1 files changed, 109 insertions, 0 deletions
diff --git a/src/csi.h b/src/csi.h
new file mode 100644
index 0000000..b4609ea
--- /dev/null
+++ b/src/csi.h
@@ -0,0 +1,109 @@
+#ifndef CSI_H
+#define CSI_H
+
+#include <stddef.h>
+#include <stdint.h>
+#include <limits.h>
+
+#define MAX_PARAMS 16
+
+struct csi {
+    int params[MAX_PARAMS];
+    int nparams;
+    uint16_t subparams;
+    char prefix, intermediate, final;
+};
+
+enum csi_phase { CSI_ENTRY, CSI_PARAMETERS, CSI_INTERMEDIATES, CSI_IGNORE };
+enum csi_result { CSI_MORE, CSI_DISPATCH, CSI_DISCARD, CSI_CONTROL };
+
+struct csi_parser {
+    struct csi csi;
+    enum csi_phase phase;
+};
+
+static inline void csi_parser_reset(struct csi_parser *p)
+{
+    p->csi.params[0] = 0;
+    p->csi.nparams = 0;
+    p->csi.subparams = 0;
+    p->csi.prefix = p->csi.intermediate = p->csi.final = 0;
+    p->phase = CSI_ENTRY;
+}
+
+static inline int csi_count(const struct csi *csi)
+{
+    return csi->params[0] > 0 ? csi->params[0] : 1;
+}
+
+static inline enum csi_result csi_read(struct csi_parser *restrict p, const char *restrict s,
+                                     size_t len, size_t *restrict consumed)
+{
+    size_t i = 0;
+    enum csi_result result = CSI_MORE;
+    while (i < len) {
+        unsigned char ch = (unsigned char)s[i];
+        if (ch < 0x20 || ch >= 0x80) {
+            result = CSI_CONTROL;
+            break;
+        }
+        i++;
+        if (ch == 0x7f) continue;
+        if (ch >= 0x40) {
+            p->csi.final = (char)ch;
+            result = p->phase == CSI_IGNORE ? CSI_DISCARD : CSI_DISPATCH;
+            break;
+        }
+        if (p->phase == CSI_IGNORE) continue;
+
+        if (ch >= '0' && ch <= ';') {
+            if (p->phase == CSI_INTERMEDIATES) {
+                p->phase = CSI_IGNORE;
+                continue;
+            }
+            p->phase = CSI_PARAMETERS;
+            int n = p->csi.nparams ? p->csi.nparams : 1;
+            int value = p->csi.params[n - 1];
+            for (;;) {
+                if (ch <= '9') {
+                    for (;;) {
+                        int digit = ch - '0';
+                        value = value < 214748364 ? value * 10 + digit : INT_MAX;
+                        if (i == len) break;
+                        ch = (unsigned char)s[i];
+                        if (ch < '0' || ch > '9') break;
+                        i++;
+                    }
+                } else {
+                    p->csi.params[n - 1] = value;
+                    if (n == MAX_PARAMS) {
+                        p->phase = CSI_IGNORE;
+                        break;
+                    }
+                    if (ch == ':') p->csi.subparams |= (uint16_t)(1u << n);
+                    n++;
+                    value = 0;
+                }
+                if (i == len) break;
+                ch = (unsigned char)s[i];
+                if (ch < '0' || ch > ';') break;
+                i++;
+            }
+            p->csi.params[n - 1] = value;
+            p->csi.nparams = n;
+        } else if (ch >= '<') {
+            if (p->phase != CSI_ENTRY || p->csi.prefix) p->phase = CSI_IGNORE;
+            else p->csi.prefix = (char)ch;
+        } else {
+            if (p->phase == CSI_INTERMEDIATES) p->phase = CSI_IGNORE;
+            else {
+                p->phase = CSI_INTERMEDIATES;
+                p->csi.intermediate = (char)ch;
+            }
+        }
+    }
+    *consumed = i;
+    return result;
+}
+
+#endif