 @@ str_istream_t istrInitLen(const char *str, usize len) {
     return res;
 }
 
+void istrScanf(str_istream_t *ctx, const char *fmt, ...) {
+    va_list va;
+    va_start(va, fmt);
+    istrScanfV(ctx, fmt, va);
+    va_end(va);
+}
+
+void istrScanfV(str_istream_t *ctx, const char *fmt, va_list args) {
+    vsscanf(ctx->cur, fmt, args);
+}
+
 char istrGet(str_istream_t *ctx) {
     return *ctx->cur++;
 }
@@ -34,6 +45,11 @@ void istrIgnore(str_istream_t *ctx, char delim) {
         ++i, ++ctx->cur);
 }
 
+void istrIgnoreAndSkip(str_istream_t *ctx, char delim) {
+    istrIgnore(ctx, delim);
+    istrSkip(ctx, 1);
+}
+
 char istrPeek(str_istream_t *ctx) {
     return *ctx->cur;
 }
@@ -75,6 +91,12 @@ void istrRewind(str_istream_t *ctx) {
     ctx->cur = ctx->start;
 }
 
+void istrRewindN(str_istream_t *ctx, usize amount) {
+    usize remaining = ctx->size - (ctx->cur - ctx->start);
+    if (amount > remaining) amount = remaining;
+    ctx->cur -= amount;
+}
+
 usize istrTell(str_istream_t ctx) {
     return ctx.cur - ctx.start;
 }
diff --git a/src/strstream.h b/src/strstream.h
index 63e91e9..b754780 100644
--- a/src/strstream.h
+++ b/src/strstream.h
@@ -23,12 +23,17 @@ typedef struct {
 str_istream_t istrInit(const char *str);
 str_istream_t istrInitLen(const char *str, usize len);
 
+void istrScanf(str_istream_t *ctx, const char *fmt, ...);
+void istrScanfV(str_istream_t *ctx, const char *fmt, va_list args);
+
 // get the current character and advance
 char istrGet(str_istream_t *ctx);
 // get the current character but don't advance
 char istrPeek(str_istream_t *ctx);
 // ignore characters until the delimiter
 void istrIgnore(str_istream_t *ctx, char delim);
+// ignore characters until the delimiter and skip it
+void istrIgnoreAndSkip(str_istream_t *ctx, char delim);
 // skip n characters
 void istrSkip(str_istream_t *ctx, usize n);
 // skips whitespace (' ', '\n', '\t', '\r')
@@ -40,6 +45,8 @@ void istrRead(str_istream_t *ctx, char *buf, usize len);
 usize istrReadMax(str_istream_t *ctx, char *buf, usize len);
 // returns to the beginning of the stream
 void istrRewind(str_istream_t *ctx);
+// returns back <amount> characters
+void istrRewindN(str_istream_t *ctx, usize amount);
 // returns the number of bytes read from beginning of stream
 usize istrTell(str_istream_t ctx);
 // returns the number of bytes left to read in the stream